glibc/backport-CVE-2021-33574-0002-Fix-mq_notify-bug-27896.patch
liqingqing_1229 15893e323a fix CVE-2021-33574
(cherry picked from commit 4297578f6cf7814cfeace0841be643edb5869e43)
2021-06-07 15:57:47 +08:00

78 lines
2.5 KiB
Diff

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>
note that this patch has few modifications to adapt glibc2.28
Conflict:NA
Reference:https://sourceware.org/git/?p=glibc.git;a=commit;h=217b6dc298156bdb0d6aea9ea93e7e394a5ff091
---
sysdeps/unix/sysv/linux/mq_notify.c | 31 +++++++++++++++++++++++++++--
1 file changed, 29 insertions(+), 2 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c
index c4091169..76963567 100644
--- a/sysdeps/unix/sysv/linux/mq_notify.c
+++ b/sysdeps/unix/sysv/linux/mq_notify.c
@@ -260,7 +260,34 @@ mq_notify (mqd_t mqdes, const struct sigevent *notification)
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 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);
--
2.23.0