From patchwork Mon Oct 28 12:14:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 1185399 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.b="hnytL4m3"; 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 471w7349R4z9sPT for ; Tue, 29 Oct 2019 00:10:07 +1100 (AEDT) Received: from localhost ([::1]:53576 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iP4ma-0004eQ-Oz for incoming@patchwork.ozlabs.org; Mon, 28 Oct 2019 09:10:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50859) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iP3xA-0003B7-CK for qemu-devel@nongnu.org; Mon, 28 Oct 2019 08:16:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iP3x4-00023s-KC for qemu-devel@nongnu.org; Mon, 28 Oct 2019 08:16:53 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:57076 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iP3x4-00021h-DQ for qemu-devel@nongnu.org; Mon, 28 Oct 2019 08:16:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1572265006; 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=BvB63R2vBgFG+G5Cw2JrFXw2RumcbXnacdA0qJFni34=; b=hnytL4m31iAaaU1r2t6vQLEuhTfXtRGn4XJFJdbYTze7ITeLiiEnAE7wO+lT0tE2tbOhPP PXAf7+81l2FtlsBTD4KnVKrOECGVsfBFs3yi+8Du1xPzEcxQTrf4FK5RU3S3bmbNtdN1YE TNZ20WhxsdJryjtYhq3GUbx2GkF82Lo= 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-342-UZlp0lupNoO8J4T6lQeAzQ-1; Mon, 28 Oct 2019 08:16:44 -0400 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 C1525800FF1; Mon, 28 Oct 2019 12:16:42 +0000 (UTC) Received: from localhost (ovpn-117-83.ams2.redhat.com [10.36.117.83]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3EEAE5D6BB; Mon, 28 Oct 2019 12:16:42 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PULL 48/69] qcow2: Keep unknown extra snapshot data Date: Mon, 28 Oct 2019 13:14:40 +0100 Message-Id: <20191028121501.15279-49-mreitz@redhat.com> In-Reply-To: <20191028121501.15279-1-mreitz@redhat.com> References: <20191028121501.15279-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-MC-Unique: UZlp0lupNoO8J4T6lQeAzQ-1 X-Mimecast-Spam-Score: 0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 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: Kevin Wolf , Peter Maydell , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" The qcow2 specification says to ignore unknown extra data fields in snapshot table entries. Currently, we discard it whenever we update the image, which is a bit different from "ignore". This patch makes the qcow2 driver keep all unknown extra data fields when updating an image's snapshot table. Signed-off-by: Max Reitz Reviewed-by: Eric Blake Message-id: 20191011152814.14791-5-mreitz@redhat.com [mreitz: Adjusted comments as proposed by Eric] Signed-off-by: Max Reitz --- block/qcow2.h | 7 +++++ block/qcow2-snapshot.c | 61 +++++++++++++++++++++++++++++++++++------- 2 files changed, 58 insertions(+), 10 deletions(-) diff --git a/block/qcow2.h b/block/qcow2.h index cc0d5eadd0..363681cfdc 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -61,6 +61,9 @@ * space for snapshot names and IDs */ #define QCOW_MAX_SNAPSHOTS_SIZE (1024 * QCOW_MAX_SNAPSHOTS) +/* Maximum amount of extra data per snapshot table entry to accept */ +#define QCOW_MAX_SNAPSHOT_EXTRA_DATA 1024 + /* Bitmap header extension constraints */ #define QCOW2_MAX_BITMAPS 65535 #define QCOW2_MAX_BITMAP_DIRECTORY_SIZE (1024 * QCOW2_MAX_BITMAPS) @@ -181,6 +184,10 @@ typedef struct QCowSnapshot { uint32_t date_sec; uint32_t date_nsec; uint64_t vm_clock_nsec; + /* Size of all extra data, including QCowSnapshotExtraData if available */ + uint32_t extra_data_size; + /* Data beyond QCowSnapshotExtraData, if any */ + void *unknown_extra_data; } QCowSnapshot; struct Qcow2Cache; diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 80d32e4504..120cb7fa09 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -37,6 +37,7 @@ void qcow2_free_snapshots(BlockDriverState *bs) for(i = 0; i < s->nb_snapshots; i++) { g_free(s->snapshots[i].name); g_free(s->snapshots[i].id_str); + g_free(s->snapshots[i].unknown_extra_data); } g_free(s->snapshots); s->snapshots = NULL; @@ -51,7 +52,6 @@ int qcow2_read_snapshots(BlockDriverState *bs, Error **errp) QCowSnapshot *sn; int i, id_str_size, name_size; int64_t offset; - uint32_t extra_data_size; int ret; if (!s->nb_snapshots) { @@ -80,31 +80,53 @@ int qcow2_read_snapshots(BlockDriverState *bs, Error **errp) sn->date_sec = be32_to_cpu(h.date_sec); sn->date_nsec = be32_to_cpu(h.date_nsec); sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec); - extra_data_size = be32_to_cpu(h.extra_data_size); + sn->extra_data_size = be32_to_cpu(h.extra_data_size); id_str_size = be16_to_cpu(h.id_str_size); name_size = be16_to_cpu(h.name_size); - /* Read extra data */ + if (sn->extra_data_size > QCOW_MAX_SNAPSHOT_EXTRA_DATA) { + ret = -EFBIG; + error_setg(errp, "Too much extra metadata in snapshot table " + "entry %i", i); + goto fail; + } + + /* Read known extra data */ ret = bdrv_pread(bs->file, offset, &extra, - MIN(sizeof(extra), extra_data_size)); + MIN(sizeof(extra), sn->extra_data_size)); if (ret < 0) { error_setg_errno(errp, -ret, "Failed to read snapshot table"); goto fail; } - offset += extra_data_size; + offset += MIN(sizeof(extra), sn->extra_data_size); - if (extra_data_size >= endof(QCowSnapshotExtraData, - vm_state_size_large)) { + if (sn->extra_data_size >= endof(QCowSnapshotExtraData, + vm_state_size_large)) { sn->vm_state_size = be64_to_cpu(extra.vm_state_size_large); } - if (extra_data_size >= endof(QCowSnapshotExtraData, disk_size)) { + if (sn->extra_data_size >= endof(QCowSnapshotExtraData, disk_size)) { sn->disk_size = be64_to_cpu(extra.disk_size); } else { sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; } + if (sn->extra_data_size > sizeof(extra)) { + /* Store unknown extra data */ + size_t unknown_extra_data_size = + sn->extra_data_size - sizeof(extra); + + sn->unknown_extra_data = g_malloc(unknown_extra_data_size); + ret = bdrv_pread(bs->file, offset, sn->unknown_extra_data, + unknown_extra_data_size); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to read snapshot table"); + goto fail; + } + offset += unknown_extra_data_size; + } + /* Read snapshot ID */ sn->id_str = g_malloc(id_str_size + 1); ret = bdrv_pread(bs->file, offset, sn->id_str, id_str_size); @@ -162,7 +184,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs) sn = s->snapshots + i; offset = ROUND_UP(offset, 8); offset += sizeof(h); - offset += sizeof(extra); + offset += MAX(sizeof(extra), sn->extra_data_size); offset += strlen(sn->id_str); offset += strlen(sn->name); @@ -209,7 +231,8 @@ static int qcow2_write_snapshots(BlockDriverState *bs) h.date_sec = cpu_to_be32(sn->date_sec); h.date_nsec = cpu_to_be32(sn->date_nsec); h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec); - h.extra_data_size = cpu_to_be32(sizeof(extra)); + h.extra_data_size = cpu_to_be32(MAX(sizeof(extra), + sn->extra_data_size)); memset(&extra, 0, sizeof(extra)); extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size); @@ -234,6 +257,22 @@ static int qcow2_write_snapshots(BlockDriverState *bs) } offset += sizeof(extra); + if (sn->extra_data_size > sizeof(extra)) { + size_t unknown_extra_data_size = + sn->extra_data_size - sizeof(extra); + + /* qcow2_read_snapshots() ensures no unbounded allocation */ + assert(unknown_extra_data_size <= BDRV_REQUEST_MAX_BYTES); + assert(sn->unknown_extra_data); + + ret = bdrv_pwrite(bs->file, offset, sn->unknown_extra_data, + unknown_extra_data_size); + if (ret < 0) { + goto fail; + } + offset += unknown_extra_data_size; + } + ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size); if (ret < 0) { goto fail; @@ -376,6 +415,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) sn->date_sec = sn_info->date_sec; sn->date_nsec = sn_info->date_nsec; sn->vm_clock_nsec = sn_info->vm_clock_nsec; + sn->extra_data_size = sizeof(QCowSnapshotExtraData); /* Allocate the L1 table of the snapshot and copy the current one there. */ l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t)); @@ -647,6 +687,7 @@ int qcow2_snapshot_delete(BlockDriverState *bs, * The snapshot is now unused, clean up. If we fail after this point, we * won't recover but just leak clusters. */ + g_free(sn.unknown_extra_data); g_free(sn.id_str); g_free(sn.name);