Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | /* |
| 3 | * linux/ipc/sem.c |
| 4 | * Copyright (C) 1992 Krishna Balasubramanian |
| 5 | * Copyright (C) 1995 Eric Schenk, Bruno Haible |
| 6 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | * /proc/sysvipc/sem support (c) 1999 Dragos Acostachioaie <dragos@iname.com> |
| 8 | * |
| 9 | * SMP-threaded, sysctl's added |
Christian Kujau | 624dffc | 2006-01-15 02:43:54 +0100 | [diff] [blame] | 10 | * (c) 1999 Manfred Spraul <manfred@colorfullife.com> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | * Enforced range limit on SEM_UNDO |
Alan Cox | 046c688 | 2009-01-05 14:06:29 +0000 | [diff] [blame] | 12 | * (c) 2001 Red Hat Inc |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | * Lockless wakeup |
| 14 | * (c) 2003 Manfred Spraul <manfred@colorfullife.com> |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 15 | * (c) 2016 Davidlohr Bueso <dave@stgolabs.net> |
Manfred Spraul | c5cf635 | 2010-05-26 14:43:43 -0700 | [diff] [blame] | 16 | * Further wakeup optimizations, documentation |
| 17 | * (c) 2010 Manfred Spraul <manfred@colorfullife.com> |
Steve Grubb | 073115d | 2006-04-02 17:07:33 -0400 | [diff] [blame] | 18 | * |
| 19 | * support for audit of ipc object properties and permission changes |
| 20 | * Dustin Kirkland <dustin.kirkland@us.ibm.com> |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 21 | * |
| 22 | * namespaces support |
| 23 | * OpenVZ, SWsoft Inc. |
| 24 | * Pavel Emelianov <xemul@openvz.org> |
Manfred Spraul | c5cf635 | 2010-05-26 14:43:43 -0700 | [diff] [blame] | 25 | * |
| 26 | * Implementation notes: (May 2010) |
| 27 | * This file implements System V semaphores. |
| 28 | * |
| 29 | * User space visible behavior: |
| 30 | * - FIFO ordering for semop() operations (just FIFO, not starvation |
| 31 | * protection) |
| 32 | * - multiple semaphore operations that alter the same semaphore in |
| 33 | * one semop() are handled. |
| 34 | * - sem_ctime (time of last semctl()) is updated in the IPC_SET, SETVAL and |
| 35 | * SETALL calls. |
| 36 | * - two Linux specific semctl() commands: SEM_STAT, SEM_INFO. |
| 37 | * - undo adjustments at process exit are limited to 0..SEMVMX. |
| 38 | * - namespace are supported. |
| 39 | * - SEMMSL, SEMMNS, SEMOPM and SEMMNI can be configured at runtine by writing |
| 40 | * to /proc/sys/kernel/sem. |
| 41 | * - statistics about the usage are reported in /proc/sysvipc/sem. |
| 42 | * |
| 43 | * Internals: |
| 44 | * - scalability: |
| 45 | * - all global variables are read-mostly. |
| 46 | * - semop() calls and semctl(RMID) are synchronized by RCU. |
| 47 | * - most operations do write operations (actually: spin_lock calls) to |
| 48 | * the per-semaphore array structure. |
| 49 | * Thus: Perfect SMP scaling between independent semaphore arrays. |
| 50 | * If multiple semaphores in one array are used, then cache line |
| 51 | * trashing on the semaphore array spinlock will limit the scaling. |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 52 | * - semncnt and semzcnt are calculated on demand in count_semcnt() |
Manfred Spraul | c5cf635 | 2010-05-26 14:43:43 -0700 | [diff] [blame] | 53 | * - the task that performs a successful semop() scans the list of all |
| 54 | * sleeping tasks and completes any pending operations that can be fulfilled. |
| 55 | * Semaphores are actively given to waiting tasks (necessary for FIFO). |
| 56 | * (see update_queue()) |
| 57 | * - To improve the scalability, the actual wake-up calls are performed after |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 58 | * dropping all locks. (see wake_up_sem_queue_prepare()) |
Manfred Spraul | c5cf635 | 2010-05-26 14:43:43 -0700 | [diff] [blame] | 59 | * - All work is done by the waker, the woken up task does not have to do |
| 60 | * anything - not even acquiring a lock or dropping a refcount. |
| 61 | * - A woken up task may not even touch the semaphore array anymore, it may |
| 62 | * have been destroyed already by a semctl(RMID). |
Manfred Spraul | c5cf635 | 2010-05-26 14:43:43 -0700 | [diff] [blame] | 63 | * - UNDO values are stored in an array (one per process and per |
| 64 | * semaphore array, lazily allocated). For backwards compatibility, multiple |
| 65 | * modes for the UNDO variables are supported (per process, per thread) |
| 66 | * (see copy_semundo, CLONE_SYSVSEM) |
| 67 | * - There are two lists of the pending operations: a per-array list |
| 68 | * and per-semaphore list (stored in the array). This allows to achieve FIFO |
| 69 | * ordering without always scanning all pending operations. |
| 70 | * The worst-case behavior is nevertheless O(N^2) for N wakeups. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | */ |
| 72 | |
Arnd Bergmann | b0d1757 | 2018-04-13 13:58:23 +0200 | [diff] [blame] | 73 | #include <linux/compat.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | #include <linux/slab.h> |
| 75 | #include <linux/spinlock.h> |
| 76 | #include <linux/init.h> |
| 77 | #include <linux/proc_fs.h> |
| 78 | #include <linux/time.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | #include <linux/security.h> |
| 80 | #include <linux/syscalls.h> |
| 81 | #include <linux/audit.h> |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 82 | #include <linux/capability.h> |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 83 | #include <linux/seq_file.h> |
Nadia Derbey | 3e148c7 | 2007-10-18 23:40:54 -0700 | [diff] [blame] | 84 | #include <linux/rwsem.h> |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 85 | #include <linux/nsproxy.h> |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 86 | #include <linux/ipc_namespace.h> |
Ingo Molnar | 84f001e | 2017-02-01 16:36:40 +0100 | [diff] [blame] | 87 | #include <linux/sched/wake_q.h> |
Davidlohr Bueso | ec67aaa | 2018-06-14 15:27:51 -0700 | [diff] [blame] | 88 | #include <linux/nospec.h> |
NeilBrown | 0eb71a9 | 2018-06-18 12:52:50 +1000 | [diff] [blame] | 89 | #include <linux/rhashtable.h> |
Ingo Molnar | 5f921ae | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 90 | |
Paul McQuade | 7153e40 | 2014-06-06 14:37:37 -0700 | [diff] [blame] | 91 | #include <linux/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | #include "util.h" |
| 93 | |
Eric W. Biederman | 1a5c134 | 2018-03-22 21:30:56 -0500 | [diff] [blame] | 94 | /* One semaphore structure for each semaphore in the system. */ |
| 95 | struct sem { |
| 96 | int semval; /* current value */ |
| 97 | /* |
| 98 | * PID of the process that last modified the semaphore. For |
| 99 | * Linux, specifically these are: |
| 100 | * - semop |
| 101 | * - semctl, via SETVAL and SETALL. |
| 102 | * - at task exit when performing undo adjustments (see exit_sem). |
| 103 | */ |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 104 | struct pid *sempid; |
Eric W. Biederman | 1a5c134 | 2018-03-22 21:30:56 -0500 | [diff] [blame] | 105 | spinlock_t lock; /* spinlock for fine-grained semtimedop */ |
| 106 | struct list_head pending_alter; /* pending single-sop operations */ |
| 107 | /* that alter the semaphore */ |
| 108 | struct list_head pending_const; /* pending single-sop operations */ |
| 109 | /* that do not alter the semaphore*/ |
Arnd Bergmann | 2a70b78 | 2018-04-12 15:19:44 +0200 | [diff] [blame] | 110 | time64_t sem_otime; /* candidate for sem_otime */ |
Eric W. Biederman | 1a5c134 | 2018-03-22 21:30:56 -0500 | [diff] [blame] | 111 | } ____cacheline_aligned_in_smp; |
| 112 | |
| 113 | /* One sem_array data structure for each set of semaphores in the system. */ |
| 114 | struct sem_array { |
| 115 | struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */ |
| 116 | time64_t sem_ctime; /* create/last semctl() time */ |
| 117 | struct list_head pending_alter; /* pending operations */ |
| 118 | /* that alter the array */ |
| 119 | struct list_head pending_const; /* pending complex operations */ |
| 120 | /* that do not alter semvals */ |
| 121 | struct list_head list_id; /* undo requests on this array */ |
| 122 | int sem_nsems; /* no. of semaphores in array */ |
| 123 | int complex_count; /* pending complex operations */ |
| 124 | unsigned int use_global_lock;/* >0: global lock required */ |
| 125 | |
| 126 | struct sem sems[]; |
| 127 | } __randomize_layout; |
Manfred Spraul | e57940d | 2011-11-02 13:38:54 -0700 | [diff] [blame] | 128 | |
| 129 | /* One queue for each sleeping process in the system. */ |
| 130 | struct sem_queue { |
Manfred Spraul | e57940d | 2011-11-02 13:38:54 -0700 | [diff] [blame] | 131 | struct list_head list; /* queue of pending operations */ |
| 132 | struct task_struct *sleeper; /* this process */ |
| 133 | struct sem_undo *undo; /* undo structure */ |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 134 | struct pid *pid; /* process id of requesting process */ |
Manfred Spraul | e57940d | 2011-11-02 13:38:54 -0700 | [diff] [blame] | 135 | int status; /* completion status of operation */ |
| 136 | struct sembuf *sops; /* array of pending operations */ |
Manfred Spraul | ed247b7 | 2014-06-06 14:37:49 -0700 | [diff] [blame] | 137 | struct sembuf *blocking; /* the operation that blocked */ |
Manfred Spraul | e57940d | 2011-11-02 13:38:54 -0700 | [diff] [blame] | 138 | int nsops; /* number of operations */ |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 139 | bool alter; /* does *sops alter the array? */ |
| 140 | bool dupsop; /* sops on more than one sem_num */ |
Manfred Spraul | e57940d | 2011-11-02 13:38:54 -0700 | [diff] [blame] | 141 | }; |
| 142 | |
| 143 | /* Each task has a list of undo requests. They are executed automatically |
| 144 | * when the process exits. |
| 145 | */ |
| 146 | struct sem_undo { |
| 147 | struct list_head list_proc; /* per-process list: * |
| 148 | * all undos from one process |
| 149 | * rcu protected */ |
| 150 | struct rcu_head rcu; /* rcu struct for sem_undo */ |
| 151 | struct sem_undo_list *ulp; /* back ptr to sem_undo_list */ |
| 152 | struct list_head list_id; /* per semaphore array list: |
| 153 | * all undos for one array */ |
| 154 | int semid; /* semaphore set identifier */ |
| 155 | short *semadj; /* array of adjustments */ |
| 156 | /* one per semaphore */ |
| 157 | }; |
| 158 | |
| 159 | /* sem_undo_list controls shared access to the list of sem_undo structures |
| 160 | * that may be shared among all a CLONE_SYSVSEM task group. |
| 161 | */ |
| 162 | struct sem_undo_list { |
Elena Reshetova | f74370b | 2017-09-08 16:17:42 -0700 | [diff] [blame] | 163 | refcount_t refcnt; |
Manfred Spraul | e57940d | 2011-11-02 13:38:54 -0700 | [diff] [blame] | 164 | spinlock_t lock; |
| 165 | struct list_head list_proc; |
| 166 | }; |
| 167 | |
| 168 | |
Pierre Peiffer | ed2ddbf | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 169 | #define sem_ids(ns) ((ns)->ids[IPC_SEM_IDS]) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | |
Nadia Derbey | 7748dbf | 2007-10-18 23:40:49 -0700 | [diff] [blame] | 171 | static int newary(struct ipc_namespace *, struct ipc_params *); |
Pierre Peiffer | 01b8b07 | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 172 | static void freeary(struct ipc_namespace *, struct kern_ipc_perm *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | #ifdef CONFIG_PROC_FS |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 174 | static int sysvipc_sem_proc_show(struct seq_file *s, void *it); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 | #endif |
| 176 | |
| 177 | #define SEMMSL_FAST 256 /* 512 bytes on stack */ |
| 178 | #define SEMOPM_FAST 64 /* ~ 372 bytes on stack */ |
| 179 | |
| 180 | /* |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 181 | * Switching from the mode suitable for simple ops |
| 182 | * to the mode for complex ops is costly. Therefore: |
| 183 | * use some hysteresis |
| 184 | */ |
| 185 | #define USE_GLOBAL_LOCK_HYSTERESIS 10 |
| 186 | |
| 187 | /* |
Manfred Spraul | 758a6ba3 | 2013-07-08 16:01:26 -0700 | [diff] [blame] | 188 | * Locking: |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 189 | * a) global sem_lock() for read/write |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | * sem_undo.id_next, |
Manfred Spraul | 758a6ba3 | 2013-07-08 16:01:26 -0700 | [diff] [blame] | 191 | * sem_array.complex_count, |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 192 | * sem_array.pending{_alter,_const}, |
| 193 | * sem_array.sem_undo |
Paul McQuade | 46c0a8c | 2014-06-06 14:37:37 -0700 | [diff] [blame] | 194 | * |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 195 | * b) global or semaphore sem_lock() for read/write: |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 196 | * sem_array.sems[i].pending_{const,alter}: |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 197 | * |
| 198 | * c) special: |
| 199 | * sem_undo_list.list_proc: |
| 200 | * * undo_list->lock for write |
| 201 | * * rcu for read |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 202 | * use_global_lock: |
| 203 | * * global sem_lock() for write |
| 204 | * * either local or global sem_lock() for read. |
| 205 | * |
| 206 | * Memory ordering: |
| 207 | * Most ordering is enforced by using spin_lock() and spin_unlock(). |
Manfred Spraul | 8116b54 | 2020-02-03 17:34:42 -0800 | [diff] [blame] | 208 | * |
| 209 | * Exceptions: |
| 210 | * 1) use_global_lock: (SEM_BARRIER_1) |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 211 | * Setting it from non-zero to 0 is a RELEASE, this is ensured by |
Manfred Spraul | 8116b54 | 2020-02-03 17:34:42 -0800 | [diff] [blame] | 212 | * using smp_store_release(): Immediately after setting it to 0, |
| 213 | * a simple op can start. |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 214 | * Testing if it is non-zero is an ACQUIRE, this is ensured by using |
| 215 | * smp_load_acquire(). |
| 216 | * Setting it from 0 to non-zero must be ordered with regards to |
| 217 | * this smp_load_acquire(), this is guaranteed because the smp_load_acquire() |
| 218 | * is inside a spin_lock() and after a write from 0 to non-zero a |
| 219 | * spin_lock()+spin_unlock() is done. |
Manfred Spraul | 8116b54 | 2020-02-03 17:34:42 -0800 | [diff] [blame] | 220 | * |
| 221 | * 2) queue.status: (SEM_BARRIER_2) |
| 222 | * Initialization is done while holding sem_lock(), so no further barrier is |
| 223 | * required. |
| 224 | * Setting it to a result code is a RELEASE, this is ensured by both a |
| 225 | * smp_store_release() (for case a) and while holding sem_lock() |
| 226 | * (for case b). |
| 227 | * The AQUIRE when reading the result code without holding sem_lock() is |
| 228 | * achieved by using READ_ONCE() + smp_acquire__after_ctrl_dep(). |
| 229 | * (case a above). |
| 230 | * Reading the result code while holding sem_lock() needs no further barriers, |
| 231 | * the locks inside sem_lock() enforce ordering (case b above) |
| 232 | * |
| 233 | * 3) current->state: |
| 234 | * current->state is set to TASK_INTERRUPTIBLE while holding sem_lock(). |
| 235 | * The wakeup is handled using the wake_q infrastructure. wake_q wakeups may |
| 236 | * happen immediately after calling wake_q_add. As wake_q_add_safe() is called |
| 237 | * when holding sem_lock(), no further barriers are required. |
| 238 | * |
| 239 | * See also ipc/mqueue.c for more details on the covered races. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | */ |
| 241 | |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 242 | #define sc_semmsl sem_ctls[0] |
| 243 | #define sc_semmns sem_ctls[1] |
| 244 | #define sc_semopm sem_ctls[2] |
| 245 | #define sc_semmni sem_ctls[3] |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | |
Davidlohr Bueso | eae04d2 | 2018-08-21 22:01:56 -0700 | [diff] [blame] | 247 | void sem_init_ns(struct ipc_namespace *ns) |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 248 | { |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 249 | ns->sc_semmsl = SEMMSL; |
| 250 | ns->sc_semmns = SEMMNS; |
| 251 | ns->sc_semopm = SEMOPM; |
| 252 | ns->sc_semmni = SEMMNI; |
| 253 | ns->used_sems = 0; |
Davidlohr Bueso | eae04d2 | 2018-08-21 22:01:56 -0700 | [diff] [blame] | 254 | ipc_init_ids(&ns->ids[IPC_SEM_IDS]); |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 255 | } |
| 256 | |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 257 | #ifdef CONFIG_IPC_NS |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 258 | void sem_exit_ns(struct ipc_namespace *ns) |
| 259 | { |
Pierre Peiffer | 01b8b07 | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 260 | free_ipcs(ns, &sem_ids(ns), freeary); |
Serge E. Hallyn | 7d6feeb | 2009-12-15 16:47:27 -0800 | [diff] [blame] | 261 | idr_destroy(&ns->ids[IPC_SEM_IDS].ipcs_idr); |
Guillaume Knispel | 0cfb6ae | 2017-09-08 16:17:55 -0700 | [diff] [blame] | 262 | rhashtable_destroy(&ns->ids[IPC_SEM_IDS].key_ht); |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 263 | } |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 264 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | |
Davidlohr Bueso | eae04d2 | 2018-08-21 22:01:56 -0700 | [diff] [blame] | 266 | void __init sem_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | { |
Davidlohr Bueso | eae04d2 | 2018-08-21 22:01:56 -0700 | [diff] [blame] | 268 | sem_init_ns(&init_ipc_ns); |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 269 | ipc_init_proc_interface("sysvipc/sem", |
| 270 | " key semid perms nsems uid gid cuid cgid otime ctime\n", |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 271 | IPC_SEM_IDS, sysvipc_sem_proc_show); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | } |
| 273 | |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 274 | /** |
| 275 | * unmerge_queues - unmerge queues, if possible. |
| 276 | * @sma: semaphore array |
| 277 | * |
| 278 | * The function unmerges the wait queues if complex_count is 0. |
| 279 | * It must be called prior to dropping the global semaphore array lock. |
| 280 | */ |
| 281 | static void unmerge_queues(struct sem_array *sma) |
| 282 | { |
| 283 | struct sem_queue *q, *tq; |
| 284 | |
| 285 | /* complex operations still around? */ |
| 286 | if (sma->complex_count) |
| 287 | return; |
| 288 | /* |
| 289 | * We will switch back to simple mode. |
| 290 | * Move all pending operation back into the per-semaphore |
| 291 | * queues. |
| 292 | */ |
| 293 | list_for_each_entry_safe(q, tq, &sma->pending_alter, list) { |
| 294 | struct sem *curr; |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 295 | curr = &sma->sems[q->sops[0].sem_num]; |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 296 | |
| 297 | list_add_tail(&q->list, &curr->pending_alter); |
| 298 | } |
| 299 | INIT_LIST_HEAD(&sma->pending_alter); |
| 300 | } |
| 301 | |
| 302 | /** |
