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/kernel/seccomp.c |
| 4 | * |
| 5 | * Copyright 2004-2005 Andrea Arcangeli <andrea@cpushare.com> |
| 6 | * |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 7 | * Copyright (C) 2012 Google, Inc. |
| 8 | * Will Drewry <wad@chromium.org> |
| 9 | * |
| 10 | * This defines a simple but solid secure-computing facility. |
| 11 | * |
| 12 | * Mode 1 uses a fixed list of allowed system calls. |
| 13 | * Mode 2 allows user-defined system call filters in the form |
| 14 | * of Berkeley Packet Filters/Linux Socket Filters. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | */ |
Kees Cook | e68f9d4 | 2020-06-15 22:02:56 -0700 | [diff] [blame] | 16 | #define pr_fmt(fmt) "seccomp: " fmt |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | |
Kees Cook | 0b5fa22 | 2017-06-26 09:24:00 -0700 | [diff] [blame] | 18 | #include <linux/refcount.h> |
Eric Paris | 85e7bac3 | 2012-01-03 14:23:05 -0500 | [diff] [blame] | 19 | #include <linux/audit.h> |
Roland McGrath | 5b10174 | 2009-02-27 23:25:54 -0800 | [diff] [blame] | 20 | #include <linux/compat.h> |
Mike Frysinger | b25e671 | 2017-01-19 22:28:57 -0600 | [diff] [blame] | 21 | #include <linux/coredump.h> |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 22 | #include <linux/kmemleak.h> |
Kees Cook | 5c30708 | 2018-05-01 15:07:31 -0700 | [diff] [blame] | 23 | #include <linux/nospec.h> |
| 24 | #include <linux/prctl.h> |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 25 | #include <linux/sched.h> |
Ingo Molnar | 68db0cf | 2017-02-08 18:51:37 +0100 | [diff] [blame] | 26 | #include <linux/sched/task_stack.h> |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 27 | #include <linux/seccomp.h> |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 28 | #include <linux/slab.h> |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 29 | #include <linux/syscalls.h> |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 30 | #include <linux/sysctl.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | |
Kees Cook | 495ac30 | 2022-02-07 20:21:13 -0800 | [diff] [blame] | 32 | /* Not exposed in headers: strictly internal use only. */ |
| 33 | #define SECCOMP_MODE_DEAD (SECCOMP_MODE_FILTER + 1) |
| 34 | |
Andy Lutomirski | a4412fc | 2014-07-21 18:49:14 -0700 | [diff] [blame] | 35 | #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 36 | #include <asm/syscall.h> |
Andy Lutomirski | a4412fc | 2014-07-21 18:49:14 -0700 | [diff] [blame] | 37 | #endif |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 38 | |
| 39 | #ifdef CONFIG_SECCOMP_FILTER |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 40 | #include <linux/file.h> |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 41 | #include <linux/filter.h> |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 42 | #include <linux/pid.h> |
Will Drewry | fb0fadf | 2012-04-12 16:48:02 -0500 | [diff] [blame] | 43 | #include <linux/ptrace.h> |
Mickaël Salaün | fb14528 | 2020-10-30 13:38:49 +0100 | [diff] [blame] | 44 | #include <linux/capability.h> |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 45 | #include <linux/uaccess.h> |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 46 | #include <linux/anon_inodes.h> |
Sargun Dhillon | 9f87dcf | 2020-06-01 04:25:32 -0700 | [diff] [blame] | 47 | #include <linux/lockdep.h> |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 48 | |
Kees Cook | 47e33c05 | 2020-06-15 15:42:46 -0700 | [diff] [blame] | 49 | /* |
| 50 | * When SECCOMP_IOCTL_NOTIF_ID_VALID was first introduced, it had the |
| 51 | * wrong direction flag in the ioctl number. This is the broken one, |
| 52 | * which the kernel needs to keep supporting until all userspaces stop |
| 53 | * using the wrong command number. |
| 54 | */ |
| 55 | #define SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR SECCOMP_IOR(2, __u64) |
| 56 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 57 | enum notify_state { |
| 58 | SECCOMP_NOTIFY_INIT, |
| 59 | SECCOMP_NOTIFY_SENT, |
| 60 | SECCOMP_NOTIFY_REPLIED, |
| 61 | }; |
| 62 | |
| 63 | struct seccomp_knotif { |
| 64 | /* The struct pid of the task whose filter triggered the notification */ |
| 65 | struct task_struct *task; |
| 66 | |
| 67 | /* The "cookie" for this request; this is unique for this filter. */ |
| 68 | u64 id; |
| 69 | |
| 70 | /* |
| 71 | * The seccomp data. This pointer is valid the entire time this |
| 72 | * notification is active, since it comes from __seccomp_filter which |
| 73 | * eclipses the entire lifecycle here. |
| 74 | */ |
| 75 | const struct seccomp_data *data; |
| 76 | |
| 77 | /* |
| 78 | * Notification states. When SECCOMP_RET_USER_NOTIF is returned, a |
| 79 | * struct seccomp_knotif is created and starts out in INIT. Once the |
| 80 | * handler reads the notification off of an FD, it transitions to SENT. |
| 81 | * If a signal is received the state transitions back to INIT and |
| 82 | * another message is sent. When the userspace handler replies, state |
| 83 | * transitions to REPLIED. |
| 84 | */ |
| 85 | enum notify_state state; |
| 86 | |
| 87 | /* The return values, only valid when in SECCOMP_NOTIFY_REPLIED */ |
| 88 | int error; |
| 89 | long val; |
Christian Brauner | fb3c5386 | 2019-09-20 10:30:05 +0200 | [diff] [blame] | 90 | u32 flags; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 91 | |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 92 | /* |
| 93 | * Signals when this has changed states, such as the listener |
| 94 | * dying, a new seccomp addfd message, or changing to REPLIED |
| 95 | */ |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 96 | struct completion ready; |
| 97 | |
| 98 | struct list_head list; |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 99 | |
| 100 | /* outstanding addfd requests */ |
| 101 | struct list_head addfd; |
| 102 | }; |
| 103 | |
| 104 | /** |
| 105 | * struct seccomp_kaddfd - container for seccomp_addfd ioctl messages |
| 106 | * |
| 107 | * @file: A reference to the file to install in the other task |
| 108 | * @fd: The fd number to install it at. If the fd number is -1, it means the |
| 109 | * installing process should allocate the fd as normal. |
| 110 | * @flags: The flags for the new file descriptor. At the moment, only O_CLOEXEC |
| 111 | * is allowed. |
Rodrigo Campos | 0ae71c7 | 2021-05-17 12:39:07 -0700 | [diff] [blame] | 112 | * @ioctl_flags: The flags used for the seccomp_addfd ioctl. |
Kees Cook | 4682286 | 2023-08-17 12:32:15 -0700 | [diff] [blame] | 113 | * @setfd: whether or not SECCOMP_ADDFD_FLAG_SETFD was set during notify_addfd |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 114 | * @ret: The return value of the installing process. It is set to the fd num |
| 115 | * upon success (>= 0). |
| 116 | * @completion: Indicates that the installing process has completed fd |
| 117 | * installation, or gone away (either due to successful |
| 118 | * reply, or signal) |
Kees Cook | 4682286 | 2023-08-17 12:32:15 -0700 | [diff] [blame] | 119 | * @list: list_head for chaining seccomp_kaddfd together. |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 120 | * |
| 121 | */ |
| 122 | struct seccomp_kaddfd { |
| 123 | struct file *file; |
| 124 | int fd; |
| 125 | unsigned int flags; |
Rodrigo Campos | 0ae71c7 | 2021-05-17 12:39:07 -0700 | [diff] [blame] | 126 | __u32 ioctl_flags; |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 127 | |
Christoph Hellwig | 42eb0d5 | 2021-03-25 09:22:09 +0100 | [diff] [blame] | 128 | union { |
| 129 | bool setfd; |
| 130 | /* To only be set on reply */ |
| 131 | int ret; |
| 132 | }; |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 133 | struct completion completion; |
| 134 | struct list_head list; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 135 | }; |
| 136 | |
| 137 | /** |
| 138 | * struct notification - container for seccomp userspace notifications. Since |
| 139 | * most seccomp filters will not have notification listeners attached and this |
| 140 | * structure is fairly large, we store the notification-specific stuff in a |
| 141 | * separate structure. |
| 142 | * |
Kees Cook | 4682286 | 2023-08-17 12:32:15 -0700 | [diff] [blame] | 143 | * @requests: A semaphore that users of this notification can wait on for |
| 144 | * changes. Actual reads and writes are still controlled with |
| 145 | * filter->notify_lock. |
| 146 | * @flags: A set of SECCOMP_USER_NOTIF_FD_* flags. |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 147 | * @next_id: The id of the next request. |
| 148 | * @notifications: A list of struct seccomp_knotif elements. |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 149 | */ |
Andrei Vagin | 48a1084 | 2023-03-07 23:31:59 -0800 | [diff] [blame] | 150 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 151 | struct notification { |
Andrei Vagin | 4943b66 | 2023-03-07 23:31:56 -0800 | [diff] [blame] | 152 | atomic_t requests; |
Andrei Vagin | 48a1084 | 2023-03-07 23:31:59 -0800 | [diff] [blame] | 153 | u32 flags; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 154 | u64 next_id; |
| 155 | struct list_head notifications; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 156 | }; |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 157 | |
YiFei Zhu | f9d480b | 2020-10-11 10:47:42 -0500 | [diff] [blame] | 158 | #ifdef SECCOMP_ARCH_NATIVE |
| 159 | /** |
| 160 | * struct action_cache - per-filter cache of seccomp actions per |
| 161 | * arch/syscall pair |
| 162 | * |
| 163 | * @allow_native: A bitmap where each bit represents whether the |
| 164 | * filter will always allow the syscall, for the |
| 165 | * native architecture. |
| 166 | * @allow_compat: A bitmap where each bit represents whether the |
| 167 | * filter will always allow the syscall, for the |
| 168 | * compat architecture. |
| 169 | */ |
| 170 | struct action_cache { |
| 171 | DECLARE_BITMAP(allow_native, SECCOMP_ARCH_NATIVE_NR); |
| 172 | #ifdef SECCOMP_ARCH_COMPAT |
| 173 | DECLARE_BITMAP(allow_compat, SECCOMP_ARCH_COMPAT_NR); |
| 174 | #endif |
| 175 | }; |
| 176 | #else |
| 177 | struct action_cache { }; |
| 178 | |
| 179 | static inline bool seccomp_cache_check_allow(const struct seccomp_filter *sfilter, |
| 180 | const struct seccomp_data *sd) |
| 181 | { |
| 182 | return false; |
| 183 | } |
YiFei Zhu | 8e01b51 | 2020-10-11 10:47:43 -0500 | [diff] [blame] | 184 | |
| 185 | static inline void seccomp_cache_prepare(struct seccomp_filter *sfilter) |
| 186 | { |
| 187 | } |
YiFei Zhu | f9d480b | 2020-10-11 10:47:42 -0500 | [diff] [blame] | 188 | #endif /* SECCOMP_ARCH_NATIVE */ |
| 189 | |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 190 | /** |
| 191 | * struct seccomp_filter - container for seccomp BPF programs |
| 192 | * |
Christian Brauner | b707dde | 2020-05-31 13:50:28 +0200 | [diff] [blame] | 193 | * @refs: Reference count to manage the object lifetime. |
| 194 | * A filter's reference count is incremented for each directly |
| 195 | * attached task, once for the dependent filter, and if |
| 196 | * requested for the user notifier. When @refs reaches zero, |
| 197 | * the filter can be freed. |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 198 | * @users: A filter's @users count is incremented for each directly |
| 199 | * attached task (filter installation, fork(), thread_sync), |
| 200 | * and once for the dependent filter (tracked in filter->prev). |
| 201 | * When it reaches zero it indicates that no direct or indirect |
| 202 | * users of that filter exist. No new tasks can get associated with |
| 203 | * this filter after reaching 0. The @users count is always smaller |
| 204 | * or equal to @refs. Hence, reaching 0 for @users does not mean |
| 205 | * the filter can be freed. |
YiFei Zhu | 8e01b51 | 2020-10-11 10:47:43 -0500 | [diff] [blame] | 206 | * @cache: cache of arch/syscall mappings to actions |
Tyler Hicks | e66a399 | 2017-08-11 04:33:56 +0000 | [diff] [blame] | 207 | * @log: true if all actions except for SECCOMP_RET_ALLOW should be logged |
Sargun Dhillon | c2aa2df | 2022-05-03 01:09:56 -0700 | [diff] [blame] | 208 | * @wait_killable_recv: Put notifying process in killable state once the |
| 209 | * notification is received by the userspace listener. |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 210 | * @prev: points to a previously installed, or inherited, filter |
Mickaël Salaün | 285fdfc | 2016-09-20 19:39:47 +0200 | [diff] [blame] | 211 | * @prog: the BPF program to evaluate |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 212 | * @notif: the struct that holds all notification related information |
| 213 | * @notify_lock: A lock for all notification-related accesses. |
Christian Brauner | 76194c4 | 2020-06-01 11:50:07 -0700 | [diff] [blame] | 214 | * @wqh: A wait queue for poll if a notifier is in use. |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 215 | * |
| 216 | * seccomp_filter objects are organized in a tree linked via the @prev |
| 217 | * pointer. For any task, it appears to be a singly-linked list starting |
| 218 | * with current->seccomp.filter, the most recently attached or inherited filter. |
| 219 | * However, multiple filters may share a @prev node, by way of fork(), which |
| 220 | * results in a unidirectional tree existing in memory. This is similar to |
| 221 | * how namespaces work. |
| 222 | * |
| 223 | * seccomp_filter objects should never be modified after being attached |
Christian Brauner | b707dde | 2020-05-31 13:50:28 +0200 | [diff] [blame] | 224 | * to a task_struct (other than @refs). |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 225 | */ |
| 226 | struct seccomp_filter { |
Christian Brauner | b707dde | 2020-05-31 13:50:28 +0200 | [diff] [blame] | 227 | refcount_t refs; |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 228 | refcount_t users; |
Tyler Hicks | e66a399 | 2017-08-11 04:33:56 +0000 | [diff] [blame] | 229 | bool log; |
Sargun Dhillon | c2aa2df | 2022-05-03 01:09:56 -0700 | [diff] [blame] | 230 | bool wait_killable_recv; |
YiFei Zhu | 8e01b51 | 2020-10-11 10:47:43 -0500 | [diff] [blame] | 231 | struct action_cache cache; |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 232 | struct seccomp_filter *prev; |
Alexei Starovoitov | 7ae457c | 2014-07-30 20:34:16 -0700 | [diff] [blame] | 233 | struct bpf_prog *prog; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 234 | struct notification *notif; |
| 235 | struct mutex notify_lock; |
Christian Brauner | 76194c4 | 2020-06-01 11:50:07 -0700 | [diff] [blame] | 236 | wait_queue_head_t wqh; |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 237 | }; |
| 238 | |
| 239 | /* Limit any path through the tree to 256KB worth of instructions. */ |
| 240 | #define MAX_INSNS_PER_PATH ((1 << 18) / sizeof(struct sock_filter)) |
| 241 | |
Alexei Starovoitov | bd4cf0e | 2014-03-28 18:58:25 +0100 | [diff] [blame] | 242 | /* |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 243 | * Endianness is explicitly ignored and left for BPF program authors to manage |
| 244 | * as per the specific architecture. |
| 245 | */ |
Alexei Starovoitov | bd4cf0e | 2014-03-28 18:58:25 +0100 | [diff] [blame] | 246 | static void populate_seccomp_data(struct seccomp_data *sd) |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 247 | { |
Denis Efremov | 2d9ca26 | 2020-08-24 15:59:21 +0300 | [diff] [blame] | 248 | /* |
| 249 | * Instead of using current_pt_reg(), we're already doing the work |
| 250 | * to safely fetch "current", so just use "task" everywhere below. |
| 251 | */ |
Alexei Starovoitov | bd4cf0e | 2014-03-28 18:58:25 +0100 | [diff] [blame] | 252 | struct task_struct *task = current; |
| 253 | struct pt_regs *regs = task_pt_regs(task); |
Daniel Borkmann | 2eac764 | 2014-04-14 21:02:59 +0200 | [diff] [blame] | 254 | unsigned long args[6]; |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 255 | |
Alexei Starovoitov | bd4cf0e | 2014-03-28 18:58:25 +0100 | [diff] [blame] | 256 | sd->nr = syscall_get_nr(task, regs); |
Dmitry V. Levin | 16add41 | 2019-03-18 02:30:18 +0300 | [diff] [blame] | 257 | sd->arch = syscall_get_arch(task); |
Steven Rostedt (Red Hat) | b35f549 | 2016-11-07 16:26:37 -0500 | [diff] [blame] | 258 | syscall_get_arguments(task, regs, args); |
Daniel Borkmann | 2eac764 | 2014-04-14 21:02:59 +0200 | [diff] [blame] | 259 | sd->args[0] = args[0]; |
| 260 | sd->args[1] = args[1]; |
| 261 | sd->args[2] = args[2]; |
| 262 | sd->args[3] = args[3]; |
| 263 | sd->args[4] = args[4]; |
| 264 | sd->args[5] = args[5]; |
Alexei Starovoitov | bd4cf0e | 2014-03-28 18:58:25 +0100 | [diff] [blame] | 265 | sd->instruction_pointer = KSTK_EIP(task); |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 266 | } |
| 267 | |
| 268 | /** |
| 269 | * seccomp_check_filter - verify seccomp filter code |
| 270 | * @filter: filter to verify |
