From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40767) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fvmOO-0000zd-Kn for qemu-devel@nongnu.org; Fri, 31 Aug 2018 12:35:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fvmOI-00059j-H1 for qemu-devel@nongnu.org; Fri, 31 Aug 2018 12:35:27 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:39784) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fvmOG-000544-7Q for qemu-devel@nongnu.org; Fri, 31 Aug 2018 12:35:21 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w7VGYRYc140240 for ; Fri, 31 Aug 2018 16:35:17 GMT Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp2120.oracle.com with ESMTP id 2m2yrqvb9b-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Fri, 31 Aug 2018 16:35:17 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w7VGZGuZ020419 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Fri, 31 Aug 2018 16:35:17 GMT Received: from abhmp0001.oracle.com (abhmp0001.oracle.com [141.146.116.7]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w7VGZGxc017696 for ; Fri, 31 Aug 2018 16:35:16 GMT From: Liam Merwick Date: Fri, 31 Aug 2018 17:36:54 +0100 Message-Id: <1535733414-6812-9-git-send-email-Liam.Merwick@oracle.com> In-Reply-To: <1535733414-6812-1-git-send-email-Liam.Merwick@oracle.com> References: <1535733414-6812-1-git-send-email-Liam.Merwick@oracle.com> Subject: [Qemu-devel] [PATCH v2 8/8] 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-devel@nongnu.org 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_names[]. 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 array bounds. Fixes: 0e4e4318eaa5 ('qcow2: add overlap check for bitmap directory') Cc: Vladimir Sementsov-Ogievskiy Signed-off-by: Liam Merwick --- block/qcow2-refcount.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 3c539f02e5ec..fb0de187cfd2 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -2719,16 +2719,26 @@ int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset, } static const char *metadata_ol_names[] = { - [QCOW2_OL_MAIN_HEADER_BITNR] = "qcow2_header", - [QCOW2_OL_ACTIVE_L1_BITNR] = "active L1 table", - [QCOW2_OL_ACTIVE_L2_BITNR] = "active L2 table", - [QCOW2_OL_REFCOUNT_TABLE_BITNR] = "refcount table", - [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = "refcount block", - [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = "snapshot table", - [QCOW2_OL_INACTIVE_L1_BITNR] = "inactive L1 table", - [QCOW2_OL_INACTIVE_L2_BITNR] = "inactive L2 table", + [QCOW2_OL_MAIN_HEADER_BITNR] = "qcow2_header", + [QCOW2_OL_ACTIVE_L1_BITNR] = "active L1 table", + [QCOW2_OL_ACTIVE_L2_BITNR] = "active L2 table", + [QCOW2_OL_REFCOUNT_TABLE_BITNR] = "refcount table", + [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = "refcount block", + [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = "snapshot table", + [QCOW2_OL_INACTIVE_L1_BITNR] = "inactive L1 table", + [QCOW2_OL_INACTIVE_L2_BITNR] = "inactive L2 table", + [QCOW2_OL_BITMAP_DIRECTORY_BITNR] = "bitmap directory", }; + +/* + * Catch at compile time the case where an overlap detection bit + * was added to QCow2MetadataOverlap in block/qcow2.h but a + * corresponding entry to metadata_ol_names[] wasn't added. + */ +QEMU_BUILD_BUG_ON(QCOW2_OL_MAX_BITNR != + (sizeof(metadata_ol_names) / sizeof(metadata_ol_names[0]))); + /* * First performs a check for metadata overlaps (through * qcow2_check_metadata_overlap); if that fails with a negative value (error -- 1.8.3.1