diff options
Diffstat (limited to 'backport-CVE-2021-38604-0002-librt-fix-NULL-pointer-dereference-bug-28213.patch')
| -rw-r--r-- | backport-CVE-2021-38604-0002-librt-fix-NULL-pointer-dereference-bug-28213.patch | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/backport-CVE-2021-38604-0002-librt-fix-NULL-pointer-dereference-bug-28213.patch b/backport-CVE-2021-38604-0002-librt-fix-NULL-pointer-dereference-bug-28213.patch new file mode 100644 index 0000000..3dca8cc --- /dev/null +++ b/backport-CVE-2021-38604-0002-librt-fix-NULL-pointer-dereference-bug-28213.patch @@ -0,0 +1,39 @@ +From b805aebd42364fe696e417808a700fdb9800c9e8 Mon Sep 17 00:00:00 2001 +From: Nikita Popov <npv1310@gmail.com> +Date: Mon, 9 Aug 2021 20:17:34 +0530 +Subject: [PATCH] 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> +--- + sysdeps/unix/sysv/linux/mq_notify.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +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); +-- +2.27.0 + |