From aedf77d56472d1fddf050c61c1017d4f51149fb1 Mon Sep 17 00:00:00 2001
From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Tue, 13 Dec 2016 10:33:34 -0800
Subject: [PATCH] FROMLIST: 9p: fix a potential acl leak

(https://lkml.org/lkml/2016/12/13/579)

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.

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: Cong Wang <xiyou.wangcong@gmail.com>
Bug: 32458736
Change-Id: Ia78da401e6fd1bfd569653bd2cd0ebd3f9c737a0
---
 fs/9p/acl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/9p/acl.c b/fs/9p/acl.c
index 9686c1f17653f..c19a66472d2eb 100644
--- a/fs/9p/acl.c
+++ b/fs/9p/acl.c
@@ -321,6 +321,7 @@ static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
 		name = POSIX_ACL_XATTR_ACCESS;
 		if (acl) {
 			struct iattr iattr;
+			struct posix_acl *old_acl = acl;
 
 			retval = posix_acl_update_mode(inode, &iattr.ia_mode, &acl);
 			if (retval)
@@ -331,6 +332,7 @@ static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
 				 * by the mode bits. So don't
 				 * update ACL.
 				 */
+				posix_acl_release(old_acl);
 				value = NULL;
 				size = 0;
 			}