blob: 4ae3232e7a28a507d5ba316d9603c4275012a7ad [file] [log] [blame]
Ingo Molnar34f192c2006-03-27 01:16:24 -08001/*
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 Emelyanovb4888932007-10-18 23:40:14 -070011#include <linux/nsproxy.h>
Ingo Molnar34f192c2006-03-27 01:16:24 -080012#include <linux/futex.h>
Kees Cookbdbb7762012-03-19 16:12:53 -070013#include <linux/ptrace.h>
Al Viro90caf582012-12-25 23:16:10 -050014#include <linux/syscalls.h>
Ingo Molnar34f192c2006-03-27 01:16:24 -080015
16#include <asm/uaccess.h>
17
Ingo Molnare3f2dde2006-07-29 05:17:57 +020018
19/*
20 * Fetch a robust-list pointer. Bit 0 signals PI futexes:
21 */
22static inline int
23fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,
Namhyung Kim1dcc41b2010-09-14 21:43:46 +090024 compat_uptr_t __user *head, unsigned int *pi)
Ingo Molnare3f2dde2006-07-29 05:17:57 +020025{
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 Viro84816642008-03-29 03:07:58 +000035static void __user *futex_uaddr(struct robust_list __user *entry,
David Miller3c5fd9c72007-11-06 21:13:56 -080036 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 Molnar34f192c2006-03-27 01:16:24 -080044/*
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 */
50void compat_exit_robust_list(struct task_struct *curr)
51{
52 struct compat_robust_list_head __user *head = curr->compat_robust_list;
Martin Schwidefsky9f96cb12007-10-01 01:20:13 -070053 struct robust_list __user *entry, *next_entry, *pending;
Darren Hart4c115e92010-11-04 15:00:00 -040054 unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
55 unsigned int uninitialized_var(next_pi);
Martin Schwidefsky9f96cb12007-10-01 01:20:13 -070056 compat_uptr_t uentry, next_uentry, upending;
Ingo Molnar34f192c2006-03-27 01:16:24 -080057 compat_long_t futex_offset;
Martin Schwidefsky9f96cb12007-10-01 01:20:13 -070058 int rc;
Ingo Molnar34f192c2006-03-27 01:16:24 -080059
Thomas Gleixnera0c1e902008-02-23 15:23:57 -080060 if (!futex_cmpxchg_enabled)
61 return;
62
Ingo Molnar34f192c2006-03-27 01:16:24 -080063 /*
64 * Fetch the list head (which was registered earlier, via
65 * sys_set_robust_list()):
66 */
Ingo Molnare3f2dde2006-07-29 05:17:57 +020067 if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
Ingo Molnar34f192c2006-03-27 01:16:24 -080068 return;
Ingo Molnar34f192c2006-03-27 01:16:24 -080069 /*
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 Molnare3f2dde2006-07-29 05:17:57 +020078 if (fetch_robust_entry(&upending, &pending,
Thomas Gleixnerce2c6b52006-08-05 12:15:15 -070079 &head->list_op_pending, &pip))
Ingo Molnar34f192c2006-03-27 01:16:24 -080080 return;
Ingo Molnar34f192c2006-03-27 01:16:24 -080081
Martin Schwidefsky9f96cb12007-10-01 01:20:13 -070082 next_entry = NULL; /* avoid warning with gcc */
Arnd Bergmann179c85e2007-09-11 15:23:49 -070083 while (entry != (struct robust_list __user *) &head->list) {
Ingo Molnar34f192c2006-03-27 01:16:24 -080084 /*
Martin Schwidefsky9f96cb12007-10-01 01:20:13 -070085 * 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 Molnar34f192c2006-03-27 01:16:24 -080091 * A pending lock might already be on the list, so
92 * dont process it twice:
93 */
David Miller3c5fd9c72007-11-06 21:13:56 -080094 if (entry != pending) {
95 void __user *uaddr = futex_uaddr(entry, futex_offset);
Ingo Molnar34f192c2006-03-27 01:16:24 -080096
David Miller3c5fd9c72007-11-06 21:13:56 -080097 if (handle_futex_death(uaddr, curr, pi))
98 return;
99 }
Martin Schwidefsky9f96cb12007-10-01 01:20:13 -0700100 if (rc)
Ingo Molnar34f192c2006-03-27 01:16:24 -0800101 return;
Martin Schwidefsky9f96cb12007-10-01 01:20:13 -0700102 uentry = next_uentry;
103 entry = next_entry;
104 pi = next_pi;
Ingo Molnar34f192c2006-03-27 01:16:24 -0800105 /*
106 * Avoid excessively long or circular lists:
107 */
108 if (!--limit)
109 break;
110
111 cond_resched();
112 }
David Miller3c5fd9c72007-11-06 21:13:56 -0800113 if (pending) {
114 void __user *uaddr = futex_uaddr(pending, futex_offset);
115
116 handle_futex_death(uaddr, curr, pip);
