linux-kernel - [PATCH 4.19 107/245] xfs: dont ever return a stale pointer from __xfs_dir3_free

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 29 Sep 2020 12:59:18 +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,
        "Darrick J. Wong" <darrick.wong@...cle.com>,
        Dave Chinner <dchinner@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 107/245] xfs: dont ever return a stale pointer from __xfs_dir3_free_read

From: Darrick J. Wong <darrick.wong@...cle.com>

[ Upstream commit 1cb5deb5bc095c070c09a4540c45f9c9ba24be43 ]

If we decide that a directory free block is corrupt, we must take care
not to leak a buffer pointer to the caller.  After xfs_trans_brelse
returns, the buffer can be freed or reused, which means that we have to
set *bpp back to NULL.

Callers are supposed to notice the nonzero return value and not use the
buffer pointer, but we should code more defensively, even if all current
callers handle this situation correctly.

Fixes: de14c5f541e7 ("xfs: verify free block header fields")
Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
Reviewed-by: Dave Chinner <dchinner@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/xfs/libxfs/xfs_dir2_node.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/xfs/libxfs/xfs_dir2_node.c b/fs/xfs/libxfs/xfs_dir2_node.c
index f1bb3434f51c7..01e99806b941f 100644
--- a/fs/xfs/libxfs/xfs_dir2_node.c
+++ b/fs/xfs/libxfs/xfs_dir2_node.c
@@ -214,6 +214,7 @@ __xfs_dir3_free_read(
 	if (fa) {
 		xfs_verifier_error(*bpp, -EFSCORRUPTED, fa);
 		xfs_trans_brelse(tp, *bpp);
+		*bpp = NULL;
 		return -EFSCORRUPTED;
 	}
 
-- 
2.25.1