Nikita Popov b805aebd42 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>

2021-08-09 20:17:34 +05:30

7.8 KiB

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