| 271 | * @flen: length of filter |
| 272 | * |
Alexei Starovoitov | 4df95ff | 2014-07-30 20:34:14 -0700 | [diff] [blame] | 273 | * Takes a previously checked filter (by bpf_check_classic) and |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 274 | * redirects all filter code that loads struct sk_buff data |
| 275 | * and related data through seccomp_bpf_load. It also |
| 276 | * enforces length and alignment checking of those loads. |
| 277 | * |
| 278 | * Returns 0 if the rule set is legal or -EINVAL if not. |
| 279 | */ |
| 280 | static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen) |
| 281 | { |
| 282 | int pc; |
| 283 | for (pc = 0; pc < flen; pc++) { |
| 284 | struct sock_filter *ftest = &filter[pc]; |
| 285 | u16 code = ftest->code; |
| 286 | u32 k = ftest->k; |
| 287 | |
| 288 | switch (code) { |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 289 | case BPF_LD | BPF_W | BPF_ABS: |
Alexei Starovoitov | bd4cf0e | 2014-03-28 18:58:25 +0100 | [diff] [blame] | 290 | ftest->code = BPF_LDX | BPF_W | BPF_ABS; |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 291 | /* 32-bit aligned and not out of bounds. */ |
| 292 | if (k >= sizeof(struct seccomp_data) || k & 3) |
| 293 | return -EINVAL; |
| 294 | continue; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 295 | case BPF_LD | BPF_W | BPF_LEN: |
Alexei Starovoitov | bd4cf0e | 2014-03-28 18:58:25 +0100 | [diff] [blame] | 296 | ftest->code = BPF_LD | BPF_IMM; |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 297 | ftest->k = sizeof(struct seccomp_data); |
| 298 | continue; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 299 | case BPF_LDX | BPF_W | BPF_LEN: |
Alexei Starovoitov | bd4cf0e | 2014-03-28 18:58:25 +0100 | [diff] [blame] | 300 | ftest->code = BPF_LDX | BPF_IMM; |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 301 | ftest->k = sizeof(struct seccomp_data); |
| 302 | continue; |
| 303 | /* Explicitly include allowed calls. */ |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 304 | case BPF_RET | BPF_K: |
| 305 | case BPF_RET | BPF_A: |
| 306 | case BPF_ALU | BPF_ADD | BPF_K: |
| 307 | case BPF_ALU | BPF_ADD | BPF_X: |
| 308 | case BPF_ALU | BPF_SUB | BPF_K: |
| 309 | case BPF_ALU | BPF_SUB | BPF_X: |
| 310 | case BPF_ALU | BPF_MUL | BPF_K: |
| 311 | case BPF_ALU | BPF_MUL | BPF_X: |
| 312 | case BPF_ALU | BPF_DIV | BPF_K: |
| 313 | case BPF_ALU | BPF_DIV | BPF_X: |
| 314 | case BPF_ALU | BPF_AND | BPF_K: |
| 315 | case BPF_ALU | BPF_AND | BPF_X: |
| 316 | case BPF_ALU | BPF_OR | BPF_K: |
| 317 | case BPF_ALU | BPF_OR | BPF_X: |
| 318 | case BPF_ALU | BPF_XOR | BPF_K: |
| 319 | case BPF_ALU | BPF_XOR | BPF_X: |
| 320 | case BPF_ALU | BPF_LSH | BPF_K: |
| 321 | case BPF_ALU | BPF_LSH | BPF_X: |
| 322 | case BPF_ALU | BPF_RSH | BPF_K: |
| 323 | case BPF_ALU | BPF_RSH | BPF_X: |
| 324 | case BPF_ALU | BPF_NEG: |
| 325 | case BPF_LD | BPF_IMM: |
| 326 | case BPF_LDX | BPF_IMM: |
| 327 | case BPF_MISC | BPF_TAX: |
| 328 | case BPF_MISC | BPF_TXA: |
| 329 | case BPF_LD | BPF_MEM: |
| 330 | case BPF_LDX | BPF_MEM: |
| 331 | case BPF_ST: |
| 332 | case BPF_STX: |
| 333 | case BPF_JMP | BPF_JA: |
| 334 | case BPF_JMP | BPF_JEQ | BPF_K: |
| 335 | case BPF_JMP | BPF_JEQ | BPF_X: |
| 336 | case BPF_JMP | BPF_JGE | BPF_K: |
| 337 | case BPF_JMP | BPF_JGE | BPF_X: |
| 338 | case BPF_JMP | BPF_JGT | BPF_K: |
| 339 | case BPF_JMP | BPF_JGT | BPF_X: |
| 340 | case BPF_JMP | BPF_JSET | BPF_K: |
| 341 | case BPF_JMP | BPF_JSET | BPF_X: |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 342 | continue; |
| 343 | default: |
| 344 | return -EINVAL; |
| 345 | } |
| 346 | } |
| 347 | return 0; |
| 348 | } |
| 349 | |
YiFei Zhu | f9d480b | 2020-10-11 10:47:42 -0500 | [diff] [blame] | 350 | #ifdef SECCOMP_ARCH_NATIVE |
| 351 | static inline bool seccomp_cache_check_allow_bitmap(const void *bitmap, |
| 352 | size_t bitmap_size, |
| 353 | int syscall_nr) |
| 354 | { |
| 355 | if (unlikely(syscall_nr < 0 || syscall_nr >= bitmap_size)) |
| 356 | return false; |
| 357 | syscall_nr = array_index_nospec(syscall_nr, bitmap_size); |
| 358 | |
| 359 | return test_bit(syscall_nr, bitmap); |
| 360 | } |
| 361 | |
| 362 | /** |
| 363 | * seccomp_cache_check_allow - lookup seccomp cache |
| 364 | * @sfilter: The seccomp filter |
| 365 | * @sd: The seccomp data to lookup the cache with |
| 366 | * |
| 367 | * Returns true if the seccomp_data is cached and allowed. |
| 368 | */ |
| 369 | static inline bool seccomp_cache_check_allow(const struct seccomp_filter *sfilter, |
| 370 | const struct seccomp_data *sd) |
| 371 | { |
| 372 | int syscall_nr = sd->nr; |
| 373 | const struct action_cache *cache = &sfilter->cache; |
| 374 | |
| 375 | #ifndef SECCOMP_ARCH_COMPAT |
| 376 | /* A native-only architecture doesn't need to check sd->arch. */ |
| 377 | return seccomp_cache_check_allow_bitmap(cache->allow_native, |
| 378 | SECCOMP_ARCH_NATIVE_NR, |
| 379 | syscall_nr); |
| 380 | #else |
| 381 | if (likely(sd->arch == SECCOMP_ARCH_NATIVE)) |
| 382 | return seccomp_cache_check_allow_bitmap(cache->allow_native, |
| 383 | SECCOMP_ARCH_NATIVE_NR, |
| 384 | syscall_nr); |
| 385 | if (likely(sd->arch == SECCOMP_ARCH_COMPAT)) |
| 386 | return seccomp_cache_check_allow_bitmap(cache->allow_compat, |
| 387 | SECCOMP_ARCH_COMPAT_NR, |
| 388 | syscall_nr); |
| 389 | #endif /* SECCOMP_ARCH_COMPAT */ |
| 390 | |
| 391 | WARN_ON_ONCE(true); |
| 392 | return false; |
| 393 | } |
| 394 | #endif /* SECCOMP_ARCH_NATIVE */ |
| 395 | |
Randy Dunlap | 0fb0624 | 2023-01-07 18:12:28 -0800 | [diff] [blame] | 396 | #define ACTION_ONLY(ret) ((s32)((ret) & (SECCOMP_RET_ACTION_FULL))) |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 397 | /** |
Mickaël Salaün | 285fdfc | 2016-09-20 19:39:47 +0200 | [diff] [blame] | 398 | * seccomp_run_filters - evaluates all seccomp filters against @sd |
| 399 | * @sd: optional seccomp data to be passed to filters |
Kees Cook | deb4de8 | 2017-08-02 15:00:40 -0700 | [diff] [blame] | 400 | * @match: stores struct seccomp_filter that resulted in the return value, |
| 401 | * unless filter returned SECCOMP_RET_ALLOW, in which case it will |
| 402 | * be unchanged. |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 403 | * |
| 404 | * Returns valid seccomp BPF response codes. |
| 405 | */ |
Kees Cook | deb4de8 | 2017-08-02 15:00:40 -0700 | [diff] [blame] | 406 | static u32 seccomp_run_filters(const struct seccomp_data *sd, |
| 407 | struct seccomp_filter **match) |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 408 | { |
Will Drewry | acf3b2c | 2012-04-12 16:47:59 -0500 | [diff] [blame] | 409 | u32 ret = SECCOMP_RET_ALLOW; |
Pranith Kumar | 8225d38 | 2014-11-21 10:06:01 -0500 | [diff] [blame] | 410 | /* Make sure cross-thread synced filter points somewhere sane. */ |
| 411 | struct seccomp_filter *f = |
Will Deacon | 506458e | 2017-10-24 11:22:48 +0100 | [diff] [blame] | 412 | READ_ONCE(current->seccomp.filter); |
Will Drewry | acf3b2c | 2012-04-12 16:47:59 -0500 | [diff] [blame] | 413 | |
| 414 | /* Ensure unexpected behavior doesn't result in failing open. */ |
Igor Stoppa | 0d42d73 | 2018-09-05 23:34:43 +0300 | [diff] [blame] | 415 | if (WARN_ON(f == NULL)) |
Kees Cook | 4d3b0b0 | 2017-08-11 13:01:39 -0700 | [diff] [blame] | 416 | return SECCOMP_RET_KILL_PROCESS; |
Will Drewry | acf3b2c | 2012-04-12 16:47:59 -0500 | [diff] [blame] | 417 | |
YiFei Zhu | f9d480b | 2020-10-11 10:47:42 -0500 | [diff] [blame] | 418 | if (seccomp_cache_check_allow(f, sd)) |
| 419 | return SECCOMP_RET_ALLOW; |
| 420 | |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 421 | /* |
| 422 | * All filters in the list are evaluated and the lowest BPF return |
Will Drewry | acf3b2c | 2012-04-12 16:47:59 -0500 | [diff] [blame] | 423 | * value always takes priority (ignoring the DATA). |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 424 | */ |
Kees Cook | 3ba2530 | 2014-06-27 15:01:35 -0700 | [diff] [blame] | 425 | for (; f; f = f->prev) { |
David Miller | 3d9f773c | 2020-02-24 15:01:43 +0100 | [diff] [blame] | 426 | u32 cur_ret = bpf_prog_run_pin_on_cpu(f->prog, sd); |
Alexei Starovoitov | 8f577ca | 2014-05-13 19:50:47 -0700 | [diff] [blame] | 427 | |
Kees Cook | 0466bdb | 2017-08-11 13:12:11 -0700 | [diff] [blame] | 428 | if (ACTION_ONLY(cur_ret) < ACTION_ONLY(ret)) { |
Will Drewry | acf3b2c | 2012-04-12 16:47:59 -0500 | [diff] [blame] | 429 | ret = cur_ret; |
Kees Cook | deb4de8 | 2017-08-02 15:00:40 -0700 | [diff] [blame] | 430 | *match = f; |
| 431 | } |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 432 | } |
| 433 | return ret; |
| 434 | } |
Kees Cook | 1f41b450 | 2014-06-25 15:38:02 -0700 | [diff] [blame] | 435 | #endif /* CONFIG_SECCOMP_FILTER */ |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 436 | |
Kees Cook | 1f41b450 | 2014-06-25 15:38:02 -0700 | [diff] [blame] | 437 | static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode) |
| 438 | { |
Guenter Roeck | 69f6a34 | 2014-08-10 20:50:30 -0700 | [diff] [blame] | 439 | assert_spin_locked(¤t->sighand->siglock); |
Kees Cook | dbd95212 | 2014-06-27 15:18:48 -0700 | [diff] [blame] | 440 | |
Kees Cook | 1f41b450 | 2014-06-25 15:38:02 -0700 | [diff] [blame] | 441 | if (current->seccomp.mode && current->seccomp.mode != seccomp_mode) |
| 442 | return false; |
| 443 | |
| 444 | return true; |
| 445 | } |
| 446 | |
Thomas Gleixner | 8bf37d8 | 2018-05-04 15:12:06 +0200 | [diff] [blame] | 447 | void __weak arch_seccomp_spec_mitigate(struct task_struct *task) { } |
Kees Cook | 5c30708 | 2018-05-01 15:07:31 -0700 | [diff] [blame] | 448 | |
Kees Cook | 3ba2530 | 2014-06-27 15:01:35 -0700 | [diff] [blame] | 449 | static inline void seccomp_assign_mode(struct task_struct *task, |
Kees Cook | 00a02d0 | 2018-05-03 14:56:12 -0700 | [diff] [blame] | 450 | unsigned long seccomp_mode, |
| 451 | unsigned long flags) |
Kees Cook | 1f41b450 | 2014-06-25 15:38:02 -0700 | [diff] [blame] | 452 | { |
Guenter Roeck | 69f6a34 | 2014-08-10 20:50:30 -0700 | [diff] [blame] | 453 | assert_spin_locked(&task->sighand->siglock); |
Kees Cook | dbd95212 | 2014-06-27 15:18:48 -0700 | [diff] [blame] | 454 | |
Kees Cook | 3ba2530 | 2014-06-27 15:01:35 -0700 | [diff] [blame] | 455 | task->seccomp.mode = seccomp_mode; |
| 456 | /* |
Gabriel Krisman Bertazi | 23d67a5 | 2020-11-16 12:42:00 -0500 | [diff] [blame] | 457 | * Make sure SYSCALL_WORK_SECCOMP cannot be set before the mode (and |
Kees Cook | 3ba2530 | 2014-06-27 15:01:35 -0700 | [diff] [blame] | 458 | * filter) is set. |
| 459 | */ |
| 460 | smp_mb__before_atomic(); |
Kees Cook | 00a02d0 | 2018-05-03 14:56:12 -0700 | [diff] [blame] | 461 | /* Assume default seccomp processes want spec flaw mitigation. */ |
| 462 | if ((flags & SECCOMP_FILTER_FLAG_SPEC_ALLOW) == 0) |
Thomas Gleixner | 8bf37d8 | 2018-05-04 15:12:06 +0200 | [diff] [blame] | 463 | arch_seccomp_spec_mitigate(task); |
Gabriel Krisman Bertazi | 23d67a5 | 2020-11-16 12:42:00 -0500 | [diff] [blame] | 464 | set_task_syscall_work(task, SECCOMP); |
Kees Cook | 1f41b450 | 2014-06-25 15:38:02 -0700 | [diff] [blame] | 465 | } |
| 466 | |
| 467 | #ifdef CONFIG_SECCOMP_FILTER |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 468 | /* Returns 1 if the parent is an ancestor of the child. */ |
| 469 | static int is_ancestor(struct seccomp_filter *parent, |
| 470 | struct seccomp_filter *child) |
| 471 | { |
| 472 | /* NULL is the root ancestor. */ |
| 473 | if (parent == NULL) |
| 474 | return 1; |
| 475 | for (; child; child = child->prev) |
| 476 | if (child == parent) |
| 477 | return 1; |
| 478 | return 0; |
| 479 | } |
| 480 | |
| 481 | /** |
| 482 | * seccomp_can_sync_threads: checks if all threads can be synchronized |
| 483 | * |
| 484 | * Expects sighand and cred_guard_mutex locks to be held. |
| 485 | * |
| 486 | * Returns 0 on success, -ve on error, or the pid of a thread which was |
Tycho Andersen | 6beff00 | 2019-03-06 13:14:12 -0700 | [diff] [blame] | 487 | * either not in the correct seccomp mode or did not have an ancestral |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 488 | * seccomp filter. |
| 489 | */ |
| 490 | static inline pid_t seccomp_can_sync_threads(void) |
| 491 | { |
| 492 | struct task_struct *thread, *caller; |
| 493 | |
| 494 | BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex)); |
Guenter Roeck | 69f6a34 | 2014-08-10 20:50:30 -0700 | [diff] [blame] | 495 | assert_spin_locked(¤t->sighand->siglock); |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 496 | |
| 497 | /* Validate all threads being eligible for synchronization. */ |
| 498 | caller = current; |
| 499 | for_each_thread(caller, thread) { |
| 500 | pid_t failed; |
| 501 | |
| 502 | /* Skip current, since it is initiating the sync. */ |
| 503 | if (thread == caller) |
| 504 | continue; |
Andrei Vagin | bfafe5e | 2024-06-28 02:10:12 +0000 | [diff] [blame] | 505 | /* Skip exited threads. */ |
| 506 | if (thread->flags & PF_EXITING) |
| 507 | continue; |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 508 | |
| 509 | if (thread->seccomp.mode == SECCOMP_MODE_DISABLED || |
| 510 | (thread->seccomp.mode == SECCOMP_MODE_FILTER && |
| 511 | is_ancestor(thread->seccomp.filter, |
| 512 | caller->seccomp.filter))) |
| 513 | continue; |
| 514 | |
| 515 | /* Return the first thread that cannot be synchronized. */ |
| 516 | failed = task_pid_vnr(thread); |
| 517 | /* If the pid cannot be resolved, then return -ESRCH */ |
Igor Stoppa | 0d42d73 | 2018-09-05 23:34:43 +0300 | [diff] [blame] | 518 | if (WARN_ON(failed == 0)) |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 519 | failed = -ESRCH; |
| 520 | return failed; |
| 521 | } |
| 522 | |
| 523 | return 0; |
| 524 | } |
| 525 | |
Christian Brauner | 3a15fb6 | 2020-05-31 13:50:29 +0200 | [diff] [blame] | 526 | static inline void seccomp_filter_free(struct seccomp_filter *filter) |
| 527 | { |
| 528 | if (filter) { |
| 529 | bpf_prog_destroy(filter->prog); |
| 530 | kfree(filter); |
| 531 | } |
| 532 | } |
| 533 | |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 534 | static void __seccomp_filter_orphan(struct seccomp_filter *orig) |
| 535 | { |
| 536 | while (orig && refcount_dec_and_test(&orig->users)) { |
| 537 | if (waitqueue_active(&orig->wqh)) |
| 538 | wake_up_poll(&orig->wqh, EPOLLHUP); |
| 539 | orig = orig->prev; |
| 540 | } |
| 541 | } |
| 542 | |
Christian Brauner | 3a15fb6 | 2020-05-31 13:50:29 +0200 | [diff] [blame] | 543 | static void __put_seccomp_filter(struct seccomp_filter *orig) |
| 544 | { |
| 545 | /* Clean up single-reference branches iteratively. */ |
| 546 | while (orig && refcount_dec_and_test(&orig->refs)) { |
| 547 | struct seccomp_filter *freeme = orig; |
| 548 | orig = orig->prev; |
| 549 | seccomp_filter_free(freeme); |
| 550 | } |
| 551 | } |
| 552 | |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 553 | static void __seccomp_filter_release(struct seccomp_filter *orig) |
| 554 | { |
| 555 | /* Notify about any unused filters in the task's former filter tree. */ |
| 556 | __seccomp_filter_orphan(orig); |
| 557 | /* Finally drop all references to the task's former tree. */ |
| 558 | __put_seccomp_filter(orig); |
| 559 | } |
| 560 | |
Christian Brauner | 3a15fb6 | 2020-05-31 13:50:29 +0200 | [diff] [blame] | 561 | /** |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 562 | * seccomp_filter_release - Detach the task from its filter tree, |
| 563 | * drop its reference count, and notify |
| 564 | * about unused filters |
Christian Brauner | 3a15fb6 | 2020-05-31 13:50:29 +0200 | [diff] [blame] | 565 | * |
Kees Cook | 4682286 | 2023-08-17 12:32:15 -0700 | [diff] [blame] | 566 | * @tsk: task the filter should be released from. |
| 567 | * |
Christian Brauner | 3a15fb6 | 2020-05-31 13:50:29 +0200 | [diff] [blame] | 568 | * This function should only be called when the task is exiting as |
Andrei Vagin | bfafe5e | 2024-06-28 02:10:12 +0000 | [diff] [blame] | 569 | * it detaches it from its filter tree. PF_EXITING has to be set |
| 570 | * for the task. |
Christian Brauner | 3a15fb6 | 2020-05-31 13:50:29 +0200 | [diff] [blame] | 571 | */ |
| 572 | void seccomp_filter_release(struct task_struct *tsk) |
| 573 | { |
Andrei Vagin | bfafe5e | 2024-06-28 02:10:12 +0000 | [diff] [blame] | 574 | struct seccomp_filter *orig; |
Christian Brauner | 3a15fb6 | 2020-05-31 13:50:29 +0200 | [diff] [blame] | 575 | |
Andrei Vagin | bfafe5e | 2024-06-28 02:10:12 +0000 | [diff] [blame] | 576 | if (WARN_ON((tsk->flags & PF_EXITING) == 0)) |
| 577 | return; |
YiFei Zhu | 0d8315d | 2020-11-11 07:33:54 -0600 | [diff] [blame] | 578 | |
Andrei Vagin | bfafe5e | 2024-06-28 02:10:12 +0000 | [diff] [blame] | 579 | spin_lock_irq(&tsk->sighand->siglock); |
| 580 | orig = tsk->seccomp.filter; |
Christian Brauner | 3a15fb6 | 2020-05-31 13:50:29 +0200 | [diff] [blame] | 581 | /* Detach task from its filter tree. */ |
