linux-kernel - [PATCH 3.12 042/142] xfs: don't allow di

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-Id: <ffd0475d31d0561b4d913fd6b84d5a70e56a8a49.1491838390.git.jslaby@suse.cz>
Date:   Mon, 10 Apr 2017 17:32:03 +0200
From:   Jiri Slaby <jslaby@...e.cz>
To:     stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        "Darrick J. Wong" <darrick.wong@...cle.com>,
        Dave Chinner <david@...morbit.com>,
        Nikolay Borisov <nborisov@...e.com>,
        Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 042/142] xfs: don't allow di_size with high bit set

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

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

===============

Commit ef388e2054feedaeb05399ed654bdb06f385d294 upstream.

The on-disk field di_size is used to set i_size, which is a signed
integer of loff_t.  If the high bit of di_size is set, we'll end up with
a negative i_size, which will cause all sorts of problems.  Since the
VFS won't let us create a file with such length, we should catch them
here in the verifier too.

[nborisov: Backported to 3.12]

Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
Reviewed-by: Dave Chinner <dchinner@...hat.com>
Signed-off-by: Dave Chinner <david@...morbit.com>
Signed-off-by: Nikolay Borisov <nborisov@...e.com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 fs/xfs/xfs_inode_buf.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/xfs/xfs_inode_buf.c b/fs/xfs/xfs_inode_buf.c
index 03d237a0f58b..1c62be0b0d0f 100644
--- a/fs/xfs/xfs_inode_buf.c
+++ b/fs/xfs/xfs_inode_buf.c
@@ -301,6 +301,14 @@ xfs_dinode_verify(
 	if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC))
 		return false;
 
+	/* don't allow invalid i_size */
+	if (be64_to_cpu(dip->di_size) & (1ULL << 63))
+		return false;
+
+	/* No zero-length symlinks. */
+	if (S_ISLNK(be16_to_cpu(dip->di_mode)) && dip->di_size == 0)
+		return false;
+
 	/* only version 3 or greater inodes are extensively verified here */
 	if (dip->di_version < 3)
 		return true;
-- 
2.12.2