Use __pthread_attr_copy in mq_notify (bug 27896)
Checks
Commit Message
Make a deep copy of the pthread attribute object to remove a potential
use-after-free issue.
---
NEWS | 4 ++++
sysdeps/unix/sysv/linux/mq_notify.c | 15 ++++++++++-----
2 files changed, 14 insertions(+), 5 deletions(-)
Comments
On 6/1/21 2:20 PM, Andreas Schwab wrote:
> Make a deep copy of the pthread attribute object to remove a potential
> use-after-free issue.
LGTM
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
> ---
> NEWS | 4 ++++
> sysdeps/unix/sysv/linux/mq_notify.c | 15 ++++++++++-----
> 2 files changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/NEWS b/NEWS
> index 266837bf2d..4460752df7 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -56,6 +56,10 @@ Security related changes:
> potentially resulting in degraded service or Denial of Service on the
> local system. Reported by Chris Schanzle.
>
> + 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:
>
> [The release manager will add the list generated by
> diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c
> index cc575a0cdd..f7ddfe5a6c 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;
> }
>
@@ -56,6 +56,10 @@ Security related changes:
potentially resulting in degraded service or Denial of Service on the
local system. Reported by Chris Schanzle.
+ 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:
[The release manager will add the list generated by
@@ -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;
}