--- /dev/null
+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
+CVE: CVE-2021-33574 patch#1
+Signed-off-by: Armin Kuster <akuster@mvista.com>
+
+---
+ NEWS | 4 ++++
+ sysdeps/unix/sysv/linux/mq_notify.c | 15 ++++++++++-----
+ 2 files changed, 14 insertions(+), 5 deletions(-)
+
+Index: git/NEWS
+===================================================================
+--- git.orig/NEWS
++++ git/NEWS
+@@ -7,6 +7,10 @@ using `glibc' in the "product" field.
+ \f
+ Version 2.31.1
+
++ CVE-2021-33574: The mq_notify function has a potential use-after-free
++ issue when using a notification type of SIGEV_THREAD and a thread
++ attribute with a non-default affinity mask.
++
+ The following bugs are resolved with this release:
+ [19519] iconv(1) with -c option hangs on illegal multi-byte sequences
+ (CVE-2016-10228)
+Index: git/sysdeps/unix/sysv/linux/mq_notify.c
+===================================================================
+--- git.orig/sysdeps/unix/sysv/linux/mq_notify.c
++++ git/sysdeps/unix/sysv/linux/mq_notify.c
+@@ -135,8 +135,11 @@ 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;
+ }
+@@ -257,8 +260,7 @@ mq_notify (mqd_t mqdes, const struct sig
+ if (data.attr == NULL)
+ return -1;
+
+- memcpy (data.attr, notification->sigev_notify_attributes,
+- sizeof (pthread_attr_t));
++ __pthread_attr_copy (data.attr, notification->sigev_notify_attributes);
+ }
+
+ /* Construct the new request. */
+@@ -272,7 +274,10 @@ mq_notify (mqd_t mqdes, const struct sig
+
+ /* If it failed, free the allocated memory. */
+ if (__glibc_unlikely (retval != 0))
+- free (data.attr);
++ {
++ pthread_attr_destroy (data.attr);
++ free (data.attr);
++ }
+
+ return retval;
+ }
--- /dev/null
+From 217b6dc298156bdb0d6aea9ea93e7e394a5ff091 Mon Sep 17 00:00:00 2001
+From: Florian Weimer <fweimer@redhat.com>
+Date: Tue, 1 Jun 2021 17:51:41 +0200
+Subject: [PATCH] Fix use of __pthread_attr_copy in mq_notify (bug 27896)
+
+__pthread_attr_copy can fail and does not initialize the attribute
+structure in that case.
+
+If __pthread_attr_copy is never called and there is no allocated
+attribute, pthread_attr_destroy should not be called, otherwise
+there is a null pointer dereference in rt/tst-mqueue6.
+
+Fixes commit 42d359350510506b87101cf77202fefcbfc790cb
+("Use __pthread_attr_copy in mq_notify (bug 27896)").
+
+Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
+
+https://sourceware.org/bugzilla/attachment.cgi?id=13497
+
+Upstream-Status: Backport
+CVE: CVE-2021-33574 patch#2
+Signed-off-by: Armin Kuster <akuster@mvista.com>
+
+---
+Index: git/sysdeps/unix/sysv/linux/mq_notify.c
+===================================================================
+--- git.orig/sysdeps/unix/sysv/linux/mq_notify.c
++++ git/sysdeps/unix/sysv/linux/mq_notify.c
+@@ -260,7 +260,34 @@ mq_notify (mqd_t mqdes, const struct sig
+ if (data.attr == NULL)
+ return -1;
+
+- __pthread_attr_copy (data.attr, notification->sigev_notify_attributes);
++ memcpy (data.attr, notification->sigev_notify_attributes,
++ sizeof (pthread_attr_t));
++
++ struct pthread_attr *source =
++ (struct pthread_attr *) (notification->sigev_notify_attributes);
++ struct pthread_attr *target = (struct pthread_attr *) (data.attr);
++ cpu_set_t *newp;
++ cpu_set_t *cpuset = source->cpuset;
++ size_t cpusetsize = source->cpusetsize;
++
++ /* alloc a new memory for cpuset to avoid use after free */
++ if (cpuset != NULL && cpusetsize > 0)
++ {
++ newp = (cpu_set_t *) malloc (cpusetsize);
++ if (newp == NULL)
++ {
++ free(data.attr);
++ return -1;
++ }
++
++ memcpy (newp, cpuset, cpusetsize);
++ target->cpuset = newp;
++ }
++ else
++ {
++ target->cpuset = NULL;
++ target->cpusetsize = 0;
++ }
+ }
+
+ /* Construct the new request. */
+@@ -273,7 +300,7 @@ mq_notify (mqd_t mqdes, const struct sig
+ int retval = INLINE_SYSCALL (mq_notify, 2, mqdes, &se);
+
+ /* If it failed, free the allocated memory. */
+- if (__glibc_unlikely (retval != 0))
++ if (retval != 0 && data.attr != NULL)
+ {
+ pthread_attr_destroy (data.attr);
+ free (data.attr);