| 582 | tsk->seccomp.filter = NULL; |
Andrei Vagin | bfafe5e | 2024-06-28 02:10:12 +0000 | [diff] [blame] | 583 | spin_unlock_irq(&tsk->sighand->siglock); |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 584 | __seccomp_filter_release(orig); |
Christian Brauner | 3a15fb6 | 2020-05-31 13:50:29 +0200 | [diff] [blame] | 585 | } |
| 586 | |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 587 | /** |
| 588 | * seccomp_sync_threads: sets all threads to use current's filter |
| 589 | * |
Kees Cook | 4682286 | 2023-08-17 12:32:15 -0700 | [diff] [blame] | 590 | * @flags: SECCOMP_FILTER_FLAG_* flags to set during sync. |
| 591 | * |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 592 | * Expects sighand and cred_guard_mutex locks to be held, and for |
| 593 | * seccomp_can_sync_threads() to have returned success already |
| 594 | * without dropping the locks. |
| 595 | * |
| 596 | */ |
Kees Cook | 00a02d0 | 2018-05-03 14:56:12 -0700 | [diff] [blame] | 597 | static inline void seccomp_sync_threads(unsigned long flags) |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 598 | { |
| 599 | struct task_struct *thread, *caller; |
| 600 | |
| 601 | BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex)); |
Guenter Roeck | 69f6a34 | 2014-08-10 20:50:30 -0700 | [diff] [blame] | 602 | assert_spin_locked(¤t->sighand->siglock); |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 603 | |
| 604 | /* Synchronize all threads. */ |
| 605 | caller = current; |
| 606 | for_each_thread(caller, thread) { |
| 607 | /* Skip current, since it needs no changes. */ |
| 608 | if (thread == caller) |
| 609 | continue; |
| 610 | |
Andrei Vagin | bfafe5e | 2024-06-28 02:10:12 +0000 | [diff] [blame] | 611 | /* |
| 612 | * Skip exited threads. seccomp_filter_release could have |
| 613 | * been already called for this task. |
| 614 | */ |
| 615 | if (thread->flags & PF_EXITING) |
| 616 | continue; |
| 617 | |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 618 | /* Get a task reference for the new leaf node. */ |
| 619 | get_seccomp_filter(caller); |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 620 | |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 621 | /* |
| 622 | * Drop the task reference to the shared ancestor since |
| 623 | * current's path will hold a reference. (This also |
| 624 | * allows a put before the assignment.) |
| 625 | */ |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 626 | __seccomp_filter_release(thread->seccomp.filter); |
| 627 | |
| 628 | /* Make our new filter tree visible. */ |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 629 | smp_store_release(&thread->seccomp.filter, |
| 630 | caller->seccomp.filter); |
Kees Cook | c818c03 | 2020-05-13 14:11:26 -0700 | [diff] [blame] | 631 | atomic_set(&thread->seccomp.filter_count, |
Hsuan-Chi Kuo | b4d8a58 | 2021-03-04 17:37:08 -0600 | [diff] [blame] | 632 | atomic_read(&caller->seccomp.filter_count)); |
Jann Horn | 103502a | 2015-12-26 06:00:48 +0100 | [diff] [blame] | 633 | |
| 634 | /* |
| 635 | * Don't let an unprivileged task work around |
| 636 | * the no_new_privs restriction by creating |
| 637 | * a thread that sets it up, enters seccomp, |
| 638 | * then dies. |
| 639 | */ |
| 640 | if (task_no_new_privs(caller)) |
| 641 | task_set_no_new_privs(thread); |
| 642 | |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 643 | /* |
| 644 | * Opt the other thread into seccomp if needed. |
| 645 | * As threads are considered to be trust-realm |
| 646 | * equivalent (see ptrace_may_access), it is safe to |
| 647 | * allow one thread to transition the other. |
| 648 | */ |
Jann Horn | 103502a | 2015-12-26 06:00:48 +0100 | [diff] [blame] | 649 | if (thread->seccomp.mode == SECCOMP_MODE_DISABLED) |
Kees Cook | 00a02d0 | 2018-05-03 14:56:12 -0700 | [diff] [blame] | 650 | seccomp_assign_mode(thread, SECCOMP_MODE_FILTER, |
| 651 | flags); |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 652 | } |
| 653 | } |
| 654 | |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 655 | /** |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 656 | * seccomp_prepare_filter: Prepares a seccomp filter for use. |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 657 | * @fprog: BPF program to install |
| 658 | * |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 659 | * Returns filter on success or an ERR_PTR on failure. |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 660 | */ |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 661 | static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog) |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 662 | { |
Daniel Borkmann | ac67eb2 | 2015-05-06 16:12:30 +0200 | [diff] [blame] | 663 | struct seccomp_filter *sfilter; |
| 664 | int ret; |
YiFei Zhu | 8e01b51 | 2020-10-11 10:47:43 -0500 | [diff] [blame] | 665 | const bool save_orig = |
| 666 | #if defined(CONFIG_CHECKPOINT_RESTORE) || defined(SECCOMP_ARCH_NATIVE) |
| 667 | true; |
| 668 | #else |
| 669 | false; |
| 670 | #endif |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 671 | |
| 672 | if (fprog->len == 0 || fprog->len > BPF_MAXINSNS) |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 673 | return ERR_PTR(-EINVAL); |
Nicolas Schichan | d9e12f42e | 2015-05-06 16:12:28 +0200 | [diff] [blame] | 674 | |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 675 | BUG_ON(INT_MAX / fprog->len < sizeof(struct sock_filter)); |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 676 | |
| 677 | /* |
Fabian Frederick | 119ce5c | 2014-06-06 14:37:53 -0700 | [diff] [blame] | 678 | * Installing a seccomp filter requires that the task has |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 679 | * CAP_SYS_ADMIN in its namespace or be running with no_new_privs. |
| 680 | * This avoids scenarios where unprivileged tasks can affect the |
| 681 | * behavior of privileged children. |
| 682 | */ |
Kees Cook | 1d4457f | 2014-05-21 15:23:46 -0700 | [diff] [blame] | 683 | if (!task_no_new_privs(current) && |
Mickaël Salaün | fb14528 | 2020-10-30 13:38:49 +0100 | [diff] [blame] | 684 | !ns_capable_noaudit(current_user_ns(), CAP_SYS_ADMIN)) |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 685 | return ERR_PTR(-EACCES); |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 686 | |
Alexei Starovoitov | bd4cf0e | 2014-03-28 18:58:25 +0100 | [diff] [blame] | 687 | /* Allocate a new seccomp_filter */ |
Daniel Borkmann | ac67eb2 | 2015-05-06 16:12:30 +0200 | [diff] [blame] | 688 | sfilter = kzalloc(sizeof(*sfilter), GFP_KERNEL | __GFP_NOWARN); |
| 689 | if (!sfilter) |
Nicolas Schichan | d9e12f42e | 2015-05-06 16:12:28 +0200 | [diff] [blame] | 690 | return ERR_PTR(-ENOMEM); |
Daniel Borkmann | ac67eb2 | 2015-05-06 16:12:30 +0200 | [diff] [blame] | 691 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 692 | mutex_init(&sfilter->notify_lock); |
Daniel Borkmann | ac67eb2 | 2015-05-06 16:12:30 +0200 | [diff] [blame] | 693 | ret = bpf_prog_create_from_user(&sfilter->prog, fprog, |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 694 | seccomp_check_filter, save_orig); |
Daniel Borkmann | ac67eb2 | 2015-05-06 16:12:30 +0200 | [diff] [blame] | 695 | if (ret < 0) { |
| 696 | kfree(sfilter); |
| 697 | return ERR_PTR(ret); |
Nicolas Schichan | d9e12f42e | 2015-05-06 16:12:28 +0200 | [diff] [blame] | 698 | } |
Alexei Starovoitov | bd4cf0e | 2014-03-28 18:58:25 +0100 | [diff] [blame] | 699 | |
Christian Brauner | b707dde | 2020-05-31 13:50:28 +0200 | [diff] [blame] | 700 | refcount_set(&sfilter->refs, 1); |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 701 | refcount_set(&sfilter->users, 1); |
Christian Brauner | 76194c4 | 2020-06-01 11:50:07 -0700 | [diff] [blame] | 702 | init_waitqueue_head(&sfilter->wqh); |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 703 | |
Daniel Borkmann | ac67eb2 | 2015-05-06 16:12:30 +0200 | [diff] [blame] | 704 | return sfilter; |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 705 | } |
| 706 | |
| 707 | /** |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 708 | * seccomp_prepare_user_filter - prepares a user-supplied sock_fprog |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 709 | * @user_filter: pointer to the user data containing a sock_fprog. |
| 710 | * |
| 711 | * Returns 0 on success and non-zero otherwise. |
| 712 | */ |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 713 | static struct seccomp_filter * |
| 714 | seccomp_prepare_user_filter(const char __user *user_filter) |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 715 | { |
| 716 | struct sock_fprog fprog; |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 717 | struct seccomp_filter *filter = ERR_PTR(-EFAULT); |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 718 | |
| 719 | #ifdef CONFIG_COMPAT |
Andy Lutomirski | 5c38065 | 2016-03-22 14:24:52 -0700 | [diff] [blame] | 720 | if (in_compat_syscall()) { |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 721 | struct compat_sock_fprog fprog32; |
| 722 | if (copy_from_user(&fprog32, user_filter, sizeof(fprog32))) |
| 723 | goto out; |
| 724 | fprog.len = fprog32.len; |
| 725 | fprog.filter = compat_ptr(fprog32.filter); |
| 726 | } else /* falls through to the if below. */ |
| 727 | #endif |
| 728 | if (copy_from_user(&fprog, user_filter, sizeof(fprog))) |
| 729 | goto out; |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 730 | filter = seccomp_prepare_filter(&fprog); |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 731 | out: |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 732 | return filter; |
| 733 | } |
| 734 | |
YiFei Zhu | 8e01b51 | 2020-10-11 10:47:43 -0500 | [diff] [blame] | 735 | #ifdef SECCOMP_ARCH_NATIVE |
| 736 | /** |
| 737 | * seccomp_is_const_allow - check if filter is constant allow with given data |
| 738 | * @fprog: The BPF programs |
| 739 | * @sd: The seccomp data to check against, only syscall number and arch |
| 740 | * number are considered constant. |
| 741 | */ |
| 742 | static bool seccomp_is_const_allow(struct sock_fprog_kern *fprog, |
| 743 | struct seccomp_data *sd) |
| 744 | { |
| 745 | unsigned int reg_value = 0; |
| 746 | unsigned int pc; |
| 747 | bool op_res; |
| 748 | |
| 749 | if (WARN_ON_ONCE(!fprog)) |
| 750 | return false; |
| 751 | |
| 752 | for (pc = 0; pc < fprog->len; pc++) { |
| 753 | struct sock_filter *insn = &fprog->filter[pc]; |
| 754 | u16 code = insn->code; |
| 755 | u32 k = insn->k; |
| 756 | |
| 757 | switch (code) { |
| 758 | case BPF_LD | BPF_W | BPF_ABS: |
| 759 | switch (k) { |
| 760 | case offsetof(struct seccomp_data, nr): |
| 761 | reg_value = sd->nr; |
| 762 | break; |
| 763 | case offsetof(struct seccomp_data, arch): |
| 764 | reg_value = sd->arch; |
| 765 | break; |
| 766 | default: |
| 767 | /* can't optimize (non-constant value load) */ |
| 768 | return false; |
| 769 | } |
| 770 | break; |
| 771 | case BPF_RET | BPF_K: |
| 772 | /* reached return with constant values only, check allow */ |
| 773 | return k == SECCOMP_RET_ALLOW; |
| 774 | case BPF_JMP | BPF_JA: |
| 775 | pc += insn->k; |
| 776 | break; |
| 777 | case BPF_JMP | BPF_JEQ | BPF_K: |
| 778 | case BPF_JMP | BPF_JGE | BPF_K: |
| 779 | case BPF_JMP | BPF_JGT | BPF_K: |
| 780 | case BPF_JMP | BPF_JSET | BPF_K: |
| 781 | switch (BPF_OP(code)) { |
| 782 | case BPF_JEQ: |
| 783 | op_res = reg_value == k; |
| 784 | break; |
| 785 | case BPF_JGE: |
| 786 | op_res = reg_value >= k; |
| 787 | break; |
| 788 | case BPF_JGT: |
| 789 | op_res = reg_value > k; |
| 790 | break; |
| 791 | case BPF_JSET: |
| 792 | op_res = !!(reg_value & k); |
| 793 | break; |
| 794 | default: |
| 795 | /* can't optimize (unknown jump) */ |
| 796 | return false; |
| 797 | } |
| 798 | |
| 799 | pc += op_res ? insn->jt : insn->jf; |
| 800 | break; |
| 801 | case BPF_ALU | BPF_AND | BPF_K: |
| 802 | reg_value &= k; |
| 803 | break; |
| 804 | default: |
| 805 | /* can't optimize (unknown insn) */ |
| 806 | return false; |
| 807 | } |
| 808 | } |
| 809 | |
| 810 | /* ran off the end of the filter?! */ |
| 811 | WARN_ON(1); |
| 812 | return false; |
| 813 | } |
| 814 | |
| 815 | static void seccomp_cache_prepare_bitmap(struct seccomp_filter *sfilter, |
| 816 | void *bitmap, const void *bitmap_prev, |
| 817 | size_t bitmap_size, int arch) |
| 818 | { |
| 819 | struct sock_fprog_kern *fprog = sfilter->prog->orig_prog; |
| 820 | struct seccomp_data sd; |
| 821 | int nr; |
| 822 | |
| 823 | if (bitmap_prev) { |
| 824 | /* The new filter must be as restrictive as the last. */ |
| 825 | bitmap_copy(bitmap, bitmap_prev, bitmap_size); |
| 826 | } else { |
| 827 | /* Before any filters, all syscalls are always allowed. */ |
| 828 | bitmap_fill(bitmap, bitmap_size); |
| 829 | } |
| 830 | |
| 831 | for (nr = 0; nr < bitmap_size; nr++) { |
| 832 | /* No bitmap change: not a cacheable action. */ |
| 833 | if (!test_bit(nr, bitmap)) |
| 834 | continue; |
| 835 | |
| 836 | sd.nr = nr; |
| 837 | sd.arch = arch; |
| 838 | |
| 839 | /* No bitmap change: continue to always allow. */ |
| 840 | if (seccomp_is_const_allow(fprog, &sd)) |
| 841 | continue; |
| 842 | |
| 843 | /* |
| 844 | * Not a cacheable action: always run filters. |
| 845 | * atomic clear_bit() not needed, filter not visible yet. |
| 846 | */ |
| 847 | __clear_bit(nr, bitmap); |
| 848 | } |
| 849 | } |
| 850 | |
| 851 | /** |
Cui GaoSheng | a3fc712 | 2021-03-30 23:07:24 -0400 | [diff] [blame] | 852 | * seccomp_cache_prepare - emulate the filter to find cacheable syscalls |
YiFei Zhu | 8e01b51 | 2020-10-11 10:47:43 -0500 | [diff] [blame] | 853 | * @sfilter: The seccomp filter |
| 854 | * |
| 855 | * Returns 0 if successful or -errno if error occurred. |
| 856 | */ |
| 857 | static void seccomp_cache_prepare(struct seccomp_filter *sfilter) |
| 858 | { |
| 859 | struct action_cache *cache = &sfilter->cache; |
| 860 | const struct action_cache *cache_prev = |
| 861 | sfilter->prev ? &sfilter->prev->cache : NULL; |
| 862 | |
| 863 | seccomp_cache_prepare_bitmap(sfilter, cache->allow_native, |
| 864 | cache_prev ? cache_prev->allow_native : NULL, |
| 865 | SECCOMP_ARCH_NATIVE_NR, |
| 866 | SECCOMP_ARCH_NATIVE); |
| 867 | |
| 868 | #ifdef SECCOMP_ARCH_COMPAT |
| 869 | seccomp_cache_prepare_bitmap(sfilter, cache->allow_compat, |
| 870 | cache_prev ? cache_prev->allow_compat : NULL, |
| 871 | SECCOMP_ARCH_COMPAT_NR, |
| 872 | SECCOMP_ARCH_COMPAT); |
| 873 | #endif /* SECCOMP_ARCH_COMPAT */ |
| 874 | } |
| 875 | #endif /* SECCOMP_ARCH_NATIVE */ |
| 876 | |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 877 | /** |
| 878 | * seccomp_attach_filter: validate and attach filter |
| 879 | * @flags: flags to change filter behavior |
| 880 | * @filter: seccomp filter to add to the current process |
| 881 | * |
Kees Cook | dbd95212 | 2014-06-27 15:18:48 -0700 | [diff] [blame] | 882 | * Caller must be holding current->sighand->siglock lock. |
| 883 | * |
Tycho Andersen | 7a0df7f | 2019-03-06 13:14:13 -0700 | [diff] [blame] | 884 | * Returns 0 on success, -ve on error, or |
| 885 | * - in TSYNC mode: the pid of a thread which was either not in the correct |
| 886 | * seccomp mode or did not have an ancestral seccomp filter |
| 887 | * - in NEW_LISTENER mode: the fd of the new listener |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 888 | */ |
| 889 | static long seccomp_attach_filter(unsigned int flags, |
| 890 | struct seccomp_filter *filter) |
| 891 | { |
| 892 | unsigned long total_insns; |
| 893 | struct seccomp_filter *walker; |
| 894 | |
Guenter Roeck | 69f6a34 | 2014-08-10 20:50:30 -0700 | [diff] [blame] | 895 | assert_spin_locked(¤t->sighand->siglock); |
Kees Cook | dbd95212 | 2014-06-27 15:18:48 -0700 | [diff] [blame] | 896 | |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 897 | /* Validate resulting filter length. */ |
| 898 | total_insns = filter->prog->len; |
| 899 | for (walker = current->seccomp.filter; walker; walker = walker->prev) |
| 900 | total_insns += walker->prog->len + 4; /* 4 instr penalty */ |
| 901 | if (total_insns > MAX_INSNS_PER_PATH) |
| 902 | return -ENOMEM; |
| 903 | |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 904 | /* If thread sync has been requested, check that it is possible. */ |
| 905 | if (flags & SECCOMP_FILTER_FLAG_TSYNC) { |
| 906 | int ret; |
| 907 | |
| 908 | ret = seccomp_can_sync_threads(); |
Tycho Andersen | 5189149 | 2020-03-04 11:05:17 -0700 | [diff] [blame] | 909 | if (ret) { |
| 910 | if (flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) |
| 911 | return -ESRCH; |
| 912 | else |
| 913 | return ret; |
| 914 | } |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 915 | } |
| 916 | |
Tyler Hicks | e66a399 | 2017-08-11 04:33:56 +0000 | [diff] [blame] | 917 | /* Set log flag, if present. */ |
| 918 | if (flags & SECCOMP_FILTER_FLAG_LOG) |
| 919 | filter->log = true; |
