Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/futex_compat.c |
| 3 | * |
| 4 | * Futex compatibililty routines. |
| 5 | * |
| 6 | * Copyright 2006, Red Hat, Inc., Ingo Molnar |
| 7 | */ |
| 8 | |
| 9 | #include <linux/linkage.h> |
| 10 | #include <linux/compat.h> |
Pavel Emelyanov | b488893 | 2007-10-18 23:40:14 -0700 | [diff] [blame] | 11 | #include <linux/nsproxy.h> |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 12 | #include <linux/futex.h> |
Kees Cook | bdbb776 | 2012-03-19 16:12:53 -0700 | [diff] [blame] | 13 | #include <linux/ptrace.h> |
Al Viro | 90caf58 | 2012-12-25 23:16:10 -0500 | [diff] [blame] | 14 | #include <linux/syscalls.h> |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 15 | |
| 16 | #include <asm/uaccess.h> |
| 17 | |
Ingo Molnar | e3f2dde | 2006-07-29 05:17:57 +0200 | [diff] [blame] | 18 | |
| 19 | /* |
| 20 | * Fetch a robust-list pointer. Bit 0 signals PI futexes: |
| 21 | */ |
| 22 | static inline int |
| 23 | fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry, |
Namhyung Kim | 1dcc41b | 2010-09-14 21:43:46 +0900 | [diff] [blame] | 24 | compat_uptr_t __user *head, unsigned int *pi) |
Ingo Molnar | e3f2dde | 2006-07-29 05:17:57 +0200 | [diff] [blame] | 25 | { |
| 26 | if (get_user(*uentry, head)) |
| 27 | return -EFAULT; |
| 28 | |
| 29 | *entry = compat_ptr((*uentry) & ~1); |
| 30 | *pi = (unsigned int)(*uentry) & 1; |
| 31 | |
| 32 | return 0; |
| 33 | } |
| 34 | |
Al Viro | 8481664 | 2008-03-29 03:07:58 +0000 | [diff] [blame] | 35 | static void __user *futex_uaddr(struct robust_list __user *entry, |
David Miller | 3c5fd9c7 | 2007-11-06 21:13:56 -0800 | [diff] [blame] | 36 | compat_long_t futex_offset) |
| 37 | { |
| 38 | compat_uptr_t base = ptr_to_compat(entry); |
| 39 | void __user *uaddr = compat_ptr(base + futex_offset); |
| 40 | |
| 41 | return uaddr; |
| 42 | } |
| 43 | |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 44 | /* |
| 45 | * Walk curr->robust_list (very carefully, it's a userspace list!) |
| 46 | * and mark any locks found there dead, and notify any waiters. |
| 47 | * |
| 48 | * We silently return on any sign of list-walking problem. |
| 49 | */ |
| 50 | void compat_exit_robust_list(struct task_struct *curr) |
| 51 | { |
| 52 | struct compat_robust_list_head __user *head = curr->compat_robust_list; |
Martin Schwidefsky | 9f96cb1 | 2007-10-01 01:20:13 -0700 | [diff] [blame] | 53 | struct robust_list __user *entry, *next_entry, *pending; |
Darren Hart | 4c115e9 | 2010-11-04 15:00:00 -0400 | [diff] [blame] | 54 | unsigned int limit = ROBUST_LIST_LIMIT, pi, pip; |
| 55 | unsigned int uninitialized_var(next_pi); |
Martin Schwidefsky | 9f96cb1 | 2007-10-01 01:20:13 -0700 | [diff] [blame] | 56 | compat_uptr_t uentry, next_uentry, upending; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 57 | compat_long_t futex_offset; |
Martin Schwidefsky | 9f96cb1 | 2007-10-01 01:20:13 -0700 | [diff] [blame] | 58 | int rc; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 59 | |
Thomas Gleixner | a0c1e90 | 2008-02-23 15:23:57 -0800 | [diff] [blame] | 60 | if (!futex_cmpxchg_enabled) |
| 61 | return; |
| 62 | |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 63 | /* |
| 64 | * Fetch the list head (which was registered earlier, via |
| 65 | * sys_set_robust_list()): |
| 66 | */ |
Ingo Molnar | e3f2dde | 2006-07-29 05:17:57 +0200 | [diff] [blame] | 67 | if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi)) |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 68 | return; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 69 | /* |
| 70 | * Fetch the relative futex offset: |
| 71 | */ |
| 72 | if (get_user(futex_offset, &head->futex_offset)) |
| 73 | return; |
| 74 | /* |
| 75 | * Fetch any possibly pending lock-add first, and handle it |