Davidlohr Bueso | 8001c85 | 2014-01-27 17:07:05 -0800 | [diff] [blame] | 303 | * merge_queues - merge single semop queues into global queue |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 304 | * @sma: semaphore array |
| 305 | * |
| 306 | * This function merges all per-semaphore queues into the global queue. |
| 307 | * It is necessary to achieve FIFO ordering for the pending single-sop |
| 308 | * operations when a multi-semop operation must sleep. |
| 309 | * Only the alter operations must be moved, the const operations can stay. |
| 310 | */ |
| 311 | static void merge_queues(struct sem_array *sma) |
| 312 | { |
| 313 | int i; |
| 314 | for (i = 0; i < sma->sem_nsems; i++) { |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 315 | struct sem *sem = &sma->sems[i]; |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 316 | |
| 317 | list_splice_init(&sem->pending_alter, &sma->pending_alter); |
| 318 | } |
| 319 | } |
| 320 | |
Davidlohr Bueso | 53dad6d | 2013-09-23 17:04:45 -0700 | [diff] [blame] | 321 | static void sem_rcu_free(struct rcu_head *head) |
| 322 | { |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 323 | struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu); |
| 324 | struct sem_array *sma = container_of(p, struct sem_array, sem_perm); |
Davidlohr Bueso | 53dad6d | 2013-09-23 17:04:45 -0700 | [diff] [blame] | 325 | |
Eric W. Biederman | aefad95 | 2018-03-22 20:52:43 -0500 | [diff] [blame] | 326 | security_sem_free(&sma->sem_perm); |
Kees Cook | e2029df | 2017-07-12 14:35:31 -0700 | [diff] [blame] | 327 | kvfree(sma); |
Davidlohr Bueso | 53dad6d | 2013-09-23 17:04:45 -0700 | [diff] [blame] | 328 | } |
| 329 | |
Nadia Derbey | 3e148c7 | 2007-10-18 23:40:54 -0700 | [diff] [blame] | 330 | /* |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 331 | * Enter the mode suitable for non-simple operations: |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 332 | * Caller must own sem_perm.lock. |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 333 | */ |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 334 | static void complexmode_enter(struct sem_array *sma) |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 335 | { |
| 336 | int i; |
| 337 | struct sem *sem; |
| 338 | |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 339 | if (sma->use_global_lock > 0) { |
| 340 | /* |
| 341 | * We are already in global lock mode. |
| 342 | * Nothing to do, just reset the |
| 343 | * counter until we return to simple mode. |
| 344 | */ |
| 345 | sma->use_global_lock = USE_GLOBAL_LOCK_HYSTERESIS; |
Manfred Spraul | 6d07b68 | 2013-09-30 13:45:06 -0700 | [diff] [blame] | 346 | return; |
| 347 | } |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 348 | sma->use_global_lock = USE_GLOBAL_LOCK_HYSTERESIS; |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 349 | |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 350 | for (i = 0; i < sma->sem_nsems; i++) { |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 351 | sem = &sma->sems[i]; |
Manfred Spraul | 27d7be1 | 2017-02-27 14:28:15 -0800 | [diff] [blame] | 352 | spin_lock(&sem->lock); |
| 353 | spin_unlock(&sem->lock); |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 354 | } |
| 355 | } |
| 356 | |
| 357 | /* |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 358 | * Try to leave the mode that disallows simple operations: |
| 359 | * Caller must own sem_perm.lock. |
| 360 | */ |
| 361 | static void complexmode_tryleave(struct sem_array *sma) |
| 362 | { |
| 363 | if (sma->complex_count) { |
| 364 | /* Complex ops are sleeping. |
| 365 | * We must stay in complex mode |
| 366 | */ |
| 367 | return; |
| 368 | } |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 369 | if (sma->use_global_lock == 1) { |
Manfred Spraul | 8116b54 | 2020-02-03 17:34:42 -0800 | [diff] [blame] | 370 | |
| 371 | /* See SEM_BARRIER_1 for purpose/pairing */ |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 372 | smp_store_release(&sma->use_global_lock, 0); |
| 373 | } else { |
| 374 | sma->use_global_lock--; |
| 375 | } |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 376 | } |
| 377 | |
| 378 | #define SEM_GLOBAL_LOCK (-1) |
| 379 | /* |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 380 | * If the request contains only one semaphore operation, and there are |
| 381 | * no complex transactions pending, lock only the semaphore involved. |
| 382 | * Otherwise, lock the entire semaphore array, since we either have |
| 383 | * multiple semaphores in our own semops, or we need to look at |
| 384 | * semaphores from other pending complex operations. |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 385 | */ |
| 386 | static inline int sem_lock(struct sem_array *sma, struct sembuf *sops, |
| 387 | int nsops) |
| 388 | { |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 389 | struct sem *sem; |
Davidlohr Bueso | ec67aaa | 2018-06-14 15:27:51 -0700 | [diff] [blame] | 390 | int idx; |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 391 | |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 392 | if (nsops != 1) { |
| 393 | /* Complex operation - acquire a full lock */ |
| 394 | ipc_lock_object(&sma->sem_perm); |
| 395 | |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 396 | /* Prevent parallel simple ops */ |
| 397 | complexmode_enter(sma); |
| 398 | return SEM_GLOBAL_LOCK; |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 399 | } |
| 400 | |
| 401 | /* |
| 402 | * Only one semaphore affected - try to optimize locking. |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 403 | * Optimized locking is possible if no complex operation |
| 404 | * is either enqueued or processed right now. |
| 405 | * |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 406 | * Both facts are tracked by use_global_mode. |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 407 | */ |
Davidlohr Bueso | ec67aaa | 2018-06-14 15:27:51 -0700 | [diff] [blame] | 408 | idx = array_index_nospec(sops->sem_num, sma->sem_nsems); |
| 409 | sem = &sma->sems[idx]; |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 410 | |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 411 | /* |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 412 | * Initial check for use_global_lock. Just an optimization, |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 413 | * no locking, no memory barrier. |
| 414 | */ |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 415 | if (!sma->use_global_lock) { |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 416 | /* |
| 417 | * It appears that no complex operation is around. |
| 418 | * Acquire the per-semaphore lock. |
| 419 | */ |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 420 | spin_lock(&sem->lock); |
| 421 | |
Manfred Spraul | 8116b54 | 2020-02-03 17:34:42 -0800 | [diff] [blame] | 422 | /* see SEM_BARRIER_1 for purpose/pairing */ |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 423 | if (!smp_load_acquire(&sma->use_global_lock)) { |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 424 | /* fast path successful! */ |
| 425 | return sops->sem_num; |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 426 | } |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 427 | spin_unlock(&sem->lock); |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 428 | } |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 429 | |
| 430 | /* slow path: acquire the full lock */ |
| 431 | ipc_lock_object(&sma->sem_perm); |
| 432 | |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 433 | if (sma->use_global_lock == 0) { |
| 434 | /* |
| 435 | * The use_global_lock mode ended while we waited for |
| 436 | * sma->sem_perm.lock. Thus we must switch to locking |
| 437 | * with sem->lock. |
| 438 | * Unlike in the fast path, there is no need to recheck |
| 439 | * sma->use_global_lock after we have acquired sem->lock: |
| 440 | * We own sma->sem_perm.lock, thus use_global_lock cannot |
| 441 | * change. |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 442 | */ |
| 443 | spin_lock(&sem->lock); |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 444 | |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 445 | ipc_unlock_object(&sma->sem_perm); |
| 446 | return sops->sem_num; |
| 447 | } else { |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 448 | /* |
| 449 | * Not a false alarm, thus continue to use the global lock |
| 450 | * mode. No need for complexmode_enter(), this was done by |
| 451 | * the caller that has set use_global_mode to non-zero. |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 452 | */ |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 453 | return SEM_GLOBAL_LOCK; |
Manfred Spraul | 5e9d527 | 2013-09-30 13:45:04 -0700 | [diff] [blame] | 454 | } |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 455 | } |
| 456 | |
| 457 | static inline void sem_unlock(struct sem_array *sma, int locknum) |
| 458 | { |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 459 | if (locknum == SEM_GLOBAL_LOCK) { |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 460 | unmerge_queues(sma); |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 461 | complexmode_tryleave(sma); |
Davidlohr Bueso | cf9d5d7 | 2013-07-08 16:01:11 -0700 | [diff] [blame] | 462 | ipc_unlock_object(&sma->sem_perm); |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 463 | } else { |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 464 | struct sem *sem = &sma->sems[locknum]; |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 465 | spin_unlock(&sem->lock); |
| 466 | } |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 467 | } |
| 468 | |
| 469 | /* |
Davidlohr Bueso | d9a605e | 2013-09-11 14:26:24 -0700 | [diff] [blame] | 470 | * sem_lock_(check_) routines are called in the paths where the rwsem |
Nadia Derbey | 3e148c7 | 2007-10-18 23:40:54 -0700 | [diff] [blame] | 471 | * is not held. |
Linus Torvalds | 321310c | 2013-05-04 10:47:57 -0700 | [diff] [blame] | 472 | * |
| 473 | * The caller holds the RCU read lock. |
Nadia Derbey | 3e148c7 | 2007-10-18 23:40:54 -0700 | [diff] [blame] | 474 | */ |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 475 | static inline struct sem_array *sem_obtain_object(struct ipc_namespace *ns, int id) |
| 476 | { |
Davidlohr Bueso | 55b7ae5 | 2015-06-30 14:58:42 -0700 | [diff] [blame] | 477 | struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&sem_ids(ns), id); |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 478 | |
| 479 | if (IS_ERR(ipcp)) |
| 480 | return ERR_CAST(ipcp); |
| 481 | |
| 482 | return container_of(ipcp, struct sem_array, sem_perm); |
| 483 | } |
| 484 | |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 485 | static inline struct sem_array *sem_obtain_object_check(struct ipc_namespace *ns, |
| 486 | int id) |
| 487 | { |
| 488 | struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&sem_ids(ns), id); |
| 489 | |
| 490 | if (IS_ERR(ipcp)) |
| 491 | return ERR_CAST(ipcp); |
Pierre Peiffer | b1ed88b | 2008-02-06 01:36:23 -0800 | [diff] [blame] | 492 | |
Nadia Derbey | 03f02c7 | 2007-10-18 23:40:51 -0700 | [diff] [blame] | 493 | return container_of(ipcp, struct sem_array, sem_perm); |
Nadia Derbey | 023a535 | 2007-10-18 23:40:51 -0700 | [diff] [blame] | 494 | } |
| 495 | |
Pierre Peiffer | 6ff3797 | 2008-04-29 01:00:46 -0700 | [diff] [blame] | 496 | static inline void sem_lock_and_putref(struct sem_array *sma) |
| 497 | { |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 498 | sem_lock(sma, NULL, -1); |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 499 | ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); |
Pierre Peiffer | 6ff3797 | 2008-04-29 01:00:46 -0700 | [diff] [blame] | 500 | } |
| 501 | |
Nadia Derbey | 7ca7e56 | 2007-10-18 23:40:48 -0700 | [diff] [blame] | 502 | static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s) |
| 503 | { |
| 504 | ipc_rmid(&sem_ids(ns), &s->sem_perm); |
| 505 | } |
| 506 | |
Kees Cook | 101ede0 | 2017-07-12 14:35:02 -0700 | [diff] [blame] | 507 | static struct sem_array *sem_alloc(size_t nsems) |
| 508 | { |
| 509 | struct sem_array *sma; |
Kees Cook | 101ede0 | 2017-07-12 14:35:02 -0700 | [diff] [blame] | 510 | |
| 511 | if (nsems > (INT_MAX - sizeof(*sma)) / sizeof(sma->sems[0])) |
| 512 | return NULL; |
| 513 | |
Gustavo A. R. Silva | 4a2ae92 | 2019-03-07 16:30:26 -0800 | [diff] [blame] | 514 | sma = kvzalloc(struct_size(sma, sems, nsems), GFP_KERNEL); |
Kees Cook | 101ede0 | 2017-07-12 14:35:02 -0700 | [diff] [blame] | 515 | if (unlikely(!sma)) |
| 516 | return NULL; |
| 517 | |
Kees Cook | 101ede0 | 2017-07-12 14:35:02 -0700 | [diff] [blame] | 518 | return sma; |
| 519 | } |
| 520 | |
Nadia Derbey | f4566f0 | 2007-10-18 23:40:53 -0700 | [diff] [blame] | 521 | /** |
| 522 | * newary - Create a new semaphore set |
| 523 | * @ns: namespace |
| 524 | * @params: ptr to the structure that contains key, semflg and nsems |
| 525 | * |
Davidlohr Bueso | d9a605e | 2013-09-11 14:26:24 -0700 | [diff] [blame] | 526 | * Called with sem_ids.rwsem held (as a writer) |
Nadia Derbey | f4566f0 | 2007-10-18 23:40:53 -0700 | [diff] [blame] | 527 | */ |
Nadia Derbey | 7748dbf | 2007-10-18 23:40:49 -0700 | [diff] [blame] | 528 | static int newary(struct ipc_namespace *ns, struct ipc_params *params) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 529 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | int retval; |
| 531 | struct sem_array *sma; |
Nadia Derbey | 7748dbf | 2007-10-18 23:40:49 -0700 | [diff] [blame] | 532 | key_t key = params->key; |
| 533 | int nsems = params->u.nsems; |
| 534 | int semflg = params->flg; |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 535 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | |
| 537 | if (!nsems) |
| 538 | return -EINVAL; |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 539 | if (ns->used_sems + nsems > ns->sc_semmns) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | return -ENOSPC; |
| 541 | |
Kees Cook | 101ede0 | 2017-07-12 14:35:02 -0700 | [diff] [blame] | 542 | sma = sem_alloc(nsems); |
Davidlohr Bueso | 3ab08fe | 2014-01-27 17:07:06 -0800 | [diff] [blame] | 543 | if (!sma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | return -ENOMEM; |
Davidlohr Bueso | 3ab08fe | 2014-01-27 17:07:06 -0800 | [diff] [blame] | 545 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 546 | sma->sem_perm.mode = (semflg & S_IRWXUGO); |
| 547 | sma->sem_perm.key = key; |
| 548 | |
| 549 | sma->sem_perm.security = NULL; |
Eric W. Biederman | aefad95 | 2018-03-22 20:52:43 -0500 | [diff] [blame] | 550 | retval = security_sem_alloc(&sma->sem_perm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 551 | if (retval) { |
Kees Cook | e2029df | 2017-07-12 14:35:31 -0700 | [diff] [blame] | 552 | kvfree(sma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 553 | return retval; |
| 554 | } |
| 555 | |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 556 | for (i = 0; i < nsems; i++) { |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 557 | INIT_LIST_HEAD(&sma->sems[i].pending_alter); |
| 558 | INIT_LIST_HEAD(&sma->sems[i].pending_const); |
| 559 | spin_lock_init(&sma->sems[i].lock); |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 560 | } |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 561 | |
| 562 | sma->complex_count = 0; |
Manfred Spraul | 9de5ab8 | 2017-02-27 14:28:18 -0800 | [diff] [blame] | 563 | sma->use_global_lock = USE_GLOBAL_LOCK_HYSTERESIS; |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 564 | INIT_LIST_HEAD(&sma->pending_alter); |
| 565 | INIT_LIST_HEAD(&sma->pending_const); |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 566 | INIT_LIST_HEAD(&sma->list_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 567 | sma->sem_nsems = nsems; |
Deepa Dinamani | e54d02b | 2017-08-02 19:51:13 -0700 | [diff] [blame] | 568 | sma->sem_ctime = ktime_get_real_seconds(); |
Manfred Spraul | e8577d1 | 2014-12-02 15:59:34 -0800 | [diff] [blame] | 569 | |
Davidlohr Bueso | 39c96a1 | 2017-11-17 15:31:11 -0800 | [diff] [blame] | 570 | /* ipc_addid() locks sma upon success. */ |
Manfred Spraul | 2ec55f8 | 2017-07-12 14:35:13 -0700 | [diff] [blame] | 571 | retval = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni); |
| 572 | if (retval < 0) { |
Manfred Spraul | 39cfffd | 2018-08-21 22:01:29 -0700 | [diff] [blame] | 573 | ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); |
Manfred Spraul | 2ec55f8 | 2017-07-12 14:35:13 -0700 | [diff] [blame] | 574 | return retval; |
Manfred Spraul | e8577d1 | 2014-12-02 15:59:34 -0800 | [diff] [blame] | 575 | } |
| 576 | ns->used_sems += nsems; |
| 577 | |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 578 | sem_unlock(sma, -1); |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 579 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 580 | |
Nadia Derbey | 7ca7e56 | 2007-10-18 23:40:48 -0700 | [diff] [blame] | 581 | return sma->sem_perm.id; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 582 | } |
| 583 | |
Nadia Derbey | 7748dbf | 2007-10-18 23:40:49 -0700 | [diff] [blame] | 584 | |
Nadia Derbey | f4566f0 | 2007-10-18 23:40:53 -0700 | [diff] [blame] | 585 | /* |
Davidlohr Bueso | d9a605e | 2013-09-11 14:26:24 -0700 | [diff] [blame] | 586 | * Called with sem_ids.rwsem and ipcp locked. |
Nadia Derbey | f4566f0 | 2007-10-18 23:40:53 -0700 | [diff] [blame] | 587 | */ |
Nadia Derbey | 03f02c7 | 2007-10-18 23:40:51 -0700 | [diff] [blame] | 588 | static inline int sem_more_checks(struct kern_ipc_perm *ipcp, |
| 589 | struct ipc_params *params) |
Nadia Derbey | 7748dbf | 2007-10-18 23:40:49 -0700 | [diff] [blame] | 590 | { |
Nadia Derbey | 03f02c7 | 2007-10-18 23:40:51 -0700 | [diff] [blame] | 591 | struct sem_array *sma; |
| 592 | |
| 593 | sma = container_of(ipcp, struct sem_array, sem_perm); |
| 594 | if (params->u.nsems > sma->sem_nsems) |
Nadia Derbey | 7748dbf | 2007-10-18 23:40:49 -0700 | [diff] [blame] | 595 | return -EINVAL; |
| 596 | |
| 597 | return 0; |
| 598 | } |
| 599 | |
Dominik Brodowski | 6989471 | 2018-03-20 19:53:58 +0100 | [diff] [blame] | 600 | long ksys_semget(key_t key, int nsems, int semflg) |
Nadia Derbey | 7748dbf | 2007-10-18 23:40:49 -0700 | [diff] [blame] | 601 | { |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 602 | struct ipc_namespace *ns; |
Mathias Krause | eb66ec4 | 2014-06-06 14:37:36 -0700 | [diff] [blame] | 603 | static const struct ipc_ops sem_ops = { |
| 604 | .getnew = newary, |
Eric W. Biederman | 50ab44b | 2018-03-23 23:41:55 -0500 | [diff] [blame] | 605 | .associate = security_sem_associate, |
Mathias Krause | eb66ec4 | 2014-06-06 14:37:36 -0700 | [diff] [blame] | 606 | .more_checks = sem_more_checks, |
| 607 | }; |