| 920 | |
Sargun Dhillon | c2aa2df | 2022-05-03 01:09:56 -0700 | [diff] [blame] | 921 | /* Set wait killable flag, if present. */ |
| 922 | if (flags & SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV) |
| 923 | filter->wait_killable_recv = true; |
| 924 | |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 925 | /* |
| 926 | * If there is an existing filter, make it the prev and don't drop its |
| 927 | * task reference. |
| 928 | */ |
| 929 | filter->prev = current->seccomp.filter; |
YiFei Zhu | 8e01b51 | 2020-10-11 10:47:43 -0500 | [diff] [blame] | 930 | seccomp_cache_prepare(filter); |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 931 | current->seccomp.filter = filter; |
Kees Cook | c818c03 | 2020-05-13 14:11:26 -0700 | [diff] [blame] | 932 | atomic_inc(¤t->seccomp.filter_count); |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 933 | |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 934 | /* Now that the new filter is in place, synchronize to all threads. */ |
| 935 | if (flags & SECCOMP_FILTER_FLAG_TSYNC) |
Kees Cook | 00a02d0 | 2018-05-03 14:56:12 -0700 | [diff] [blame] | 936 | seccomp_sync_threads(flags); |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 937 | |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 938 | return 0; |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 939 | } |
| 940 | |
Colin Ian King | 084f560 | 2017-09-29 14:26:48 +0100 | [diff] [blame] | 941 | static void __get_seccomp_filter(struct seccomp_filter *filter) |
Oleg Nesterov | 66a733e | 2017-09-27 09:25:30 -0600 | [diff] [blame] | 942 | { |
Christian Brauner | b707dde | 2020-05-31 13:50:28 +0200 | [diff] [blame] | 943 | refcount_inc(&filter->refs); |
Oleg Nesterov | 66a733e | 2017-09-27 09:25:30 -0600 | [diff] [blame] | 944 | } |
| 945 | |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 946 | /* get_seccomp_filter - increments the reference count of the filter on @tsk */ |
| 947 | void get_seccomp_filter(struct task_struct *tsk) |
| 948 | { |
| 949 | struct seccomp_filter *orig = tsk->seccomp.filter; |
| 950 | if (!orig) |
| 951 | return; |
Oleg Nesterov | 66a733e | 2017-09-27 09:25:30 -0600 | [diff] [blame] | 952 | __get_seccomp_filter(orig); |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 953 | refcount_inc(&orig->users); |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 954 | } |
| 955 | |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 956 | #endif /* CONFIG_SECCOMP_FILTER */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 957 | |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 958 | /* For use with seccomp_actions_logged */ |
Kees Cook | 4d3b0b0 | 2017-08-11 13:01:39 -0700 | [diff] [blame] | 959 | #define SECCOMP_LOG_KILL_PROCESS (1 << 0) |
| 960 | #define SECCOMP_LOG_KILL_THREAD (1 << 1) |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 961 | #define SECCOMP_LOG_TRAP (1 << 2) |
| 962 | #define SECCOMP_LOG_ERRNO (1 << 3) |
| 963 | #define SECCOMP_LOG_TRACE (1 << 4) |
Tyler Hicks | 59f5cf4 | 2017-08-11 04:33:57 +0000 | [diff] [blame] | 964 | #define SECCOMP_LOG_LOG (1 << 5) |
| 965 | #define SECCOMP_LOG_ALLOW (1 << 6) |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 966 | #define SECCOMP_LOG_USER_NOTIF (1 << 7) |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 967 | |
Kees Cook | 4d3b0b0 | 2017-08-11 13:01:39 -0700 | [diff] [blame] | 968 | static u32 seccomp_actions_logged = SECCOMP_LOG_KILL_PROCESS | |
| 969 | SECCOMP_LOG_KILL_THREAD | |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 970 | SECCOMP_LOG_TRAP | |
| 971 | SECCOMP_LOG_ERRNO | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 972 | SECCOMP_LOG_USER_NOTIF | |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 973 | SECCOMP_LOG_TRACE | |
Tyler Hicks | 59f5cf4 | 2017-08-11 04:33:57 +0000 | [diff] [blame] | 974 | SECCOMP_LOG_LOG; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 975 | |
Tyler Hicks | e66a399 | 2017-08-11 04:33:56 +0000 | [diff] [blame] | 976 | static inline void seccomp_log(unsigned long syscall, long signr, u32 action, |
| 977 | bool requested) |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 978 | { |
| 979 | bool log = false; |
| 980 | |
| 981 | switch (action) { |
| 982 | case SECCOMP_RET_ALLOW: |
Tyler Hicks | e66a399 | 2017-08-11 04:33:56 +0000 | [diff] [blame] | 983 | break; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 984 | case SECCOMP_RET_TRAP: |
Tyler Hicks | e66a399 | 2017-08-11 04:33:56 +0000 | [diff] [blame] | 985 | log = requested && seccomp_actions_logged & SECCOMP_LOG_TRAP; |
| 986 | break; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 987 | case SECCOMP_RET_ERRNO: |
Tyler Hicks | e66a399 | 2017-08-11 04:33:56 +0000 | [diff] [blame] | 988 | log = requested && seccomp_actions_logged & SECCOMP_LOG_ERRNO; |
| 989 | break; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 990 | case SECCOMP_RET_TRACE: |
Tyler Hicks | e66a399 | 2017-08-11 04:33:56 +0000 | [diff] [blame] | 991 | log = requested && seccomp_actions_logged & SECCOMP_LOG_TRACE; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 992 | break; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 993 | case SECCOMP_RET_USER_NOTIF: |
| 994 | log = requested && seccomp_actions_logged & SECCOMP_LOG_USER_NOTIF; |
| 995 | break; |
Tyler Hicks | 59f5cf4 | 2017-08-11 04:33:57 +0000 | [diff] [blame] | 996 | case SECCOMP_RET_LOG: |
| 997 | log = seccomp_actions_logged & SECCOMP_LOG_LOG; |
| 998 | break; |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 999 | case SECCOMP_RET_KILL_THREAD: |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 1000 | log = seccomp_actions_logged & SECCOMP_LOG_KILL_THREAD; |
Kees Cook | 4d3b0b0 | 2017-08-11 13:01:39 -0700 | [diff] [blame] | 1001 | break; |
| 1002 | case SECCOMP_RET_KILL_PROCESS: |
| 1003 | default: |
| 1004 | log = seccomp_actions_logged & SECCOMP_LOG_KILL_PROCESS; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 1005 | } |
| 1006 | |
| 1007 | /* |
Tyler Hicks | 326bee0 | 2018-05-04 01:08:15 +0000 | [diff] [blame] | 1008 | * Emit an audit message when the action is RET_KILL_*, RET_LOG, or the |
| 1009 | * FILTER_FLAG_LOG bit was set. The admin has the ability to silence |
| 1010 | * any action from being logged by removing the action name from the |
| 1011 | * seccomp_actions_logged sysctl. |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 1012 | */ |
Tyler Hicks | 326bee0 | 2018-05-04 01:08:15 +0000 | [diff] [blame] | 1013 | if (!log) |
| 1014 | return; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 1015 | |
Tyler Hicks | 326bee0 | 2018-05-04 01:08:15 +0000 | [diff] [blame] | 1016 | audit_seccomp(syscall, signr, action); |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 1017 | } |
| 1018 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1019 | /* |
| 1020 | * Secure computing mode 1 allows only read/write/exit/sigreturn. |
| 1021 | * To be fully secure this must be combined with rlimit |
| 1022 | * to limit the stack allocations too. |
| 1023 | */ |
Matt Redfearn | cb4253a | 2016-03-29 09:35:34 +0100 | [diff] [blame] | 1024 | static const int mode1_syscalls[] = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1025 | __NR_seccomp_read, __NR_seccomp_write, __NR_seccomp_exit, __NR_seccomp_sigreturn, |
Kees Cook | fe4bfff8 | 2020-06-19 12:20:15 -0700 | [diff] [blame] | 1026 | -1, /* negative terminated */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1027 | }; |
| 1028 | |
Andy Lutomirski | a4412fc | 2014-07-21 18:49:14 -0700 | [diff] [blame] | 1029 | static void __secure_computing_strict(int this_syscall) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1030 | { |
Kees Cook | fe4bfff8 | 2020-06-19 12:20:15 -0700 | [diff] [blame] | 1031 | const int *allowed_syscalls = mode1_syscalls; |
Andy Lutomirski | a4412fc | 2014-07-21 18:49:14 -0700 | [diff] [blame] | 1032 | #ifdef CONFIG_COMPAT |
Andy Lutomirski | 5c38065 | 2016-03-22 14:24:52 -0700 | [diff] [blame] | 1033 | if (in_compat_syscall()) |
Kees Cook | fe4bfff8 | 2020-06-19 12:20:15 -0700 | [diff] [blame] | 1034 | allowed_syscalls = get_compat_mode1_syscalls(); |
Andy Lutomirski | a4412fc | 2014-07-21 18:49:14 -0700 | [diff] [blame] | 1035 | #endif |
| 1036 | do { |
Kees Cook | fe4bfff8 | 2020-06-19 12:20:15 -0700 | [diff] [blame] | 1037 | if (*allowed_syscalls == this_syscall) |
Andy Lutomirski | a4412fc | 2014-07-21 18:49:14 -0700 | [diff] [blame] | 1038 | return; |
Kees Cook | fe4bfff8 | 2020-06-19 12:20:15 -0700 | [diff] [blame] | 1039 | } while (*++allowed_syscalls != -1); |
Andy Lutomirski | a4412fc | 2014-07-21 18:49:14 -0700 | [diff] [blame] | 1040 | |
| 1041 | #ifdef SECCOMP_DEBUG |
| 1042 | dump_stack(); |
| 1043 | #endif |
Kees Cook | 495ac30 | 2022-02-07 20:21:13 -0800 | [diff] [blame] | 1044 | current->seccomp.mode = SECCOMP_MODE_DEAD; |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 1045 | seccomp_log(this_syscall, SIGKILL, SECCOMP_RET_KILL_THREAD, true); |
Andy Lutomirski | a4412fc | 2014-07-21 18:49:14 -0700 | [diff] [blame] | 1046 | do_exit(SIGKILL); |
| 1047 | } |
| 1048 | |
| 1049 | #ifndef CONFIG_HAVE_ARCH_SECCOMP_FILTER |
| 1050 | void secure_computing_strict(int this_syscall) |
| 1051 | { |
| 1052 | int mode = current->seccomp.mode; |
| 1053 | |
Masahiro Yamada | 97f2645 | 2016-08-03 13:45:50 -0700 | [diff] [blame] | 1054 | if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) && |
Tycho Andersen | 13c4a90 | 2015-06-13 09:02:48 -0600 | [diff] [blame] | 1055 | unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) |
| 1056 | return; |
| 1057 | |
Kees Cook | 221272f | 2015-06-15 15:29:16 -0700 | [diff] [blame] | 1058 | if (mode == SECCOMP_MODE_DISABLED) |
Andy Lutomirski | a4412fc | 2014-07-21 18:49:14 -0700 | [diff] [blame] | 1059 | return; |
| 1060 | else if (mode == SECCOMP_MODE_STRICT) |
| 1061 | __secure_computing_strict(this_syscall); |
| 1062 | else |
| 1063 | BUG(); |
| 1064 | } |
| 1065 | #else |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1066 | |
| 1067 | #ifdef CONFIG_SECCOMP_FILTER |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1068 | static u64 seccomp_next_notify_id(struct seccomp_filter *filter) |
| 1069 | { |
| 1070 | /* |
| 1071 | * Note: overflow is ok here, the id just needs to be unique per |
| 1072 | * filter. |
| 1073 | */ |
| 1074 | lockdep_assert_held(&filter->notify_lock); |
| 1075 | return filter->notif->next_id++; |
| 1076 | } |
| 1077 | |
Rodrigo Campos | 0ae71c7 | 2021-05-17 12:39:07 -0700 | [diff] [blame] | 1078 | static void seccomp_handle_addfd(struct seccomp_kaddfd *addfd, struct seccomp_knotif *n) |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1079 | { |
Rodrigo Campos | 0ae71c7 | 2021-05-17 12:39:07 -0700 | [diff] [blame] | 1080 | int fd; |
| 1081 | |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1082 | /* |
| 1083 | * Remove the notification, and reset the list pointers, indicating |
| 1084 | * that it has been handled. |
| 1085 | */ |
| 1086 | list_del_init(&addfd->list); |
Christoph Hellwig | 42eb0d5 | 2021-03-25 09:22:09 +0100 | [diff] [blame] | 1087 | if (!addfd->setfd) |
Christian Brauner | 4e94ddf | 2023-11-30 13:49:11 +0100 | [diff] [blame] | 1088 | fd = receive_fd(addfd->file, NULL, addfd->flags); |
Christoph Hellwig | 42eb0d5 | 2021-03-25 09:22:09 +0100 | [diff] [blame] | 1089 | else |
Rodrigo Campos | 0ae71c7 | 2021-05-17 12:39:07 -0700 | [diff] [blame] | 1090 | fd = receive_fd_replace(addfd->fd, addfd->file, addfd->flags); |
| 1091 | addfd->ret = fd; |
| 1092 | |
| 1093 | if (addfd->ioctl_flags & SECCOMP_ADDFD_FLAG_SEND) { |
| 1094 | /* If we fail reset and return an error to the notifier */ |
| 1095 | if (fd < 0) { |
| 1096 | n->state = SECCOMP_NOTIFY_SENT; |
| 1097 | } else { |
| 1098 | /* Return the FD we just added */ |
| 1099 | n->flags = 0; |
| 1100 | n->error = 0; |
| 1101 | n->val = fd; |
| 1102 | } |
| 1103 | } |
| 1104 | |
| 1105 | /* |
| 1106 | * Mark the notification as completed. From this point, addfd mem |
| 1107 | * might be invalidated and we can't safely read it anymore. |
| 1108 | */ |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1109 | complete(&addfd->completion); |
| 1110 | } |
| 1111 | |
Sargun Dhillon | c2aa2df | 2022-05-03 01:09:56 -0700 | [diff] [blame] | 1112 | static bool should_sleep_killable(struct seccomp_filter *match, |
| 1113 | struct seccomp_knotif *n) |
| 1114 | { |
| 1115 | return match->wait_killable_recv && n->state == SECCOMP_NOTIFY_SENT; |
| 1116 | } |
| 1117 | |
Christian Brauner | fb3c5386 | 2019-09-20 10:30:05 +0200 | [diff] [blame] | 1118 | static int seccomp_do_user_notification(int this_syscall, |
| 1119 | struct seccomp_filter *match, |
| 1120 | const struct seccomp_data *sd) |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1121 | { |
| 1122 | int err; |
Christian Brauner | fb3c5386 | 2019-09-20 10:30:05 +0200 | [diff] [blame] | 1123 | u32 flags = 0; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1124 | long ret = 0; |
| 1125 | struct seccomp_knotif n = {}; |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1126 | struct seccomp_kaddfd *addfd, *tmp; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1127 | |
| 1128 | mutex_lock(&match->notify_lock); |
| 1129 | err = -ENOSYS; |
| 1130 | if (!match->notif) |
| 1131 | goto out; |
| 1132 | |
| 1133 | n.task = current; |
| 1134 | n.state = SECCOMP_NOTIFY_INIT; |
| 1135 | n.data = sd; |
| 1136 | n.id = seccomp_next_notify_id(match); |
| 1137 | init_completion(&n.ready); |
Sargun Dhillon | 4cbf6f6 | 2022-04-27 18:54:46 -0700 | [diff] [blame] | 1138 | list_add_tail(&n.list, &match->notif->notifications); |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1139 | INIT_LIST_HEAD(&n.addfd); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1140 | |
Andrei Vagin | 4943b66 | 2023-03-07 23:31:56 -0800 | [diff] [blame] | 1141 | atomic_inc(&match->notif->requests); |
Andrei Vagin | 48a1084 | 2023-03-07 23:31:59 -0800 | [diff] [blame] | 1142 | if (match->notif->flags & SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP) |
| 1143 | wake_up_poll_on_current_cpu(&match->wqh, EPOLLIN | EPOLLRDNORM); |
| 1144 | else |
| 1145 | wake_up_poll(&match->wqh, EPOLLIN | EPOLLRDNORM); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1146 | |
| 1147 | /* |
| 1148 | * This is where we wait for a reply from userspace. |
| 1149 | */ |
Sargun Dhillon | ddc4739 | 2021-05-17 12:39:06 -0700 | [diff] [blame] | 1150 | do { |
Sargun Dhillon | c2aa2df | 2022-05-03 01:09:56 -0700 | [diff] [blame] | 1151 | bool wait_killable = should_sleep_killable(match, &n); |
| 1152 | |
Sargun Dhillon | ddc4739 | 2021-05-17 12:39:06 -0700 | [diff] [blame] | 1153 | mutex_unlock(&match->notify_lock); |
Sargun Dhillon | c2aa2df | 2022-05-03 01:09:56 -0700 | [diff] [blame] | 1154 | if (wait_killable) |
| 1155 | err = wait_for_completion_killable(&n.ready); |
| 1156 | else |
| 1157 | err = wait_for_completion_interruptible(&n.ready); |
Sargun Dhillon | ddc4739 | 2021-05-17 12:39:06 -0700 | [diff] [blame] | 1158 | mutex_lock(&match->notify_lock); |
Sargun Dhillon | c2aa2df | 2022-05-03 01:09:56 -0700 | [diff] [blame] | 1159 | |
| 1160 | if (err != 0) { |
| 1161 | /* |
| 1162 | * Check to see if the notifcation got picked up and |
| 1163 | * whether we should switch to wait killable. |
| 1164 | */ |
| 1165 | if (!wait_killable && should_sleep_killable(match, &n)) |
| 1166 | continue; |
| 1167 | |
Sargun Dhillon | ddc4739 | 2021-05-17 12:39:06 -0700 | [diff] [blame] | 1168 | goto interrupted; |
Sargun Dhillon | c2aa2df | 2022-05-03 01:09:56 -0700 | [diff] [blame] | 1169 | } |
Sargun Dhillon | ddc4739 | 2021-05-17 12:39:06 -0700 | [diff] [blame] | 1170 | |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1171 | addfd = list_first_entry_or_null(&n.addfd, |
| 1172 | struct seccomp_kaddfd, list); |
Sargun Dhillon | ddc4739 | 2021-05-17 12:39:06 -0700 | [diff] [blame] | 1173 | /* Check if we were woken up by a addfd message */ |
| 1174 | if (addfd) |
Rodrigo Campos | 0ae71c7 | 2021-05-17 12:39:07 -0700 | [diff] [blame] | 1175 | seccomp_handle_addfd(addfd, &n); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1176 | |
Sargun Dhillon | ddc4739 | 2021-05-17 12:39:06 -0700 | [diff] [blame] | 1177 | } while (n.state != SECCOMP_NOTIFY_REPLIED); |
| 1178 | |
| 1179 | ret = n.val; |
| 1180 | err = n.error; |
| 1181 | flags = n.flags; |
| 1182 | |
| 1183 | interrupted: |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1184 | /* If there were any pending addfd calls, clear them out */ |
| 1185 | list_for_each_entry_safe(addfd, tmp, &n.addfd, list) { |
| 1186 | /* The process went away before we got a chance to handle it */ |
| 1187 | addfd->ret = -ESRCH; |
| 1188 | list_del_init(&addfd->list); |
| 1189 | complete(&addfd->completion); |
| 1190 | } |
| 1191 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1192 | /* |
