glibc: Fix CVE-2021-33574

Source: https://sourceware.org/git/glibc.git
Tracking -- https://sourceware.org/bugzilla/show_bug.cgi?id=27896

Backported upstream commit 42d359350510506b87101cf77202fefcbfc790cb to
glibc-2.33 source with dependent commit id 217b6dc298156bdb0d6aea9ea93e7e394a5ff091.

Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=commit;h=42d359350510506b87101cf77202fefcbfc790cb]

(From OE-Core rev: b4bc29cf19d811c0ec948dbe69c0bc79fe31e0e8)

Signed-off-by: Vinay Kumar <vinay.m.engg@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 61 insertions, 0 deletions

diff --git a/meta/recipes-core/glibc/glibc/CVE-2021-33574.patch b/meta/recipes-core/glibc/glibc/CVE-2021-33574.patch
new file mode 100644
index 0000000000..fd73b23c88
--- /dev/null
+++ b/meta/recipes-core/glibc/glibc/CVE-2021-33574.patch
@@ -0,0 +1,61 @@
+From 42d359350510506b87101cf77202fefcbfc790cb Mon Sep 17 00:00:00 2001
+From: Andreas Schwab <schwab@linux-m68k.org>
+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.
+
+Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=commit;h=42d359350510506b87101cf77202fefcbfc790cb]
+CVE: CVE-2021-33574
+Signed-off-by: Vinay Kumar <vinay.m.engg@gmail.com>
+---
+diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c
+index cc575a0cdd8..6f46d29d1dc 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 (&notify_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 +258,14 @@ 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));
++      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.  */
+@@ -269,8 +278,11 @@ 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))
+-    free (data.attr);
++  if (retval != 0 && data.attr != NULL)
++    {
++      pthread_attr_destroy (data.attr);
++      free (data.attr);
++    }
+ 
+   return retval;
+ }