| Message ID | 87wnrd1nor.fsf@oldenburg.str.redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | Fix use of __pthread_attr_copy in mq_notify (bug 27896) | expand |
On 6/1/21 11:18 PM, Florian Weimer via Libc-alpha wrote: > __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)"). > > Tested on i686-linux-gnu and x86_64-linux-gnu. Thanks, I missed that in my review. LGTM. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org> > > --- > sysdeps/unix/sysv/linux/mq_notify.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c > index f7ddfe5a6c..6f46d29d1d 100644 > --- a/sysdeps/unix/sysv/linux/mq_notify.c > +++ b/sysdeps/unix/sysv/linux/mq_notify.c > @@ -258,7 +258,14 @@ mq_notify (mqd_t mqdes, const struct sigevent *notification) > if (data.attr == NULL) > return -1; > > - __pthread_attr_copy (data.attr, notification->sigev_notify_attributes); > + int ret = __pthread_attr_copy (data.attr, > + notification->sigev_notify_attributes); > + if (ret != 0) > + { > + free (data.attr); > + __set_errno (ret); > + return -1; > + } > } > > /* Construct the new request. */ > @@ -271,7 +278,7 @@ mq_notify (mqd_t mqdes, const struct sigevent *notification) > 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); >
diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c index f7ddfe5a6c..6f46d29d1d 100644 --- a/sysdeps/unix/sysv/linux/mq_notify.c +++ b/sysdeps/unix/sysv/linux/mq_notify.c @@ -258,7 +258,14 @@ mq_notify (mqd_t mqdes, const struct sigevent *notification) if (data.attr == NULL) return -1; - __pthread_attr_copy (data.attr, notification->sigev_notify_attributes); + int ret = __pthread_attr_copy (data.attr, + notification->sigev_notify_attributes); + if (ret != 0) + { + free (data.attr); + __set_errno (ret); + return -1; + } } /* Construct the new request. */ @@ -271,7 +278,7 @@ mq_notify (mqd_t mqdes, const struct sigevent *notification) 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);
__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)"). Tested on i686-linux-gnu and x86_64-linux-gnu. --- sysdeps/unix/sysv/linux/mq_notify.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)