* [COMMITTED 2.32] Use __pthread_attr_copy in mq_notify (bug 27896)
@ 2021-06-10 13:09 Arjun Shankar
0 siblings, 0 replies; only message in thread
From: Arjun Shankar @ 2021-06-10 13:09 UTC (permalink / raw)
To: libc-stable
Make a deep copy of the pthread attribute object to remove a potential
use-after-free issue.
(cherry picked from commit 42d359350510506b87101cf77202fefcbfc790cb)
---
NEWS | 4 ++++
sysdeps/unix/sysv/linux/mq_notify.c | 15 ++++++++++-----
2 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/NEWS b/NEWS
index f278041512..2afe250ccf 100644
--- a/NEWS
+++ b/NEWS
@@ -208,6 +208,10 @@ Security related changes:
invoked with input containing redundant shift sequences in the IBM1364,
IBM1371, IBM1388, IBM1390, or IBM1399 character sets.
+ 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:
[9809] localedata: ckb_IQ: new Kurdish Sorani locale
diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c
index 61bbb03b64..f404acfdfe 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 +258,7 @@ 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));
+ __pthread_attr_copy (data.attr, notification->sigev_notify_attributes);
}
/* Construct the new request. */
@@ -270,7 +272,10 @@ mq_notify (mqd_t mqdes, const struct sigevent *notification)
/* 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;
}
--
2.31.1
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