Nadia Derbey | 7748dbf | 2007-10-18 23:40:49 -0700 | [diff] [blame] | 608 | struct ipc_params sem_params; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 609 | |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 610 | ns = current->nsproxy->ipc_ns; |
| 611 | |
| 612 | if (nsems < 0 || nsems > ns->sc_semmsl) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 613 | return -EINVAL; |
Nadia Derbey | 7ca7e56 | 2007-10-18 23:40:48 -0700 | [diff] [blame] | 614 | |
Nadia Derbey | 7748dbf | 2007-10-18 23:40:49 -0700 | [diff] [blame] | 615 | sem_params.key = key; |
| 616 | sem_params.flg = semflg; |
| 617 | sem_params.u.nsems = nsems; |
Nadia Derbey | 7ca7e56 | 2007-10-18 23:40:48 -0700 | [diff] [blame] | 618 | |
Nadia Derbey | 7748dbf | 2007-10-18 23:40:49 -0700 | [diff] [blame] | 619 | return ipcget(ns, &sem_ids(ns), &sem_ops, &sem_params); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | } |
| 621 | |
Dominik Brodowski | 6989471 | 2018-03-20 19:53:58 +0100 | [diff] [blame] | 622 | SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg) |
| 623 | { |
| 624 | return ksys_semget(key, nsems, semflg); |
| 625 | } |
| 626 | |
Petr Mladek | 78f5009 | 2014-01-27 17:07:00 -0800 | [diff] [blame] | 627 | /** |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 628 | * perform_atomic_semop[_slow] - Attempt to perform semaphore |
| 629 | * operations on a given array. |
Manfred Spraul | 758a6ba3 | 2013-07-08 16:01:26 -0700 | [diff] [blame] | 630 | * @sma: semaphore array |
Manfred Spraul | d198cd6 | 2014-06-06 14:37:49 -0700 | [diff] [blame] | 631 | * @q: struct sem_queue that describes the operation |
Manfred Spraul | 758a6ba3 | 2013-07-08 16:01:26 -0700 | [diff] [blame] | 632 | * |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 633 | * Caller blocking are as follows, based the value |
| 634 | * indicated by the semaphore operation (sem_op): |
| 635 | * |
| 636 | * (1) >0 never blocks. |
| 637 | * (2) 0 (wait-for-zero operation): semval is non-zero. |
| 638 | * (3) <0 attempting to decrement semval to a value smaller than zero. |
| 639 | * |
Manfred Spraul | 758a6ba3 | 2013-07-08 16:01:26 -0700 | [diff] [blame] | 640 | * Returns 0 if the operation was possible. |
| 641 | * Returns 1 if the operation is impossible, the caller must sleep. |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 642 | * Returns <0 for error codes. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 643 | */ |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 644 | static int perform_atomic_semop_slow(struct sem_array *sma, struct sem_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | { |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 646 | int result, sem_op, nsops; |
| 647 | struct pid *pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | struct sembuf *sop; |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 649 | struct sem *curr; |
Manfred Spraul | d198cd6 | 2014-06-06 14:37:49 -0700 | [diff] [blame] | 650 | struct sembuf *sops; |
| 651 | struct sem_undo *un; |
| 652 | |
| 653 | sops = q->sops; |
| 654 | nsops = q->nsops; |
| 655 | un = q->undo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | |
| 657 | for (sop = sops; sop < sops + nsops; sop++) { |
Davidlohr Bueso | ec67aaa | 2018-06-14 15:27:51 -0700 | [diff] [blame] | 658 | int idx = array_index_nospec(sop->sem_num, sma->sem_nsems); |
| 659 | curr = &sma->sems[idx]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 660 | sem_op = sop->sem_op; |
| 661 | result = curr->semval; |
Petr Mladek | 78f5009 | 2014-01-27 17:07:00 -0800 | [diff] [blame] | 662 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | if (!sem_op && result) |
| 664 | goto would_block; |
| 665 | |
| 666 | result += sem_op; |
| 667 | if (result < 0) |
| 668 | goto would_block; |
| 669 | if (result > SEMVMX) |
| 670 | goto out_of_range; |
Petr Mladek | 78f5009 | 2014-01-27 17:07:00 -0800 | [diff] [blame] | 671 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | if (sop->sem_flg & SEM_UNDO) { |
| 673 | int undo = un->semadj[sop->sem_num] - sem_op; |
Petr Mladek | 78f5009 | 2014-01-27 17:07:00 -0800 | [diff] [blame] | 674 | /* Exceeding the undo range is an error. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 675 | if (undo < (-SEMAEM - 1) || undo > SEMAEM) |
| 676 | goto out_of_range; |
Petr Mladek | 78f5009 | 2014-01-27 17:07:00 -0800 | [diff] [blame] | 677 | un->semadj[sop->sem_num] = undo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | } |
Petr Mladek | 78f5009 | 2014-01-27 17:07:00 -0800 | [diff] [blame] | 679 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | curr->semval = result; |
| 681 | } |
| 682 | |
| 683 | sop--; |
Manfred Spraul | d198cd6 | 2014-06-06 14:37:49 -0700 | [diff] [blame] | 684 | pid = q->pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 685 | while (sop >= sops) { |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 686 | ipc_update_pid(&sma->sems[sop->sem_num].sempid, pid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 687 | sop--; |
| 688 | } |
Petr Mladek | 78f5009 | 2014-01-27 17:07:00 -0800 | [diff] [blame] | 689 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 690 | return 0; |
| 691 | |
| 692 | out_of_range: |
| 693 | result = -ERANGE; |
| 694 | goto undo; |
| 695 | |
| 696 | would_block: |
Manfred Spraul | ed247b7 | 2014-06-06 14:37:49 -0700 | [diff] [blame] | 697 | q->blocking = sop; |
| 698 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 699 | if (sop->sem_flg & IPC_NOWAIT) |
| 700 | result = -EAGAIN; |
| 701 | else |
| 702 | result = 1; |
| 703 | |
| 704 | undo: |
| 705 | sop--; |
| 706 | while (sop >= sops) { |
Petr Mladek | 78f5009 | 2014-01-27 17:07:00 -0800 | [diff] [blame] | 707 | sem_op = sop->sem_op; |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 708 | sma->sems[sop->sem_num].semval -= sem_op; |
Petr Mladek | 78f5009 | 2014-01-27 17:07:00 -0800 | [diff] [blame] | 709 | if (sop->sem_flg & SEM_UNDO) |
| 710 | un->semadj[sop->sem_num] += sem_op; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 711 | sop--; |
| 712 | } |
| 713 | |
| 714 | return result; |
| 715 | } |
| 716 | |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 717 | static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q) |
| 718 | { |
| 719 | int result, sem_op, nsops; |
| 720 | struct sembuf *sop; |
| 721 | struct sem *curr; |
| 722 | struct sembuf *sops; |
| 723 | struct sem_undo *un; |
| 724 | |
| 725 | sops = q->sops; |
| 726 | nsops = q->nsops; |
| 727 | un = q->undo; |
| 728 | |
| 729 | if (unlikely(q->dupsop)) |
| 730 | return perform_atomic_semop_slow(sma, q); |
| 731 | |
| 732 | /* |
| 733 | * We scan the semaphore set twice, first to ensure that the entire |
| 734 | * operation can succeed, therefore avoiding any pointless writes |
| 735 | * to shared memory and having to undo such changes in order to block |
| 736 | * until the operations can go through. |
| 737 | */ |
| 738 | for (sop = sops; sop < sops + nsops; sop++) { |
Davidlohr Bueso | ec67aaa | 2018-06-14 15:27:51 -0700 | [diff] [blame] | 739 | int idx = array_index_nospec(sop->sem_num, sma->sem_nsems); |
| 740 | |
| 741 | curr = &sma->sems[idx]; |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 742 | sem_op = sop->sem_op; |
| 743 | result = curr->semval; |
| 744 | |
| 745 | if (!sem_op && result) |
| 746 | goto would_block; /* wait-for-zero */ |
| 747 | |
| 748 | result += sem_op; |
| 749 | if (result < 0) |
| 750 | goto would_block; |
| 751 | |
| 752 | if (result > SEMVMX) |
| 753 | return -ERANGE; |
| 754 | |
| 755 | if (sop->sem_flg & SEM_UNDO) { |
| 756 | int undo = un->semadj[sop->sem_num] - sem_op; |
| 757 | |
| 758 | /* Exceeding the undo range is an error. */ |
| 759 | if (undo < (-SEMAEM - 1) || undo > SEMAEM) |
| 760 | return -ERANGE; |
| 761 | } |
| 762 | } |
| 763 | |
| 764 | for (sop = sops; sop < sops + nsops; sop++) { |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 765 | curr = &sma->sems[sop->sem_num]; |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 766 | sem_op = sop->sem_op; |
| 767 | result = curr->semval; |
| 768 | |
| 769 | if (sop->sem_flg & SEM_UNDO) { |
| 770 | int undo = un->semadj[sop->sem_num] - sem_op; |
| 771 | |
| 772 | un->semadj[sop->sem_num] = undo; |
| 773 | } |
| 774 | curr->semval += sem_op; |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 775 | ipc_update_pid(&curr->sempid, q->pid); |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 776 | } |
| 777 | |
| 778 | return 0; |
| 779 | |
| 780 | would_block: |
| 781 | q->blocking = sop; |
| 782 | return sop->sem_flg & IPC_NOWAIT ? -EAGAIN : 1; |
| 783 | } |
| 784 | |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 785 | static inline void wake_up_sem_queue_prepare(struct sem_queue *q, int error, |
| 786 | struct wake_q_head *wake_q) |
Nick Piggin | d421209 | 2009-12-15 16:47:30 -0800 | [diff] [blame] | 787 | { |
Manfred Spraul | 8116b54 | 2020-02-03 17:34:42 -0800 | [diff] [blame] | 788 | get_task_struct(q->sleeper); |
| 789 | |
| 790 | /* see SEM_BARRIER_2 for purpuse/pairing */ |
| 791 | smp_store_release(&q->status, error); |
| 792 | |
| 793 | wake_q_add_safe(wake_q, q->sleeper); |
Nick Piggin | d421209 | 2009-12-15 16:47:30 -0800 | [diff] [blame] | 794 | } |
| 795 | |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 796 | static void unlink_queue(struct sem_array *sma, struct sem_queue *q) |
| 797 | { |
| 798 | list_del(&q->list); |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 799 | if (q->nsops > 1) |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 800 | sma->complex_count--; |
| 801 | } |
| 802 | |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 803 | /** check_restart(sma, q) |
| 804 | * @sma: semaphore array |
| 805 | * @q: the operation that just completed |
| 806 | * |
| 807 | * update_queue is O(N^2) when it restarts scanning the whole queue of |
| 808 | * waiting operations. Therefore this function checks if the restart is |
| 809 | * really necessary. It is called after a previously waiting operation |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 810 | * modified the array. |
| 811 | * Note that wait-for-zero operations are handled without restart. |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 812 | */ |
Davidlohr Bueso | 4663d3e | 2016-12-14 15:06:40 -0800 | [diff] [blame] | 813 | static inline int check_restart(struct sem_array *sma, struct sem_queue *q) |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 814 | { |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 815 | /* pending complex alter operations are too difficult to analyse */ |
| 816 | if (!list_empty(&sma->pending_alter)) |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 817 | return 1; |
| 818 | |
| 819 | /* we were a sleeping complex operation. Too difficult */ |
| 820 | if (q->nsops > 1) |
| 821 | return 1; |
| 822 | |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 823 | /* It is impossible that someone waits for the new value: |
| 824 | * - complex operations always restart. |
| 825 | * - wait-for-zero are handled seperately. |
| 826 | * - q is a previously sleeping simple operation that |
| 827 | * altered the array. It must be a decrement, because |
| 828 | * simple increments never sleep. |
| 829 | * - If there are older (higher priority) decrements |
| 830 | * in the queue, then they have observed the original |
| 831 | * semval value and couldn't proceed. The operation |
| 832 | * decremented to value - thus they won't proceed either. |
| 833 | */ |
| 834 | return 0; |
| 835 | } |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 836 | |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 837 | /** |
Davidlohr Bueso | 8001c85 | 2014-01-27 17:07:05 -0800 | [diff] [blame] | 838 | * wake_const_ops - wake up non-alter tasks |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 839 | * @sma: semaphore array. |
| 840 | * @semnum: semaphore that was modified. |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 841 | * @wake_q: lockless wake-queue head. |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 842 | * |
| 843 | * wake_const_ops must be called after a semaphore in a semaphore array |
| 844 | * was set to 0. If complex const operations are pending, wake_const_ops must |
| 845 | * be called with semnum = -1, as well as with the number of each modified |
| 846 | * semaphore. |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 847 | * The tasks that must be woken up are added to @wake_q. The return code |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 848 | * is stored in q->pid. |
| 849 | * The function returns 1 if at least one operation was completed successfully. |
| 850 | */ |
| 851 | static int wake_const_ops(struct sem_array *sma, int semnum, |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 852 | struct wake_q_head *wake_q) |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 853 | { |
Davidlohr Bueso | f150f02 | 2016-12-14 15:06:43 -0800 | [diff] [blame] | 854 | struct sem_queue *q, *tmp; |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 855 | struct list_head *pending_list; |
| 856 | int semop_completed = 0; |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 857 | |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 858 | if (semnum == -1) |
| 859 | pending_list = &sma->pending_const; |
| 860 | else |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 861 | pending_list = &sma->sems[semnum].pending_const; |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 862 | |
Davidlohr Bueso | f150f02 | 2016-12-14 15:06:43 -0800 | [diff] [blame] | 863 | list_for_each_entry_safe(q, tmp, pending_list, list) { |
| 864 | int error = perform_atomic_semop(sma, q); |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 865 | |
Davidlohr Bueso | f150f02 | 2016-12-14 15:06:43 -0800 | [diff] [blame] | 866 | if (error > 0) |
| 867 | continue; |
| 868 | /* operation completed, remove from queue & wakeup */ |
| 869 | unlink_queue(sma, q); |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 870 | |
Davidlohr Bueso | f150f02 | 2016-12-14 15:06:43 -0800 | [diff] [blame] | 871 | wake_up_sem_queue_prepare(q, error, wake_q); |
| 872 | if (error == 0) |
| 873 | semop_completed = 1; |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 874 | } |
Davidlohr Bueso | f150f02 | 2016-12-14 15:06:43 -0800 | [diff] [blame] | 875 | |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 876 | return semop_completed; |
| 877 | } |
| 878 | |
| 879 | /** |
Davidlohr Bueso | 8001c85 | 2014-01-27 17:07:05 -0800 | [diff] [blame] | 880 | * do_smart_wakeup_zero - wakeup all wait for zero tasks |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 881 | * @sma: semaphore array |
| 882 | * @sops: operations that were performed |
| 883 | * @nsops: number of operations |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 884 | * @wake_q: lockless wake-queue head |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 885 | * |
Davidlohr Bueso | 8001c85 | 2014-01-27 17:07:05 -0800 | [diff] [blame] | 886 | * Checks all required queue for wait-for-zero operations, based |
| 887 | * on the actual changes that were performed on the semaphore array. |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 888 | * The function returns 1 if at least one operation was completed successfully. |
| 889 | */ |
| 890 | static int do_smart_wakeup_zero(struct sem_array *sma, struct sembuf *sops, |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 891 | int nsops, struct wake_q_head *wake_q) |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 892 | { |
| 893 | int i; |
| 894 | int semop_completed = 0; |
| 895 | int got_zero = 0; |
| 896 | |
| 897 | /* first: the per-semaphore queues, if known */ |
| 898 | if (sops) { |
| 899 | for (i = 0; i < nsops; i++) { |
| 900 | int num = sops[i].sem_num; |
| 901 | |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 902 | if (sma->sems[num].semval == 0) { |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 903 | got_zero = 1; |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 904 | semop_completed |= wake_const_ops(sma, num, wake_q); |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 905 | } |
| 906 | } |
| 907 | } else { |
| 908 | /* |
| 909 | * No sops means modified semaphores not known. |
| 910 | * Assume all were changed. |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 911 | */ |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 912 | for (i = 0; i < sma->sem_nsems; i++) { |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 913 | if (sma->sems[i].semval == 0) { |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 914 | got_zero = 1; |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 915 | semop_completed |= wake_const_ops(sma, i, wake_q); |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 916 | } |
| 917 | } |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 918 | } |
| 919 | /* |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 920 | * If one of the modified semaphores got 0, |
| 921 | * then check the global queue, too. |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 922 | */ |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 923 | if (got_zero) |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 924 | semop_completed |= wake_const_ops(sma, -1, wake_q); |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 925 | |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 926 | return semop_completed; |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 927 | } |
| 928 | |
Manfred Spraul | 636c6be | 2009-12-15 16:47:33 -0800 | [diff] [blame] | 929 | |
| 930 | /** |
Davidlohr Bueso | 8001c85 | 2014-01-27 17:07:05 -0800 | [diff] [blame] | 931 | * update_queue - look for tasks that can be completed. |
Manfred Spraul | 636c6be | 2009-12-15 16:47:33 -0800 | [diff] [blame] | 932 | * @sma: semaphore array. |
| 933 | * @semnum: semaphore that was modified. |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 934 | * @wake_q: lockless wake-queue head. |
Manfred Spraul | 636c6be | 2009-12-15 16:47:33 -0800 | [diff] [blame] | 935 | * |
| 936 | * update_queue must be called after a semaphore in a semaphore array |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 937 | * was modified. If multiple semaphores were modified, update_queue must |
| 938 | * be called with semnum = -1, as well as with the number of each modified |
| 939 | * semaphore. |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 940 | * The tasks that must be woken up are added to @wake_q. The return code |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 941 | * is stored in q->pid. |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 942 | * The function internally checks if const operations can now succeed. |