| 1193 | * Note that it's possible the listener died in between the time when |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1194 | * we were notified of a response (or a signal) and when we were able to |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1195 | * re-acquire the lock, so only delete from the list if the |
| 1196 | * notification actually exists. |
| 1197 | * |
| 1198 | * Also note that this test is only valid because there's no way to |
| 1199 | * *reattach* to a notifier right now. If one is added, we'll need to |
| 1200 | * keep track of the notif itself and make sure they match here. |
| 1201 | */ |
| 1202 | if (match->notif) |
| 1203 | list_del(&n.list); |
| 1204 | out: |
| 1205 | mutex_unlock(&match->notify_lock); |
Christian Brauner | fb3c5386 | 2019-09-20 10:30:05 +0200 | [diff] [blame] | 1206 | |
| 1207 | /* Userspace requests to continue the syscall. */ |
| 1208 | if (flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE) |
| 1209 | return 0; |
| 1210 | |
Denis Efremov | 2d9ca26 | 2020-08-24 15:59:21 +0300 | [diff] [blame] | 1211 | syscall_set_return_value(current, current_pt_regs(), |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1212 | err, ret); |
Christian Brauner | fb3c5386 | 2019-09-20 10:30:05 +0200 | [diff] [blame] | 1213 | return -1; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1214 | } |
| 1215 | |
Kees Cook | ce6526e | 2016-06-01 19:29:15 -0700 | [diff] [blame] | 1216 | static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, |
| 1217 | const bool recheck_after_trace) |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1218 | { |
| 1219 | u32 filter_ret, action; |
Kees Cook | deb4de8 | 2017-08-02 15:00:40 -0700 | [diff] [blame] | 1220 | struct seccomp_filter *match = NULL; |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1221 | int data; |
Tycho Andersen | db51139 | 2018-12-09 11:24:11 -0700 | [diff] [blame] | 1222 | struct seccomp_data sd_local; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1223 | |
Kees Cook | 3ba2530 | 2014-06-27 15:01:35 -0700 | [diff] [blame] | 1224 | /* |
| 1225 | * Make sure that any changes to mode from another thread have |
Gabriel Krisman Bertazi | 23d67a5 | 2020-11-16 12:42:00 -0500 | [diff] [blame] | 1226 | * been seen after SYSCALL_WORK_SECCOMP was seen. |
Kees Cook | 3ba2530 | 2014-06-27 15:01:35 -0700 | [diff] [blame] | 1227 | */ |
wanghongzhe | a381b70 | 2021-02-05 11:34:09 +0800 | [diff] [blame] | 1228 | smp_rmb(); |
Kees Cook | 3ba2530 | 2014-06-27 15:01:35 -0700 | [diff] [blame] | 1229 | |
Tycho Andersen | db51139 | 2018-12-09 11:24:11 -0700 | [diff] [blame] | 1230 | if (!sd) { |
| 1231 | populate_seccomp_data(&sd_local); |
| 1232 | sd = &sd_local; |
| 1233 | } |
| 1234 | |
Kees Cook | deb4de8 | 2017-08-02 15:00:40 -0700 | [diff] [blame] | 1235 | filter_ret = seccomp_run_filters(sd, &match); |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1236 | data = filter_ret & SECCOMP_RET_DATA; |
Kees Cook | 0466bdb | 2017-08-11 13:12:11 -0700 | [diff] [blame] | 1237 | action = filter_ret & SECCOMP_RET_ACTION_FULL; |
Andy Lutomirski | 87b526d | 2012-10-01 11:40:45 -0700 | [diff] [blame] | 1238 | |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1239 | switch (action) { |
| 1240 | case SECCOMP_RET_ERRNO: |
Kees Cook | 580c57f | 2015-02-17 13:48:00 -0800 | [diff] [blame] | 1241 | /* Set low-order bits as an errno, capped at MAX_ERRNO. */ |
| 1242 | if (data > MAX_ERRNO) |
| 1243 | data = MAX_ERRNO; |
Denis Efremov | 2d9ca26 | 2020-08-24 15:59:21 +0300 | [diff] [blame] | 1244 | syscall_set_return_value(current, current_pt_regs(), |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1245 | -data, 0); |
| 1246 | goto skip; |
| 1247 | |
| 1248 | case SECCOMP_RET_TRAP: |
| 1249 | /* Show the handler the original registers. */ |
Denis Efremov | 2d9ca26 | 2020-08-24 15:59:21 +0300 | [diff] [blame] | 1250 | syscall_rollback(current, current_pt_regs()); |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1251 | /* Let the filter pass back 16 bits of data. */ |
Eric W. Biederman | 307d522 | 2021-06-23 16:44:32 -0500 | [diff] [blame] | 1252 | force_sig_seccomp(this_syscall, data, false); |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1253 | goto skip; |
| 1254 | |
| 1255 | case SECCOMP_RET_TRACE: |
Kees Cook | ce6526e | 2016-06-01 19:29:15 -0700 | [diff] [blame] | 1256 | /* We've been put in this state by the ptracer already. */ |
| 1257 | if (recheck_after_trace) |
| 1258 | return 0; |
| 1259 | |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1260 | /* ENOSYS these calls if there is no tracer attached. */ |
| 1261 | if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) { |
| 1262 | syscall_set_return_value(current, |
Denis Efremov | 2d9ca26 | 2020-08-24 15:59:21 +0300 | [diff] [blame] | 1263 | current_pt_regs(), |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1264 | -ENOSYS, 0); |
| 1265 | goto skip; |
| 1266 | } |
| 1267 | |
| 1268 | /* Allow the BPF to provide the event message */ |
| 1269 | ptrace_event(PTRACE_EVENT_SECCOMP, data); |
| 1270 | /* |
| 1271 | * The delivery of a fatal signal during event |
Kees Cook | 485a252 | 2016-08-10 16:28:09 -0700 | [diff] [blame] | 1272 | * notification may silently skip tracer notification, |
| 1273 | * which could leave us with a potentially unmodified |
| 1274 | * syscall that the tracer would have liked to have |
| 1275 | * changed. Since the process is about to die, we just |
| 1276 | * force the syscall to be skipped and let the signal |
| 1277 | * kill the process and correctly handle any tracer exit |
| 1278 | * notifications. |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1279 | */ |
| 1280 | if (fatal_signal_pending(current)) |
Kees Cook | 485a252 | 2016-08-10 16:28:09 -0700 | [diff] [blame] | 1281 | goto skip; |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1282 | /* Check if the tracer forced the syscall to be skipped. */ |
Denis Efremov | 2d9ca26 | 2020-08-24 15:59:21 +0300 | [diff] [blame] | 1283 | this_syscall = syscall_get_nr(current, current_pt_regs()); |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1284 | if (this_syscall < 0) |
| 1285 | goto skip; |
| 1286 | |
Kees Cook | ce6526e | 2016-06-01 19:29:15 -0700 | [diff] [blame] | 1287 | /* |
| 1288 | * Recheck the syscall, since it may have changed. This |
| 1289 | * intentionally uses a NULL struct seccomp_data to force |
| 1290 | * a reload of all registers. This does not goto skip since |
| 1291 | * a skip would have already been reported. |
| 1292 | */ |
| 1293 | if (__seccomp_filter(this_syscall, NULL, true)) |
| 1294 | return -1; |
| 1295 | |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1296 | return 0; |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1297 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1298 | case SECCOMP_RET_USER_NOTIF: |
Christian Brauner | fb3c5386 | 2019-09-20 10:30:05 +0200 | [diff] [blame] | 1299 | if (seccomp_do_user_notification(this_syscall, match, sd)) |
| 1300 | goto skip; |
| 1301 | |
| 1302 | return 0; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1303 | |
Tyler Hicks | 59f5cf4 | 2017-08-11 04:33:57 +0000 | [diff] [blame] | 1304 | case SECCOMP_RET_LOG: |
| 1305 | seccomp_log(this_syscall, 0, action, true); |
| 1306 | return 0; |
| 1307 | |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1308 | case SECCOMP_RET_ALLOW: |
Kees Cook | deb4de8 | 2017-08-02 15:00:40 -0700 | [diff] [blame] | 1309 | /* |
| 1310 | * Note that the "match" filter will always be NULL for |
| 1311 | * this action since SECCOMP_RET_ALLOW is the starting |
| 1312 | * state in seccomp_run_filters(). |
| 1313 | */ |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1314 | return 0; |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1315 | |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 1316 | case SECCOMP_RET_KILL_THREAD: |
Kees Cook | 4d3b0b0 | 2017-08-11 13:01:39 -0700 | [diff] [blame] | 1317 | case SECCOMP_RET_KILL_PROCESS: |
Kees Cook | 131b635 | 2017-02-23 09:24:24 -0800 | [diff] [blame] | 1318 | default: |
Kees Cook | 495ac30 | 2022-02-07 20:21:13 -0800 | [diff] [blame] | 1319 | current->seccomp.mode = SECCOMP_MODE_DEAD; |
Tyler Hicks | e66a399 | 2017-08-11 04:33:56 +0000 | [diff] [blame] | 1320 | seccomp_log(this_syscall, SIGSYS, action, true); |
Kees Cook | d7276e3 | 2017-02-07 15:18:51 -0800 | [diff] [blame] | 1321 | /* Dump core only if this is the last remaining thread. */ |
Rich Felker | 4d671d9 | 2020-08-28 21:56:13 -0400 | [diff] [blame] | 1322 | if (action != SECCOMP_RET_KILL_THREAD || |
Eric W. Biederman | d21918e | 2021-06-23 16:51:49 -0500 | [diff] [blame] | 1323 | (atomic_read(¤t->signal->live) == 1)) { |
Kees Cook | d7276e3 | 2017-02-07 15:18:51 -0800 | [diff] [blame] | 1324 | /* Show the original registers in the dump. */ |
Denis Efremov | 2d9ca26 | 2020-08-24 15:59:21 +0300 | [diff] [blame] | 1325 | syscall_rollback(current, current_pt_regs()); |
Eric W. Biederman | 307d522 | 2021-06-23 16:44:32 -0500 | [diff] [blame] | 1326 | /* Trigger a coredump with SIGSYS */ |
| 1327 | force_sig_seccomp(this_syscall, data, true); |
| 1328 | } else { |
Kees Cook | 4d3b0b0 | 2017-08-11 13:01:39 -0700 | [diff] [blame] | 1329 | do_exit(SIGSYS); |
Eric W. Biederman | 307d522 | 2021-06-23 16:44:32 -0500 | [diff] [blame] | 1330 | } |
| 1331 | return -1; /* skip the syscall go directly to signal handling */ |
Will Drewry | 8156b45 | 2012-04-17 14:48:58 -0500 | [diff] [blame] | 1332 | } |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1333 | |
| 1334 | unreachable(); |
| 1335 | |
| 1336 | skip: |
Tyler Hicks | e66a399 | 2017-08-11 04:33:56 +0000 | [diff] [blame] | 1337 | seccomp_log(this_syscall, 0, action, match ? match->log : false); |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1338 | return -1; |
| 1339 | } |
| 1340 | #else |
Kees Cook | ce6526e | 2016-06-01 19:29:15 -0700 | [diff] [blame] | 1341 | static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, |
| 1342 | const bool recheck_after_trace) |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1343 | { |
| 1344 | BUG(); |
Paul Cercueil | 04b38d0 | 2021-01-11 17:28:39 +0000 | [diff] [blame] | 1345 | |
| 1346 | return -1; |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1347 | } |
| 1348 | #endif |
| 1349 | |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1350 | int __secure_computing(const struct seccomp_data *sd) |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1351 | { |
| 1352 | int mode = current->seccomp.mode; |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1353 | int this_syscall; |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1354 | |
Masahiro Yamada | 97f2645 | 2016-08-03 13:45:50 -0700 | [diff] [blame] | 1355 | if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) && |
Tycho Andersen | 13c4a90 | 2015-06-13 09:02:48 -0600 | [diff] [blame] | 1356 | unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1357 | return 0; |
| 1358 | |
| 1359 | this_syscall = sd ? sd->nr : |
Denis Efremov | 2d9ca26 | 2020-08-24 15:59:21 +0300 | [diff] [blame] | 1360 | syscall_get_nr(current, current_pt_regs()); |
Tycho Andersen | 13c4a90 | 2015-06-13 09:02:48 -0600 | [diff] [blame] | 1361 | |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1362 | switch (mode) { |
| 1363 | case SECCOMP_MODE_STRICT: |
| 1364 | __secure_computing_strict(this_syscall); /* may call do_exit */ |
Kees Cook | 8112c4f | 2016-06-01 16:02:17 -0700 | [diff] [blame] | 1365 | return 0; |
Andy Lutomirski | 13aa72f | 2014-07-21 18:49:15 -0700 | [diff] [blame] | 1366 | case SECCOMP_MODE_FILTER: |
Kees Cook | ce6526e | 2016-06-01 19:29:15 -0700 | [diff] [blame] | 1367 | return __seccomp_filter(this_syscall, sd, false); |
Kees Cook | 495ac30 | 2022-02-07 20:21:13 -0800 | [diff] [blame] | 1368 | /* Surviving SECCOMP_RET_KILL_* must be proactively impossible. */ |
| 1369 | case SECCOMP_MODE_DEAD: |
| 1370 | WARN_ON_ONCE(1); |
| 1371 | do_exit(SIGKILL); |
| 1372 | return -1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1373 | default: |
| 1374 | BUG(); |
| 1375 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1376 | } |
Andy Lutomirski | a4412fc | 2014-07-21 18:49:14 -0700 | [diff] [blame] | 1377 | #endif /* CONFIG_HAVE_ARCH_SECCOMP_FILTER */ |
Andrea Arcangeli | 1d9d02f | 2007-07-15 23:41:32 -0700 | [diff] [blame] | 1378 | |
| 1379 | long prctl_get_seccomp(void) |
| 1380 | { |
| 1381 | return current->seccomp.mode; |
| 1382 | } |
| 1383 | |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 1384 | /** |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1385 | * seccomp_set_mode_strict: internal function for setting strict seccomp |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 1386 | * |
| 1387 | * Once current->seccomp.mode is non-zero, it may not be changed. |
| 1388 | * |
| 1389 | * Returns 0 on success or -EINVAL on failure. |
| 1390 | */ |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1391 | static long seccomp_set_mode_strict(void) |
Andrea Arcangeli | 1d9d02f | 2007-07-15 23:41:32 -0700 | [diff] [blame] | 1392 | { |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1393 | const unsigned long seccomp_mode = SECCOMP_MODE_STRICT; |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 1394 | long ret = -EINVAL; |
Andrea Arcangeli | 1d9d02f | 2007-07-15 23:41:32 -0700 | [diff] [blame] | 1395 | |
Kees Cook | dbd95212 | 2014-06-27 15:18:48 -0700 | [diff] [blame] | 1396 | spin_lock_irq(¤t->sighand->siglock); |
| 1397 | |
Kees Cook | 1f41b450 | 2014-06-25 15:38:02 -0700 | [diff] [blame] | 1398 | if (!seccomp_may_assign_mode(seccomp_mode)) |
Andrea Arcangeli | 1d9d02f | 2007-07-15 23:41:32 -0700 | [diff] [blame] | 1399 | goto out; |
| 1400 | |
Andrea Arcangeli | cf99aba | 2007-07-15 23:41:33 -0700 | [diff] [blame] | 1401 | #ifdef TIF_NOTSC |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1402 | disable_TSC(); |
Andrea Arcangeli | cf99aba | 2007-07-15 23:41:33 -0700 | [diff] [blame] | 1403 | #endif |
Kees Cook | 00a02d0 | 2018-05-03 14:56:12 -0700 | [diff] [blame] | 1404 | seccomp_assign_mode(current, seccomp_mode, 0); |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1405 | ret = 0; |
| 1406 | |
| 1407 | out: |
Kees Cook | dbd95212 | 2014-06-27 15:18:48 -0700 | [diff] [blame] | 1408 | spin_unlock_irq(¤t->sighand->siglock); |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1409 | |
| 1410 | return ret; |
| 1411 | } |
| 1412 | |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 1413 | #ifdef CONFIG_SECCOMP_FILTER |
Tycho Andersen | e839317 | 2020-09-02 08:09:53 -0600 | [diff] [blame] | 1414 | static void seccomp_notify_free(struct seccomp_filter *filter) |
| 1415 | { |
| 1416 | kfree(filter->notif); |
| 1417 | filter->notif = NULL; |
| 1418 | } |
| 1419 | |
Tycho Andersen | a566a90 | 2020-09-01 19:40:16 -0600 | [diff] [blame] | 1420 | static void seccomp_notify_detach(struct seccomp_filter *filter) |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1421 | { |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1422 | struct seccomp_knotif *knotif; |
| 1423 | |
Tycho Andersen | a811dc6 | 2019-01-12 11:24:20 -0700 | [diff] [blame] | 1424 | if (!filter) |
Tycho Andersen | a566a90 | 2020-09-01 19:40:16 -0600 | [diff] [blame] | 1425 | return; |
Tycho Andersen | a811dc6 | 2019-01-12 11:24:20 -0700 | [diff] [blame] | 1426 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1427 | mutex_lock(&filter->notify_lock); |
| 1428 | |
| 1429 | /* |
| 1430 | * If this file is being closed because e.g. the task who owned it |
| 1431 | * died, let's wake everyone up who was waiting on us. |
| 1432 | */ |
| 1433 | list_for_each_entry(knotif, &filter->notif->notifications, list) { |
| 1434 | if (knotif->state == SECCOMP_NOTIFY_REPLIED) |
| 1435 | continue; |
| 1436 | |
| 1437 | knotif->state = SECCOMP_NOTIFY_REPLIED; |
| 1438 | knotif->error = -ENOSYS; |
| 1439 | knotif->val = 0; |
| 1440 | |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1441 | /* |
| 1442 | * We do not need to wake up any pending addfd messages, as |
| 1443 | * the notifier will do that for us, as this just looks |
| 1444 | * like a standard reply. |
| 1445 | */ |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1446 | complete(&knotif->ready); |
| 1447 | } |
| 1448 | |
Tycho Andersen | e839317 | 2020-09-02 08:09:53 -0600 | [diff] [blame] | 1449 | seccomp_notify_free(filter); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1450 | mutex_unlock(&filter->notify_lock); |
Tycho Andersen | a566a90 | 2020-09-01 19:40:16 -0600 | [diff] [blame] | 1451 | } |
| 1452 | |
| 1453 | static int seccomp_notify_release(struct inode *inode, struct file *file) |
| 1454 | { |
| 1455 | struct seccomp_filter *filter = file->private_data; |
| 1456 | |
| 1457 | seccomp_notify_detach(filter); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1458 | __put_seccomp_filter(filter); |
