From 42d359350510506b87101cf77202fefcbfc790cb Mon Sep 17 00:00:00 2001 From: Andreas Schwab 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. Conflict:NA Reference:https://sourceware.org/git/?p=glibc.git;a=commit;h=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 eb31aca6..9dff5e82 100644 --- a/NEWS +++ b/NEWS @@ -224,6 +224,10 @@ Changes to build and runtime requirements: Security related changes: + 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. + CVE-2016-6261, CVE-2016-6263, CVE-2017-14062: Various vulnerabilities have been fixed by removing the glibc-internal IDNA implementation and using the system-provided libidn2 library instead. Originally reported by Hanno diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c index 3563e82c..c4091169 100644 --- a/sysdeps/unix/sysv/linux/mq_notify.c +++ b/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 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. */ @@ -272,7 +274,10 @@ 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; } -- 2.23.0