| 943 | * |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 944 | * The function return 1 if at least one semop was completed successfully. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 945 | */ |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 946 | static int update_queue(struct sem_array *sma, int semnum, struct wake_q_head *wake_q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 947 | { |
Davidlohr Bueso | f150f02 | 2016-12-14 15:06:43 -0800 | [diff] [blame] | 948 | struct sem_queue *q, *tmp; |
Manfred Spraul | 636c6be | 2009-12-15 16:47:33 -0800 | [diff] [blame] | 949 | struct list_head *pending_list; |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 950 | int semop_completed = 0; |
Manfred Spraul | 636c6be | 2009-12-15 16:47:33 -0800 | [diff] [blame] | 951 | |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 952 | if (semnum == -1) |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 953 | pending_list = &sma->pending_alter; |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 954 | else |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 955 | pending_list = &sma->sems[semnum].pending_alter; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 956 | |
Nick Piggin | 9cad200 | 2009-12-15 16:47:29 -0800 | [diff] [blame] | 957 | again: |
Davidlohr Bueso | f150f02 | 2016-12-14 15:06:43 -0800 | [diff] [blame] | 958 | list_for_each_entry_safe(q, tmp, pending_list, list) { |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 959 | int error, restart; |
Manfred Spraul | 636c6be | 2009-12-15 16:47:33 -0800 | [diff] [blame] | 960 | |
Manfred Spraul | d987f8b2 | 2009-12-15 16:47:34 -0800 | [diff] [blame] | 961 | /* If we are scanning the single sop, per-semaphore list of |
| 962 | * one semaphore and that semaphore is 0, then it is not |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 963 | * necessary to scan further: simple increments |
Manfred Spraul | d987f8b2 | 2009-12-15 16:47:34 -0800 | [diff] [blame] | 964 | * that affect only one entry succeed immediately and cannot |
| 965 | * be in the per semaphore pending queue, and decrements |
| 966 | * cannot be successful if the value is already 0. |
| 967 | */ |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 968 | if (semnum != -1 && sma->sems[semnum].semval == 0) |
Manfred Spraul | d987f8b2 | 2009-12-15 16:47:34 -0800 | [diff] [blame] | 969 | break; |
| 970 | |
Manfred Spraul | d198cd6 | 2014-06-06 14:37:49 -0700 | [diff] [blame] | 971 | error = perform_atomic_semop(sma, q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 972 | |
| 973 | /* Does q->sleeper still need to sleep? */ |
Nick Piggin | 9cad200 | 2009-12-15 16:47:29 -0800 | [diff] [blame] | 974 | if (error > 0) |
| 975 | continue; |
Manfred Spraul | a1193f8 | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 976 | |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 977 | unlink_queue(sma, q); |
Manfred Spraul | a1193f8 | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 978 | |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 979 | if (error) { |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 980 | restart = 0; |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 981 | } else { |
| 982 | semop_completed = 1; |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 983 | do_smart_wakeup_zero(sma, q->sops, q->nsops, wake_q); |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 984 | restart = check_restart(sma, q); |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 985 | } |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 986 | |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 987 | wake_up_sem_queue_prepare(q, error, wake_q); |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 988 | if (restart) |
Nick Piggin | 9cad200 | 2009-12-15 16:47:29 -0800 | [diff] [blame] | 989 | goto again; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 990 | } |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 991 | return semop_completed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 992 | } |
| 993 | |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 994 | /** |
Davidlohr Bueso | 8001c85 | 2014-01-27 17:07:05 -0800 | [diff] [blame] | 995 | * set_semotime - set sem_otime |
Manfred Spraul | 0e8c665 | 2013-09-30 13:45:25 -0700 | [diff] [blame] | 996 | * @sma: semaphore array |
| 997 | * @sops: operations that modified the array, may be NULL |
| 998 | * |
| 999 | * sem_otime is replicated to avoid cache line trashing. |
| 1000 | * This function sets one instance to the current time. |
| 1001 | */ |
| 1002 | static void set_semotime(struct sem_array *sma, struct sembuf *sops) |
| 1003 | { |
| 1004 | if (sops == NULL) { |
Arnd Bergmann | 2a70b78 | 2018-04-12 15:19:44 +0200 | [diff] [blame] | 1005 | sma->sems[0].sem_otime = ktime_get_real_seconds(); |
Manfred Spraul | 0e8c665 | 2013-09-30 13:45:25 -0700 | [diff] [blame] | 1006 | } else { |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 1007 | sma->sems[sops[0].sem_num].sem_otime = |
Arnd Bergmann | 2a70b78 | 2018-04-12 15:19:44 +0200 | [diff] [blame] | 1008 | ktime_get_real_seconds(); |
Manfred Spraul | 0e8c665 | 2013-09-30 13:45:25 -0700 | [diff] [blame] | 1009 | } |
| 1010 | } |
| 1011 | |
| 1012 | /** |
Davidlohr Bueso | 8001c85 | 2014-01-27 17:07:05 -0800 | [diff] [blame] | 1013 | * do_smart_update - optimized update_queue |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 1014 | * @sma: semaphore array |
| 1015 | * @sops: operations that were performed |
| 1016 | * @nsops: number of operations |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 1017 | * @otime: force setting otime |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1018 | * @wake_q: lockless wake-queue head |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 1019 | * |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 1020 | * do_smart_update() does the required calls to update_queue and wakeup_zero, |
| 1021 | * based on the actual changes that were performed on the semaphore array. |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 1022 | * Note that the function does not do the actual wake-up: the caller is |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1023 | * responsible for calling wake_up_q(). |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 1024 | * It is safe to perform this call after dropping all locks. |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 1025 | */ |
Manfred Spraul | 0a2b9d4 | 2010-05-26 14:43:41 -0700 | [diff] [blame] | 1026 | static void do_smart_update(struct sem_array *sma, struct sembuf *sops, int nsops, |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1027 | int otime, struct wake_q_head *wake_q) |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 1028 | { |
| 1029 | int i; |
| 1030 | |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1031 | otime |= do_smart_wakeup_zero(sma, sops, nsops, wake_q); |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 1032 | |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 1033 | if (!list_empty(&sma->pending_alter)) { |
| 1034 | /* semaphore array uses the global queue - just process it. */ |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1035 | otime |= update_queue(sma, -1, wake_q); |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 1036 | } else { |
| 1037 | if (!sops) { |
| 1038 | /* |
| 1039 | * No sops, thus the modified semaphores are not |
| 1040 | * known. Check all. |
| 1041 | */ |
| 1042 | for (i = 0; i < sma->sem_nsems; i++) |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1043 | otime |= update_queue(sma, i, wake_q); |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 1044 | } else { |
| 1045 | /* |
| 1046 | * Check the semaphores that were increased: |
| 1047 | * - No complex ops, thus all sleeping ops are |
| 1048 | * decrease. |
| 1049 | * - if we decreased the value, then any sleeping |
| 1050 | * semaphore ops wont be able to run: If the |
| 1051 | * previous value was too small, then the new |
| 1052 | * value will be too small, too. |
| 1053 | */ |
| 1054 | for (i = 0; i < nsops; i++) { |
| 1055 | if (sops[i].sem_op > 0) { |
| 1056 | otime |= update_queue(sma, |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1057 | sops[i].sem_num, wake_q); |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 1058 | } |
Manfred Spraul | ab465df | 2013-05-26 11:08:52 +0200 | [diff] [blame] | 1059 | } |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 1060 | } |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 1061 | } |
Manfred Spraul | 0e8c665 | 2013-09-30 13:45:25 -0700 | [diff] [blame] | 1062 | if (otime) |
| 1063 | set_semotime(sma, sops); |
Manfred Spraul | fd5db42 | 2010-05-26 14:43:40 -0700 | [diff] [blame] | 1064 | } |
| 1065 | |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1066 | /* |
Manfred Spraul | b220c57 | 2014-06-06 14:37:51 -0700 | [diff] [blame] | 1067 | * check_qop: Test if a queued operation sleeps on the semaphore semnum |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1068 | */ |
| 1069 | static int check_qop(struct sem_array *sma, int semnum, struct sem_queue *q, |
| 1070 | bool count_zero) |
| 1071 | { |
Manfred Spraul | b220c57 | 2014-06-06 14:37:51 -0700 | [diff] [blame] | 1072 | struct sembuf *sop = q->blocking; |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1073 | |
Manfred Spraul | 9b44ee2 | 2014-06-06 14:37:52 -0700 | [diff] [blame] | 1074 | /* |
| 1075 | * Linux always (since 0.99.10) reported a task as sleeping on all |
| 1076 | * semaphores. This violates SUS, therefore it was changed to the |
| 1077 | * standard compliant behavior. |
| 1078 | * Give the administrators a chance to notice that an application |
| 1079 | * might misbehave because it relies on the Linux behavior. |
| 1080 | */ |
| 1081 | pr_info_once("semctl(GETNCNT/GETZCNT) is since 3.16 Single Unix Specification compliant.\n" |
| 1082 | "The task %s (%d) triggered the difference, watch for misbehavior.\n", |
| 1083 | current->comm, task_pid_nr(current)); |
| 1084 | |
Manfred Spraul | b220c57 | 2014-06-06 14:37:51 -0700 | [diff] [blame] | 1085 | if (sop->sem_num != semnum) |
| 1086 | return 0; |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1087 | |
Manfred Spraul | b220c57 | 2014-06-06 14:37:51 -0700 | [diff] [blame] | 1088 | if (count_zero && sop->sem_op == 0) |
| 1089 | return 1; |
| 1090 | if (!count_zero && sop->sem_op < 0) |
| 1091 | return 1; |
| 1092 | |
| 1093 | return 0; |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1094 | } |
| 1095 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1096 | /* The following counts are associated to each semaphore: |
| 1097 | * semncnt number of tasks waiting on semval being nonzero |
| 1098 | * semzcnt number of tasks waiting on semval being zero |
Manfred Spraul | b220c57 | 2014-06-06 14:37:51 -0700 | [diff] [blame] | 1099 | * |
| 1100 | * Per definition, a task waits only on the semaphore of the first semop |
| 1101 | * that cannot proceed, even if additional operation would block, too. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1102 | */ |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1103 | static int count_semcnt(struct sem_array *sma, ushort semnum, |
| 1104 | bool count_zero) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1105 | { |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1106 | struct list_head *l; |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1107 | struct sem_queue *q; |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1108 | int semcnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1109 | |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1110 | semcnt = 0; |
| 1111 | /* First: check the simple operations. They are easy to evaluate */ |
| 1112 | if (count_zero) |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 1113 | l = &sma->sems[semnum].pending_const; |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1114 | else |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 1115 | l = &sma->sems[semnum].pending_alter; |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1116 | |
| 1117 | list_for_each_entry(q, l, list) { |
| 1118 | /* all task on a per-semaphore list sleep on exactly |
| 1119 | * that semaphore |
| 1120 | */ |
| 1121 | semcnt++; |
Rik van Riel | de2657f | 2013-05-09 16:59:59 -0400 | [diff] [blame] | 1122 | } |
| 1123 | |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1124 | /* Then: check the complex operations. */ |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 1125 | list_for_each_entry(q, &sma->pending_alter, list) { |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1126 | semcnt += check_qop(sma, semnum, q, count_zero); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1127 | } |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1128 | if (count_zero) { |
| 1129 | list_for_each_entry(q, &sma->pending_const, list) { |
| 1130 | semcnt += check_qop(sma, semnum, q, count_zero); |
| 1131 | } |
Rik van Riel | ebc2e5e | 2013-05-09 16:53:28 -0400 | [diff] [blame] | 1132 | } |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1133 | return semcnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1134 | } |
| 1135 | |
Davidlohr Bueso | d9a605e | 2013-09-11 14:26:24 -0700 | [diff] [blame] | 1136 | /* Free a semaphore set. freeary() is called with sem_ids.rwsem locked |
| 1137 | * as a writer and the spinlock for this semaphore set hold. sem_ids.rwsem |
Nadia Derbey | 3e148c7 | 2007-10-18 23:40:54 -0700 | [diff] [blame] | 1138 | * remains locked on exit. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1139 | */ |
Pierre Peiffer | 01b8b07 | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 1140 | static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1141 | { |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1142 | struct sem_undo *un, *tu; |
| 1143 | struct sem_queue *q, *tq; |
Pierre Peiffer | 01b8b07 | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 1144 | struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm); |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 1145 | int i; |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1146 | DEFINE_WAKE_Q(wake_q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1147 | |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1148 | /* Free the existing undo structures for this semaphore set. */ |
Davidlohr Bueso | cf9d5d7 | 2013-07-08 16:01:11 -0700 | [diff] [blame] | 1149 | ipc_assert_locked_object(&sma->sem_perm); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1150 | list_for_each_entry_safe(un, tu, &sma->list_id, list_id) { |
| 1151 | list_del(&un->list_id); |
| 1152 | spin_lock(&un->ulp->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1153 | un->semid = -1; |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1154 | list_del_rcu(&un->list_proc); |
| 1155 | spin_unlock(&un->ulp->lock); |
Lai Jiangshan | 693a8b6 | 2011-03-18 12:09:35 +0800 | [diff] [blame] | 1156 | kfree_rcu(un, rcu); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1157 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1158 | |
| 1159 | /* Wake up all pending processes and let them fail with EIDRM. */ |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 1160 | list_for_each_entry_safe(q, tq, &sma->pending_const, list) { |
| 1161 | unlink_queue(sma, q); |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1162 | wake_up_sem_queue_prepare(q, -EIDRM, &wake_q); |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 1163 | } |
| 1164 | |
| 1165 | list_for_each_entry_safe(q, tq, &sma->pending_alter, list) { |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 1166 | unlink_queue(sma, q); |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1167 | wake_up_sem_queue_prepare(q, -EIDRM, &wake_q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1168 | } |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 1169 | for (i = 0; i < sma->sem_nsems; i++) { |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 1170 | struct sem *sem = &sma->sems[i]; |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 1171 | list_for_each_entry_safe(q, tq, &sem->pending_const, list) { |
| 1172 | unlink_queue(sma, q); |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1173 | wake_up_sem_queue_prepare(q, -EIDRM, &wake_q); |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 1174 | } |
| 1175 | list_for_each_entry_safe(q, tq, &sem->pending_alter, list) { |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 1176 | unlink_queue(sma, q); |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1177 | wake_up_sem_queue_prepare(q, -EIDRM, &wake_q); |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 1178 | } |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 1179 | ipc_update_pid(&sem->sempid, NULL); |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 1180 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1181 | |
Nadia Derbey | 7ca7e56 | 2007-10-18 23:40:48 -0700 | [diff] [blame] | 1182 | /* Remove the semaphore set from the IDR */ |
| 1183 | sem_rmid(ns, sma); |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1184 | sem_unlock(sma, -1); |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 1185 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1186 | |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1187 | wake_up_q(&wake_q); |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 1188 | ns->used_sems -= sma->sem_nsems; |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 1189 | ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1190 | } |
| 1191 | |
| 1192 | static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in, int version) |
| 1193 | { |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1194 | switch (version) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1195 | case IPC_64: |
| 1196 | return copy_to_user(buf, in, sizeof(*in)); |
| 1197 | case IPC_OLD: |
| 1198 | { |
| 1199 | struct semid_ds out; |
| 1200 | |
Dan Rosenberg | 982f7c2 | 2010-09-30 15:15:31 -0700 | [diff] [blame] | 1201 | memset(&out, 0, sizeof(out)); |
| 1202 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1203 | ipc64_perm_to_ipc_perm(&in->sem_perm, &out.sem_perm); |
| 1204 | |
| 1205 | out.sem_otime = in->sem_otime; |
| 1206 | out.sem_ctime = in->sem_ctime; |
| 1207 | out.sem_nsems = in->sem_nsems; |
| 1208 | |
| 1209 | return copy_to_user(buf, &out, sizeof(out)); |
| 1210 | } |
| 1211 | default: |
| 1212 | return -EINVAL; |
| 1213 | } |
| 1214 | } |
| 1215 | |
Deepa Dinamani | e54d02b | 2017-08-02 19:51:13 -0700 | [diff] [blame] | 1216 | static time64_t get_semotime(struct sem_array *sma) |
Manfred Spraul | d12e1e5 | 2013-07-08 16:01:25 -0700 | [diff] [blame] | 1217 | { |
