linux-kernel - [PATCH 4.9 001/103] 9p: fix a potential acl leak

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Message-Id: <20170511141210.897366408@linuxfoundation.org>
Date:   Thu, 11 May 2017 16:11:30 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Cong Wang <xiyou.wangcong@...il.com>,
        Mark Salyzyn <salyzyn@...roid.com>, Jan Kara <jack@...e.cz>,
        Greg Kurz <groug@...d.org>,
        Eric Van Hensbergen <ericvh@...il.com>,
        Ron Minnich <rminnich@...dia.gov>,
        Latchesar Ionkov <lucho@...kov.net>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 4.9 001/103] 9p: fix a potential acl leak

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Cong Wang <xiyou.wangcong@...il.com>

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@...il.com>
Reported-by: Mark Salyzyn <salyzyn@...roid.com>
Reviewed-by: Jan Kara <jack@...e.cz>
Reviewed-by: Greg Kurz <groug@...d.org>
Cc: Eric Van Hensbergen <ericvh@...il.com>
Cc: Ron Minnich <rminnich@...dia.gov>
Cc: Latchesar Ionkov <lucho@...kov.net>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/9p/acl.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/9p/acl.c
+++ b/fs/9p/acl.c
@@ -277,6 +277,7 @@ static int v9fs_xattr_set_acl(const stru
 	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)
@@ -287,6 +288,7 @@ static int v9fs_xattr_set_acl(const stru
 				 * by the mode bits. So don't
 				 * update ACL.
 				 */
+				posix_acl_release(old_acl);
 				value = NULL;
 				size = 0;
 			}