| 76 | * if it exists: |
| 77 | */ |
Ingo Molnar | e3f2dde | 2006-07-29 05:17:57 +0200 | [diff] [blame] | 78 | if (fetch_robust_entry(&upending, &pending, |
Thomas Gleixner | ce2c6b5 | 2006-08-05 12:15:15 -0700 | [diff] [blame] | 79 | &head->list_op_pending, &pip)) |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 80 | return; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 81 | |
Martin Schwidefsky | 9f96cb1 | 2007-10-01 01:20:13 -0700 | [diff] [blame] | 82 | next_entry = NULL; /* avoid warning with gcc */ |
Arnd Bergmann | 179c85e | 2007-09-11 15:23:49 -0700 | [diff] [blame] | 83 | while (entry != (struct robust_list __user *) &head->list) { |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 84 | /* |
Martin Schwidefsky | 9f96cb1 | 2007-10-01 01:20:13 -0700 | [diff] [blame] | 85 | * Fetch the next entry in the list before calling |
| 86 | * handle_futex_death: |
| 87 | */ |
| 88 | rc = fetch_robust_entry(&next_uentry, &next_entry, |
| 89 | (compat_uptr_t __user *)&entry->next, &next_pi); |
| 90 | /* |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 91 | * A pending lock might already be on the list, so |
| 92 | * dont process it twice: |
| 93 | */ |
David Miller | 3c5fd9c7 | 2007-11-06 21:13:56 -0800 | [diff] [blame] | 94 | if (entry != pending) { |
| 95 | void __user *uaddr = futex_uaddr(entry, futex_offset); |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 96 | |
David Miller | 3c5fd9c7 | 2007-11-06 21:13:56 -0800 | [diff] [blame] | 97 | if (handle_futex_death(uaddr, curr, pi)) |
| 98 | return; |
| 99 | } |
Martin Schwidefsky | 9f96cb1 | 2007-10-01 01:20:13 -0700 | [diff] [blame] | 100 | if (rc) |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 101 | return; |
Martin Schwidefsky | 9f96cb1 | 2007-10-01 01:20:13 -0700 | [diff] [blame] | 102 | uentry = next_uentry; |
| 103 | entry = next_entry; |
| 104 | pi = next_pi; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 105 | /* |
| 106 | * Avoid excessively long or circular lists: |
| 107 | */ |
| 108 | if (!--limit) |
| 109 | break; |
| 110 | |
| 111 | cond_resched(); |
| 112 | } |
David Miller | 3c5fd9c7 | 2007-11-06 21:13:56 -0800 | [diff] [blame] | 113 | if (pending) { |
| 114 | void __user *uaddr = futex_uaddr(pending, futex_offset); |
| 115 | |
| 116 | handle_futex_death(uaddr, curr, pip); |
| 117 | } |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 118 | } |
| 119 | |
Al Viro | 90caf58 | 2012-12-25 23:16:10 -0500 | [diff] [blame] | 120 | COMPAT_SYSCALL_DEFINE2(set_robust_list, |
| 121 | struct compat_robust_list_head __user *, head, |
| 122 | compat_size_t, len) |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 123 | { |
Thomas Gleixner | a0c1e90 | 2008-02-23 15:23:57 -0800 | [diff] [blame] | 124 | if (!futex_cmpxchg_enabled) |
| 125 | return -ENOSYS; |
| 126 | |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 127 | if (unlikely(len != sizeof(*head))) |
| 128 | return -EINVAL; |
| 129 | |
| 130 | current->compat_robust_list = head; |
| 131 | |
| 132 | return 0; |
| 133 | } |
| 134 | |
Al Viro | 90caf58 | 2012-12-25 23:16:10 -0500 | [diff] [blame] | 135 | COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid, |
| 136 | compat_uptr_t __user *, head_ptr, |
| 137 | compat_size_t __user *, len_ptr) |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 138 | { |
Al Viro | ba46df9 | 2006-10-10 22:46:07 +0100 | [diff] [blame] | 139 | struct compat_robust_list_head __user *head; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 140 | unsigned long ret; |
Kees Cook | bdbb776 | 2012-03-19 16:12:53 -0700 | [diff] [blame] | 141 | struct task_struct *p; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 142 | |
