From c3c6760dc4785b78dd7246c3ec9dbfac9c40fe4e Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 25 Mar 2014 11:45:33 +0100 Subject: [PATCH 15/48] qcow2: Fix NULL dereference in qcow2_open() error path (CVE-2014-0146) RH-Author: Kevin Wolf Message-id: <1395744364-16049-15-git-send-email-kwolf@redhat.com> Patchwork-id: n/a O-Subject: [EMBARGOED RHEL-6.6/6.5.z qemu-kvm PATCH v2 14/45] qcow2: Fix NULL dereference in qcow2_open() error path (CVE-2014-0146) Bugzilla: 1079331 RH-Acked-by: Max Reitz RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Jeff Cody Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1079331 Upstream status: Embargoed The qcow2 code assumes that s->snapshots is non-NULL if s->nb_snapshots != 0. By having the initialisation of both fields separated in qcow2_open(), any error occuring in between would cause the error path to dereference NULL in qcow2_free_snapshots() if the image had any snapshots. Signed-off-by: Kevin Wolf Conflicts: tests/qemu-iotests/080 tests/qemu-iotests/080.out Signed-off-by: Kevin Wolf --- block/qcow2.c | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 3672db8..ec85f44 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -289,9 +289,6 @@ static int qcow2_open(BlockDriverState *bs, int flags) goto fail; } - s->snapshots_offset = header.snapshots_offset; - s->nb_snapshots = header.nb_snapshots; - /* read the level 1 table */ if (header.l1_size > 0x2000000) { /* 32 MB L1 table is enough for 2 PB images at 64k cluster size @@ -390,6 +387,10 @@ static int qcow2_open(BlockDriverState *bs, int flags) bs->backing_file[len] = '\0'; } + /* Internal snapshots */ + s->snapshots_offset = header.snapshots_offset; + s->nb_snapshots = header.nb_snapshots; + ret = qcow2_read_snapshots(bs); if (ret < 0) { goto fail; -- 1.7.1