| 1459 | return 0; |
| 1460 | } |
| 1461 | |
Sargun Dhillon | 9f87dcf | 2020-06-01 04:25:32 -0700 | [diff] [blame] | 1462 | /* must be called with notif_lock held */ |
| 1463 | static inline struct seccomp_knotif * |
| 1464 | find_notification(struct seccomp_filter *filter, u64 id) |
| 1465 | { |
| 1466 | struct seccomp_knotif *cur; |
| 1467 | |
| 1468 | lockdep_assert_held(&filter->notify_lock); |
| 1469 | |
| 1470 | list_for_each_entry(cur, &filter->notif->notifications, list) { |
| 1471 | if (cur->id == id) |
| 1472 | return cur; |
| 1473 | } |
| 1474 | |
| 1475 | return NULL; |
| 1476 | } |
| 1477 | |
Andrei Vagin | 4943b66 | 2023-03-07 23:31:56 -0800 | [diff] [blame] | 1478 | static int recv_wake_function(wait_queue_entry_t *wait, unsigned int mode, int sync, |
| 1479 | void *key) |
| 1480 | { |
| 1481 | /* Avoid a wakeup if event not interesting for us. */ |
Andrei Vagin | 95036a7 | 2024-06-28 02:10:11 +0000 | [diff] [blame] | 1482 | if (key && !(key_to_poll(key) & (EPOLLIN | EPOLLERR | EPOLLHUP))) |
Andrei Vagin | 4943b66 | 2023-03-07 23:31:56 -0800 | [diff] [blame] | 1483 | return 0; |
| 1484 | return autoremove_wake_function(wait, mode, sync, key); |
| 1485 | } |
| 1486 | |
| 1487 | static int recv_wait_event(struct seccomp_filter *filter) |
| 1488 | { |
| 1489 | DEFINE_WAIT_FUNC(wait, recv_wake_function); |
| 1490 | int ret; |
| 1491 | |
Andrei Vagin | 95036a7 | 2024-06-28 02:10:11 +0000 | [diff] [blame] | 1492 | if (refcount_read(&filter->users) == 0) |
| 1493 | return 0; |
| 1494 | |
Andrei Vagin | 4943b66 | 2023-03-07 23:31:56 -0800 | [diff] [blame] | 1495 | if (atomic_dec_if_positive(&filter->notif->requests) >= 0) |
| 1496 | return 0; |
| 1497 | |
| 1498 | for (;;) { |
| 1499 | ret = prepare_to_wait_event(&filter->wqh, &wait, TASK_INTERRUPTIBLE); |
| 1500 | |
| 1501 | if (atomic_dec_if_positive(&filter->notif->requests) >= 0) |
| 1502 | break; |
Andrei Vagin | 95036a7 | 2024-06-28 02:10:11 +0000 | [diff] [blame] | 1503 | if (refcount_read(&filter->users) == 0) |
| 1504 | break; |
Andrei Vagin | 4943b66 | 2023-03-07 23:31:56 -0800 | [diff] [blame] | 1505 | |
| 1506 | if (ret) |
| 1507 | return ret; |
| 1508 | |
| 1509 | schedule(); |
| 1510 | } |
| 1511 | finish_wait(&filter->wqh, &wait); |
| 1512 | return 0; |
| 1513 | } |
Sargun Dhillon | 9f87dcf | 2020-06-01 04:25:32 -0700 | [diff] [blame] | 1514 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1515 | static long seccomp_notify_recv(struct seccomp_filter *filter, |
| 1516 | void __user *buf) |
| 1517 | { |
| 1518 | struct seccomp_knotif *knotif = NULL, *cur; |
| 1519 | struct seccomp_notif unotif; |
| 1520 | ssize_t ret; |
| 1521 | |
Sargun Dhillon | 2882d53 | 2019-12-28 22:24:50 -0800 | [diff] [blame] | 1522 | /* Verify that we're not given garbage to keep struct extensible. */ |
| 1523 | ret = check_zeroed_user(buf, sizeof(unotif)); |
| 1524 | if (ret < 0) |
| 1525 | return ret; |
| 1526 | if (!ret) |
| 1527 | return -EINVAL; |
| 1528 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1529 | memset(&unotif, 0, sizeof(unotif)); |
| 1530 | |
Andrei Vagin | 4943b66 | 2023-03-07 23:31:56 -0800 | [diff] [blame] | 1531 | ret = recv_wait_event(filter); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1532 | if (ret < 0) |
| 1533 | return ret; |
| 1534 | |
| 1535 | mutex_lock(&filter->notify_lock); |
| 1536 | list_for_each_entry(cur, &filter->notif->notifications, list) { |
| 1537 | if (cur->state == SECCOMP_NOTIFY_INIT) { |
| 1538 | knotif = cur; |
| 1539 | break; |
| 1540 | } |
| 1541 | } |
| 1542 | |
| 1543 | /* |
| 1544 | * If we didn't find a notification, it could be that the task was |
| 1545 | * interrupted by a fatal signal between the time we were woken and |
| 1546 | * when we were able to acquire the rw lock. |
| 1547 | */ |
| 1548 | if (!knotif) { |
| 1549 | ret = -ENOENT; |
| 1550 | goto out; |
| 1551 | } |
| 1552 | |
| 1553 | unotif.id = knotif->id; |
| 1554 | unotif.pid = task_pid_vnr(knotif->task); |
| 1555 | unotif.data = *(knotif->data); |
| 1556 | |
| 1557 | knotif->state = SECCOMP_NOTIFY_SENT; |
Christian Brauner | 76194c4 | 2020-06-01 11:50:07 -0700 | [diff] [blame] | 1558 | wake_up_poll(&filter->wqh, EPOLLOUT | EPOLLWRNORM); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1559 | ret = 0; |
| 1560 | out: |
| 1561 | mutex_unlock(&filter->notify_lock); |
| 1562 | |
| 1563 | if (ret == 0 && copy_to_user(buf, &unotif, sizeof(unotif))) { |
| 1564 | ret = -EFAULT; |
| 1565 | |
| 1566 | /* |
| 1567 | * Userspace screwed up. To make sure that we keep this |
| 1568 | * notification alive, let's reset it back to INIT. It |
| 1569 | * may have died when we released the lock, so we need to make |
| 1570 | * sure it's still around. |
| 1571 | */ |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1572 | mutex_lock(&filter->notify_lock); |
Sargun Dhillon | 9f87dcf | 2020-06-01 04:25:32 -0700 | [diff] [blame] | 1573 | knotif = find_notification(filter, unotif.id); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1574 | if (knotif) { |
Sargun Dhillon | c2aa2df | 2022-05-03 01:09:56 -0700 | [diff] [blame] | 1575 | /* Reset the process to make sure it's not stuck */ |
| 1576 | if (should_sleep_killable(filter, knotif)) |
| 1577 | complete(&knotif->ready); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1578 | knotif->state = SECCOMP_NOTIFY_INIT; |
Andrei Vagin | 4943b66 | 2023-03-07 23:31:56 -0800 | [diff] [blame] | 1579 | atomic_inc(&filter->notif->requests); |
| 1580 | wake_up_poll(&filter->wqh, EPOLLIN | EPOLLRDNORM); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1581 | } |
| 1582 | mutex_unlock(&filter->notify_lock); |
| 1583 | } |
| 1584 | |
| 1585 | return ret; |
| 1586 | } |
| 1587 | |
| 1588 | static long seccomp_notify_send(struct seccomp_filter *filter, |
| 1589 | void __user *buf) |
| 1590 | { |
| 1591 | struct seccomp_notif_resp resp = {}; |
Sargun Dhillon | 9f87dcf | 2020-06-01 04:25:32 -0700 | [diff] [blame] | 1592 | struct seccomp_knotif *knotif; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1593 | long ret; |
| 1594 | |
| 1595 | if (copy_from_user(&resp, buf, sizeof(resp))) |
| 1596 | return -EFAULT; |
| 1597 | |
Christian Brauner | fb3c5386 | 2019-09-20 10:30:05 +0200 | [diff] [blame] | 1598 | if (resp.flags & ~SECCOMP_USER_NOTIF_FLAG_CONTINUE) |
| 1599 | return -EINVAL; |
| 1600 | |
| 1601 | if ((resp.flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE) && |
| 1602 | (resp.error || resp.val)) |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1603 | return -EINVAL; |
| 1604 | |
| 1605 | ret = mutex_lock_interruptible(&filter->notify_lock); |
| 1606 | if (ret < 0) |
| 1607 | return ret; |
| 1608 | |
Sargun Dhillon | 9f87dcf | 2020-06-01 04:25:32 -0700 | [diff] [blame] | 1609 | knotif = find_notification(filter, resp.id); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1610 | if (!knotif) { |
| 1611 | ret = -ENOENT; |
| 1612 | goto out; |
| 1613 | } |
| 1614 | |
| 1615 | /* Allow exactly one reply. */ |
| 1616 | if (knotif->state != SECCOMP_NOTIFY_SENT) { |
| 1617 | ret = -EINPROGRESS; |
| 1618 | goto out; |
| 1619 | } |
| 1620 | |
| 1621 | ret = 0; |
| 1622 | knotif->state = SECCOMP_NOTIFY_REPLIED; |
| 1623 | knotif->error = resp.error; |
| 1624 | knotif->val = resp.val; |
Christian Brauner | fb3c5386 | 2019-09-20 10:30:05 +0200 | [diff] [blame] | 1625 | knotif->flags = resp.flags; |
Andrei Vagin | 48a1084 | 2023-03-07 23:31:59 -0800 | [diff] [blame] | 1626 | if (filter->notif->flags & SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP) |
| 1627 | complete_on_current_cpu(&knotif->ready); |
| 1628 | else |
| 1629 | complete(&knotif->ready); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1630 | out: |
| 1631 | mutex_unlock(&filter->notify_lock); |
| 1632 | return ret; |
| 1633 | } |
| 1634 | |
| 1635 | static long seccomp_notify_id_valid(struct seccomp_filter *filter, |
| 1636 | void __user *buf) |
| 1637 | { |
Sargun Dhillon | 9f87dcf | 2020-06-01 04:25:32 -0700 | [diff] [blame] | 1638 | struct seccomp_knotif *knotif; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1639 | u64 id; |
| 1640 | long ret; |
| 1641 | |
| 1642 | if (copy_from_user(&id, buf, sizeof(id))) |
| 1643 | return -EFAULT; |
| 1644 | |
| 1645 | ret = mutex_lock_interruptible(&filter->notify_lock); |
| 1646 | if (ret < 0) |
| 1647 | return ret; |
| 1648 | |
Sargun Dhillon | 9f87dcf | 2020-06-01 04:25:32 -0700 | [diff] [blame] | 1649 | knotif = find_notification(filter, id); |
| 1650 | if (knotif && knotif->state == SECCOMP_NOTIFY_SENT) |
| 1651 | ret = 0; |
| 1652 | else |
| 1653 | ret = -ENOENT; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1654 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1655 | mutex_unlock(&filter->notify_lock); |
| 1656 | return ret; |
| 1657 | } |
| 1658 | |
Andrei Vagin | 48a1084 | 2023-03-07 23:31:59 -0800 | [diff] [blame] | 1659 | static long seccomp_notify_set_flags(struct seccomp_filter *filter, |
| 1660 | unsigned long flags) |
| 1661 | { |
| 1662 | long ret; |
| 1663 | |
| 1664 | if (flags & ~SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP) |
| 1665 | return -EINVAL; |
| 1666 | |
| 1667 | ret = mutex_lock_interruptible(&filter->notify_lock); |
| 1668 | if (ret < 0) |
| 1669 | return ret; |
| 1670 | filter->notif->flags = flags; |
| 1671 | mutex_unlock(&filter->notify_lock); |
| 1672 | return 0; |
| 1673 | } |
| 1674 | |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1675 | static long seccomp_notify_addfd(struct seccomp_filter *filter, |
| 1676 | struct seccomp_notif_addfd __user *uaddfd, |
| 1677 | unsigned int size) |
| 1678 | { |
| 1679 | struct seccomp_notif_addfd addfd; |
| 1680 | struct seccomp_knotif *knotif; |
| 1681 | struct seccomp_kaddfd kaddfd; |
| 1682 | int ret; |
| 1683 | |
| 1684 | BUILD_BUG_ON(sizeof(addfd) < SECCOMP_NOTIFY_ADDFD_SIZE_VER0); |
| 1685 | BUILD_BUG_ON(sizeof(addfd) != SECCOMP_NOTIFY_ADDFD_SIZE_LATEST); |
| 1686 | |
| 1687 | if (size < SECCOMP_NOTIFY_ADDFD_SIZE_VER0 || size >= PAGE_SIZE) |
| 1688 | return -EINVAL; |
| 1689 | |
| 1690 | ret = copy_struct_from_user(&addfd, sizeof(addfd), uaddfd, size); |
| 1691 | if (ret) |
| 1692 | return ret; |
| 1693 | |
| 1694 | if (addfd.newfd_flags & ~O_CLOEXEC) |
| 1695 | return -EINVAL; |
| 1696 | |
Rodrigo Campos | 0ae71c7 | 2021-05-17 12:39:07 -0700 | [diff] [blame] | 1697 | if (addfd.flags & ~(SECCOMP_ADDFD_FLAG_SETFD | SECCOMP_ADDFD_FLAG_SEND)) |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1698 | return -EINVAL; |
| 1699 | |
| 1700 | if (addfd.newfd && !(addfd.flags & SECCOMP_ADDFD_FLAG_SETFD)) |
| 1701 | return -EINVAL; |
| 1702 | |
| 1703 | kaddfd.file = fget(addfd.srcfd); |
| 1704 | if (!kaddfd.file) |
| 1705 | return -EBADF; |
| 1706 | |
Rodrigo Campos | 0ae71c7 | 2021-05-17 12:39:07 -0700 | [diff] [blame] | 1707 | kaddfd.ioctl_flags = addfd.flags; |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1708 | kaddfd.flags = addfd.newfd_flags; |
Christoph Hellwig | 42eb0d5 | 2021-03-25 09:22:09 +0100 | [diff] [blame] | 1709 | kaddfd.setfd = addfd.flags & SECCOMP_ADDFD_FLAG_SETFD; |
| 1710 | kaddfd.fd = addfd.newfd; |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1711 | init_completion(&kaddfd.completion); |
| 1712 | |
| 1713 | ret = mutex_lock_interruptible(&filter->notify_lock); |
| 1714 | if (ret < 0) |
| 1715 | goto out; |
| 1716 | |
| 1717 | knotif = find_notification(filter, addfd.id); |
| 1718 | if (!knotif) { |
| 1719 | ret = -ENOENT; |
| 1720 | goto out_unlock; |
| 1721 | } |
| 1722 | |
| 1723 | /* |
| 1724 | * We do not want to allow for FD injection to occur before the |
| 1725 | * notification has been picked up by a userspace handler, or after |
| 1726 | * the notification has been replied to. |
| 1727 | */ |
| 1728 | if (knotif->state != SECCOMP_NOTIFY_SENT) { |
| 1729 | ret = -EINPROGRESS; |
| 1730 | goto out_unlock; |
| 1731 | } |
| 1732 | |
Rodrigo Campos | 0ae71c7 | 2021-05-17 12:39:07 -0700 | [diff] [blame] | 1733 | if (addfd.flags & SECCOMP_ADDFD_FLAG_SEND) { |
| 1734 | /* |
| 1735 | * Disallow queuing an atomic addfd + send reply while there are |
| 1736 | * some addfd requests still to process. |
| 1737 | * |
| 1738 | * There is no clear reason to support it and allows us to keep |
| 1739 | * the loop on the other side straight-forward. |
| 1740 | */ |
| 1741 | if (!list_empty(&knotif->addfd)) { |
| 1742 | ret = -EBUSY; |
| 1743 | goto out_unlock; |
| 1744 | } |
| 1745 | |
| 1746 | /* Allow exactly only one reply */ |
| 1747 | knotif->state = SECCOMP_NOTIFY_REPLIED; |
| 1748 | } |
| 1749 | |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1750 | list_add(&kaddfd.list, &knotif->addfd); |
| 1751 | complete(&knotif->ready); |
| 1752 | mutex_unlock(&filter->notify_lock); |
| 1753 | |
| 1754 | /* Now we wait for it to be processed or be interrupted */ |
| 1755 | ret = wait_for_completion_interruptible(&kaddfd.completion); |
| 1756 | if (ret == 0) { |
| 1757 | /* |
| 1758 | * We had a successful completion. The other side has already |
| 1759 | * removed us from the addfd queue, and |
| 1760 | * wait_for_completion_interruptible has a memory barrier upon |
| 1761 | * success that lets us read this value directly without |
| 1762 | * locking. |
| 1763 | */ |
| 1764 | ret = kaddfd.ret; |
| 1765 | goto out; |
| 1766 | } |
| 1767 | |
| 1768 | mutex_lock(&filter->notify_lock); |
| 1769 | /* |
| 1770 | * Even though we were woken up by a signal and not a successful |
| 1771 | * completion, a completion may have happened in the mean time. |
| 1772 | * |
| 1773 | * We need to check again if the addfd request has been handled, |
| 1774 | * and if not, we will remove it from the queue. |
| 1775 | */ |
| 1776 | if (list_empty(&kaddfd.list)) |
| 1777 | ret = kaddfd.ret; |
| 1778 | else |
| 1779 | list_del(&kaddfd.list); |
| 1780 | |
| 1781 | out_unlock: |
| 1782 | mutex_unlock(&filter->notify_lock); |
| 1783 | out: |
| 1784 | fput(kaddfd.file); |
| 1785 | |
| 1786 | return ret; |
| 1787 | } |
| 1788 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1789 | static long seccomp_notify_ioctl(struct file *file, unsigned int cmd, |
| 1790 | unsigned long arg) |
| 1791 | { |
| 1792 | struct seccomp_filter *filter = file->private_data; |
| 1793 | void __user *buf = (void __user *)arg; |
| 1794 | |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1795 | /* Fixed-size ioctls */ |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1796 | switch (cmd) { |
| 1797 | case SECCOMP_IOCTL_NOTIF_RECV: |
| 1798 | return seccomp_notify_recv(filter, buf); |
| 1799 | case SECCOMP_IOCTL_NOTIF_SEND: |
| 1800 | return seccomp_notify_send(filter, buf); |
Kees Cook | 47e33c05 | 2020-06-15 15:42:46 -0700 | [diff] [blame] | 1801 | case SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR: |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1802 | case SECCOMP_IOCTL_NOTIF_ID_VALID: |
| 1803 | return seccomp_notify_id_valid(filter, buf); |
Andrei Vagin | 48a1084 | 2023-03-07 23:31:59 -0800 | [diff] [blame] | 1804 | case SECCOMP_IOCTL_NOTIF_SET_FLAGS: |
| 1805 | return seccomp_notify_set_flags(filter, arg); |
Sargun Dhillon | 7cf97b1 | 2020-06-02 18:10:43 -0700 | [diff] [blame] | 1806 | } |
| 1807 | |
| 1808 | /* Extensible Argument ioctls */ |
| 1809 | #define EA_IOCTL(cmd) ((cmd) & ~(IOC_INOUT | IOCSIZE_MASK)) |
| 1810 | switch (EA_IOCTL(cmd)) { |
| 1811 | case EA_IOCTL(SECCOMP_IOCTL_NOTIF_ADDFD): |
| 1812 | return seccomp_notify_addfd(filter, buf, _IOC_SIZE(cmd)); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1813 | default: |
| 1814 | return -EINVAL; |
| 1815 | } |
| 1816 | } |
| 1817 | |
| 1818 | static __poll_t seccomp_notify_poll(struct file *file, |
| 1819 | struct poll_table_struct *poll_tab) |
| 1820 | { |
| 1821 | struct seccomp_filter *filter = file->private_data; |
| 1822 | __poll_t ret = 0; |
| 1823 | struct seccomp_knotif *cur; |
| 1824 | |
Christian Brauner | 76194c4 | 2020-06-01 11:50:07 -0700 | [diff] [blame] | 1825 | poll_wait(file, &filter->wqh, poll_tab); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1826 | |
Tycho Andersen | 319deec | 2018-12-12 19:46:54 -0700 | [diff] [blame] | 1827 | if (mutex_lock_interruptible(&filter->notify_lock) < 0) |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1828 | return EPOLLERR; |
| 1829 | |
| 1830 | list_for_each_entry(cur, &filter->notif->notifications, list) { |
| 1831 | if (cur->state == SECCOMP_NOTIFY_INIT) |
| 1832 | ret |= EPOLLIN | EPOLLRDNORM; |
| 1833 | if (cur->state == SECCOMP_NOTIFY_SENT) |
| 1834 | ret |= EPOLLOUT | EPOLLWRNORM; |
| 1835 | if ((ret & EPOLLIN) && (ret & EPOLLOUT)) |
| 1836 | break; |
| 1837 | } |
| 1838 | |
| 1839 | mutex_unlock(&filter->notify_lock); |
| 1840 | |
Christian Brauner | 99cdb8b | 2020-05-31 13:50:30 +0200 | [diff] [blame] | 1841 | if (refcount_read(&filter->users) == 0) |
