From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:41932) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S23N8-0002Sn-Km for qemu-devel@nongnu.org; Mon, 27 Feb 2012 11:24:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S23N2-00012p-Nq for qemu-devel@nongnu.org; Mon, 27 Feb 2012 11:24:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:7538) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S23N2-00012j-Fe for qemu-devel@nongnu.org; Mon, 27 Feb 2012 11:24:16 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q1RGOF8t030133 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 27 Feb 2012 11:24:15 -0500 From: Kevin Wolf Date: Mon, 27 Feb 2012 17:27:45 +0100 Message-Id: <1330360065-27334-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PATCH] qcow2: Reject unrealistically large header extensions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com Image files that make qemu-img info read several gigabytes into the unknown header extensions list are bad. Just fail opening the image if an extension claims to be large. Signed-off-by: Kevin Wolf --- block/qcow2.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index f68f0e1..077fe05 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -108,6 +108,11 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, #ifdef DEBUG_EXT printf("ext.magic = 0x%x\n", ext.magic); #endif + if (ext.len > 65536) { + error_report("Header extension larger than 64k - this looks wrong"); + return -ENOTSUP; + } + switch (ext.magic) { case QCOW2_EXT_MAGIC_END: return 0; -- 1.7.6.5