linux-kernel - [PATCH 3.2 63/87] ext4: fix memory leak in xattr

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Message-ID: <lsq.1385387069.431840285@decadent.org.uk>
Date:	Mon, 25 Nov 2013 13:44:29 +0000
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org, "Eric Sandeen" <sandeen@...hat.com>,
	"Theodore Ts'o" <tytso@....edu>, "Dave Jones" <davej@...hat.com>,
	"Dave Jones" <davej@...oraproject.org>
Subject: [PATCH 3.2 63/87] ext4: fix memory leak in xattr

3.2.53-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Dave Jones <davej@...hat.com>

commit 6e4ea8e33b2057b85d75175dd89b93f5e26de3bc upstream.

If we take the 2nd retry path in ext4_expand_extra_isize_ea, we
potentionally return from the function without having freed these
allocations.  If we don't do the return, we over-write the previous
allocation pointers, so we leak either way.

Spotted with Coverity.

[ Fixed by tytso to set is and bs to NULL after freeing these
  pointers, in case in the retry loop we later end up triggering an
  error causing a jump to cleanup, at which point we could have a double
  free bug. -- Ted ]

Signed-off-by: Dave Jones <davej@...oraproject.org>
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
Reviewed-by: Eric Sandeen <sandeen@...hat.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/ext4/xattr.c | 2 ++
 1 file changed, 2 insertions(+)

--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1269,6 +1269,8 @@ retry:
 				    s_min_extra_isize) {
 					tried_min_extra_isize++;
 					new_extra_isize = s_min_extra_isize;
+					kfree(is); is = NULL;
+					kfree(bs); bs = NULL;
 					goto retry;
 				}
 				error = -1;

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