From b269057d62756f206ec0d97a42115c7a6dd38a11 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Tue, 25 Mar 2014 11:45:20 +0100
Subject: [PATCH 02/48] qcow2: Check backing_file_offset (CVE-2014-0144)
RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <1395744364-16049-2-git-send-email-kwolf@redhat.com>
Patchwork-id: n/a
O-Subject: [EMBARGOED RHEL-6.6/6.5.z qemu-kvm PATCH v2 01/45]
qcow2: Check backing_file_offset (CVE-2014-0144)
Bugzilla: 1079453
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Jeff Cody <jcody@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1079453
Upstream status: Embargoed
Header, header extension and the backing file name must all be stored in
the first cluster. Setting the backing file to a much higher value
allowed header extensions to become much bigger than we want them to be
(unbounded allocation).
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Conflicts:
block/qcow2.c
tests/qemu-iotests/080
tests/qemu-iotests/080.out
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block/qcow2.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 71c7b23..f402cd7 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -277,6 +277,12 @@ static int qcow2_open(BlockDriverState *bs, int flags)
QLIST_INIT(&s->cluster_allocs);
/* read qcow2 extensions */
+ if (header.backing_file_offset > s->cluster_size) {
+ qerror_report(QERR_GENERIC_ERROR, "Invalid backing file offset");
+ ret = -EINVAL;
+ goto fail;
+ }
+
if (header.backing_file_offset) {
ext_end = header.backing_file_offset;
} else {
--
1.7.1