Thomas Gleixner | a0c1e90 | 2008-02-23 15:23:57 -0800 | [diff] [blame] | 143 | if (!futex_cmpxchg_enabled) |
| 144 | return -ENOSYS; |
| 145 | |
Kees Cook | bdbb776 | 2012-03-19 16:12:53 -0700 | [diff] [blame] | 146 | rcu_read_lock(); |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 147 | |
Kees Cook | bdbb776 | 2012-03-19 16:12:53 -0700 | [diff] [blame] | 148 | ret = -ESRCH; |
| 149 | if (!pid) |
| 150 | p = current; |
| 151 | else { |
Pavel Emelyanov | 228ebcb | 2007-10-18 23:40:16 -0700 | [diff] [blame] | 152 | p = find_task_by_vpid(pid); |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 153 | if (!p) |
| 154 | goto err_unlock; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 155 | } |
| 156 | |
Kees Cook | bdbb776 | 2012-03-19 16:12:53 -0700 | [diff] [blame] | 157 | ret = -EPERM; |
| 158 | if (!ptrace_may_access(p, PTRACE_MODE_READ)) |
| 159 | goto err_unlock; |
| 160 | |
| 161 | head = p->compat_robust_list; |
| 162 | rcu_read_unlock(); |
| 163 | |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 164 | if (put_user(sizeof(*head), len_ptr)) |
| 165 | return -EFAULT; |
| 166 | return put_user(ptr_to_compat(head), head_ptr); |
| 167 | |
| 168 | err_unlock: |
Thomas Gleixner | f409adf | 2009-12-01 14:02:00 +0100 | [diff] [blame] | 169 | rcu_read_unlock(); |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 170 | |
| 171 | return ret; |
| 172 | } |
| 173 | |
Al Viro | 90caf58 | 2012-12-25 23:16:10 -0500 | [diff] [blame] | 174 | COMPAT_SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, |
| 175 | struct compat_timespec __user *, utime, u32 __user *, uaddr2, |
| 176 | u32, val3) |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 177 | { |
Pierre Peiffer | c19384b | 2007-05-09 02:35:02 -0700 | [diff] [blame] | 178 | struct timespec ts; |
| 179 | ktime_t t, *tp = NULL; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 180 | int val2 = 0; |
Ulrich Drepper | f0ede66 | 2007-06-01 00:46:41 -0700 | [diff] [blame] | 181 | int cmd = op & FUTEX_CMD_MASK; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 182 | |
Thomas Gleixner | cd689985 | 2008-02-01 17:45:14 +0100 | [diff] [blame] | 183 | if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI || |
Dinakar Guniguntala | 4dc8802 | 2009-08-10 18:31:42 +0530 | [diff] [blame] | 184 | cmd == FUTEX_WAIT_BITSET || |
| 185 | cmd == FUTEX_WAIT_REQUEUE_PI)) { |
H. Peter Anvin | 81993e8 | 2014-02-01 18:54:11 -0800 | [diff] [blame] | 186 | if (compat_get_timespec(&ts, utime)) |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 187 | return -EFAULT; |
Pierre Peiffer | c19384b | 2007-05-09 02:35:02 -0700 | [diff] [blame] | 188 | if (!timespec_valid(&ts)) |
Thomas Gleixner | 9741ef96 | 2006-03-31 02:31:32 -0800 | [diff] [blame] | 189 | return -EINVAL; |
Pierre Peiffer | c19384b | 2007-05-09 02:35:02 -0700 | [diff] [blame] | 190 | |
| 191 | t = timespec_to_ktime(ts); |
Ulrich Drepper | f0ede66 | 2007-06-01 00:46:41 -0700 | [diff] [blame] | 192 | if (cmd == FUTEX_WAIT) |
Thomas Gleixner | 5a7780e | 2008-02-13 09:20:43 +0100 | [diff] [blame] | 193 | t = ktime_add_safe(ktime_get(), t); |
Pierre Peiffer | c19384b | 2007-05-09 02:35:02 -0700 | [diff] [blame] | 194 | tp = &t; |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 195 | } |
Dinakar Guniguntala | 4dc8802 | 2009-08-10 18:31:42 +0530 | [diff] [blame] | 196 | if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE || |
| 197 | cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP) |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 198 | val2 = (int) (unsigned long) utime; |
| 199 | |
Pierre Peiffer | c19384b | 2007-05-09 02:35:02 -0700 | [diff] [blame] | 200 | return do_futex(uaddr, op, val, tp, uaddr2, val2, val3); |
Ingo Molnar | 34f192c | 2006-03-27 01:16:24 -0800 | [diff] [blame] | 201 | } |