117 }
Ingo Molnar34f192c2006-03-27 01:16:24 -0800118}
119
Al Viro90caf582012-12-25 23:16:10 -0500120COMPAT_SYSCALL_DEFINE2(set_robust_list,
121 struct compat_robust_list_head __user *, head,
122 compat_size_t, len)
Ingo Molnar34f192c2006-03-27 01:16:24 -0800123{
Thomas Gleixnera0c1e902008-02-23 15:23:57 -0800124 if (!futex_cmpxchg_enabled)
125 return -ENOSYS;
126
Ingo Molnar34f192c2006-03-27 01:16:24 -0800127 if (unlikely(len != sizeof(*head)))
128 return -EINVAL;
129
130 current->compat_robust_list = head;
131
132 return 0;
133}
134
Al Viro90caf582012-12-25 23:16:10 -0500135COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,
136 compat_uptr_t __user *, head_ptr,
137 compat_size_t __user *, len_ptr)
Ingo Molnar34f192c2006-03-27 01:16:24 -0800138{
Al Viroba46df92006-10-10 22:46:07 +0100139 struct compat_robust_list_head __user *head;
Ingo Molnar34f192c2006-03-27 01:16:24 -0800140 unsigned long ret;
Kees Cookbdbb7762012-03-19 16:12:53 -0700141 struct task_struct *p;
Ingo Molnar34f192c2006-03-27 01:16:24 -0800142
Thomas Gleixnera0c1e902008-02-23 15:23:57 -0800143 if (!futex_cmpxchg_enabled)
144 return -ENOSYS;
145
Kees Cookbdbb7762012-03-19 16:12:53 -0700146 rcu_read_lock();
Ingo Molnar34f192c2006-03-27 01:16:24 -0800147
Kees Cookbdbb7762012-03-19 16:12:53 -0700148 ret = -ESRCH;
149 if (!pid)
150 p = current;
151 else {
Pavel Emelyanov228ebcb2007-10-18 23:40:16 -0700152 p = find_task_by_vpid(pid);
Ingo Molnar34f192c2006-03-27 01:16:24 -0800153 if (!p)
154 goto err_unlock;
Ingo Molnar34f192c2006-03-27 01:16:24 -0800155 }
156
Kees Cookbdbb7762012-03-19 16:12:53 -0700157 ret = -EPERM;
Jann Horncaaee622016-01-20 15:00:04 -0800158 if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
Kees Cookbdbb7762012-03-19 16:12:53 -0700159 goto err_unlock;
160
161 head = p->compat_robust_list;
162 rcu_read_unlock();
163
Ingo Molnar34f192c2006-03-27 01:16:24 -0800164 if (put_user(sizeof(*head), len_ptr))
165 return -EFAULT;
166 return put_user(ptr_to_compat(head), head_ptr);
167
168err_unlock:
Thomas Gleixnerf409adf2009-12-01 14:02:00 +0100169 rcu_read_unlock();
Ingo Molnar34f192c2006-03-27 01:16:24 -0800170
171 return ret;
172}
173
Al Viro90caf582012-12-25 23:16:10 -0500174COMPAT_SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
175 struct compat_timespec __user *, utime, u32 __user *, uaddr2,
176 u32, val3)
Ingo Molnar34f192c2006-03-27 01:16:24 -0800177{
Pierre Peifferc19384b2007-05-09 02:35:02 -0700178 struct timespec ts;
179 ktime_t t, *tp = NULL;
Ingo Molnar34f192c2006-03-27 01:16:24 -0800180 int val2 = 0;
Ulrich Drepperf0ede662007-06-01 00:46:41 -0700181 int cmd = op & FUTEX_CMD_MASK;
Ingo Molnar34f192c2006-03-27 01:16:24 -0800182
Thomas Gleixnercd689982008-02-01 17:45:14 +0100183 if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI ||
Dinakar Guniguntala4dc88022009-08-10 18:31:42 +0530184 cmd == FUTEX_WAIT_BITSET ||
185 cmd == FUTEX_WAIT_REQUEUE_PI)) {
H. Peter Anvin81993e82014-02-01 18:54:11 -0800186 if (compat_get_timespec(&ts, utime))
Ingo Molnar34f192c2006-03-27 01:16:24 -0800187 return -EFAULT;
Pierre Peifferc19384b2007-05-09 02:35:02 -0700188 if (!timespec_valid(&ts))
Thomas Gleixner9741ef962006-03-31 02:31:32 -0800189 return -EINVAL;
Pierre Peifferc19384b2007-05-09 02:35:02 -0700190
191 t = timespec_to_ktime(ts);
Ulrich Drepperf0ede662007-06-01 00:46:41 -0700192 if (cmd == FUTEX_WAIT)
Thomas Gleixner5a7780e2008-02-13 09:20:43 +0100193 t = ktime_add_safe(ktime_get(), t);
Pierre Peifferc19384b2007-05-09 02:35:02 -0700194 tp = &t;
Ingo Molnar34f192c2006-03-27 01:16:24 -0800195 }
Dinakar Guniguntala4dc88022009-08-10 18:31:42 +0530196 if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE ||
197 cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP)
Ingo Molnar34f192c2006-03-27 01:16:24 -0800198 val2 = (int) (unsigned long) utime;
199
Pierre Peifferc19384b2007-05-09 02:35:02 -0700200 return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
Ingo Molnar34f192c2006-03-27 01:16:24 -0800201}