mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![Serge E. Hallyn](/assets/img/avatar_default.png)
CAP_IPC_OWNER and CAP_IPC_LOCK can be checked against current_user_ns(), because the resource comes from current's own ipc namespace. setuid/setgid are to uids in own namespace, so again checks can be against current_user_ns(). Changelog: Jan 11: Use task_ns_capable() in place of sched_capable(). Jan 11: Use nsown_capable() as suggested by Bastian Blank. Jan 11: Clarify (hopefully) some logic in futex and sched.c Feb 15: use ns_capable for ipc, not nsown_capable Feb 23: let copy_ipcs handle setting ipc_ns->user_ns Feb 23: pass ns down rather than taking it from current [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Daniel Lezcano <daniel.lezcano@free.fr> Acked-by: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
210 lines
4.9 KiB
C
210 lines
4.9 KiB
C
/*
|
|
* 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 <asm/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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
}
|
|
|
|
asmlinkage long
|
|
compat_sys_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;
|
|
}
|
|
|
|
asmlinkage long
|
|
compat_sys_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;
|
|
const struct cred *cred = current_cred(), *pcred;
|
|
|
|
if (!futex_cmpxchg_enabled)
|
|
return -ENOSYS;
|
|
|
|
if (!pid)
|
|
head = current->compat_robust_list;
|
|
else {
|
|
struct task_struct *p;
|
|
|
|
ret = -ESRCH;
|
|
rcu_read_lock();
|
|
p = find_task_by_vpid(pid);
|
|
if (!p)
|
|
goto err_unlock;
|
|
ret = -EPERM;
|
|
pcred = __task_cred(p);
|
|
/* If victim is in different user_ns, then uids are not
|
|
comparable, so we must have CAP_SYS_PTRACE */
|
|
if (cred->user->user_ns != pcred->user->user_ns) {
|
|
if (!ns_capable(pcred->user->user_ns, CAP_SYS_PTRACE))
|
|
goto err_unlock;
|
|
goto ok;
|
|
}
|
|
/* If victim is in same user_ns, then uids are comparable */
|
|
if (cred->euid != pcred->euid &&
|
|
cred->euid != pcred->uid &&
|
|
!ns_capable(pcred->user->user_ns, CAP_SYS_PTRACE))
|
|
goto err_unlock;
|
|
ok:
|
|
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;
|
|
}
|
|
|
|
asmlinkage long compat_sys_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 (get_compat_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);
|
|
}
|