From patchwork Tue Feb 28 12:53:54 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 733529 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3vXfjB1KTgz9s7c for ; Wed, 1 Mar 2017 00:35:42 +1100 (AEDT) Received: from localhost ([::1]:32826 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cihwJ-0007Ju-Jz for incoming@patchwork.ozlabs.org; Tue, 28 Feb 2017 08:35:39 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43230) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cihIw-000428-3e for qemu-devel@nongnu.org; Tue, 28 Feb 2017 07:54:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cihIt-00041Y-G0 for qemu-devel@nongnu.org; Tue, 28 Feb 2017 07:54:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60376) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cihIr-00040G-7n; Tue, 28 Feb 2017 07:54:53 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4F4A485365; Tue, 28 Feb 2017 12:54:53 +0000 (UTC) Received: from noname.redhat.com (ovpn-116-177.ams2.redhat.com [10.36.116.177]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v1SCsXQB029713; Tue, 28 Feb 2017 07:54:51 -0500 From: Kevin Wolf To: qemu-block@nongnu.org Date: Tue, 28 Feb 2017 13:53:54 +0100 Message-Id: <1488286469-9381-10-git-send-email-kwolf@redhat.com> In-Reply-To: <1488286469-9381-1-git-send-email-kwolf@redhat.com> References: <1488286469-9381-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 28 Feb 2017 12:54:53 +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] [PATCH v3 09/44] vvfat: Implement .bdrv_child_perm() 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: kwolf@redhat.com, jcody@redhat.com, famz@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" vvfat is the last remaining driver that can have children, but doesn't implement .bdrv_child_perm() yet. The default handlers aren't suitable here, so let's implement a very simple driver-specific one that protects the internal child from being used by other users as good as our permissions permit. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz --- block.c | 2 +- block/vvfat.c | 22 ++++++++++++++++++++++ include/block/block_int.h | 1 + 3 files changed, 24 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index d67819f..281ce7b 100644 --- a/block.c +++ b/block.c @@ -823,7 +823,7 @@ static void bdrv_backing_options(int *child_flags, QDict *child_options, *child_flags = flags; } -static const BdrvChildRole child_backing = { +const BdrvChildRole child_backing = { .inherit_options = bdrv_backing_options, .drained_begin = bdrv_child_cb_drained_begin, .drained_end = bdrv_child_cb_drained_end, diff --git a/block/vvfat.c b/block/vvfat.c index 7f230be..72b482c 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -3052,6 +3052,27 @@ err: return ret; } +static void vvfat_child_perm(BlockDriverState *bs, BdrvChild *c, + const BdrvChildRole *role, + uint64_t perm, uint64_t shared, + uint64_t *nperm, uint64_t *nshared) +{ + BDRVVVFATState *s = bs->opaque; + + assert(c == s->qcow || role == &child_backing); + + if (c == s->qcow) { + /* This is a private node, nobody should try to attach to it */ + *nperm = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE; + *nshared = BLK_PERM_WRITE_UNCHANGED; + } else { + /* The backing file is there so 'commit' can use it. vvfat doesn't + * access it in any way. */ + *nperm = 0; + *nshared = BLK_PERM_ALL; + } +} + static void vvfat_close(BlockDriverState *bs) { BDRVVVFATState *s = bs->opaque; @@ -3077,6 +3098,7 @@ static BlockDriver bdrv_vvfat = { .bdrv_file_open = vvfat_open, .bdrv_refresh_limits = vvfat_refresh_limits, .bdrv_close = vvfat_close, + .bdrv_child_perm = vvfat_child_perm, .bdrv_co_preadv = vvfat_co_preadv, .bdrv_co_pwritev = vvfat_co_pwritev, diff --git a/include/block/block_int.h b/include/block/block_int.h index eb0598e..63d5446 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -466,6 +466,7 @@ struct BdrvChildRole { extern const BdrvChildRole child_file; extern const BdrvChildRole child_format; +extern const BdrvChildRole child_backing; struct BdrvChild { BlockDriverState *bs;