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nptl: Fix abort in case of set*id failure [BZ #17135]

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If a call to the set*id functions fails in a multi-threaded program,
the abort introduced in commit 13f7fe35ae
was triggered.

We address by checking that all calls to set*id on all threads give
the same result, and only abort if we see success followed by failure
(or vice versa).
This commit is contained in:
Florian Weimer
2014-07-10 17:34:46 +02:00
parent bc1da1765e
commit 771eb1415f
8 changed files with 149 additions and 6 deletions
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27
nptl/allocatestack.c
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@ -1059,6 +1059,25 @@ setxid_signal_thread (struct xid_command *cmdp, struct pthread *t)
return 0;
}
/* Check for consistency across set*id system call results. The abort
should not happen as long as all privileges changes happen through
the glibc wrappers. ERROR must be 0 (no error) or an errno
code. */
void
attribute_hidden
__nptl_setxid_error (struct xid_command *cmdp, int error)
{
do
{
int olderror = cmdp->error;
if (olderror == error)
break;
if (olderror != -1)
/* Mismatch between current and previous results. */
abort ();
}
while (atomic_compare_and_exchange_bool_acq (&cmdp->error, error, -1));
}
int
attribute_hidden
@ -1070,6 +1089,7 @@ __nptl_setxid (struct xid_command *cmdp)
__xidcmd = cmdp;
cmdp->cntr = 0;
cmdp->error = -1;
struct pthread *self = THREAD_SELF;
@ -1153,11 +1173,14 @@ __nptl_setxid (struct xid_command *cmdp)
INTERNAL_SYSCALL_DECL (err);
result = INTERNAL_SYSCALL_NCS (cmdp->syscall_no, err, 3,
cmdp->id[0], cmdp->id[1], cmdp->id[2]);
if (INTERNAL_SYSCALL_ERROR_P (result, err))
int error = 0;
if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err)))
{
__set_errno (INTERNAL_SYSCALL_ERRNO (result, err));
error = INTERNAL_SYSCALL_ERRNO (result, err);
__set_errno (error);
result = -1;
}
__nptl_setxid_error (cmdp, error);
lll_unlock (stack_cache_lock, LLL_PRIVATE);
return result;