| 1218 | int i; |
Deepa Dinamani | e54d02b | 2017-08-02 19:51:13 -0700 | [diff] [blame] | 1219 | time64_t res; |
Manfred Spraul | d12e1e5 | 2013-07-08 16:01:25 -0700 | [diff] [blame] | 1220 | |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 1221 | res = sma->sems[0].sem_otime; |
Manfred Spraul | d12e1e5 | 2013-07-08 16:01:25 -0700 | [diff] [blame] | 1222 | for (i = 1; i < sma->sem_nsems; i++) { |
Deepa Dinamani | e54d02b | 2017-08-02 19:51:13 -0700 | [diff] [blame] | 1223 | time64_t to = sma->sems[i].sem_otime; |
Manfred Spraul | d12e1e5 | 2013-07-08 16:01:25 -0700 | [diff] [blame] | 1224 | |
| 1225 | if (to > res) |
| 1226 | res = to; |
| 1227 | } |
| 1228 | return res; |
| 1229 | } |
| 1230 | |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1231 | static int semctl_stat(struct ipc_namespace *ns, int semid, |
| 1232 | int cmd, struct semid64_ds *semid64) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1233 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1234 | struct sem_array *sma; |
Arnd Bergmann | c2ab975 | 2015-04-28 21:39:50 +0200 | [diff] [blame] | 1235 | time64_t semotime; |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1236 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1237 | |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1238 | memset(semid64, 0, sizeof(*semid64)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1239 | |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1240 | rcu_read_lock(); |
Davidlohr Bueso | a280d6d | 2018-04-10 16:35:26 -0700 | [diff] [blame] | 1241 | if (cmd == SEM_STAT || cmd == SEM_STAT_ANY) { |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1242 | sma = sem_obtain_object(ns, semid); |
| 1243 | if (IS_ERR(sma)) { |
| 1244 | err = PTR_ERR(sma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1245 | goto out_unlock; |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1246 | } |
Davidlohr Bueso | a280d6d | 2018-04-10 16:35:26 -0700 | [diff] [blame] | 1247 | } else { /* IPC_STAT */ |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1248 | sma = sem_obtain_object_check(ns, semid); |
| 1249 | if (IS_ERR(sma)) { |
| 1250 | err = PTR_ERR(sma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1251 | goto out_unlock; |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1252 | } |
| 1253 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1254 | |
Davidlohr Bueso | a280d6d | 2018-04-10 16:35:26 -0700 | [diff] [blame] | 1255 | /* see comment for SHM_STAT_ANY */ |
| 1256 | if (cmd == SEM_STAT_ANY) |
| 1257 | audit_ipc_obj(&sma->sem_perm); |
| 1258 | else { |
| 1259 | err = -EACCES; |
| 1260 | if (ipcperms(ns, &sma->sem_perm, S_IRUGO)) |
| 1261 | goto out_unlock; |
| 1262 | } |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1263 | |
Eric W. Biederman | aefad95 | 2018-03-22 20:52:43 -0500 | [diff] [blame] | 1264 | err = security_sem_semctl(&sma->sem_perm, cmd); |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1265 | if (err) |
| 1266 | goto out_unlock; |
| 1267 | |
Philippe Mikoyan | 87ad4b0 | 2018-02-06 15:40:49 -0800 | [diff] [blame] | 1268 | ipc_lock_object(&sma->sem_perm); |
| 1269 | |
| 1270 | if (!ipc_valid_object(&sma->sem_perm)) { |
| 1271 | ipc_unlock_object(&sma->sem_perm); |
| 1272 | err = -EIDRM; |
| 1273 | goto out_unlock; |
| 1274 | } |
| 1275 | |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1276 | kernel_to_ipc64_perm(&sma->sem_perm, &semid64->sem_perm); |
Arnd Bergmann | c2ab975 | 2015-04-28 21:39:50 +0200 | [diff] [blame] | 1277 | semotime = get_semotime(sma); |
| 1278 | semid64->sem_otime = semotime; |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1279 | semid64->sem_ctime = sma->sem_ctime; |
Arnd Bergmann | c2ab975 | 2015-04-28 21:39:50 +0200 | [diff] [blame] | 1280 | #ifndef CONFIG_64BIT |
| 1281 | semid64->sem_otime_high = semotime >> 32; |
| 1282 | semid64->sem_ctime_high = sma->sem_ctime >> 32; |
| 1283 | #endif |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1284 | semid64->sem_nsems = sma->sem_nsems; |
Philippe Mikoyan | 87ad4b0 | 2018-02-06 15:40:49 -0800 | [diff] [blame] | 1285 | |
Manfred Spraul | 615c999 | 2018-08-21 22:01:21 -0700 | [diff] [blame] | 1286 | if (cmd == IPC_STAT) { |
| 1287 | /* |
| 1288 | * As defined in SUS: |
| 1289 | * Return 0 on success |
| 1290 | */ |
| 1291 | err = 0; |
| 1292 | } else { |
| 1293 | /* |
| 1294 | * SEM_STAT and SEM_STAT_ANY (both Linux specific) |
| 1295 | * Return the full id, including the sequence number |
| 1296 | */ |
| 1297 | err = sma->sem_perm.id; |
| 1298 | } |
Philippe Mikoyan | 87ad4b0 | 2018-02-06 15:40:49 -0800 | [diff] [blame] | 1299 | ipc_unlock_object(&sma->sem_perm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1300 | out_unlock: |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 1301 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1302 | return err; |
| 1303 | } |
| 1304 | |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1305 | static int semctl_info(struct ipc_namespace *ns, int semid, |
| 1306 | int cmd, void __user *p) |
| 1307 | { |
| 1308 | struct seminfo seminfo; |
Manfred Spraul | 27c331a | 2018-08-21 22:02:00 -0700 | [diff] [blame] | 1309 | int max_idx; |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1310 | int err; |
| 1311 | |
| 1312 | err = security_sem_semctl(NULL, cmd); |
| 1313 | if (err) |
| 1314 | return err; |
| 1315 | |
| 1316 | memset(&seminfo, 0, sizeof(seminfo)); |
| 1317 | seminfo.semmni = ns->sc_semmni; |
| 1318 | seminfo.semmns = ns->sc_semmns; |
| 1319 | seminfo.semmsl = ns->sc_semmsl; |
| 1320 | seminfo.semopm = ns->sc_semopm; |
| 1321 | seminfo.semvmx = SEMVMX; |
| 1322 | seminfo.semmnu = SEMMNU; |
| 1323 | seminfo.semmap = SEMMAP; |
| 1324 | seminfo.semume = SEMUME; |
| 1325 | down_read(&sem_ids(ns).rwsem); |
| 1326 | if (cmd == SEM_INFO) { |
| 1327 | seminfo.semusz = sem_ids(ns).in_use; |
| 1328 | seminfo.semaem = ns->used_sems; |
| 1329 | } else { |
| 1330 | seminfo.semusz = SEMUSZ; |
| 1331 | seminfo.semaem = SEMAEM; |
| 1332 | } |
Manfred Spraul | 27c331a | 2018-08-21 22:02:00 -0700 | [diff] [blame] | 1333 | max_idx = ipc_get_maxidx(&sem_ids(ns)); |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1334 | up_read(&sem_ids(ns).rwsem); |
| 1335 | if (copy_to_user(p, &seminfo, sizeof(struct seminfo))) |
| 1336 | return -EFAULT; |
Manfred Spraul | 27c331a | 2018-08-21 22:02:00 -0700 | [diff] [blame] | 1337 | return (max_idx < 0) ? 0 : max_idx; |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1338 | } |
| 1339 | |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1340 | static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum, |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1341 | int val) |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1342 | { |
| 1343 | struct sem_undo *un; |
| 1344 | struct sem_array *sma; |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1345 | struct sem *curr; |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1346 | int err; |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1347 | DEFINE_WAKE_Q(wake_q); |
| 1348 | |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1349 | if (val > SEMVMX || val < 0) |
| 1350 | return -ERANGE; |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1351 | |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1352 | rcu_read_lock(); |
| 1353 | sma = sem_obtain_object_check(ns, semid); |
| 1354 | if (IS_ERR(sma)) { |
| 1355 | rcu_read_unlock(); |
| 1356 | return PTR_ERR(sma); |
| 1357 | } |
| 1358 | |
| 1359 | if (semnum < 0 || semnum >= sma->sem_nsems) { |
| 1360 | rcu_read_unlock(); |
| 1361 | return -EINVAL; |
| 1362 | } |
| 1363 | |
| 1364 | |
| 1365 | if (ipcperms(ns, &sma->sem_perm, S_IWUGO)) { |
| 1366 | rcu_read_unlock(); |
| 1367 | return -EACCES; |
| 1368 | } |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1369 | |
Eric W. Biederman | aefad95 | 2018-03-22 20:52:43 -0500 | [diff] [blame] | 1370 | err = security_sem_semctl(&sma->sem_perm, SETVAL); |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1371 | if (err) { |
| 1372 | rcu_read_unlock(); |
| 1373 | return -EACCES; |
| 1374 | } |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1375 | |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1376 | sem_lock(sma, NULL, -1); |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1377 | |
Rafael Aquini | 0f3d2b0 | 2014-01-27 17:07:01 -0800 | [diff] [blame] | 1378 | if (!ipc_valid_object(&sma->sem_perm)) { |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 1379 | sem_unlock(sma, -1); |
| 1380 | rcu_read_unlock(); |
| 1381 | return -EIDRM; |
| 1382 | } |
| 1383 | |
Davidlohr Bueso | ec67aaa | 2018-06-14 15:27:51 -0700 | [diff] [blame] | 1384 | semnum = array_index_nospec(semnum, sma->sem_nsems); |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 1385 | curr = &sma->sems[semnum]; |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1386 | |
Davidlohr Bueso | cf9d5d7 | 2013-07-08 16:01:11 -0700 | [diff] [blame] | 1387 | ipc_assert_locked_object(&sma->sem_perm); |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1388 | list_for_each_entry(un, &sma->list_id, list_id) |
| 1389 | un->semadj[semnum] = 0; |
| 1390 | |
| 1391 | curr->semval = val; |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 1392 | ipc_update_pid(&curr->sempid, task_tgid(current)); |
Deepa Dinamani | e54d02b | 2017-08-02 19:51:13 -0700 | [diff] [blame] | 1393 | sma->sem_ctime = ktime_get_real_seconds(); |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1394 | /* maybe some queued-up processes were waiting for this */ |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1395 | do_smart_update(sma, NULL, 0, 0, &wake_q); |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1396 | sem_unlock(sma, -1); |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 1397 | rcu_read_unlock(); |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1398 | wake_up_q(&wake_q); |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1399 | return 0; |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1400 | } |
| 1401 | |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 1402 | static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1403 | int cmd, void __user *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1404 | { |
| 1405 | struct sem_array *sma; |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1406 | struct sem *curr; |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 1407 | int err, nsems; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1408 | ushort fast_sem_io[SEMMSL_FAST]; |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1409 | ushort *sem_io = fast_sem_io; |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1410 | DEFINE_WAKE_Q(wake_q); |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 1411 | |
| 1412 | rcu_read_lock(); |
| 1413 | sma = sem_obtain_object_check(ns, semid); |
| 1414 | if (IS_ERR(sma)) { |
| 1415 | rcu_read_unlock(); |
| 1416 | return PTR_ERR(sma); |
| 1417 | } |
| 1418 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1419 | nsems = sma->sem_nsems; |
| 1420 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1421 | err = -EACCES; |
Linus Torvalds | c728b9c | 2013-05-04 11:04:29 -0700 | [diff] [blame] | 1422 | if (ipcperms(ns, &sma->sem_perm, cmd == SETALL ? S_IWUGO : S_IRUGO)) |
| 1423 | goto out_rcu_wakeup; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1424 | |
Eric W. Biederman | aefad95 | 2018-03-22 20:52:43 -0500 | [diff] [blame] | 1425 | err = security_sem_semctl(&sma->sem_perm, cmd); |
Linus Torvalds | c728b9c | 2013-05-04 11:04:29 -0700 | [diff] [blame] | 1426 | if (err) |
| 1427 | goto out_rcu_wakeup; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1428 | |
| 1429 | err = -EACCES; |
| 1430 | switch (cmd) { |
| 1431 | case GETALL: |
| 1432 | { |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1433 | ushort __user *array = p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1434 | int i; |
| 1435 | |
Al Viro | ce85722 | 2013-05-03 00:30:49 +0100 | [diff] [blame] | 1436 | sem_lock(sma, NULL, -1); |
Rafael Aquini | 0f3d2b0 | 2014-01-27 17:07:01 -0800 | [diff] [blame] | 1437 | if (!ipc_valid_object(&sma->sem_perm)) { |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 1438 | err = -EIDRM; |
| 1439 | goto out_unlock; |
| 1440 | } |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1441 | if (nsems > SEMMSL_FAST) { |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 1442 | if (!ipc_rcu_getref(&sma->sem_perm)) { |
Al Viro | ce85722 | 2013-05-03 00:30:49 +0100 | [diff] [blame] | 1443 | err = -EIDRM; |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 1444 | goto out_unlock; |
Al Viro | ce85722 | 2013-05-03 00:30:49 +0100 | [diff] [blame] | 1445 | } |
| 1446 | sem_unlock(sma, -1); |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 1447 | rcu_read_unlock(); |
Kees Cook | f8dbe8d | 2017-07-12 14:34:47 -0700 | [diff] [blame] | 1448 | sem_io = kvmalloc_array(nsems, sizeof(ushort), |
| 1449 | GFP_KERNEL); |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1450 | if (sem_io == NULL) { |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 1451 | ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1452 | return -ENOMEM; |
| 1453 | } |
| 1454 | |
Linus Torvalds | 4091fd9 | 2013-05-04 10:13:40 -0700 | [diff] [blame] | 1455 | rcu_read_lock(); |
Pierre Peiffer | 6ff3797 | 2008-04-29 01:00:46 -0700 | [diff] [blame] | 1456 | sem_lock_and_putref(sma); |
Rafael Aquini | 0f3d2b0 | 2014-01-27 17:07:01 -0800 | [diff] [blame] | 1457 | if (!ipc_valid_object(&sma->sem_perm)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1458 | err = -EIDRM; |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 1459 | goto out_unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1460 | } |
Al Viro | ce85722 | 2013-05-03 00:30:49 +0100 | [diff] [blame] | 1461 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1462 | for (i = 0; i < sma->sem_nsems; i++) |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 1463 | sem_io[i] = sma->sems[i].semval; |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1464 | sem_unlock(sma, -1); |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 1465 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1466 | err = 0; |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1467 | if (copy_to_user(array, sem_io, nsems*sizeof(ushort))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1468 | err = -EFAULT; |
| 1469 | goto out_free; |
| 1470 | } |
| 1471 | case SETALL: |
| 1472 | { |
| 1473 | int i; |
| 1474 | struct sem_undo *un; |
| 1475 | |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 1476 | if (!ipc_rcu_getref(&sma->sem_perm)) { |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 1477 | err = -EIDRM; |
| 1478 | goto out_rcu_wakeup; |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1479 | } |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 1480 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1481 | |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1482 | if (nsems > SEMMSL_FAST) { |
Kees Cook | f8dbe8d | 2017-07-12 14:34:47 -0700 | [diff] [blame] | 1483 | sem_io = kvmalloc_array(nsems, sizeof(ushort), |
| 1484 | GFP_KERNEL); |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1485 | if (sem_io == NULL) { |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 1486 | ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1487 | return -ENOMEM; |
| 1488 | } |
| 1489 | } |
| 1490 | |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1491 | if (copy_from_user(sem_io, p, nsems*sizeof(ushort))) { |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 1492 | ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1493 | err = -EFAULT; |
| 1494 | goto out_free; |
| 1495 | } |
| 1496 | |
| 1497 | for (i = 0; i < nsems; i++) { |
| 1498 | if (sem_io[i] > SEMVMX) { |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 1499 | ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1500 | err = -ERANGE; |
| 1501 | goto out_free; |
| 1502 | } |
| 1503 | } |
Linus Torvalds | 4091fd9 | 2013-05-04 10:13:40 -0700 | [diff] [blame] | 1504 | rcu_read_lock(); |
Pierre Peiffer | 6ff3797 | 2008-04-29 01:00:46 -0700 | [diff] [blame] | 1505 | sem_lock_and_putref(sma); |
Rafael Aquini | 0f3d2b0 | 2014-01-27 17:07:01 -0800 | [diff] [blame] | 1506 | if (!ipc_valid_object(&sma->sem_perm)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1507 | err = -EIDRM; |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 1508 | goto out_unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1509 | } |
| 1510 | |
Davidlohr Bueso | a5f4db8 | 2016-03-22 14:27:48 -0700 | [diff] [blame] | 1511 | for (i = 0; i < nsems; i++) { |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 1512 | sma->sems[i].semval = sem_io[i]; |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 1513 | ipc_update_pid(&sma->sems[i].sempid, task_tgid(current)); |
Davidlohr Bueso | a5f4db8 | 2016-03-22 14:27:48 -0700 | [diff] [blame] | 1514 | } |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1515 | |
Davidlohr Bueso | cf9d5d7 | 2013-07-08 16:01:11 -0700 | [diff] [blame] | 1516 | ipc_assert_locked_object(&sma->sem_perm); |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1517 | list_for_each_entry(un, &sma->list_id, list_id) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1518 | for (i = 0; i < nsems; i++) |
| 1519 | un->semadj[i] = 0; |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1520 | } |
Deepa Dinamani | e54d02b | 2017-08-02 19:51:13 -0700 | [diff] [blame] | 1521 | sma->sem_ctime = ktime_get_real_seconds(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1522 | /* maybe some queued-up processes were waiting for this */ |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1523 | do_smart_update(sma, NULL, 0, 0, &wake_q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1524 | err = 0; |
| 1525 | goto out_unlock; |
| 1526 | } |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1527 | /* GETVAL, GETPID, GETNCTN, GETZCNT: fall-through */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1528 | } |
| 1529 | err = -EINVAL; |
Linus Torvalds | c728b9c | 2013-05-04 11:04:29 -0700 | [diff] [blame] | 1530 | if (semnum < 0 || semnum >= nsems) |
| 1531 | goto out_rcu_wakeup; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1532 | |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1533 | sem_lock(sma, NULL, -1); |
Rafael Aquini | 0f3d2b0 | 2014-01-27 17:07:01 -0800 | [diff] [blame] | 1534 | if (!ipc_valid_object(&sma->sem_perm)) { |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 1535 | err = -EIDRM; |
| 1536 | goto out_unlock; |
| 1537 | } |
Davidlohr Bueso | ec67aaa | 2018-06-14 15:27:51 -0700 | [diff] [blame] | 1538 | |
