From patchwork Thu Jul 16 14:26:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 1330319 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=MmnfHJH1; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4B6xQg1lWyz9sTS for ; Fri, 17 Jul 2020 00:26:51 +1000 (AEST) Received: from localhost ([::1]:48884 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jw4qW-0001Kw-Pf for incoming@patchwork.ozlabs.org; Thu, 16 Jul 2020 10:26:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43798) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jw4qB-0001Id-Qt for qemu-devel@nongnu.org; Thu, 16 Jul 2020 10:26:27 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:31373 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jw4q8-0005bC-11 for qemu-devel@nongnu.org; Thu, 16 Jul 2020 10:26:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594909583; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6E9xU7LhkbbodOrHzPzfIt1jVa8hx/fUfxgN+TWD1KQ=; b=MmnfHJH1q969fxpVqA+IshL0lN+n2OJ613UHPt4k46SUkASNJqXxU6IWV5rRAj8vZ2t8Rl VypBPS4Iq2HuDV2RGoPAFlfX++KovTAcR8z//1BniI71WrL6R6ezYio0HtX0XPsQ09E5aD XAgS1iKnnYkFzLJPZb/yqRSfllaHYC8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-265-4eHvQhAgOba9McxwHEfmVw-1; Thu, 16 Jul 2020 10:26:21 -0400 X-MC-Unique: 4eHvQhAgOba9McxwHEfmVw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 97CE28014D7; Thu, 16 Jul 2020 14:26:20 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-114-172.ams2.redhat.com [10.36.114.172]) by smtp.corp.redhat.com (Postfix) with ESMTP id 751CB710A0; Thu, 16 Jul 2020 14:26:19 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH for-5.1 v2 1/2] block: Require aligned image size to avoid assertion failure Date: Thu, 16 Jul 2020 16:26:00 +0200 Message-Id: <20200716142601.111237-2-kwolf@redhat.com> In-Reply-To: <20200716142601.111237-1-kwolf@redhat.com> References: <20200716142601.111237-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=kwolf@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/16 04:25:38 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Unaligned requests will automatically be aligned to bl.request_alignment and we can't extend write requests to access space beyond the end of the image without resizing the image, so if we have the WRITE permission, but not the RESIZE one, it's required that the image size is aligned. Failing to meet this requirement could cause assertion failures like this if RESIZE permissions weren't requested: qemu-img: block/io.c:1910: bdrv_co_write_req_prepare: Assertion `end_sector <= bs->total_sectors || child->perm & BLK_PERM_RESIZE' failed. This was e.g. triggered by qemu-img converting to a target image with 4k request alignment when the image was only aligned to 512 bytes, but not to 4k. Turn this into a graceful error in bdrv_check_perm() so that WRITE without RESIZE can only be taken if the image size is aligned. If a user holds both permissions and drops only RESIZE, the function will return an error, but bdrv_child_try_set_perm() will ignore the failure silently if permissions are only requested to be relaxed and just keep both permissions while returning success. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz --- block.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/block.c b/block.c index 35a372df57..6371928edb 100644 --- a/block.c +++ b/block.c @@ -2025,6 +2025,22 @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, return -EPERM; } + /* + * Unaligned requests will automatically be aligned to bl.request_alignment + * and without RESIZE we can't extend requests to write to space beyond the + * end of the image, so it's required that the image size is aligned. + */ + if ((cumulative_perms & BLK_PERM_WRITE) && + !(cumulative_perms & BLK_PERM_RESIZE)) + { + if ((bs->total_sectors * BDRV_SECTOR_SIZE) % bs->bl.request_alignment) { + error_setg(errp, "Cannot get 'write' permission without 'resize': " + "Image size is not a multiple of request " + "alignment"); + return -EPERM; + } + } + /* Check this node */ if (!drv) { return 0;