From patchwork Thu Sep 17 09:44:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 305162 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, MIME_BASE64_TEXT,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE054C43461 for ; Thu, 17 Sep 2020 09:47:32 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 38DAC20770 for ; Thu, 17 Sep 2020 09:47:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hWvCw6PU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 38DAC20770 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45208 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kIqVn-00020V-4v for qemu-devel@archiver.kernel.org; Thu, 17 Sep 2020 05:47:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53298) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kIqTr-0000aq-5L for qemu-devel@nongnu.org; Thu, 17 Sep 2020 05:45:31 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:39878 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 1kIqTn-0008WK-Hl for qemu-devel@nongnu.org; Thu, 17 Sep 2020 05:45:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600335926; 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=HE6Ac8pBnUa/ZYBkVcJrlTvMckV1JEQyDqyHau2eeWE=; b=hWvCw6PUWmyzhiHt8ZvZyUJowEPmCovgumgxYZUxWGRYP8AJDaEr8hAhqhfk/GAI/ZlhTz Gl3SLbPOTM1PtX0yIoNAvmo13xTM2dqelEAtK1CJPt7V+TCmhn4T5+kiD3BYEOGdWGDK1R +BitIjyNQwRzNokufYyuPy8UAvzRxLs= 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-504-wYtZVFgMNu-POgv5y-cylA-1; Thu, 17 Sep 2020 05:45:20 -0400 X-MC-Unique: wYtZVFgMNu-POgv5y-cylA-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 8B53D101872D; Thu, 17 Sep 2020 09:45:19 +0000 (UTC) Received: from localhost (ovpn-114-232.ams2.redhat.com [10.36.114.232]) by smtp.corp.redhat.com (Postfix) with ESMTP id EDF0371775; Thu, 17 Sep 2020 09:45:12 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH v2 2/3] virtio-blk: undo destructive iov_discard_*() operations Date: Thu, 17 Sep 2020 10:44:54 +0100 Message-Id: <20200917094455.822379-3-stefanha@redhat.com> In-Reply-To: <20200917094455.822379-1-stefanha@redhat.com> References: <20200917094455.822379-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.120; envelope-from=stefanha@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/17 02:30:14 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.999, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: Kevin Wolf , qemu-block@nongnu.org, "Michael S. Tsirkin" , Max Reitz , Alexander Bulekov , "Gonglei \(Arei\)" , Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Fuzzing discovered that virtqueue_unmap_sg() is being called on modified req->in/out_sg iovecs. This means dma_memory_map() and dma_memory_unmap() calls do not have matching memory addresses. Fuzzing discovered that non-RAM addresses trigger a bug: void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len, bool is_write, hwaddr access_len) { if (buffer != bounce.buffer) { ^^^^^^^^^^^^^^^^^^^^^^^ A modified iov->iov_base is no longer recognized as a bounce buffer and the wrong branch is taken. There are more potential bugs: dirty memory is not tracked correctly and MemoryRegion refcounts can be leaked. Use the new iov_discard_undo() API to restore elem->in/out_sg before virtqueue_push() is called. Reported-by: Alexander Bulekov Buglink: https://bugs.launchpad.net/qemu/+bug/1890360 Fixes: 827805a2492c1bbf1c0712ed18ee069b4ebf3dd6 ("virtio-blk: Convert VirtIOBlockReq.out to structrue") Signed-off-by: Stefan Hajnoczi Reviewed-by: Li Qiang --- include/hw/virtio/virtio-blk.h | 2 ++ hw/block/virtio-blk.c | 11 +++++++++-- 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h index 29c9f32353..df3876d49c 100644 --- a/include/hw/virtio/virtio-blk.h +++ b/include/hw/virtio/virtio-blk.h @@ -72,6 +72,8 @@ typedef struct VirtIOBlockReq { int64_t sector_num; VirtIOBlock *dev; VirtQueue *vq; + IOVDiscardUndo inhdr_undo; + IOVDiscardUndo outhdr_undo; struct virtio_blk_inhdr *in; struct virtio_blk_outhdr out; QEMUIOVector qiov; diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 2204ba149e..bac2d6fa2b 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -80,6 +80,8 @@ static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status) trace_virtio_blk_req_complete(vdev, req, status); stb_p(&req->in->status, status); + iov_discard_undo(&req->inhdr_undo); + iov_discard_undo(&req->outhdr_undo); virtqueue_push(req->vq, &req->elem, req->in_len); if (s->dataplane_started && !s->dataplane_disabled) { virtio_blk_data_plane_notify(s->dataplane, req->vq); @@ -632,10 +634,12 @@ static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) return -1; } - iov_discard_front(&out_iov, &out_num, sizeof(req->out)); + iov_discard_front_undoable(&out_iov, &out_num, sizeof(req->out), + &req->outhdr_undo); if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) { virtio_error(vdev, "virtio-blk request inhdr too short"); + iov_discard_undo(&req->outhdr_undo); return -1; } @@ -644,7 +648,8 @@ static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) req->in = (void *)in_iov[in_num - 1].iov_base + in_iov[in_num - 1].iov_len - sizeof(struct virtio_blk_inhdr); - iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr)); + iov_discard_back_undoable(in_iov, &in_num, sizeof(struct virtio_blk_inhdr), + &req->inhdr_undo); type = virtio_ldl_p(vdev, &req->out.type); @@ -739,6 +744,8 @@ static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) if (unlikely(iov_to_buf(out_iov, out_num, 0, &dwz_hdr, sizeof(dwz_hdr)) != sizeof(dwz_hdr))) { + iov_discard_undo(&req->inhdr_undo); + iov_discard_undo(&req->outhdr_undo); virtio_error(vdev, "virtio-blk discard/write_zeroes header" " too short"); return -1;