Release 4.15 kernel/futex_compat.c
// SPDX-License-Identifier: GPL-2.0
/*
* linux/kernel/futex_compat.c
*
* Futex compatibililty routines.
*
* Copyright 2006, Red Hat, Inc., Ingo Molnar
*/
#include <linux/linkage.h>
#include <linux/compat.h>
#include <linux/nsproxy.h>
#include <linux/futex.h>
#include <linux/ptrace.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
/*
* Fetch a robust-list pointer. Bit 0 signals PI futexes:
*/
static inline int
fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,
compat_uptr_t __user *head, unsigned int *pi)
{
if (get_user(*uentry, head))
return -EFAULT;
*entry = compat_ptr((*uentry) & ~1);
*pi = (unsigned int)(*uentry) & 1;
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Ingo Molnar | 71 | 97.26% | 1 | 33.33% |
| Al Viro | 1 | 1.37% | 1 | 33.33% |
| Namhyung Kim | 1 | 1.37% | 1 | 33.33% |
| Total | 73 | 100.00% | 3 | 100.00% |
static void __user *futex_uaddr(struct robust_list __user *entry,
compat_long_t futex_offset)
{
compat_uptr_t base = ptr_to_compat(entry);
void __user *uaddr = compat_ptr(base + futex_offset);
return uaddr;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| David S. Miller | 39 | 97.50% | 1 | 50.00% |
| Al Viro | 1 | 2.50% | 1 | 50.00% |
| Total | 40 | 100.00% | 2 | 100.00% |
/*
* Walk curr->robust_list (very carefully, it's a userspace list!)
* and mark any locks found there dead, and notify any waiters.
*
* We silently return on any sign of list-walking problem.
*/
void compat_exit_robust_list(struct task_struct *curr)
{
struct compat_robust_list_head __user *head = curr->compat_robust_list;
struct robust_list __user *entry, *next_entry, *pending;
unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
unsigned int uninitialized_var(next_pi);
compat_uptr_t uentry, next_uentry, upending;
compat_long_t futex_offset;
int rc;
if (!futex_cmpxchg_enabled)
return;
/*
* Fetch the list head (which was registered earlier, via
* sys_set_robust_list()):
*/
if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
return;
/*
* Fetch the relative futex offset:
*/
if (get_user(futex_offset, &head->futex_offset))
return;
/*
* Fetch any possibly pending lock-add first, and handle it
* if it exists:
*/
if (fetch_robust_entry(&upending, &pending,
&head->list_op_pending, &pip))
return;
next_entry = NULL; /* avoid warning with gcc */
while (entry != (struct robust_list __user *) &head->list) {
/*
* Fetch the next entry in the list before calling
* handle_futex_death:
*/
rc = fetch_robust_entry(&next_uentry, &next_entry,
(compat_uptr_t __user *)&entry->next, &next_pi);
/*
* A pending lock might already be on the list, so
* dont process it twice:
*/
if (entry != pending) {
void __user *uaddr = futex_uaddr(entry, futex_offset);
if (handle_futex_death(uaddr, curr, pi))
return;
}
if (rc)
return;
uentry = next_uentry;
entry = next_entry;
pi = next_pi;
/*
* Avoid excessively long or circular lists:
*/
if (!--limit)
break;
cond_resched();
}
if (pending) {
void __user *uaddr = futex_uaddr(pending, futex_offset);
handle_futex_death(uaddr, curr, pip);
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Ingo Molnar | 146 | 55.94% | 2 | 22.22% |
| Martin Schwidefsky | 63 | 24.14% | 1 | 11.11% |
| David S. Miller | 28 | 10.73% | 1 | 11.11% |
| Thomas Gleixner | 9 | 3.45% | 2 | 22.22% |
| Arnd Bergmann | 7 | 2.68% | 1 | 11.11% |
| Darren Hart | 7 | 2.68% | 1 | 11.11% |
| Al Viro | 1 | 0.38% | 1 | 11.11% |
| Total | 261 | 100.00% | 9 | 100.00% |
COMPAT_SYSCALL_DEFINE2(set_robust_list,
struct compat_robust_list_head __user *, head,
compat_size_t, len)
{
if (!futex_cmpxchg_enabled)
return -ENOSYS;
if (unlikely(len != sizeof(*head)))
return -EINVAL;
current->compat_robust_list = head;
return 0;
}
COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,
compat_uptr_t __user *, head_ptr,
compat_size_t __user *, len_ptr)
{
struct compat_robust_list_head __user *head;
unsigned long ret;
struct task_struct *p;
if (!futex_cmpxchg_enabled)
return -ENOSYS;
rcu_read_lock();
ret = -ESRCH;
if (!pid)
p = current;
else {
p = find_task_by_vpid(pid);
if (!p)
goto err_unlock;
}
ret = -EPERM;
if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
goto err_unlock;
head = p->compat_robust_list;
rcu_read_unlock();
if (put_user(sizeof(*head), len_ptr))
return -EFAULT;
return put_user(ptr_to_compat(head), head_ptr);
err_unlock:
rcu_read_unlock();
return ret;
}
COMPAT_SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
struct compat_timespec __user *, utime, u32 __user *, uaddr2,
u32, val3)
{
struct timespec ts;
ktime_t t, *tp = NULL;
int val2 = 0;
int cmd = op & FUTEX_CMD_MASK;
if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI ||
cmd == FUTEX_WAIT_BITSET ||
cmd == FUTEX_WAIT_REQUEUE_PI)) {
if (compat_get_timespec(&ts, utime))
return -EFAULT;
if (!timespec_valid(&ts))
return -EINVAL;
t = timespec_to_ktime(ts);
if (cmd == FUTEX_WAIT)
t = ktime_add_safe(ktime_get(), t);
tp = &t;
}
if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE ||
cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP)
val2 = (int) (unsigned long) utime;
return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
}
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Ingo Molnar | 434 | 56.51% | 3 | 10.00% |
| David S. Miller | 67 | 8.72% | 1 | 3.33% |
| Al Viro | 63 | 8.20% | 3 | 10.00% |
| Martin Schwidefsky | 63 | 8.20% | 1 | 3.33% |
| Thomas Gleixner | 50 | 6.51% | 6 | 20.00% |
| Pierre Peiffer | 23 | 2.99% | 1 | 3.33% |
| Kees Cook | 17 | 2.21% | 1 | 3.33% |
| Ulrich Drepper | 12 | 1.56% | 1 | 3.33% |
| Dinakar Guniguntala | 12 | 1.56% | 1 | 3.33% |
| Arnd Bergmann | 7 | 0.91% | 1 | 3.33% |
| Darren Hart | 7 | 0.91% | 1 | 3.33% |
| Pavel Emelyanov | 4 | 0.52% | 2 | 6.67% |
| David Howells | 3 | 0.39% | 2 | 6.67% |
| Linus Torvalds | 1 | 0.13% | 1 | 3.33% |
| Jann Horn | 1 | 0.13% | 1 | 3.33% |
| Serge E. Hallyn | 1 | 0.13% | 1 | 3.33% |
| H. Peter Anvin | 1 | 0.13% | 1 | 3.33% |
| Greg Kroah-Hartman | 1 | 0.13% | 1 | 3.33% |
| Namhyung Kim | 1 | 0.13% | 1 | 3.33% |
| Total | 768 | 100.00% | 30 | 100.00% |
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