| 1539 | semnum = array_index_nospec(semnum, nsems); |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 1540 | curr = &sma->sems[semnum]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1541 | |
| 1542 | switch (cmd) { |
| 1543 | case GETVAL: |
| 1544 | err = curr->semval; |
| 1545 | goto out_unlock; |
| 1546 | case GETPID: |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 1547 | err = pid_vnr(curr->sempid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1548 | goto out_unlock; |
| 1549 | case GETNCNT: |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1550 | err = count_semcnt(sma, semnum, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1551 | goto out_unlock; |
| 1552 | case GETZCNT: |
Manfred Spraul | 2f2ed41d | 2014-06-06 14:37:48 -0700 | [diff] [blame] | 1553 | err = count_semcnt(sma, semnum, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1554 | goto out_unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1555 | } |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 1556 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1557 | out_unlock: |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1558 | sem_unlock(sma, -1); |
Linus Torvalds | c728b9c | 2013-05-04 11:04:29 -0700 | [diff] [blame] | 1559 | out_rcu_wakeup: |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 1560 | rcu_read_unlock(); |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 1561 | wake_up_q(&wake_q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1562 | out_free: |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1563 | if (sem_io != fast_sem_io) |
Kees Cook | f8dbe8d | 2017-07-12 14:34:47 -0700 | [diff] [blame] | 1564 | kvfree(sem_io); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1565 | return err; |
| 1566 | } |
| 1567 | |
Pierre Peiffer | 016d713 | 2008-04-29 01:00:50 -0700 | [diff] [blame] | 1568 | static inline unsigned long |
| 1569 | copy_semid_from_user(struct semid64_ds *out, void __user *buf, int version) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1570 | { |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1571 | switch (version) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1572 | case IPC_64: |
Pierre Peiffer | 016d713 | 2008-04-29 01:00:50 -0700 | [diff] [blame] | 1573 | if (copy_from_user(out, buf, sizeof(*out))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1574 | return -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1575 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1576 | case IPC_OLD: |
| 1577 | { |
| 1578 | struct semid_ds tbuf_old; |
| 1579 | |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1580 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1581 | return -EFAULT; |
| 1582 | |
Pierre Peiffer | 016d713 | 2008-04-29 01:00:50 -0700 | [diff] [blame] | 1583 | out->sem_perm.uid = tbuf_old.sem_perm.uid; |
| 1584 | out->sem_perm.gid = tbuf_old.sem_perm.gid; |
| 1585 | out->sem_perm.mode = tbuf_old.sem_perm.mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1586 | |
| 1587 | return 0; |
| 1588 | } |
| 1589 | default: |
| 1590 | return -EINVAL; |
| 1591 | } |
| 1592 | } |
| 1593 | |
Pierre Peiffer | 522bb2a | 2008-04-29 01:00:49 -0700 | [diff] [blame] | 1594 | /* |
Davidlohr Bueso | d9a605e | 2013-09-11 14:26:24 -0700 | [diff] [blame] | 1595 | * This function handles some semctl commands which require the rwsem |
Pierre Peiffer | 522bb2a | 2008-04-29 01:00:49 -0700 | [diff] [blame] | 1596 | * to be held in write mode. |
Davidlohr Bueso | d9a605e | 2013-09-11 14:26:24 -0700 | [diff] [blame] | 1597 | * NOTE: no locks must be held, the rwsem is taken inside this function. |
Pierre Peiffer | 522bb2a | 2008-04-29 01:00:49 -0700 | [diff] [blame] | 1598 | */ |
Pierre Peiffer | 21a4826 | 2008-04-29 01:00:49 -0700 | [diff] [blame] | 1599 | static int semctl_down(struct ipc_namespace *ns, int semid, |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1600 | int cmd, struct semid64_ds *semid64) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1601 | { |
| 1602 | struct sem_array *sma; |
| 1603 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1604 | struct kern_ipc_perm *ipcp; |
| 1605 | |
Davidlohr Bueso | d9a605e | 2013-09-11 14:26:24 -0700 | [diff] [blame] | 1606 | down_write(&sem_ids(ns).rwsem); |
Davidlohr Bueso | 7b4cc5d | 2013-07-08 16:01:12 -0700 | [diff] [blame] | 1607 | rcu_read_lock(); |
| 1608 | |
Manfred Spraul | 4241c1a | 2018-08-21 22:01:34 -0700 | [diff] [blame] | 1609 | ipcp = ipcctl_obtain_check(ns, &sem_ids(ns), semid, cmd, |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1610 | &semid64->sem_perm, 0); |
Davidlohr Bueso | 7b4cc5d | 2013-07-08 16:01:12 -0700 | [diff] [blame] | 1611 | if (IS_ERR(ipcp)) { |
| 1612 | err = PTR_ERR(ipcp); |
Davidlohr Bueso | 7b4cc5d | 2013-07-08 16:01:12 -0700 | [diff] [blame] | 1613 | goto out_unlock1; |
| 1614 | } |
Steve Grubb | 073115d | 2006-04-02 17:07:33 -0400 | [diff] [blame] | 1615 | |
Pierre Peiffer | a5f75e7 | 2008-04-29 01:00:54 -0700 | [diff] [blame] | 1616 | sma = container_of(ipcp, struct sem_array, sem_perm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1617 | |
Eric W. Biederman | aefad95 | 2018-03-22 20:52:43 -0500 | [diff] [blame] | 1618 | err = security_sem_semctl(&sma->sem_perm, cmd); |
Davidlohr Bueso | 7b4cc5d | 2013-07-08 16:01:12 -0700 | [diff] [blame] | 1619 | if (err) |
| 1620 | goto out_unlock1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1621 | |
Davidlohr Bueso | 7b4cc5d | 2013-07-08 16:01:12 -0700 | [diff] [blame] | 1622 | switch (cmd) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1623 | case IPC_RMID: |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1624 | sem_lock(sma, NULL, -1); |
Davidlohr Bueso | 7b4cc5d | 2013-07-08 16:01:12 -0700 | [diff] [blame] | 1625 | /* freeary unlocks the ipc object and rcu */ |
Pierre Peiffer | 01b8b07 | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 1626 | freeary(ns, ipcp); |
Pierre Peiffer | 522bb2a | 2008-04-29 01:00:49 -0700 | [diff] [blame] | 1627 | goto out_up; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1628 | case IPC_SET: |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1629 | sem_lock(sma, NULL, -1); |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1630 | err = ipc_update_perm(&semid64->sem_perm, ipcp); |
Eric W. Biederman | 1efdb69 | 2012-02-07 16:54:11 -0800 | [diff] [blame] | 1631 | if (err) |
Davidlohr Bueso | 7b4cc5d | 2013-07-08 16:01:12 -0700 | [diff] [blame] | 1632 | goto out_unlock0; |
Deepa Dinamani | e54d02b | 2017-08-02 19:51:13 -0700 | [diff] [blame] | 1633 | sma->sem_ctime = ktime_get_real_seconds(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1634 | break; |
| 1635 | default: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1636 | err = -EINVAL; |
Davidlohr Bueso | 7b4cc5d | 2013-07-08 16:01:12 -0700 | [diff] [blame] | 1637 | goto out_unlock1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1638 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1639 | |
Davidlohr Bueso | 7b4cc5d | 2013-07-08 16:01:12 -0700 | [diff] [blame] | 1640 | out_unlock0: |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1641 | sem_unlock(sma, -1); |
Davidlohr Bueso | 7b4cc5d | 2013-07-08 16:01:12 -0700 | [diff] [blame] | 1642 | out_unlock1: |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 1643 | rcu_read_unlock(); |
Pierre Peiffer | 522bb2a | 2008-04-29 01:00:49 -0700 | [diff] [blame] | 1644 | out_up: |
Davidlohr Bueso | d9a605e | 2013-09-11 14:26:24 -0700 | [diff] [blame] | 1645 | up_write(&sem_ids(ns).rwsem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1646 | return err; |
| 1647 | } |
| 1648 | |
Arnd Bergmann | 275f221 | 2018-12-31 22:22:40 +0100 | [diff] [blame] | 1649 | static long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg, int version) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1650 | { |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 1651 | struct ipc_namespace *ns; |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1652 | void __user *p = (void __user *)arg; |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1653 | struct semid64_ds semid64; |
| 1654 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1655 | |
| 1656 | if (semid < 0) |
| 1657 | return -EINVAL; |
| 1658 | |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 1659 | ns = current->nsproxy->ipc_ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1660 | |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1661 | switch (cmd) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1662 | case IPC_INFO: |
| 1663 | case SEM_INFO: |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1664 | return semctl_info(ns, semid, cmd, p); |
Pierre Peiffer | 4b9fcb0 | 2008-02-08 04:18:56 -0800 | [diff] [blame] | 1665 | case IPC_STAT: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1666 | case SEM_STAT: |
Davidlohr Bueso | a280d6d | 2018-04-10 16:35:26 -0700 | [diff] [blame] | 1667 | case SEM_STAT_ANY: |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1668 | err = semctl_stat(ns, semid, cmd, &semid64); |
| 1669 | if (err < 0) |
| 1670 | return err; |
| 1671 | if (copy_semid_to_user(p, &semid64, version)) |
| 1672 | err = -EFAULT; |
| 1673 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1674 | case GETALL: |
| 1675 | case GETVAL: |
| 1676 | case GETPID: |
| 1677 | case GETNCNT: |
| 1678 | case GETZCNT: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1679 | case SETALL: |
Al Viro | e1fd1f4 | 2013-03-05 15:04:55 -0500 | [diff] [blame] | 1680 | return semctl_main(ns, semid, semnum, cmd, p); |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1681 | case SETVAL: { |
| 1682 | int val; |
| 1683 | #if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN) |
| 1684 | /* big-endian 64bit */ |
| 1685 | val = arg >> 32; |
| 1686 | #else |
| 1687 | /* 32bit or little-endian 64bit */ |
| 1688 | val = arg; |
| 1689 | #endif |
| 1690 | return semctl_setval(ns, semid, semnum, val); |
| 1691 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1692 | case IPC_SET: |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1693 | if (copy_semid_from_user(&semid64, p, version)) |
| 1694 | return -EFAULT; |
Mathieu Malaterre | 667da6a | 2019-03-07 16:30:23 -0800 | [diff] [blame] | 1695 | /* fall through */ |
Al Viro | 45a4a64 | 2017-07-09 09:11:00 -0400 | [diff] [blame] | 1696 | case IPC_RMID: |
| 1697 | return semctl_down(ns, semid, cmd, &semid64); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1698 | default: |
| 1699 | return -EINVAL; |
| 1700 | } |
| 1701 | } |
| 1702 | |
Dominik Brodowski | d969c6f | 2018-03-20 20:00:39 +0100 | [diff] [blame] | 1703 | SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg) |
| 1704 | { |
Arnd Bergmann | 275f221 | 2018-12-31 22:22:40 +0100 | [diff] [blame] | 1705 | return ksys_semctl(semid, semnum, cmd, arg, IPC_64); |
Dominik Brodowski | d969c6f | 2018-03-20 20:00:39 +0100 | [diff] [blame] | 1706 | } |
| 1707 | |
Arnd Bergmann | 275f221 | 2018-12-31 22:22:40 +0100 | [diff] [blame] | 1708 | #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
| 1709 | long ksys_old_semctl(int semid, int semnum, int cmd, unsigned long arg) |
| 1710 | { |
| 1711 | int version = ipc_parse_version(&cmd); |
| 1712 | |
| 1713 | return ksys_semctl(semid, semnum, cmd, arg, version); |
| 1714 | } |
| 1715 | |
| 1716 | SYSCALL_DEFINE4(old_semctl, int, semid, int, semnum, int, cmd, unsigned long, arg) |
| 1717 | { |
| 1718 | return ksys_old_semctl(semid, semnum, cmd, arg); |
| 1719 | } |
| 1720 | #endif |
| 1721 | |
Al Viro | c0ebccb | 2017-07-09 10:03:23 -0400 | [diff] [blame] | 1722 | #ifdef CONFIG_COMPAT |
| 1723 | |
| 1724 | struct compat_semid_ds { |
| 1725 | struct compat_ipc_perm sem_perm; |
Arnd Bergmann | 9afc5ee | 2018-07-13 12:52:28 +0200 | [diff] [blame] | 1726 | old_time32_t sem_otime; |
| 1727 | old_time32_t sem_ctime; |
Al Viro | c0ebccb | 2017-07-09 10:03:23 -0400 | [diff] [blame] | 1728 | compat_uptr_t sem_base; |
| 1729 | compat_uptr_t sem_pending; |
| 1730 | compat_uptr_t sem_pending_last; |
| 1731 | compat_uptr_t undo; |
| 1732 | unsigned short sem_nsems; |
| 1733 | }; |
| 1734 | |
| 1735 | static int copy_compat_semid_from_user(struct semid64_ds *out, void __user *buf, |
| 1736 | int version) |
| 1737 | { |
| 1738 | memset(out, 0, sizeof(*out)); |
| 1739 | if (version == IPC_64) { |
Linus Torvalds | 6aa211e | 2017-09-25 18:37:28 -0700 | [diff] [blame] | 1740 | struct compat_semid64_ds __user *p = buf; |
Al Viro | c0ebccb | 2017-07-09 10:03:23 -0400 | [diff] [blame] | 1741 | return get_compat_ipc64_perm(&out->sem_perm, &p->sem_perm); |
| 1742 | } else { |
Linus Torvalds | 6aa211e | 2017-09-25 18:37:28 -0700 | [diff] [blame] | 1743 | struct compat_semid_ds __user *p = buf; |
Al Viro | c0ebccb | 2017-07-09 10:03:23 -0400 | [diff] [blame] | 1744 | return get_compat_ipc_perm(&out->sem_perm, &p->sem_perm); |
| 1745 | } |
| 1746 | } |
| 1747 | |
| 1748 | static int copy_compat_semid_to_user(void __user *buf, struct semid64_ds *in, |
| 1749 | int version) |
| 1750 | { |
| 1751 | if (version == IPC_64) { |
| 1752 | struct compat_semid64_ds v; |
| 1753 | memset(&v, 0, sizeof(v)); |
| 1754 | to_compat_ipc64_perm(&v.sem_perm, &in->sem_perm); |
Arnd Bergmann | c2ab975 | 2015-04-28 21:39:50 +0200 | [diff] [blame] | 1755 | v.sem_otime = lower_32_bits(in->sem_otime); |
| 1756 | v.sem_otime_high = upper_32_bits(in->sem_otime); |
| 1757 | v.sem_ctime = lower_32_bits(in->sem_ctime); |
| 1758 | v.sem_ctime_high = upper_32_bits(in->sem_ctime); |
Al Viro | c0ebccb | 2017-07-09 10:03:23 -0400 | [diff] [blame] | 1759 | v.sem_nsems = in->sem_nsems; |
| 1760 | return copy_to_user(buf, &v, sizeof(v)); |
| 1761 | } else { |
| 1762 | struct compat_semid_ds v; |
| 1763 | memset(&v, 0, sizeof(v)); |
| 1764 | to_compat_ipc_perm(&v.sem_perm, &in->sem_perm); |
| 1765 | v.sem_otime = in->sem_otime; |
| 1766 | v.sem_ctime = in->sem_ctime; |
| 1767 | v.sem_nsems = in->sem_nsems; |
| 1768 | return copy_to_user(buf, &v, sizeof(v)); |
| 1769 | } |
| 1770 | } |
| 1771 | |
Arnd Bergmann | 275f221 | 2018-12-31 22:22:40 +0100 | [diff] [blame] | 1772 | static long compat_ksys_semctl(int semid, int semnum, int cmd, int arg, int version) |
Al Viro | c0ebccb | 2017-07-09 10:03:23 -0400 | [diff] [blame] | 1773 | { |
| 1774 | void __user *p = compat_ptr(arg); |
| 1775 | struct ipc_namespace *ns; |
| 1776 | struct semid64_ds semid64; |
Al Viro | c0ebccb | 2017-07-09 10:03:23 -0400 | [diff] [blame] | 1777 | int err; |
| 1778 | |
| 1779 | ns = current->nsproxy->ipc_ns; |
| 1780 | |
| 1781 | if (semid < 0) |
| 1782 | return -EINVAL; |
| 1783 | |
| 1784 | switch (cmd & (~IPC_64)) { |
| 1785 | case IPC_INFO: |
| 1786 | case SEM_INFO: |
| 1787 | return semctl_info(ns, semid, cmd, p); |
| 1788 | case IPC_STAT: |
| 1789 | case SEM_STAT: |
Davidlohr Bueso | a280d6d | 2018-04-10 16:35:26 -0700 | [diff] [blame] | 1790 | case SEM_STAT_ANY: |
Al Viro | c0ebccb | 2017-07-09 10:03:23 -0400 | [diff] [blame] | 1791 | err = semctl_stat(ns, semid, cmd, &semid64); |
| 1792 | if (err < 0) |
| 1793 | return err; |
| 1794 | if (copy_compat_semid_to_user(p, &semid64, version)) |
| 1795 | err = -EFAULT; |
| 1796 | return err; |
| 1797 | case GETVAL: |
| 1798 | case GETPID: |
| 1799 | case GETNCNT: |
| 1800 | case GETZCNT: |
| 1801 | case GETALL: |
| 1802 | case SETALL: |
| 1803 | return semctl_main(ns, semid, semnum, cmd, p); |
| 1804 | case SETVAL: |
| 1805 | return semctl_setval(ns, semid, semnum, arg); |
| 1806 | case IPC_SET: |
| 1807 | if (copy_compat_semid_from_user(&semid64, p, version)) |
| 1808 | return -EFAULT; |
| 1809 | /* fallthru */ |
| 1810 | case IPC_RMID: |
| 1811 | return semctl_down(ns, semid, cmd, &semid64); |
| 1812 | default: |
| 1813 | return -EINVAL; |
| 1814 | } |
| 1815 | } |
Dominik Brodowski | d969c6f | 2018-03-20 20:00:39 +0100 | [diff] [blame] | 1816 | |
| 1817 | COMPAT_SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, int, arg) |
| 1818 | { |
Arnd Bergmann | 275f221 | 2018-12-31 22:22:40 +0100 | [diff] [blame] | 1819 | return compat_ksys_semctl(semid, semnum, cmd, arg, IPC_64); |
Dominik Brodowski | d969c6f | 2018-03-20 20:00:39 +0100 | [diff] [blame] | 1820 | } |
Arnd Bergmann | 275f221 | 2018-12-31 22:22:40 +0100 | [diff] [blame] | 1821 | |
| 1822 | #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION |
| 1823 | long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg) |
| 1824 | { |
| 1825 | int version = compat_ipc_parse_version(&cmd); |
| 1826 | |
| 1827 | return compat_ksys_semctl(semid, semnum, cmd, arg, version); |
| 1828 | } |
| 1829 | |
| 1830 | COMPAT_SYSCALL_DEFINE4(old_semctl, int, semid, int, semnum, int, cmd, int, arg) |
| 1831 | { |
| 1832 | return compat_ksys_old_semctl(semid, semnum, cmd, arg); |
| 1833 | } |
| 1834 | #endif |
Al Viro | c0ebccb | 2017-07-09 10:03:23 -0400 | [diff] [blame] | 1835 | #endif |
| 1836 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1837 | /* If the task doesn't already have a undo_list, then allocate one |
| 1838 | * here. We guarantee there is only one thread using this undo list, |
| 1839 | * and current is THE ONE |
| 1840 | * |
| 1841 | * If this allocation and assignment succeeds, but later |
| 1842 | * portions of this code fail, there is no need to free the sem_undo_list. |
| 1843 | * Just let it stay associated with the task, and it'll be freed later |
| 1844 | * at exit time. |
| 1845 | * |
| 1846 | * This can block, so callers must hold no locks. |
| 1847 | */ |
| 1848 | static inline int get_undo_list(struct sem_undo_list **undo_listp) |
| 1849 | { |
| 1850 | struct sem_undo_list *undo_list; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1851 | |
| 1852 | undo_list = current->sysvsem.undo_list; |
| 1853 | if (!undo_list) { |
Matt Helsley | 2453a30 | 2006-10-02 02:18:25 -0700 | [diff] [blame] | 1854 | undo_list = kzalloc(sizeof(*undo_list), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1855 | if (undo_list == NULL) |
| 1856 | return -ENOMEM; |
Ingo Molnar | 00a5dfd | 2005-08-05 23:05:27 +0200 | [diff] [blame] | 1857 | spin_lock_init(&undo_list->lock); |
Elena Reshetova | f74370b | 2017-09-08 16:17:42 -0700 | [diff] [blame] | 1858 | refcount_set(&undo_list->refcnt, 1); |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1859 | INIT_LIST_HEAD(&undo_list->list_proc); |
| 1860 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1861 | current->sysvsem.undo_list = undo_list; |
| 1862 | } |
| 1863 | *undo_listp = undo_list; |
| 1864 | return 0; |
| 1865 | } |
| 1866 | |
Nick Piggin | bf17bb7 | 2009-12-15 16:47:28 -0800 | [diff] [blame] | 1867 | static struct sem_undo *__lookup_undo(struct sem_undo_list *ulp, int semid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1868 | { |
