0001-CVE-2021-38604.patch 1.8 KB

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  1. From b805aebd42364fe696e417808a700fdb9800c9e8 Mon Sep 17 00:00:00 2001
  2. From: Nikita Popov <npv1310@gmail.com>
  3. Date: Mon, 9 Aug 2021 20:17:34 +0530
  4. Subject: [PATCH] librt: fix NULL pointer dereference (bug 28213)
  5. Helper thread frees copied attribute on NOTIFY_REMOVED message
  6. received from the OS kernel. Unfortunately, it fails to check whether
  7. copied attribute actually exists (data.attr != NULL). This worked
  8. earlier because free() checks passed pointer before actually
  9. attempting to release corresponding memory. But
  10. __pthread_attr_destroy assumes pointer is not NULL.
  11. So passing NULL pointer to __pthread_attr_destroy will result in
  12. segmentation fault. This scenario is possible if
  13. notification->sigev_notify_attributes == NULL (which means default
  14. thread attributes should be used).
  15. Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=commit;h=b805aebd42364fe696e417808a700fdb9800c9e8]
  16. CVE: CVE-2021-38604
  17. Signed-off-by: Nikita Popov <npv1310@gmail.com>
  18. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
  19. Signed-off-by: Vinay Kumar <vinay.m.engg@gmail.com>
  20. ---
  21. sysdeps/unix/sysv/linux/mq_notify.c | 2 +-
  22. 1 file changed, 1 insertion(+), 1 deletion(-)
  23. diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c
  24. index 9799dcdaa4..eccae2e4c6 100644
  25. --- a/sysdeps/unix/sysv/linux/mq_notify.c
  26. +++ b/sysdeps/unix/sysv/linux/mq_notify.c
  27. @@ -131,7 +131,7 @@ helper_thread (void *arg)
  28. to wait until it is done with it. */
  29. (void) __pthread_barrier_wait (&notify_barrier);
  30. }
  31. - else if (data.raw[NOTIFY_COOKIE_LEN - 1] == NOTIFY_REMOVED)
  32. + else if (data.raw[NOTIFY_COOKIE_LEN - 1] == NOTIFY_REMOVED && data.attr != NULL)
  33. {
  34. /* The only state we keep is the copy of the thread attributes. */
  35. __pthread_attr_destroy (data.attr);
  36. --
  37. 2.31.1