| From 42d359350510506b87101cf77202fefcbfc790cb Mon Sep 17 00:00:00 2001 |
| From: Andreas Schwab <schwab@linux-m68k.org> |
| Date: Thu, 27 May 2021 12:49:47 +0200 |
| Subject: [PATCH] Use __pthread_attr_copy in mq_notify (bug 27896) |
| |
| Make a deep copy of the pthread attribute object to remove a potential |
| use-after-free issue. |
| |
| Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=commit;h=42d359350510506b87101cf77202fefcbfc790cb] |
| CVE: CVE-2021-33574 |
| Signed-off-by: Vinay Kumar <vinay.m.engg@gmail.com> |
| --- |
| diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c |
| index cc575a0cdd8..6f46d29d1dc 100644 |
| --- a/sysdeps/unix/sysv/linux/mq_notify.c |
| +++ b/sysdeps/unix/sysv/linux/mq_notify.c |
| @@ -133,8 +133,11 @@ helper_thread (void *arg) |
| (void) __pthread_barrier_wait (¬ify_barrier); |
| } |
| else if (data.raw[NOTIFY_COOKIE_LEN - 1] == NOTIFY_REMOVED) |
| - /* The only state we keep is the copy of the thread attributes. */ |
| - free (data.attr); |
| + { |
| + /* The only state we keep is the copy of the thread attributes. */ |
| + pthread_attr_destroy (data.attr); |
| + free (data.attr); |
| + } |
| } |
| return NULL; |
| } |
| @@ -255,8 +258,14 @@ mq_notify (mqd_t mqdes, const struct sigevent *notification) |
| if (data.attr == NULL) |
| return -1; |
| |
| - memcpy (data.attr, notification->sigev_notify_attributes, |
| - sizeof (pthread_attr_t)); |
| + int ret = __pthread_attr_copy (data.attr, |
| + notification->sigev_notify_attributes); |
| + if (ret != 0) |
| + { |
| + free (data.attr); |
| + __set_errno (ret); |
| + return -1; |
| + } |
| } |
| |
| /* Construct the new request. */ |
| @@ -269,8 +278,11 @@ mq_notify (mqd_t mqdes, const struct sigevent *notification) |
| int retval = INLINE_SYSCALL (mq_notify, 2, mqdes, &se); |
| |
| /* If it failed, free the allocated memory. */ |
| - if (__glibc_unlikely (retval != 0)) |
| - free (data.attr); |
| + if (retval != 0 && data.attr != NULL) |
| + { |
| + pthread_attr_destroy (data.attr); |
| + free (data.attr); |
| + } |
| |
| return retval; |
| } |