From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60029) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gMFfq-0000lr-MW for qemu-devel@nongnu.org; Mon, 12 Nov 2018 12:06:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gMFfp-0007JU-Md for qemu-devel@nongnu.org; Mon, 12 Nov 2018 12:06:54 -0500 From: Kevin Wolf Date: Mon, 12 Nov 2018 18:06:03 +0100 Message-Id: <20181112170603.23986-15-kwolf@redhat.com> In-Reply-To: <20181112170603.23986-1-kwolf@redhat.com> References: <20181112170603.23986-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 14/14] qcow2: Read outside array bounds in qcow2_pre_write_overlap_check() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org From: Liam Merwick The commit for 0e4e4318eaa5 increments QCOW2_OL_MAX_BITNR but does not add an array entry for QCOW2_OL_BITMAP_DIRECTORY_BITNR to metadata_ol_nam= es[]. As a result, an array dereference of metadata_ol_names[8] in qcow2_pre_write_overlap_check() could result in a read outside of the arr= ay bounds. Fixes: 0e4e4318eaa5 ('qcow2: add overlap check for bitmap directory') Cc: Vladimir Sementsov-Ogievskiy Signed-off-by: Liam Merwick Reviewed-by: Eric Blake Reviewed-by: Max Reitz Message-id: 1541453919-25973-6-git-send-email-Liam.Merwick@oracle.com Signed-off-by: Max Reitz --- block/qcow2-refcount.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 3c539f02e5..46082aeac1 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -2719,15 +2719,17 @@ int qcow2_check_metadata_overlap(BlockDriverState= *bs, int ign, int64_t offset, } =20 static const char *metadata_ol_names[] =3D { - [QCOW2_OL_MAIN_HEADER_BITNR] =3D "qcow2_header", - [QCOW2_OL_ACTIVE_L1_BITNR] =3D "active L1 table", - [QCOW2_OL_ACTIVE_L2_BITNR] =3D "active L2 table", - [QCOW2_OL_REFCOUNT_TABLE_BITNR] =3D "refcount table", - [QCOW2_OL_REFCOUNT_BLOCK_BITNR] =3D "refcount block", - [QCOW2_OL_SNAPSHOT_TABLE_BITNR] =3D "snapshot table", - [QCOW2_OL_INACTIVE_L1_BITNR] =3D "inactive L1 table", - [QCOW2_OL_INACTIVE_L2_BITNR] =3D "inactive L2 table", + [QCOW2_OL_MAIN_HEADER_BITNR] =3D "qcow2_header", + [QCOW2_OL_ACTIVE_L1_BITNR] =3D "active L1 table", + [QCOW2_OL_ACTIVE_L2_BITNR] =3D "active L2 table", + [QCOW2_OL_REFCOUNT_TABLE_BITNR] =3D "refcount table", + [QCOW2_OL_REFCOUNT_BLOCK_BITNR] =3D "refcount block", + [QCOW2_OL_SNAPSHOT_TABLE_BITNR] =3D "snapshot table", + [QCOW2_OL_INACTIVE_L1_BITNR] =3D "inactive L1 table", + [QCOW2_OL_INACTIVE_L2_BITNR] =3D "inactive L2 table", + [QCOW2_OL_BITMAP_DIRECTORY_BITNR] =3D "bitmap directory", }; +QEMU_BUILD_BUG_ON(QCOW2_OL_MAX_BITNR !=3D ARRAY_SIZE(metadata_ol_names))= ; =20 /* * First performs a check for metadata overlaps (through --=20 2.19.1