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| author | Nikita Popov <npv1310@gmail.com> | 2021-08-09 20:17:34 +0530 |
|---|---|---|
| committer | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2021-08-09 20:17:34 +0530 |
| commit | b805aebd42364fe696e417808a700fdb9800c9e8 (patch) | |
| tree | 9c933c8dee81700749fa69dd0ceb31d33c6a30df | |
| parent | 60b4dd25790342b40e8942e3a4115f511a6b6911 (diff) | |
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librt: fix NULL pointer dereference (bug 28213)
Helper thread frees copied attribute on NOTIFY_REMOVED message
received from the OS kernel. Unfortunately, it fails to check whether
copied attribute actually exists (data.attr != NULL). This worked
earlier because free() checks passed pointer before actually
attempting to release corresponding memory. But
__pthread_attr_destroy assumes pointer is not NULL.
So passing NULL pointer to __pthread_attr_destroy will result in
segmentation fault. This scenario is possible if
notification->sigev_notify_attributes == NULL (which means default
thread attributes should be used).
Signed-off-by: Nikita Popov <npv1310@gmail.com>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
| -rw-r--r-- | sysdeps/unix/sysv/linux/mq_notify.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c index 9799dcdaa4..eccae2e4c6 100644 --- a/sysdeps/unix/sysv/linux/mq_notify.c +++ b/sysdeps/unix/sysv/linux/mq_notify.c @@ -131,7 +131,7 @@ helper_thread (void *arg) to wait until it is done with it. */ (void) __pthread_barrier_wait (¬ify_barrier); } - else if (data.raw[NOTIFY_COOKIE_LEN - 1] == NOTIFY_REMOVED) + else if (data.raw[NOTIFY_COOKIE_LEN - 1] == NOTIFY_REMOVED && data.attr != NULL) { /* The only state we keep is the copy of the thread attributes. */ __pthread_attr_destroy (data.attr); |