Nick Piggin | bf17bb7 | 2009-12-15 16:47:28 -0800 | [diff] [blame] | 1869 | struct sem_undo *un; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1870 | |
Joel Fernandes (Google) | 984035a | 2019-09-25 16:48:20 -0700 | [diff] [blame] | 1871 | list_for_each_entry_rcu(un, &ulp->list_proc, list_proc, |
| 1872 | spin_is_locked(&ulp->lock)) { |
Nick Piggin | bf17bb7 | 2009-12-15 16:47:28 -0800 | [diff] [blame] | 1873 | if (un->semid == semid) |
| 1874 | return un; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1875 | } |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1876 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1877 | } |
| 1878 | |
Nick Piggin | bf17bb7 | 2009-12-15 16:47:28 -0800 | [diff] [blame] | 1879 | static struct sem_undo *lookup_undo(struct sem_undo_list *ulp, int semid) |
| 1880 | { |
| 1881 | struct sem_undo *un; |
| 1882 | |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1883 | assert_spin_locked(&ulp->lock); |
Nick Piggin | bf17bb7 | 2009-12-15 16:47:28 -0800 | [diff] [blame] | 1884 | |
| 1885 | un = __lookup_undo(ulp, semid); |
| 1886 | if (un) { |
| 1887 | list_del_rcu(&un->list_proc); |
| 1888 | list_add_rcu(&un->list_proc, &ulp->list_proc); |
| 1889 | } |
| 1890 | return un; |
| 1891 | } |
| 1892 | |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1893 | /** |
Davidlohr Bueso | 8001c85 | 2014-01-27 17:07:05 -0800 | [diff] [blame] | 1894 | * find_alloc_undo - lookup (and if not present create) undo array |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1895 | * @ns: namespace |
| 1896 | * @semid: semaphore array id |
| 1897 | * |
| 1898 | * The function looks up (and if not present creates) the undo structure. |
| 1899 | * The size of the undo structure depends on the size of the semaphore |
| 1900 | * array, thus the alloc path is not that straightforward. |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1901 | * Lifetime-rules: sem_undo is rcu-protected, on success, the function |
| 1902 | * performs a rcu_read_lock(). |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1903 | */ |
| 1904 | static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1905 | { |
| 1906 | struct sem_array *sma; |
| 1907 | struct sem_undo_list *ulp; |
| 1908 | struct sem_undo *un, *new; |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1909 | int nsems, error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1910 | |
| 1911 | error = get_undo_list(&ulp); |
| 1912 | if (error) |
| 1913 | return ERR_PTR(error); |
| 1914 | |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1915 | rcu_read_lock(); |
Pierre Peiffer | c530c6a | 2007-10-18 23:40:55 -0700 | [diff] [blame] | 1916 | spin_lock(&ulp->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1917 | un = lookup_undo(ulp, semid); |
Pierre Peiffer | c530c6a | 2007-10-18 23:40:55 -0700 | [diff] [blame] | 1918 | spin_unlock(&ulp->lock); |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1919 | if (likely(un != NULL)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1920 | goto out; |
| 1921 | |
| 1922 | /* no undo structure around - allocate one. */ |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1923 | /* step 1: figure out the size of the semaphore array */ |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 1924 | sma = sem_obtain_object_check(ns, semid); |
| 1925 | if (IS_ERR(sma)) { |
| 1926 | rcu_read_unlock(); |
Julia Lawall | 4de85cd | 2010-05-26 14:43:44 -0700 | [diff] [blame] | 1927 | return ERR_CAST(sma); |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 1928 | } |
Nadia Derbey | 023a535 | 2007-10-18 23:40:51 -0700 | [diff] [blame] | 1929 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1930 | nsems = sma->sem_nsems; |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 1931 | if (!ipc_rcu_getref(&sma->sem_perm)) { |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1932 | rcu_read_unlock(); |
| 1933 | un = ERR_PTR(-EIDRM); |
| 1934 | goto out; |
| 1935 | } |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 1936 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1937 | |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1938 | /* step 2: allocate new undo structure */ |
Burman Yan | 4668edc | 2006-12-06 20:38:51 -0800 | [diff] [blame] | 1939 | new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1940 | if (!new) { |
Manfred Spraul | dba4cdd | 2017-07-12 14:34:41 -0700 | [diff] [blame] | 1941 | ipc_rcu_putref(&sma->sem_perm, sem_rcu_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1942 | return ERR_PTR(-ENOMEM); |
| 1943 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1944 | |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1945 | /* step 3: Acquire the lock on semaphore array */ |
Linus Torvalds | 4091fd9 | 2013-05-04 10:13:40 -0700 | [diff] [blame] | 1946 | rcu_read_lock(); |
Pierre Peiffer | 6ff3797 | 2008-04-29 01:00:46 -0700 | [diff] [blame] | 1947 | sem_lock_and_putref(sma); |
Rafael Aquini | 0f3d2b0 | 2014-01-27 17:07:01 -0800 | [diff] [blame] | 1948 | if (!ipc_valid_object(&sma->sem_perm)) { |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1949 | sem_unlock(sma, -1); |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 1950 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1951 | kfree(new); |
| 1952 | un = ERR_PTR(-EIDRM); |
| 1953 | goto out; |
| 1954 | } |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1955 | spin_lock(&ulp->lock); |
| 1956 | |
| 1957 | /* |
| 1958 | * step 4: check for races: did someone else allocate the undo struct? |
| 1959 | */ |
| 1960 | un = lookup_undo(ulp, semid); |
| 1961 | if (un) { |
| 1962 | kfree(new); |
| 1963 | goto success; |
| 1964 | } |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1965 | /* step 5: initialize & link new undo structure */ |
| 1966 | new->semadj = (short *) &new[1]; |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1967 | new->ulp = ulp; |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1968 | new->semid = semid; |
| 1969 | assert_spin_locked(&ulp->lock); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1970 | list_add_rcu(&new->list_proc, &ulp->list_proc); |
Davidlohr Bueso | cf9d5d7 | 2013-07-08 16:01:11 -0700 | [diff] [blame] | 1971 | ipc_assert_locked_object(&sma->sem_perm); |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1972 | list_add(&new->list_id, &sma->list_id); |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 1973 | un = new; |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 1974 | |
| 1975 | success: |
| 1976 | spin_unlock(&ulp->lock); |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 1977 | sem_unlock(sma, -1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1978 | out: |
| 1979 | return un; |
| 1980 | } |
| 1981 | |
Al Viro | 44ee454 | 2017-07-09 10:50:14 -0400 | [diff] [blame] | 1982 | static long do_semtimedop(int semid, struct sembuf __user *tsops, |
Deepa Dinamani | 3ef56dc | 2017-08-02 19:51:10 -0700 | [diff] [blame] | 1983 | unsigned nsops, const struct timespec64 *timeout) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1984 | { |
| 1985 | int error = -EINVAL; |
| 1986 | struct sem_array *sma; |
| 1987 | struct sembuf fast_sops[SEMOPM_FAST]; |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 1988 | struct sembuf *sops = fast_sops, *sop; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1989 | struct sem_undo *un; |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 1990 | int max, locknum; |
| 1991 | bool undos = false, alter = false, dupsop = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1992 | struct sem_queue queue; |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 1993 | unsigned long dup = 0, jiffies_left = 0; |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 1994 | struct ipc_namespace *ns; |
| 1995 | |
| 1996 | ns = current->nsproxy->ipc_ns; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1997 | |
| 1998 | if (nsops < 1 || semid < 0) |
| 1999 | return -EINVAL; |
Kirill Korotaev | e389353 | 2006-10-02 02:18:22 -0700 | [diff] [blame] | 2000 | if (nsops > ns->sc_semopm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2001 | return -E2BIG; |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 2002 | if (nsops > SEMOPM_FAST) { |
Kees Cook | 344476e | 2018-06-12 14:04:32 -0700 | [diff] [blame] | 2003 | sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL); |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 2004 | if (sops == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2005 | return -ENOMEM; |
| 2006 | } |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 2007 | |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 2008 | if (copy_from_user(sops, tsops, nsops * sizeof(*tsops))) { |
| 2009 | error = -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2010 | goto out_free; |
| 2011 | } |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 2012 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2013 | if (timeout) { |
Al Viro | 44ee454 | 2017-07-09 10:50:14 -0400 | [diff] [blame] | 2014 | if (timeout->tv_sec < 0 || timeout->tv_nsec < 0 || |
| 2015 | timeout->tv_nsec >= 1000000000L) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2016 | error = -EINVAL; |
| 2017 | goto out_free; |
| 2018 | } |
Deepa Dinamani | 3ef56dc | 2017-08-02 19:51:10 -0700 | [diff] [blame] | 2019 | jiffies_left = timespec64_to_jiffies(timeout); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2020 | } |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 2021 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2022 | max = 0; |
| 2023 | for (sop = sops; sop < sops + nsops; sop++) { |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 2024 | unsigned long mask = 1ULL << ((sop->sem_num) % BITS_PER_LONG); |
| 2025 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2026 | if (sop->sem_num >= max) |
| 2027 | max = sop->sem_num; |
| 2028 | if (sop->sem_flg & SEM_UNDO) |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 2029 | undos = true; |
| 2030 | if (dup & mask) { |
| 2031 | /* |
| 2032 | * There was a previous alter access that appears |
| 2033 | * to have accessed the same semaphore, thus use |
| 2034 | * the dupsop logic. "appears", because the detection |
| 2035 | * can only check % BITS_PER_LONG. |
| 2036 | */ |
| 2037 | dupsop = true; |
| 2038 | } |
| 2039 | if (sop->sem_op != 0) { |
| 2040 | alter = true; |
| 2041 | dup |= mask; |
| 2042 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2043 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2044 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2045 | if (undos) { |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2046 | /* On success, find_alloc_undo takes the rcu_read_lock */ |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 2047 | un = find_alloc_undo(ns, semid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2048 | if (IS_ERR(un)) { |
| 2049 | error = PTR_ERR(un); |
| 2050 | goto out_free; |
| 2051 | } |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2052 | } else { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2053 | un = NULL; |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2054 | rcu_read_lock(); |
| 2055 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2056 | |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 2057 | sma = sem_obtain_object_check(ns, semid); |
Nadia Derbey | 023a535 | 2007-10-18 23:40:51 -0700 | [diff] [blame] | 2058 | if (IS_ERR(sma)) { |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2059 | rcu_read_unlock(); |
Nadia Derbey | 023a535 | 2007-10-18 23:40:51 -0700 | [diff] [blame] | 2060 | error = PTR_ERR(sma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2061 | goto out_free; |
Nadia Derbey | 023a535 | 2007-10-18 23:40:51 -0700 | [diff] [blame] | 2062 | } |
| 2063 | |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 2064 | error = -EFBIG; |
Davidlohr Bueso | 248e735 | 2016-12-14 15:06:31 -0800 | [diff] [blame] | 2065 | if (max >= sma->sem_nsems) { |
| 2066 | rcu_read_unlock(); |
| 2067 | goto out_free; |
| 2068 | } |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 2069 | |
| 2070 | error = -EACCES; |
Davidlohr Bueso | 248e735 | 2016-12-14 15:06:31 -0800 | [diff] [blame] | 2071 | if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO)) { |
| 2072 | rcu_read_unlock(); |
| 2073 | goto out_free; |
| 2074 | } |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 2075 | |
Eric W. Biederman | aefad95 | 2018-03-22 20:52:43 -0500 | [diff] [blame] | 2076 | error = security_sem_semop(&sma->sem_perm, sops, nsops, alter); |
Davidlohr Bueso | 248e735 | 2016-12-14 15:06:31 -0800 | [diff] [blame] | 2077 | if (error) { |
| 2078 | rcu_read_unlock(); |
| 2079 | goto out_free; |
| 2080 | } |
Davidlohr Bueso | 16df367 | 2013-04-30 19:15:29 -0700 | [diff] [blame] | 2081 | |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 2082 | error = -EIDRM; |
| 2083 | locknum = sem_lock(sma, sops, nsops); |
Rafael Aquini | 0f3d2b0 | 2014-01-27 17:07:01 -0800 | [diff] [blame] | 2084 | /* |
| 2085 | * We eventually might perform the following check in a lockless |
| 2086 | * fashion, considering ipc_valid_object() locking constraints. |
| 2087 | * If nsops == 1 and there is no contention for sem_perm.lock, then |
| 2088 | * only a per-semaphore lock is held and it's OK to proceed with the |
| 2089 | * check below. More details on the fine grained locking scheme |
| 2090 | * entangled here and why it's RMID race safe on comments at sem_lock() |
| 2091 | */ |
| 2092 | if (!ipc_valid_object(&sma->sem_perm)) |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 2093 | goto out_unlock_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2094 | /* |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 2095 | * semid identifiers are not unique - find_alloc_undo may have |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2096 | * allocated an undo structure, it was invalidated by an RMID |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 2097 | * and now a new array with received the same id. Check and fail. |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 2098 | * This case can be detected checking un->semid. The existence of |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2099 | * "un" itself is guaranteed by rcu. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2100 | */ |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2101 | if (un && un->semid == -1) |
| 2102 | goto out_unlock_free; |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 2103 | |
Manfred Spraul | d198cd6 | 2014-06-06 14:37:49 -0700 | [diff] [blame] | 2104 | queue.sops = sops; |
| 2105 | queue.nsops = nsops; |
| 2106 | queue.undo = un; |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 2107 | queue.pid = task_tgid(current); |
Manfred Spraul | d198cd6 | 2014-06-06 14:37:49 -0700 | [diff] [blame] | 2108 | queue.alter = alter; |
Davidlohr Bueso | 4ce33ec | 2016-12-14 15:06:37 -0800 | [diff] [blame] | 2109 | queue.dupsop = dupsop; |
Manfred Spraul | d198cd6 | 2014-06-06 14:37:49 -0700 | [diff] [blame] | 2110 | |
| 2111 | error = perform_atomic_semop(sma, &queue); |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 2112 | if (error == 0) { /* non-blocking succesfull path */ |
| 2113 | DEFINE_WAKE_Q(wake_q); |
| 2114 | |
| 2115 | /* |
| 2116 | * If the operation was successful, then do |
Manfred Spraul | 0e8c665 | 2013-09-30 13:45:25 -0700 | [diff] [blame] | 2117 | * the required updates. |
| 2118 | */ |
| 2119 | if (alter) |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 2120 | do_smart_update(sma, sops, nsops, 1, &wake_q); |
Manfred Spraul | 0e8c665 | 2013-09-30 13:45:25 -0700 | [diff] [blame] | 2121 | else |
| 2122 | set_semotime(sma, sops); |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 2123 | |
| 2124 | sem_unlock(sma, locknum); |
| 2125 | rcu_read_unlock(); |
| 2126 | wake_up_q(&wake_q); |
| 2127 | |
| 2128 | goto out_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2129 | } |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 2130 | if (error < 0) /* non-blocking error path */ |
Manfred Spraul | 0e8c665 | 2013-09-30 13:45:25 -0700 | [diff] [blame] | 2131 | goto out_unlock_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2132 | |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 2133 | /* |
| 2134 | * We need to sleep on this operation, so we put the current |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2135 | * task into the pending queue and go to sleep. |
| 2136 | */ |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 2137 | if (nsops == 1) { |
| 2138 | struct sem *curr; |
Davidlohr Bueso | ec67aaa | 2018-06-14 15:27:51 -0700 | [diff] [blame] | 2139 | int idx = array_index_nospec(sops->sem_num, sma->sem_nsems); |
| 2140 | curr = &sma->sems[idx]; |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 2141 | |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 2142 | if (alter) { |
| 2143 | if (sma->complex_count) { |
| 2144 | list_add_tail(&queue.list, |
| 2145 | &sma->pending_alter); |
| 2146 | } else { |
| 2147 | |
| 2148 | list_add_tail(&queue.list, |
| 2149 | &curr->pending_alter); |
| 2150 | } |
| 2151 | } else { |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 2152 | list_add_tail(&queue.list, &curr->pending_const); |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 2153 | } |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 2154 | } else { |
Manfred Spraul | f269f40 | 2013-07-08 16:01:24 -0700 | [diff] [blame] | 2155 | if (!sma->complex_count) |
| 2156 | merge_queues(sma); |
| 2157 | |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 2158 | if (alter) |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 2159 | list_add_tail(&queue.list, &sma->pending_alter); |
Rik van Riel | 9f1bc2c9 | 2013-04-30 19:15:39 -0700 | [diff] [blame] | 2160 | else |
Manfred Spraul | 1a82e9e | 2013-07-08 16:01:23 -0700 | [diff] [blame] | 2161 | list_add_tail(&queue.list, &sma->pending_const); |
| 2162 | |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 2163 | sma->complex_count++; |
| 2164 | } |
| 2165 | |
Davidlohr Bueso | b5fa01a | 2016-12-14 15:06:46 -0800 | [diff] [blame] | 2166 | do { |
Manfred Spraul | 8116b54 | 2020-02-03 17:34:42 -0800 | [diff] [blame] | 2167 | /* memory ordering ensured by the lock in sem_lock() */ |
Davidlohr Bueso | f075faa | 2018-07-26 16:37:19 -0700 | [diff] [blame] | 2168 | WRITE_ONCE(queue.status, -EINTR); |
Davidlohr Bueso | b5fa01a | 2016-12-14 15:06:46 -0800 | [diff] [blame] | 2169 | queue.sleeper = current; |
Manfred Spraul | 0b0577f | 2011-11-02 13:38:52 -0700 | [diff] [blame] | 2170 | |
Manfred Spraul | 8116b54 | 2020-02-03 17:34:42 -0800 | [diff] [blame] | 2171 | /* memory ordering is ensured by the lock in sem_lock() */ |
