From patchwork Tue Nov 14 17:23:59 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 10057961 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1661F602A7 for ; Tue, 14 Nov 2017 17:28:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EE9EA29803 for ; Tue, 14 Nov 2017 17:28:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E35AD29808; Tue, 14 Nov 2017 17:28:39 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 0B68F29803 for ; Tue, 14 Nov 2017 17:28:38 +0000 (UTC) Received: from localhost ([::1]:60993 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eEf0o-0001E8-0s for patchwork-qemu-devel@patchwork.kernel.org; Tue, 14 Nov 2017 12:28:38 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53539) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eEewo-0005Pd-ES for qemu-devel@nongnu.org; Tue, 14 Nov 2017 12:24:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eEewn-00048k-8y for qemu-devel@nongnu.org; Tue, 14 Nov 2017 12:24:30 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41290) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eEewk-00044b-Jb; Tue, 14 Nov 2017 12:24:26 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BE3C05DA03; Tue, 14 Nov 2017 17:24:25 +0000 (UTC) Received: from localhost (unknown [10.40.205.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 393564C7; Tue, 14 Nov 2017 17:24:24 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Tue, 14 Nov 2017 18:23:59 +0100 Message-Id: <20171114172417.7654-3-mreitz@redhat.com> In-Reply-To: <20171114172417.7654-1-mreitz@redhat.com> References: <20171114172417.7654-1-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 14 Nov 2017 17:24:25 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 02/20] qcow2: Prevent allocating L2 tables at offset 0 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Peter Maydell , Alberto Garcia , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Alberto Garcia If the refcount data is corrupted then we can end up trying to allocate a new L2 table at offset 0 in the image, triggering an assertion in the qcow2 cache that would crash QEMU: qcow2_cache_entry_mark_dirty: Assertion `c->entries[i].offset != 0' failed This patch adds an explicit check for this scenario and a new test case. Signed-off-by: Alberto Garcia Reviewed-by: Max Reitz Message-id: 92dac37191ae7844a2da22c122204eb493cc3133.1509718618.git.berto@igalia.com Signed-off-by: Max Reitz --- block/qcow2-cluster.c | 8 ++++++++ tests/qemu-iotests/060 | 7 +++++++ tests/qemu-iotests/060.out | 6 ++++++ 3 files changed, 21 insertions(+) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index fb10e26068..2e072ed155 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -278,6 +278,14 @@ static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table) goto fail; } + /* If we're allocating the table at offset 0 then something is wrong */ + if (l2_offset == 0) { + qcow2_signal_corruption(bs, true, -1, -1, "Preventing invalid " + "allocation of L2 table at offset 0"); + ret = -EIO; + goto fail; + } + ret = qcow2_cache_flush(bs, s->refcount_block_cache); if (ret < 0) { goto fail; diff --git a/tests/qemu-iotests/060 b/tests/qemu-iotests/060 index dead26aeaf..40f85cc216 100755 --- a/tests/qemu-iotests/060 +++ b/tests/qemu-iotests/060 @@ -253,6 +253,13 @@ poke_file "$TEST_IMG" "$rt_offset" "\x00\x00\x00\x00\x00\x00\x00\x00" # causing a refcount block to be allocated at offset 0 $QEMU_IO -c "write 0 128k" "$TEST_IMG" | _filter_qemu_io +echo +echo "=== Testing empty refcount block ===" +echo +_make_test_img 64M +poke_file "$TEST_IMG" "$rb_offset" "\x00\x00\x00\x00\x00\x00\x00\x00" +$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io + # success, all done echo "*** done" rm -f $seq.full diff --git a/tests/qemu-iotests/060.out b/tests/qemu-iotests/060.out index 872719009c..5b8b518486 100644 --- a/tests/qemu-iotests/060.out +++ b/tests/qemu-iotests/060.out @@ -189,4 +189,10 @@ wrote 65536/65536 bytes at offset 0 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) qcow2: Marking image as corrupt: Preventing invalid allocation of refcount block at offset 0; further corruption events will be suppressed write failed: Input/output error + +=== Testing empty refcount block === + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qcow2: Marking image as corrupt: Preventing invalid allocation of L2 table at offset 0; further corruption events will be suppressed +write failed: Input/output error *** done