From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Wed, 22 Feb 2017 23:40:53 +0000 (-0800)
Subject: 9p: fix a potential acl leak
X-Git-Tag: v4.4.68~58
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=436188eb0447fc5117bba45963c783769c44600e;p=thirdparty%2Fkernel%2Fstable.git

9p: fix a potential acl leak

commit b5c66bab72a6a65edb15beb60b90d3cb84c5763b upstream.

posix_acl_update_mode() could possibly clear 'acl', if so we leak the
memory pointed by 'acl'.  Save this pointer before calling
posix_acl_update_mode() and release the memory if 'acl' really gets
cleared.

Link: http://lkml.kernel.org/r/1486678332-2430-1-git-send-email-xiyou.wangcong@gmail.com
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reported-by: Mark Salyzyn <salyzyn@android.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Greg Kurz <groug@kaod.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/9p/acl.c b/fs/9p/acl.c
index 929b618da43bb..c30c6ceac2c43 100644
--- a/fs/9p/acl.c
+++ b/fs/9p/acl.c
@@ -283,6 +283,7 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
 	case ACL_TYPE_ACCESS:
 		if (acl) {
 			struct iattr iattr;
+			struct posix_acl *old_acl = acl;
 
 			retval = posix_acl_update_mode(inode, &iattr.ia_mode, &acl);
 			if (retval)
@@ -293,6 +294,7 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
 				 * by the mode bits. So don't
 				 * update ACL.
 				 */
+				posix_acl_release(old_acl);
 				value = NULL;
 				size = 0;
 			}