Patrick Williams | 213cb26 | 2021-08-07 19:21:33 -0500 | [diff] [blame^] | 1 | From 42d359350510506b87101cf77202fefcbfc790cb Mon Sep 17 00:00:00 2001 |
| 2 | From: Andreas Schwab <schwab@linux-m68k.org> |
| 3 | Date: Thu, 27 May 2021 12:49:47 +0200 |
| 4 | Subject: [PATCH] Use __pthread_attr_copy in mq_notify (bug 27896) |
| 5 | |
| 6 | Make a deep copy of the pthread attribute object to remove a potential |
| 7 | use-after-free issue. |
| 8 | |
| 9 | Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=commit;h=42d359350510506b87101cf77202fefcbfc790cb] |
| 10 | CVE: CVE-2021-33574 |
| 11 | Signed-off-by: Vinay Kumar <vinay.m.engg@gmail.com> |
| 12 | --- |
| 13 | diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c |
| 14 | index cc575a0cdd8..6f46d29d1dc 100644 |
| 15 | --- a/sysdeps/unix/sysv/linux/mq_notify.c |
| 16 | +++ b/sysdeps/unix/sysv/linux/mq_notify.c |
| 17 | @@ -133,8 +133,11 @@ helper_thread (void *arg) |
| 18 | (void) __pthread_barrier_wait (¬ify_barrier); |
| 19 | } |
| 20 | else if (data.raw[NOTIFY_COOKIE_LEN - 1] == NOTIFY_REMOVED) |
| 21 | - /* The only state we keep is the copy of the thread attributes. */ |
| 22 | - free (data.attr); |
| 23 | + { |
| 24 | + /* The only state we keep is the copy of the thread attributes. */ |
| 25 | + pthread_attr_destroy (data.attr); |
| 26 | + free (data.attr); |
| 27 | + } |
| 28 | } |
| 29 | return NULL; |
| 30 | } |
| 31 | @@ -255,8 +258,14 @@ mq_notify (mqd_t mqdes, const struct sigevent *notification) |
| 32 | if (data.attr == NULL) |
| 33 | return -1; |
| 34 | |
| 35 | - memcpy (data.attr, notification->sigev_notify_attributes, |
| 36 | - sizeof (pthread_attr_t)); |
| 37 | + int ret = __pthread_attr_copy (data.attr, |
| 38 | + notification->sigev_notify_attributes); |
| 39 | + if (ret != 0) |
| 40 | + { |
| 41 | + free (data.attr); |
| 42 | + __set_errno (ret); |
| 43 | + return -1; |
| 44 | + } |
| 45 | } |
| 46 | |
| 47 | /* Construct the new request. */ |
| 48 | @@ -269,8 +278,11 @@ mq_notify (mqd_t mqdes, const struct sigevent *notification) |
| 49 | int retval = INLINE_SYSCALL (mq_notify, 2, mqdes, &se); |
| 50 | |
| 51 | /* If it failed, free the allocated memory. */ |
| 52 | - if (__glibc_unlikely (retval != 0)) |
| 53 | - free (data.attr); |
| 54 | + if (retval != 0 && data.attr != NULL) |
| 55 | + { |
| 56 | + pthread_attr_destroy (data.attr); |
| 57 | + free (data.attr); |
| 58 | + } |
| 59 | |
| 60 | return retval; |
| 61 | } |