| 1842 | ret |= EPOLLHUP; |
| 1843 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1844 | return ret; |
| 1845 | } |
| 1846 | |
| 1847 | static const struct file_operations seccomp_notify_ops = { |
| 1848 | .poll = seccomp_notify_poll, |
| 1849 | .release = seccomp_notify_release, |
| 1850 | .unlocked_ioctl = seccomp_notify_ioctl, |
Sven Schnelle | 3db81af | 2020-03-10 13:33:32 +0100 | [diff] [blame] | 1851 | .compat_ioctl = seccomp_notify_ioctl, |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1852 | }; |
| 1853 | |
| 1854 | static struct file *init_listener(struct seccomp_filter *filter) |
| 1855 | { |
Jann Horn | dfe719f | 2020-10-05 03:44:01 +0200 | [diff] [blame] | 1856 | struct file *ret; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1857 | |
| 1858 | ret = ERR_PTR(-ENOMEM); |
| 1859 | filter->notif = kzalloc(sizeof(*(filter->notif)), GFP_KERNEL); |
| 1860 | if (!filter->notif) |
| 1861 | goto out; |
| 1862 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1863 | filter->notif->next_id = get_random_u64(); |
| 1864 | INIT_LIST_HEAD(&filter->notif->notifications); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1865 | |
| 1866 | ret = anon_inode_getfile("seccomp notify", &seccomp_notify_ops, |
| 1867 | filter, O_RDWR); |
| 1868 | if (IS_ERR(ret)) |
| 1869 | goto out_notif; |
| 1870 | |
| 1871 | /* The file has a reference to it now */ |
| 1872 | __get_seccomp_filter(filter); |
| 1873 | |
| 1874 | out_notif: |
| 1875 | if (IS_ERR(ret)) |
Tycho Andersen | e839317 | 2020-09-02 08:09:53 -0600 | [diff] [blame] | 1876 | seccomp_notify_free(filter); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1877 | out: |
| 1878 | return ret; |
| 1879 | } |
| 1880 | |
Jann Horn | dfe719f | 2020-10-05 03:44:01 +0200 | [diff] [blame] | 1881 | /* |
| 1882 | * Does @new_child have a listener while an ancestor also has a listener? |
| 1883 | * If so, we'll want to reject this filter. |
| 1884 | * This only has to be tested for the current process, even in the TSYNC case, |
| 1885 | * because TSYNC installs @child with the same parent on all threads. |
| 1886 | * Note that @new_child is not hooked up to its parent at this point yet, so |
| 1887 | * we use current->seccomp.filter. |
| 1888 | */ |
| 1889 | static bool has_duplicate_listener(struct seccomp_filter *new_child) |
| 1890 | { |
| 1891 | struct seccomp_filter *cur; |
| 1892 | |
| 1893 | /* must be protected against concurrent TSYNC */ |
| 1894 | lockdep_assert_held(¤t->sighand->siglock); |
| 1895 | |
| 1896 | if (!new_child->notif) |
| 1897 | return false; |
| 1898 | for (cur = current->seccomp.filter; cur; cur = cur->prev) { |
| 1899 | if (cur->notif) |
| 1900 | return true; |
| 1901 | } |
| 1902 | |
| 1903 | return false; |
| 1904 | } |
| 1905 | |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1906 | /** |
| 1907 | * seccomp_set_mode_filter: internal function for setting seccomp filter |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 1908 | * @flags: flags to change filter behavior |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1909 | * @filter: struct sock_fprog containing filter |
| 1910 | * |
| 1911 | * This function may be called repeatedly to install additional filters. |
| 1912 | * Every filter successfully installed will be evaluated (in reverse order) |
| 1913 | * for each system call the task makes. |
| 1914 | * |
| 1915 | * Once current->seccomp.mode is non-zero, it may not be changed. |
| 1916 | * |
| 1917 | * Returns 0 on success or -EINVAL on failure. |
| 1918 | */ |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 1919 | static long seccomp_set_mode_filter(unsigned int flags, |
| 1920 | const char __user *filter) |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1921 | { |
| 1922 | const unsigned long seccomp_mode = SECCOMP_MODE_FILTER; |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 1923 | struct seccomp_filter *prepared = NULL; |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1924 | long ret = -EINVAL; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1925 | int listener = -1; |
| 1926 | struct file *listener_f = NULL; |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1927 | |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 1928 | /* Validate flags. */ |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 1929 | if (flags & ~SECCOMP_FILTER_FLAG_MASK) |
Kees Cook | dbd95212 | 2014-06-27 15:18:48 -0700 | [diff] [blame] | 1930 | return -EINVAL; |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 1931 | |
Tycho Andersen | 7a0df7f | 2019-03-06 13:14:13 -0700 | [diff] [blame] | 1932 | /* |
| 1933 | * In the successful case, NEW_LISTENER returns the new listener fd. |
| 1934 | * But in the failure case, TSYNC returns the thread that died. If you |
| 1935 | * combine these two flags, there's no way to tell whether something |
Tycho Andersen | 5189149 | 2020-03-04 11:05:17 -0700 | [diff] [blame] | 1936 | * succeeded or failed. So, let's disallow this combination if the user |
| 1937 | * has not explicitly requested no errors from TSYNC. |
Tycho Andersen | 7a0df7f | 2019-03-06 13:14:13 -0700 | [diff] [blame] | 1938 | */ |
| 1939 | if ((flags & SECCOMP_FILTER_FLAG_TSYNC) && |
Tycho Andersen | 5189149 | 2020-03-04 11:05:17 -0700 | [diff] [blame] | 1940 | (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) && |
| 1941 | ((flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) == 0)) |
Tycho Andersen | 7a0df7f | 2019-03-06 13:14:13 -0700 | [diff] [blame] | 1942 | return -EINVAL; |
| 1943 | |
Sargun Dhillon | c2aa2df | 2022-05-03 01:09:56 -0700 | [diff] [blame] | 1944 | /* |
| 1945 | * The SECCOMP_FILTER_FLAG_WAIT_KILLABLE_SENT flag doesn't make sense |
| 1946 | * without the SECCOMP_FILTER_FLAG_NEW_LISTENER flag. |
| 1947 | */ |
| 1948 | if ((flags & SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV) && |
| 1949 | ((flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) == 0)) |
| 1950 | return -EINVAL; |
| 1951 | |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 1952 | /* Prepare the new filter before holding any locks. */ |
| 1953 | prepared = seccomp_prepare_user_filter(filter); |
| 1954 | if (IS_ERR(prepared)) |
| 1955 | return PTR_ERR(prepared); |
| 1956 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1957 | if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) { |
| 1958 | listener = get_unused_fd_flags(O_CLOEXEC); |
| 1959 | if (listener < 0) { |
| 1960 | ret = listener; |
| 1961 | goto out_free; |
| 1962 | } |
| 1963 | |
| 1964 | listener_f = init_listener(prepared); |
| 1965 | if (IS_ERR(listener_f)) { |
| 1966 | put_unused_fd(listener); |
| 1967 | ret = PTR_ERR(listener_f); |
| 1968 | goto out_free; |
| 1969 | } |
| 1970 | } |
| 1971 | |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 1972 | /* |
| 1973 | * Make sure we cannot change seccomp or nnp state via TSYNC |
| 1974 | * while another thread is in the middle of calling exec. |
| 1975 | */ |
| 1976 | if (flags & SECCOMP_FILTER_FLAG_TSYNC && |
| 1977 | mutex_lock_killable(¤t->signal->cred_guard_mutex)) |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 1978 | goto out_put_fd; |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 1979 | |
Kees Cook | dbd95212 | 2014-06-27 15:18:48 -0700 | [diff] [blame] | 1980 | spin_lock_irq(¤t->sighand->siglock); |
| 1981 | |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1982 | if (!seccomp_may_assign_mode(seccomp_mode)) |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 1983 | goto out; |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1984 | |
Jann Horn | dfe719f | 2020-10-05 03:44:01 +0200 | [diff] [blame] | 1985 | if (has_duplicate_listener(prepared)) { |
| 1986 | ret = -EBUSY; |
| 1987 | goto out; |
| 1988 | } |
| 1989 | |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 1990 | ret = seccomp_attach_filter(flags, prepared); |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 1991 | if (ret) |
| 1992 | goto out; |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 1993 | /* Do not free the successfully attached filter. */ |
| 1994 | prepared = NULL; |
Andrea Arcangeli | 1d9d02f | 2007-07-15 23:41:32 -0700 | [diff] [blame] | 1995 | |
Kees Cook | 00a02d0 | 2018-05-03 14:56:12 -0700 | [diff] [blame] | 1996 | seccomp_assign_mode(current, seccomp_mode, flags); |
Will Drewry | e2cfabdf | 2012-04-12 16:47:57 -0500 | [diff] [blame] | 1997 | out: |
Kees Cook | dbd95212 | 2014-06-27 15:18:48 -0700 | [diff] [blame] | 1998 | spin_unlock_irq(¤t->sighand->siglock); |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 1999 | if (flags & SECCOMP_FILTER_FLAG_TSYNC) |
| 2000 | mutex_unlock(¤t->signal->cred_guard_mutex); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 2001 | out_put_fd: |
| 2002 | if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) { |
Tycho Andersen | 7a0df7f | 2019-03-06 13:14:13 -0700 | [diff] [blame] | 2003 | if (ret) { |
Tycho Andersen | a811dc6 | 2019-01-12 11:24:20 -0700 | [diff] [blame] | 2004 | listener_f->private_data = NULL; |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 2005 | fput(listener_f); |
| 2006 | put_unused_fd(listener); |
Tycho Andersen | a566a90 | 2020-09-01 19:40:16 -0600 | [diff] [blame] | 2007 | seccomp_notify_detach(prepared); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 2008 | } else { |
| 2009 | fd_install(listener, listener_f); |
| 2010 | ret = listener; |
| 2011 | } |
| 2012 | } |
Kees Cook | c2e1f2e | 2014-06-05 00:23:17 -0700 | [diff] [blame] | 2013 | out_free: |
Kees Cook | c8bee43 | 2014-06-27 15:16:33 -0700 | [diff] [blame] | 2014 | seccomp_filter_free(prepared); |
Andrea Arcangeli | 1d9d02f | 2007-07-15 23:41:32 -0700 | [diff] [blame] | 2015 | return ret; |
| 2016 | } |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 2017 | #else |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 2018 | static inline long seccomp_set_mode_filter(unsigned int flags, |
| 2019 | const char __user *filter) |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 2020 | { |
| 2021 | return -EINVAL; |
| 2022 | } |
| 2023 | #endif |
Kees Cook | d78ab02 | 2014-05-21 15:02:11 -0700 | [diff] [blame] | 2024 | |
Tyler Hicks | d612b1f | 2017-08-11 04:33:53 +0000 | [diff] [blame] | 2025 | static long seccomp_get_action_avail(const char __user *uaction) |
| 2026 | { |
| 2027 | u32 action; |
| 2028 | |
| 2029 | if (copy_from_user(&action, uaction, sizeof(action))) |
| 2030 | return -EFAULT; |
| 2031 | |
| 2032 | switch (action) { |
Kees Cook | 0466bdb | 2017-08-11 13:12:11 -0700 | [diff] [blame] | 2033 | case SECCOMP_RET_KILL_PROCESS: |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 2034 | case SECCOMP_RET_KILL_THREAD: |
Tyler Hicks | d612b1f | 2017-08-11 04:33:53 +0000 | [diff] [blame] | 2035 | case SECCOMP_RET_TRAP: |
| 2036 | case SECCOMP_RET_ERRNO: |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 2037 | case SECCOMP_RET_USER_NOTIF: |
Tyler Hicks | d612b1f | 2017-08-11 04:33:53 +0000 | [diff] [blame] | 2038 | case SECCOMP_RET_TRACE: |
Tyler Hicks | 59f5cf4 | 2017-08-11 04:33:57 +0000 | [diff] [blame] | 2039 | case SECCOMP_RET_LOG: |
Tyler Hicks | d612b1f | 2017-08-11 04:33:53 +0000 | [diff] [blame] | 2040 | case SECCOMP_RET_ALLOW: |
| 2041 | break; |
| 2042 | default: |
| 2043 | return -EOPNOTSUPP; |
| 2044 | } |
| 2045 | |
| 2046 | return 0; |
| 2047 | } |
| 2048 | |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 2049 | static long seccomp_get_notif_sizes(void __user *usizes) |
| 2050 | { |
| 2051 | struct seccomp_notif_sizes sizes = { |
| 2052 | .seccomp_notif = sizeof(struct seccomp_notif), |
| 2053 | .seccomp_notif_resp = sizeof(struct seccomp_notif_resp), |
| 2054 | .seccomp_data = sizeof(struct seccomp_data), |
| 2055 | }; |
| 2056 | |
| 2057 | if (copy_to_user(usizes, &sizes, sizeof(sizes))) |
| 2058 | return -EFAULT; |
| 2059 | |
| 2060 | return 0; |
| 2061 | } |
| 2062 | |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 2063 | /* Common entry point for both prctl and syscall. */ |
| 2064 | static long do_seccomp(unsigned int op, unsigned int flags, |
Tycho Andersen | a5662e4 | 2018-12-09 11:24:12 -0700 | [diff] [blame] | 2065 | void __user *uargs) |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 2066 | { |
| 2067 | switch (op) { |
| 2068 | case SECCOMP_SET_MODE_STRICT: |
| 2069 | if (flags != 0 || uargs != NULL) |
| 2070 | return -EINVAL; |
| 2071 | return seccomp_set_mode_strict(); |
| 2072 | case SECCOMP_SET_MODE_FILTER: |
| 2073 | return seccomp_set_mode_filter(flags, uargs); |
Tyler Hicks | d612b1f | 2017-08-11 04:33:53 +0000 | [diff] [blame] | 2074 | case SECCOMP_GET_ACTION_AVAIL: |
| 2075 | if (flags != 0) |
| 2076 | return -EINVAL; |
| 2077 | |
| 2078 | return seccomp_get_action_avail(uargs); |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 2079 | case SECCOMP_GET_NOTIF_SIZES: |
| 2080 | if (flags != 0) |
| 2081 | return -EINVAL; |
| 2082 | |
| 2083 | return seccomp_get_notif_sizes(uargs); |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 2084 | default: |
| 2085 | return -EINVAL; |
| 2086 | } |
| 2087 | } |
| 2088 | |
| 2089 | SYSCALL_DEFINE3(seccomp, unsigned int, op, unsigned int, flags, |
Tycho Andersen | a5662e4 | 2018-12-09 11:24:12 -0700 | [diff] [blame] | 2090 | void __user *, uargs) |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 2091 | { |
| 2092 | return do_seccomp(op, flags, uargs); |
| 2093 | } |
| 2094 | |
Kees Cook | d78ab02 | 2014-05-21 15:02:11 -0700 | [diff] [blame] | 2095 | /** |
| 2096 | * prctl_set_seccomp: configures current->seccomp.mode |
| 2097 | * @seccomp_mode: requested mode to use |
| 2098 | * @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER |
| 2099 | * |
| 2100 | * Returns 0 on success or -EINVAL on failure. |
| 2101 | */ |
Tycho Andersen | a5662e4 | 2018-12-09 11:24:12 -0700 | [diff] [blame] | 2102 | long prctl_set_seccomp(unsigned long seccomp_mode, void __user *filter) |
Kees Cook | d78ab02 | 2014-05-21 15:02:11 -0700 | [diff] [blame] | 2103 | { |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 2104 | unsigned int op; |
Tycho Andersen | a5662e4 | 2018-12-09 11:24:12 -0700 | [diff] [blame] | 2105 | void __user *uargs; |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 2106 | |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 2107 | switch (seccomp_mode) { |
| 2108 | case SECCOMP_MODE_STRICT: |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 2109 | op = SECCOMP_SET_MODE_STRICT; |
| 2110 | /* |
| 2111 | * Setting strict mode through prctl always ignored filter, |
| 2112 | * so make sure it is always NULL here to pass the internal |
| 2113 | * check in do_seccomp(). |
| 2114 | */ |
| 2115 | uargs = NULL; |
| 2116 | break; |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 2117 | case SECCOMP_MODE_FILTER: |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 2118 | op = SECCOMP_SET_MODE_FILTER; |
| 2119 | uargs = filter; |
| 2120 | break; |
Kees Cook | 3b23dd1 | 2014-06-25 15:55:25 -0700 | [diff] [blame] | 2121 | default: |
| 2122 | return -EINVAL; |
| 2123 | } |
Kees Cook | 48dc92b | 2014-06-25 16:08:24 -0700 | [diff] [blame] | 2124 | |
| 2125 | /* prctl interface doesn't have flags, so they are always zero. */ |
| 2126 | return do_seccomp(op, 0, uargs); |
Kees Cook | d78ab02 | 2014-05-21 15:02:11 -0700 | [diff] [blame] | 2127 | } |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 2128 | |
| 2129 | #if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE) |
Tycho Andersen | f06eae8 | 2017-10-11 09:39:20 -0600 | [diff] [blame] | 2130 | static struct seccomp_filter *get_nth_filter(struct task_struct *task, |
| 2131 | unsigned long filter_off) |
| 2132 | { |
| 2133 | struct seccomp_filter *orig, *filter; |
| 2134 | unsigned long count; |
| 2135 | |
| 2136 | /* |
| 2137 | * Note: this is only correct because the caller should be the (ptrace) |
| 2138 | * tracer of the task, otherwise lock_task_sighand is needed. |
| 2139 | */ |
| 2140 | spin_lock_irq(&task->sighand->siglock); |
| 2141 | |
| 2142 | if (task->seccomp.mode != SECCOMP_MODE_FILTER) { |
| 2143 | spin_unlock_irq(&task->sighand->siglock); |
| 2144 | return ERR_PTR(-EINVAL); |
| 2145 | } |
| 2146 | |
| 2147 | orig = task->seccomp.filter; |
| 2148 | __get_seccomp_filter(orig); |
| 2149 | spin_unlock_irq(&task->sighand->siglock); |
| 2150 | |
| 2151 | count = 0; |
| 2152 | for (filter = orig; filter; filter = filter->prev) |
| 2153 | count++; |
| 2154 | |
| 2155 | if (filter_off >= count) { |
| 2156 | filter = ERR_PTR(-ENOENT); |
| 2157 | goto out; |
| 2158 | } |
| 2159 | |
| 2160 | count -= filter_off; |
| 2161 | for (filter = orig; filter && count > 1; filter = filter->prev) |
| 2162 | count--; |
| 2163 | |
| 2164 | if (WARN_ON(count != 1 || !filter)) { |
| 2165 | filter = ERR_PTR(-ENOENT); |
| 2166 | goto out; |
| 2167 | } |
| 2168 | |
| 2169 | __get_seccomp_filter(filter); |