Davidlohr Bueso | b5fa01a | 2016-12-14 15:06:46 -0800 | [diff] [blame] | 2172 | __set_current_state(TASK_INTERRUPTIBLE); |
| 2173 | sem_unlock(sma, locknum); |
Linus Torvalds | 321310c | 2013-05-04 10:47:57 -0700 | [diff] [blame] | 2174 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2175 | |
Davidlohr Bueso | b5fa01a | 2016-12-14 15:06:46 -0800 | [diff] [blame] | 2176 | if (timeout) |
| 2177 | jiffies_left = schedule_timeout(jiffies_left); |
| 2178 | else |
| 2179 | schedule(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2180 | |
Davidlohr Bueso | b5fa01a | 2016-12-14 15:06:46 -0800 | [diff] [blame] | 2181 | /* |
| 2182 | * fastpath: the semop has completed, either successfully or |
| 2183 | * not, from the syscall pov, is quite irrelevant to us at this |
| 2184 | * point; we're done. |
| 2185 | * |
| 2186 | * We _do_ care, nonetheless, about being awoken by a signal or |
| 2187 | * spuriously. The queue.status is checked again in the |
| 2188 | * slowpath (aka after taking sem_lock), such that we can detect |
| 2189 | * scenarios where we were awakened externally, during the |
| 2190 | * window between wake_q_add() and wake_up_q(). |
| 2191 | */ |
| 2192 | error = READ_ONCE(queue.status); |
| 2193 | if (error != -EINTR) { |
Manfred Spraul | 8116b54 | 2020-02-03 17:34:42 -0800 | [diff] [blame] | 2194 | /* see SEM_BARRIER_2 for purpose/pairing */ |
| 2195 | smp_acquire__after_ctrl_dep(); |
Davidlohr Bueso | b5fa01a | 2016-12-14 15:06:46 -0800 | [diff] [blame] | 2196 | goto out_free; |
| 2197 | } |
Manfred Spraul | 0b0577f | 2011-11-02 13:38:52 -0700 | [diff] [blame] | 2198 | |
Davidlohr Bueso | b5fa01a | 2016-12-14 15:06:46 -0800 | [diff] [blame] | 2199 | rcu_read_lock(); |
Manfred Spraul | c626bc4 | 2017-01-10 16:57:48 -0800 | [diff] [blame] | 2200 | locknum = sem_lock(sma, sops, nsops); |
Davidlohr Bueso | b5fa01a | 2016-12-14 15:06:46 -0800 | [diff] [blame] | 2201 | |
Davidlohr Bueso | 370b262 | 2016-12-14 15:06:49 -0800 | [diff] [blame] | 2202 | if (!ipc_valid_object(&sma->sem_perm)) |
| 2203 | goto out_unlock_free; |
| 2204 | |
Manfred Spraul | 8116b54 | 2020-02-03 17:34:42 -0800 | [diff] [blame] | 2205 | /* |
| 2206 | * No necessity for any barrier: We are protect by sem_lock() |
| 2207 | */ |
Davidlohr Bueso | 370b262 | 2016-12-14 15:06:49 -0800 | [diff] [blame] | 2208 | error = READ_ONCE(queue.status); |
Davidlohr Bueso | b5fa01a | 2016-12-14 15:06:46 -0800 | [diff] [blame] | 2209 | |
| 2210 | /* |
| 2211 | * If queue.status != -EINTR we are woken up by another process. |
| 2212 | * Leave without unlink_queue(), but with sem_unlock(). |
| 2213 | */ |
| 2214 | if (error != -EINTR) |
| 2215 | goto out_unlock_free; |
| 2216 | |
| 2217 | /* |
| 2218 | * If an interrupt occurred we have to clean up the queue. |
| 2219 | */ |
| 2220 | if (timeout && jiffies_left == 0) |
| 2221 | error = -EAGAIN; |
| 2222 | } while (error == -EINTR && !signal_pending(current)); /* spurious */ |
Manfred Spraul | 0b0577f | 2011-11-02 13:38:52 -0700 | [diff] [blame] | 2223 | |
Manfred Spraul | b97e820 | 2009-12-15 16:47:32 -0800 | [diff] [blame] | 2224 | unlink_queue(sma, &queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2225 | |
| 2226 | out_unlock_free: |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2227 | sem_unlock(sma, locknum); |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 2228 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2229 | out_free: |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 2230 | if (sops != fast_sops) |
Davidlohr Bueso | e4243b8 | 2017-09-08 16:17:52 -0700 | [diff] [blame] | 2231 | kvfree(sops); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2232 | return error; |
| 2233 | } |
| 2234 | |
Dominik Brodowski | 41f4f0e | 2018-03-20 19:48:14 +0100 | [diff] [blame] | 2235 | long ksys_semtimedop(int semid, struct sembuf __user *tsops, |
Arnd Bergmann | 21fc538 | 2018-04-13 13:58:00 +0200 | [diff] [blame] | 2236 | unsigned int nsops, const struct __kernel_timespec __user *timeout) |
Al Viro | 44ee454 | 2017-07-09 10:50:14 -0400 | [diff] [blame] | 2237 | { |
| 2238 | if (timeout) { |
Deepa Dinamani | 3ef56dc | 2017-08-02 19:51:10 -0700 | [diff] [blame] | 2239 | struct timespec64 ts; |
| 2240 | if (get_timespec64(&ts, timeout)) |
Al Viro | 44ee454 | 2017-07-09 10:50:14 -0400 | [diff] [blame] | 2241 | return -EFAULT; |
| 2242 | return do_semtimedop(semid, tsops, nsops, &ts); |
| 2243 | } |
| 2244 | return do_semtimedop(semid, tsops, nsops, NULL); |
| 2245 | } |
| 2246 | |
Dominik Brodowski | 41f4f0e | 2018-03-20 19:48:14 +0100 | [diff] [blame] | 2247 | SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, |
Arnd Bergmann | 21fc538 | 2018-04-13 13:58:00 +0200 | [diff] [blame] | 2248 | unsigned int, nsops, const struct __kernel_timespec __user *, timeout) |
Dominik Brodowski | 41f4f0e | 2018-03-20 19:48:14 +0100 | [diff] [blame] | 2249 | { |
| 2250 | return ksys_semtimedop(semid, tsops, nsops, timeout); |
| 2251 | } |
| 2252 | |
Arnd Bergmann | b0d1757 | 2018-04-13 13:58:23 +0200 | [diff] [blame] | 2253 | #ifdef CONFIG_COMPAT_32BIT_TIME |
Dominik Brodowski | 41f4f0e | 2018-03-20 19:48:14 +0100 | [diff] [blame] | 2254 | long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems, |
| 2255 | unsigned int nsops, |
Arnd Bergmann | 9afc5ee | 2018-07-13 12:52:28 +0200 | [diff] [blame] | 2256 | const struct old_timespec32 __user *timeout) |
Al Viro | 44ee454 | 2017-07-09 10:50:14 -0400 | [diff] [blame] | 2257 | { |
| 2258 | if (timeout) { |
Deepa Dinamani | 3ef56dc | 2017-08-02 19:51:10 -0700 | [diff] [blame] | 2259 | struct timespec64 ts; |
Arnd Bergmann | 9afc5ee | 2018-07-13 12:52:28 +0200 | [diff] [blame] | 2260 | if (get_old_timespec32(&ts, timeout)) |
Al Viro | 44ee454 | 2017-07-09 10:50:14 -0400 | [diff] [blame] | 2261 | return -EFAULT; |
| 2262 | return do_semtimedop(semid, tsems, nsops, &ts); |
| 2263 | } |
| 2264 | return do_semtimedop(semid, tsems, nsops, NULL); |
| 2265 | } |
Dominik Brodowski | 41f4f0e | 2018-03-20 19:48:14 +0100 | [diff] [blame] | 2266 | |
Arnd Bergmann | 8dabe72 | 2019-01-07 00:33:08 +0100 | [diff] [blame] | 2267 | SYSCALL_DEFINE4(semtimedop_time32, int, semid, struct sembuf __user *, tsems, |
Dominik Brodowski | 41f4f0e | 2018-03-20 19:48:14 +0100 | [diff] [blame] | 2268 | unsigned int, nsops, |
Arnd Bergmann | 9afc5ee | 2018-07-13 12:52:28 +0200 | [diff] [blame] | 2269 | const struct old_timespec32 __user *, timeout) |
Dominik Brodowski | 41f4f0e | 2018-03-20 19:48:14 +0100 | [diff] [blame] | 2270 | { |
| 2271 | return compat_ksys_semtimedop(semid, tsems, nsops, timeout); |
| 2272 | } |
Al Viro | 44ee454 | 2017-07-09 10:50:14 -0400 | [diff] [blame] | 2273 | #endif |
| 2274 | |
Heiko Carstens | d5460c9 | 2009-01-14 14:14:27 +0100 | [diff] [blame] | 2275 | SYSCALL_DEFINE3(semop, int, semid, struct sembuf __user *, tsops, |
| 2276 | unsigned, nsops) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2277 | { |
Al Viro | 44ee454 | 2017-07-09 10:50:14 -0400 | [diff] [blame] | 2278 | return do_semtimedop(semid, tsops, nsops, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2279 | } |
| 2280 | |
| 2281 | /* If CLONE_SYSVSEM is set, establish sharing of SEM_UNDO state between |
| 2282 | * parent and child tasks. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2283 | */ |
| 2284 | |
| 2285 | int copy_semundo(unsigned long clone_flags, struct task_struct *tsk) |
| 2286 | { |
| 2287 | struct sem_undo_list *undo_list; |
| 2288 | int error; |
| 2289 | |
| 2290 | if (clone_flags & CLONE_SYSVSEM) { |
| 2291 | error = get_undo_list(&undo_list); |
| 2292 | if (error) |
| 2293 | return error; |
Elena Reshetova | f74370b | 2017-09-08 16:17:42 -0700 | [diff] [blame] | 2294 | refcount_inc(&undo_list->refcnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2295 | tsk->sysvsem.undo_list = undo_list; |
Paul McQuade | 46c0a8c | 2014-06-06 14:37:37 -0700 | [diff] [blame] | 2296 | } else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2297 | tsk->sysvsem.undo_list = NULL; |
| 2298 | |
| 2299 | return 0; |
| 2300 | } |
| 2301 | |
| 2302 | /* |
| 2303 | * add semadj values to semaphores, free undo structures. |
| 2304 | * undo structures are not freed when semaphore arrays are destroyed |
| 2305 | * so some of them may be out of date. |
| 2306 | * IMPLEMENTATION NOTE: There is some confusion over whether the |
| 2307 | * set of adjustments that needs to be done should be done in an atomic |
| 2308 | * manner or not. That is, if we are attempting to decrement the semval |
| 2309 | * should we queue up and wait until we can do so legally? |
| 2310 | * The original implementation attempted to do this (queue and wait). |
| 2311 | * The current implementation does not do so. The POSIX standard |
| 2312 | * and SVID should be consulted to determine what behavior is mandated. |
| 2313 | */ |
| 2314 | void exit_sem(struct task_struct *tsk) |
| 2315 | { |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 2316 | struct sem_undo_list *ulp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2317 | |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 2318 | ulp = tsk->sysvsem.undo_list; |
| 2319 | if (!ulp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2320 | return; |
Manfred Spraul | 9edff4a | 2008-04-29 01:00:57 -0700 | [diff] [blame] | 2321 | tsk->sysvsem.undo_list = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2322 | |
Elena Reshetova | f74370b | 2017-09-08 16:17:42 -0700 | [diff] [blame] | 2323 | if (!refcount_dec_and_test(&ulp->refcnt)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2324 | return; |
| 2325 | |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2326 | for (;;) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2327 | struct sem_array *sma; |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2328 | struct sem_undo *un; |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2329 | int semid, i; |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 2330 | DEFINE_WAKE_Q(wake_q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2331 | |
Nikolay Borisov | 2a1613a | 2016-10-11 13:55:05 -0700 | [diff] [blame] | 2332 | cond_resched(); |
| 2333 | |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2334 | rcu_read_lock(); |
Jiri Pirko | 05725f7 | 2009-04-14 20:17:16 +0200 | [diff] [blame] | 2335 | un = list_entry_rcu(ulp->list_proc.next, |
| 2336 | struct sem_undo, list_proc); |
Herton R. Krzesinski | 602b859 | 2015-08-14 15:35:02 -0700 | [diff] [blame] | 2337 | if (&un->list_proc == &ulp->list_proc) { |
| 2338 | /* |
| 2339 | * We must wait for freeary() before freeing this ulp, |
| 2340 | * in case we raced with last sem_undo. There is a small |
| 2341 | * possibility where we exit while freeary() didn't |
| 2342 | * finish unlocking sem_undo_list. |
| 2343 | */ |
Paul E. McKenney | e0892e0 | 2017-06-29 12:59:32 -0700 | [diff] [blame] | 2344 | spin_lock(&ulp->lock); |
| 2345 | spin_unlock(&ulp->lock); |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2346 | rcu_read_unlock(); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2347 | break; |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2348 | } |
Herton R. Krzesinski | 602b859 | 2015-08-14 15:35:02 -0700 | [diff] [blame] | 2349 | spin_lock(&ulp->lock); |
| 2350 | semid = un->semid; |
| 2351 | spin_unlock(&ulp->lock); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2352 | |
Herton R. Krzesinski | 602b859 | 2015-08-14 15:35:02 -0700 | [diff] [blame] | 2353 | /* exit_sem raced with IPC_RMID, nothing to do */ |
| 2354 | if (semid == -1) { |
| 2355 | rcu_read_unlock(); |
| 2356 | continue; |
| 2357 | } |
| 2358 | |
| 2359 | sma = sem_obtain_object_check(tsk->nsproxy->ipc_ns, semid); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2360 | /* exit_sem raced with IPC_RMID, nothing to do */ |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2361 | if (IS_ERR(sma)) { |
| 2362 | rcu_read_unlock(); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2363 | continue; |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2364 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2365 | |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2366 | sem_lock(sma, NULL, -1); |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 2367 | /* exit_sem raced with IPC_RMID, nothing to do */ |
Rafael Aquini | 0f3d2b0 | 2014-01-27 17:07:01 -0800 | [diff] [blame] | 2368 | if (!ipc_valid_object(&sma->sem_perm)) { |
Manfred Spraul | 6e224f9 | 2013-10-16 13:46:45 -0700 | [diff] [blame] | 2369 | sem_unlock(sma, -1); |
| 2370 | rcu_read_unlock(); |
| 2371 | continue; |
| 2372 | } |
Nick Piggin | bf17bb7 | 2009-12-15 16:47:28 -0800 | [diff] [blame] | 2373 | un = __lookup_undo(ulp, semid); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2374 | if (un == NULL) { |
| 2375 | /* exit_sem raced with IPC_RMID+semget() that created |
| 2376 | * exactly the same semid. Nothing to do. |
| 2377 | */ |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2378 | sem_unlock(sma, -1); |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 2379 | rcu_read_unlock(); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2380 | continue; |
| 2381 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2382 | |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2383 | /* remove un from the linked lists */ |
Davidlohr Bueso | cf9d5d7 | 2013-07-08 16:01:11 -0700 | [diff] [blame] | 2384 | ipc_assert_locked_object(&sma->sem_perm); |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 2385 | list_del(&un->list_id); |
| 2386 | |
Ioanna Alifieraki | edf28f4 | 2020-02-20 20:04:00 -0800 | [diff] [blame] | 2387 | spin_lock(&ulp->lock); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2388 | list_del_rcu(&un->list_proc); |
Ioanna Alifieraki | edf28f4 | 2020-02-20 20:04:00 -0800 | [diff] [blame] | 2389 | spin_unlock(&ulp->lock); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2390 | |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 2391 | /* perform adjustments registered in un */ |
| 2392 | for (i = 0; i < sma->sem_nsems; i++) { |
Manfred Spraul | 1a23395 | 2017-07-12 14:34:38 -0700 | [diff] [blame] | 2393 | struct sem *semaphore = &sma->sems[i]; |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 2394 | if (un->semadj[i]) { |
| 2395 | semaphore->semval += un->semadj[i]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2396 | /* |
| 2397 | * Range checks of the new semaphore value, |
| 2398 | * not defined by sus: |
| 2399 | * - Some unices ignore the undo entirely |
| 2400 | * (e.g. HP UX 11i 11.22, Tru64 V5.1) |
| 2401 | * - some cap the value (e.g. FreeBSD caps |
| 2402 | * at 0, but doesn't enforce SEMVMX) |
| 2403 | * |
| 2404 | * Linux caps the semaphore value, both at 0 |
| 2405 | * and at SEMVMX. |
| 2406 | * |
Manfred Spraul | 239521f | 2014-01-27 17:07:04 -0800 | [diff] [blame] | 2407 | * Manfred <manfred@colorfullife.com> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2408 | */ |
Ingo Molnar | 5f921ae | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 2409 | if (semaphore->semval < 0) |
| 2410 | semaphore->semval = 0; |
| 2411 | if (semaphore->semval > SEMVMX) |
| 2412 | semaphore->semval = SEMVMX; |
Eric W. Biederman | 51d6f26 | 2018-03-23 01:11:29 -0500 | [diff] [blame] | 2413 | ipc_update_pid(&semaphore->sempid, task_tgid(current)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2414 | } |
| 2415 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2416 | /* maybe some queued-up processes were waiting for this */ |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 2417 | do_smart_update(sma, NULL, 0, 1, &wake_q); |
Rik van Riel | 6062a8d | 2013-04-30 19:15:44 -0700 | [diff] [blame] | 2418 | sem_unlock(sma, -1); |
Linus Torvalds | 6d49dab | 2013-05-03 15:04:40 -0700 | [diff] [blame] | 2419 | rcu_read_unlock(); |
Davidlohr Bueso | 9ae949f | 2016-12-14 15:06:34 -0800 | [diff] [blame] | 2420 | wake_up_q(&wake_q); |
Manfred Spraul | 380af1b | 2008-07-25 01:48:06 -0700 | [diff] [blame] | 2421 | |
Lai Jiangshan | 693a8b6 | 2011-03-18 12:09:35 +0800 | [diff] [blame] | 2422 | kfree_rcu(un, rcu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2423 | } |
Manfred Spraul | 4daa28f | 2008-07-25 01:48:04 -0700 | [diff] [blame] | 2424 | kfree(ulp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2425 | } |
| 2426 | |
| 2427 | #ifdef CONFIG_PROC_FS |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 2428 | static int sysvipc_sem_proc_show(struct seq_file *s, void *it) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2429 | { |
Eric W. Biederman | 1efdb69 | 2012-02-07 16:54:11 -0800 | [diff] [blame] | 2430 | struct user_namespace *user_ns = seq_user_ns(s); |
Kees Cook | ade9f91 | 2017-08-02 13:32:21 -0700 | [diff] [blame] | 2431 | struct kern_ipc_perm *ipcp = it; |
| 2432 | struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm); |
Deepa Dinamani | e54d02b | 2017-08-02 19:51:13 -0700 | [diff] [blame] | 2433 | time64_t sem_otime; |
Manfred Spraul | d12e1e5 | 2013-07-08 16:01:25 -0700 | [diff] [blame] | 2434 | |
Manfred Spraul | d8c6337 | 2013-09-30 13:45:07 -0700 | [diff] [blame] | 2435 | /* |
| 2436 | * The proc interface isn't aware of sem_lock(), it calls |
| 2437 | * ipc_lock_object() directly (in sysvipc_find_ipc). |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 2438 | * In order to stay compatible with sem_lock(), we must |
| 2439 | * enter / leave complex_mode. |
Manfred Spraul | d8c6337 | 2013-09-30 13:45:07 -0700 | [diff] [blame] | 2440 | */ |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 2441 | complexmode_enter(sma); |
Manfred Spraul | d8c6337 | 2013-09-30 13:45:07 -0700 | [diff] [blame] | 2442 | |
Manfred Spraul | d12e1e5 | 2013-07-08 16:01:25 -0700 | [diff] [blame] | 2443 | sem_otime = get_semotime(sma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2444 | |
Joe Perches | 7f032d6 | 2015-04-15 16:17:54 -0700 | [diff] [blame] | 2445 | seq_printf(s, |
Deepa Dinamani | e54d02b | 2017-08-02 19:51:13 -0700 | [diff] [blame] | 2446 | "%10d %10d %4o %10u %5u %5u %5u %5u %10llu %10llu\n", |
Joe Perches | 7f032d6 | 2015-04-15 16:17:54 -0700 | [diff] [blame] | 2447 | sma->sem_perm.key, |
| 2448 | sma->sem_perm.id, |
| 2449 | sma->sem_perm.mode, |
| 2450 | sma->sem_nsems, |
| 2451 | from_kuid_munged(user_ns, sma->sem_perm.uid), |
| 2452 | from_kgid_munged(user_ns, sma->sem_perm.gid), |
| 2453 | from_kuid_munged(user_ns, sma->sem_perm.cuid), |
| 2454 | from_kgid_munged(user_ns, sma->sem_perm.cgid), |
| 2455 | sem_otime, |
| 2456 | sma->sem_ctime); |
| 2457 | |
Manfred Spraul | 5864a2f | 2016-10-11 13:54:50 -0700 | [diff] [blame] | 2458 | complexmode_tryleave(sma); |
| 2459 | |
Joe Perches | 7f032d6 | 2015-04-15 16:17:54 -0700 | [diff] [blame] | 2460 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2461 | } |
| 2462 | #endif |