| 2170 | |
| 2171 | out: |
| 2172 | __put_seccomp_filter(orig); |
| 2173 | return filter; |
| 2174 | } |
| 2175 | |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 2176 | long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, |
| 2177 | void __user *data) |
| 2178 | { |
| 2179 | struct seccomp_filter *filter; |
| 2180 | struct sock_fprog_kern *fprog; |
| 2181 | long ret; |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 2182 | |
| 2183 | if (!capable(CAP_SYS_ADMIN) || |
| 2184 | current->seccomp.mode != SECCOMP_MODE_DISABLED) { |
| 2185 | return -EACCES; |
| 2186 | } |
| 2187 | |
Tycho Andersen | f06eae8 | 2017-10-11 09:39:20 -0600 | [diff] [blame] | 2188 | filter = get_nth_filter(task, filter_off); |
| 2189 | if (IS_ERR(filter)) |
| 2190 | return PTR_ERR(filter); |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 2191 | |
| 2192 | fprog = filter->prog->orig_prog; |
| 2193 | if (!fprog) { |
Mickaël Salaün | 470bf1f | 2016-03-24 02:46:33 +0100 | [diff] [blame] | 2194 | /* This must be a new non-cBPF filter, since we save |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 2195 | * every cBPF filter's orig_prog above when |
| 2196 | * CONFIG_CHECKPOINT_RESTORE is enabled. |
| 2197 | */ |
| 2198 | ret = -EMEDIUMTYPE; |
| 2199 | goto out; |
| 2200 | } |
| 2201 | |
| 2202 | ret = fprog->len; |
| 2203 | if (!data) |
| 2204 | goto out; |
| 2205 | |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 2206 | if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog))) |
| 2207 | ret = -EFAULT; |
| 2208 | |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 2209 | out: |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 2210 | __put_seccomp_filter(filter); |
| 2211 | return ret; |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 2212 | } |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 2213 | |
Tycho Andersen | 2650047 | 2017-10-11 09:39:21 -0600 | [diff] [blame] | 2214 | long seccomp_get_metadata(struct task_struct *task, |
| 2215 | unsigned long size, void __user *data) |
| 2216 | { |
| 2217 | long ret; |
| 2218 | struct seccomp_filter *filter; |
| 2219 | struct seccomp_metadata kmd = {}; |
| 2220 | |
| 2221 | if (!capable(CAP_SYS_ADMIN) || |
| 2222 | current->seccomp.mode != SECCOMP_MODE_DISABLED) { |
| 2223 | return -EACCES; |
| 2224 | } |
| 2225 | |
| 2226 | size = min_t(unsigned long, size, sizeof(kmd)); |
| 2227 | |
Tycho Andersen | 63bb004 | 2018-02-20 19:47:46 -0700 | [diff] [blame] | 2228 | if (size < sizeof(kmd.filter_off)) |
| 2229 | return -EINVAL; |
| 2230 | |
| 2231 | if (copy_from_user(&kmd.filter_off, data, sizeof(kmd.filter_off))) |
Tycho Andersen | 2650047 | 2017-10-11 09:39:21 -0600 | [diff] [blame] | 2232 | return -EFAULT; |
| 2233 | |
| 2234 | filter = get_nth_filter(task, kmd.filter_off); |
| 2235 | if (IS_ERR(filter)) |
| 2236 | return PTR_ERR(filter); |
| 2237 | |
Tycho Andersen | 2650047 | 2017-10-11 09:39:21 -0600 | [diff] [blame] | 2238 | if (filter->log) |
| 2239 | kmd.flags |= SECCOMP_FILTER_FLAG_LOG; |
| 2240 | |
| 2241 | ret = size; |
| 2242 | if (copy_to_user(data, &kmd, size)) |
| 2243 | ret = -EFAULT; |
| 2244 | |
| 2245 | __put_seccomp_filter(filter); |
Tycho Andersen | f8e529ed | 2015-10-27 09:23:59 +0900 | [diff] [blame] | 2246 | return ret; |
| 2247 | } |
| 2248 | #endif |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 2249 | |
| 2250 | #ifdef CONFIG_SYSCTL |
| 2251 | |
| 2252 | /* Human readable action names for friendly sysctl interaction */ |
Kees Cook | 0466bdb | 2017-08-11 13:12:11 -0700 | [diff] [blame] | 2253 | #define SECCOMP_RET_KILL_PROCESS_NAME "kill_process" |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 2254 | #define SECCOMP_RET_KILL_THREAD_NAME "kill_thread" |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 2255 | #define SECCOMP_RET_TRAP_NAME "trap" |
| 2256 | #define SECCOMP_RET_ERRNO_NAME "errno" |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 2257 | #define SECCOMP_RET_USER_NOTIF_NAME "user_notif" |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 2258 | #define SECCOMP_RET_TRACE_NAME "trace" |
Tyler Hicks | 59f5cf4 | 2017-08-11 04:33:57 +0000 | [diff] [blame] | 2259 | #define SECCOMP_RET_LOG_NAME "log" |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 2260 | #define SECCOMP_RET_ALLOW_NAME "allow" |
| 2261 | |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 2262 | static const char seccomp_actions_avail[] = |
Kees Cook | 0466bdb | 2017-08-11 13:12:11 -0700 | [diff] [blame] | 2263 | SECCOMP_RET_KILL_PROCESS_NAME " " |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 2264 | SECCOMP_RET_KILL_THREAD_NAME " " |
| 2265 | SECCOMP_RET_TRAP_NAME " " |
| 2266 | SECCOMP_RET_ERRNO_NAME " " |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 2267 | SECCOMP_RET_USER_NOTIF_NAME " " |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 2268 | SECCOMP_RET_TRACE_NAME " " |
| 2269 | SECCOMP_RET_LOG_NAME " " |
| 2270 | SECCOMP_RET_ALLOW_NAME; |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 2271 | |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2272 | struct seccomp_log_name { |
| 2273 | u32 log; |
| 2274 | const char *name; |
| 2275 | }; |
| 2276 | |
| 2277 | static const struct seccomp_log_name seccomp_log_names[] = { |
Kees Cook | 0466bdb | 2017-08-11 13:12:11 -0700 | [diff] [blame] | 2278 | { SECCOMP_LOG_KILL_PROCESS, SECCOMP_RET_KILL_PROCESS_NAME }, |
Kees Cook | fd76875 | 2017-08-11 12:53:18 -0700 | [diff] [blame] | 2279 | { SECCOMP_LOG_KILL_THREAD, SECCOMP_RET_KILL_THREAD_NAME }, |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2280 | { SECCOMP_LOG_TRAP, SECCOMP_RET_TRAP_NAME }, |
| 2281 | { SECCOMP_LOG_ERRNO, SECCOMP_RET_ERRNO_NAME }, |
Tycho Andersen | 6a21cc5 | 2018-12-09 11:24:13 -0700 | [diff] [blame] | 2282 | { SECCOMP_LOG_USER_NOTIF, SECCOMP_RET_USER_NOTIF_NAME }, |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2283 | { SECCOMP_LOG_TRACE, SECCOMP_RET_TRACE_NAME }, |
Tyler Hicks | 59f5cf4 | 2017-08-11 04:33:57 +0000 | [diff] [blame] | 2284 | { SECCOMP_LOG_LOG, SECCOMP_RET_LOG_NAME }, |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2285 | { SECCOMP_LOG_ALLOW, SECCOMP_RET_ALLOW_NAME }, |
| 2286 | { } |
| 2287 | }; |
| 2288 | |
| 2289 | static bool seccomp_names_from_actions_logged(char *names, size_t size, |
Tyler Hicks | beb44ac | 2018-05-04 01:08:13 +0000 | [diff] [blame] | 2290 | u32 actions_logged, |
| 2291 | const char *sep) |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2292 | { |
| 2293 | const struct seccomp_log_name *cur; |
Tyler Hicks | beb44ac | 2018-05-04 01:08:13 +0000 | [diff] [blame] | 2294 | bool append_sep = false; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2295 | |
| 2296 | for (cur = seccomp_log_names; cur->name && size; cur++) { |
| 2297 | ssize_t ret; |
| 2298 | |
| 2299 | if (!(actions_logged & cur->log)) |
| 2300 | continue; |
| 2301 | |
Tyler Hicks | beb44ac | 2018-05-04 01:08:13 +0000 | [diff] [blame] | 2302 | if (append_sep) { |
| 2303 | ret = strscpy(names, sep, size); |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2304 | if (ret < 0) |
| 2305 | return false; |
| 2306 | |
| 2307 | names += ret; |
| 2308 | size -= ret; |
| 2309 | } else |
Tyler Hicks | beb44ac | 2018-05-04 01:08:13 +0000 | [diff] [blame] | 2310 | append_sep = true; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2311 | |
| 2312 | ret = strscpy(names, cur->name, size); |
| 2313 | if (ret < 0) |
| 2314 | return false; |
| 2315 | |
| 2316 | names += ret; |
| 2317 | size -= ret; |
| 2318 | } |
| 2319 | |
| 2320 | return true; |
| 2321 | } |
| 2322 | |
| 2323 | static bool seccomp_action_logged_from_name(u32 *action_logged, |
| 2324 | const char *name) |
| 2325 | { |
| 2326 | const struct seccomp_log_name *cur; |
| 2327 | |
| 2328 | for (cur = seccomp_log_names; cur->name; cur++) { |
| 2329 | if (!strcmp(cur->name, name)) { |
| 2330 | *action_logged = cur->log; |
| 2331 | return true; |
| 2332 | } |
| 2333 | } |
| 2334 | |
| 2335 | return false; |
| 2336 | } |
| 2337 | |
| 2338 | static bool seccomp_actions_logged_from_names(u32 *actions_logged, char *names) |
| 2339 | { |
| 2340 | char *name; |
| 2341 | |
| 2342 | *actions_logged = 0; |
| 2343 | while ((name = strsep(&names, " ")) && *name) { |
| 2344 | u32 action_logged = 0; |
| 2345 | |
| 2346 | if (!seccomp_action_logged_from_name(&action_logged, name)) |
| 2347 | return false; |
| 2348 | |
| 2349 | *actions_logged |= action_logged; |
| 2350 | } |
| 2351 | |
| 2352 | return true; |
| 2353 | } |
| 2354 | |
Kees Cook | e406737 | 2024-05-08 10:13:41 -0700 | [diff] [blame] | 2355 | static int read_actions_logged(const struct ctl_table *ro_table, void *buffer, |
Tyler Hicks | d013db0 | 2018-05-04 01:08:12 +0000 | [diff] [blame] | 2356 | size_t *lenp, loff_t *ppos) |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2357 | { |
| 2358 | char names[sizeof(seccomp_actions_avail)]; |
| 2359 | struct ctl_table table; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2360 | |
| 2361 | memset(names, 0, sizeof(names)); |
| 2362 | |
Tyler Hicks | d013db0 | 2018-05-04 01:08:12 +0000 | [diff] [blame] | 2363 | if (!seccomp_names_from_actions_logged(names, sizeof(names), |
Tyler Hicks | beb44ac | 2018-05-04 01:08:13 +0000 | [diff] [blame] | 2364 | seccomp_actions_logged, " ")) |
Tyler Hicks | d013db0 | 2018-05-04 01:08:12 +0000 | [diff] [blame] | 2365 | return -EINVAL; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2366 | |
| 2367 | table = *ro_table; |
| 2368 | table.data = names; |
| 2369 | table.maxlen = sizeof(names); |
Tyler Hicks | d013db0 | 2018-05-04 01:08:12 +0000 | [diff] [blame] | 2370 | return proc_dostring(&table, 0, buffer, lenp, ppos); |
| 2371 | } |
| 2372 | |
Kees Cook | e406737 | 2024-05-08 10:13:41 -0700 | [diff] [blame] | 2373 | static int write_actions_logged(const struct ctl_table *ro_table, void *buffer, |
Tyler Hicks | ea6eca7 | 2018-05-04 01:08:14 +0000 | [diff] [blame] | 2374 | size_t *lenp, loff_t *ppos, u32 *actions_logged) |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2375 | { |
| 2376 | char names[sizeof(seccomp_actions_avail)]; |
| 2377 | struct ctl_table table; |
| 2378 | int ret; |
| 2379 | |
Tyler Hicks | d013db0 | 2018-05-04 01:08:12 +0000 | [diff] [blame] | 2380 | if (!capable(CAP_SYS_ADMIN)) |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2381 | return -EPERM; |
| 2382 | |
| 2383 | memset(names, 0, sizeof(names)); |
| 2384 | |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2385 | table = *ro_table; |
| 2386 | table.data = names; |
| 2387 | table.maxlen = sizeof(names); |
Tyler Hicks | d013db0 | 2018-05-04 01:08:12 +0000 | [diff] [blame] | 2388 | ret = proc_dostring(&table, 1, buffer, lenp, ppos); |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2389 | if (ret) |
| 2390 | return ret; |
| 2391 | |
Tyler Hicks | ea6eca7 | 2018-05-04 01:08:14 +0000 | [diff] [blame] | 2392 | if (!seccomp_actions_logged_from_names(actions_logged, table.data)) |
Tyler Hicks | d013db0 | 2018-05-04 01:08:12 +0000 | [diff] [blame] | 2393 | return -EINVAL; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2394 | |
Tyler Hicks | ea6eca7 | 2018-05-04 01:08:14 +0000 | [diff] [blame] | 2395 | if (*actions_logged & SECCOMP_LOG_ALLOW) |
Tyler Hicks | d013db0 | 2018-05-04 01:08:12 +0000 | [diff] [blame] | 2396 | return -EINVAL; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2397 | |
Tyler Hicks | ea6eca7 | 2018-05-04 01:08:14 +0000 | [diff] [blame] | 2398 | seccomp_actions_logged = *actions_logged; |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2399 | return 0; |
| 2400 | } |
| 2401 | |
Tyler Hicks | ea6eca7 | 2018-05-04 01:08:14 +0000 | [diff] [blame] | 2402 | static void audit_actions_logged(u32 actions_logged, u32 old_actions_logged, |
| 2403 | int ret) |
| 2404 | { |
| 2405 | char names[sizeof(seccomp_actions_avail)]; |
| 2406 | char old_names[sizeof(seccomp_actions_avail)]; |
| 2407 | const char *new = names; |
| 2408 | const char *old = old_names; |
| 2409 | |
| 2410 | if (!audit_enabled) |
| 2411 | return; |
| 2412 | |
| 2413 | memset(names, 0, sizeof(names)); |
| 2414 | memset(old_names, 0, sizeof(old_names)); |
| 2415 | |
| 2416 | if (ret) |
| 2417 | new = "?"; |
| 2418 | else if (!actions_logged) |
| 2419 | new = "(none)"; |
| 2420 | else if (!seccomp_names_from_actions_logged(names, sizeof(names), |
| 2421 | actions_logged, ",")) |
| 2422 | new = "?"; |
| 2423 | |
| 2424 | if (!old_actions_logged) |
| 2425 | old = "(none)"; |
| 2426 | else if (!seccomp_names_from_actions_logged(old_names, |
| 2427 | sizeof(old_names), |
| 2428 | old_actions_logged, ",")) |
| 2429 | old = "?"; |
| 2430 | |
| 2431 | return audit_seccomp_actions_logged(new, old, !ret); |
| 2432 | } |
| 2433 | |
Joel Granados | 78eb4ea | 2024-07-24 20:59:29 +0200 | [diff] [blame] | 2434 | static int seccomp_actions_logged_handler(const struct ctl_table *ro_table, int write, |
Christoph Hellwig | 3292739 | 2020-04-24 08:43:38 +0200 | [diff] [blame] | 2435 | void *buffer, size_t *lenp, |
Tyler Hicks | d013db0 | 2018-05-04 01:08:12 +0000 | [diff] [blame] | 2436 | loff_t *ppos) |
| 2437 | { |
Tyler Hicks | ea6eca7 | 2018-05-04 01:08:14 +0000 | [diff] [blame] | 2438 | int ret; |
| 2439 | |
| 2440 | if (write) { |
| 2441 | u32 actions_logged = 0; |
| 2442 | u32 old_actions_logged = seccomp_actions_logged; |
| 2443 | |
| 2444 | ret = write_actions_logged(ro_table, buffer, lenp, ppos, |
| 2445 | &actions_logged); |
| 2446 | audit_actions_logged(actions_logged, old_actions_logged, ret); |
| 2447 | } else |
| 2448 | ret = read_actions_logged(ro_table, buffer, lenp, ppos); |
| 2449 | |
| 2450 | return ret; |
Tyler Hicks | d013db0 | 2018-05-04 01:08:12 +0000 | [diff] [blame] | 2451 | } |
| 2452 | |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 2453 | static struct ctl_table seccomp_sysctl_table[] = { |
| 2454 | { |
| 2455 | .procname = "actions_avail", |
| 2456 | .data = (void *) &seccomp_actions_avail, |
| 2457 | .maxlen = sizeof(seccomp_actions_avail), |
| 2458 | .mode = 0444, |
| 2459 | .proc_handler = proc_dostring, |
| 2460 | }, |
Tyler Hicks | 0ddec0f | 2017-08-11 04:33:54 +0000 | [diff] [blame] | 2461 | { |
| 2462 | .procname = "actions_logged", |
| 2463 | .mode = 0644, |
| 2464 | .proc_handler = seccomp_actions_logged_handler, |
| 2465 | }, |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 2466 | }; |
| 2467 | |
| 2468 | static int __init seccomp_sysctl_init(void) |
| 2469 | { |
Luis Chamberlain | 02a6b45 | 2023-03-02 12:28:22 -0800 | [diff] [blame] | 2470 | register_sysctl_init("kernel/seccomp", seccomp_sysctl_table); |
Tyler Hicks | 8e5f1ad | 2017-08-11 04:33:52 +0000 | [diff] [blame] | 2471 | return 0; |
| 2472 | } |
| 2473 | |
| 2474 | device_initcall(seccomp_sysctl_init) |
| 2475 | |
| 2476 | #endif /* CONFIG_SYSCTL */ |
YiFei Zhu | 0d8315d | 2020-11-11 07:33:54 -0600 | [diff] [blame] | 2477 | |
| 2478 | #ifdef CONFIG_SECCOMP_CACHE_DEBUG |
| 2479 | /* Currently CONFIG_SECCOMP_CACHE_DEBUG implies SECCOMP_ARCH_NATIVE */ |
| 2480 | static void proc_pid_seccomp_cache_arch(struct seq_file *m, const char *name, |
| 2481 | const void *bitmap, size_t bitmap_size) |
| 2482 | { |
| 2483 | int nr; |
| 2484 | |
| 2485 | for (nr = 0; nr < bitmap_size; nr++) { |
| 2486 | bool cached = test_bit(nr, bitmap); |
| 2487 | char *status = cached ? "ALLOW" : "FILTER"; |
| 2488 | |
| 2489 | seq_printf(m, "%s %d %s\n", name, nr, status); |
| 2490 | } |
| 2491 | } |
| 2492 | |
| 2493 | int proc_pid_seccomp_cache(struct seq_file *m, struct pid_namespace *ns, |
| 2494 | struct pid *pid, struct task_struct *task) |
| 2495 | { |
| 2496 | struct seccomp_filter *f; |
| 2497 | unsigned long flags; |
| 2498 | |
| 2499 | /* |
| 2500 | * We don't want some sandboxed process to know what their seccomp |
| 2501 | * filters consist of. |
| 2502 | */ |
| 2503 | if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) |
| 2504 | return -EACCES; |
| 2505 | |
| 2506 | if (!lock_task_sighand(task, &flags)) |
| 2507 | return -ESRCH; |
| 2508 | |
| 2509 | f = READ_ONCE(task->seccomp.filter); |
| 2510 | if (!f) { |
| 2511 | unlock_task_sighand(task, &flags); |
| 2512 | return 0; |
| 2513 | } |
| 2514 | |
| 2515 | /* prevent filter from being freed while we are printing it */ |
| 2516 | __get_seccomp_filter(f); |
| 2517 | unlock_task_sighand(task, &flags); |
| 2518 | |
| 2519 | proc_pid_seccomp_cache_arch(m, SECCOMP_ARCH_NATIVE_NAME, |
| 2520 | f->cache.allow_native, |
| 2521 | SECCOMP_ARCH_NATIVE_NR); |
| 2522 | |
| 2523 | #ifdef SECCOMP_ARCH_COMPAT |
| 2524 | proc_pid_seccomp_cache_arch(m, SECCOMP_ARCH_COMPAT_NAME, |
| 2525 | f->cache.allow_compat, |
| 2526 | SECCOMP_ARCH_COMPAT_NR); |
| 2527 | #endif /* SECCOMP_ARCH_COMPAT */ |
| 2528 | |
| 2529 | __put_seccomp_filter(f); |
| 2530 | return 0; |
| 2531 | } |
| 2532 | #endif /* CONFIG_SECCOMP_CACHE_DEBUG */ |