From patchwork Wed Aug 12 10:49:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 11710627 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B5B59109B for ; Wed, 12 Aug 2020 10:50:28 +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 8145520885 for ; Wed, 12 Aug 2020 10:50:28 +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="VgFmkvra" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8145520885 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:53404 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k5oKx-0004lC-KP for patchwork-qemu-devel@patchwork.kernel.org; Wed, 12 Aug 2020 06:50:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33418) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k5oK6-0003eg-F2 for qemu-devel@nongnu.org; Wed, 12 Aug 2020 06:49:34 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:42978 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 1k5oK3-00077X-LU for qemu-devel@nongnu.org; Wed, 12 Aug 2020 06:49:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597229370; 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; bh=gUDQ32AHBp1nfSHgJ75ZEyv6YxqcPG2HqWc+zH5vGUw=; b=VgFmkvra85x7NlUacvTiAoBvs/ohORXCi9BL/2sASm1g3D9O2ZRjOhf/55xW09aQjoyHKi fXl+nGWHpA1mDY4FYn3OKvhooyWPgGGYK2IvKBshR/Eti4WgxqtZCZS94OJ56wiJJ+eHyE n/lcbSGsJyRDxlA7mECBAoMe6cqz6HE= 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-165-i4HzSOPkPAeHtL62HJTM-w-1; Wed, 12 Aug 2020 06:49:28 -0400 X-MC-Unique: i4HzSOPkPAeHtL62HJTM-w-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E16A4101C8AA; Wed, 12 Aug 2020 10:49:26 +0000 (UTC) Received: from localhost (ovpn-114-96.ams2.redhat.com [10.36.114.96]) by smtp.corp.redhat.com (Postfix) with ESMTP id 067F810631E2; Wed, 12 Aug 2020 10:49:19 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 0/3] virtio: restore elem->in/out_sg after iov_discard_front/back() Date: Wed, 12 Aug 2020 11:49:15 +0100 Message-Id: <20200812104918.107116-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=stefanha@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/12 06:16:38 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" Both virtio-blk and virtio-crypto use destructive iov_discard_front/back() operations on elem->in/out_sg. virtqueue_push() calls dma_memory_unmap() on t= he modified iovec arrays. The memory addresses may not match those originally mapped with dma_memory_map(). This raises several issues: 1. MemoryRegion references can be leaked. 2. Dirty memory may not be tracked. 3. The non-RAM bounce buffer can be leaked. This patch series solves the issue in two ways: 1. virtio-blk uses a new iov_discard_undo() API to restore iovec arrays. 2. virtio-crypto uses g_memdup() to avoid modifying the original iovec arrays. The g_memdup() approach is slower than iov_discard_undo() but less complex/fragile. I am less familiar with the virtio-crypto code and it uses more complex sequences of iov_discard_front/back() calls than virtio-blk. If anyone feels like optimizing virtio-crypto, please go ahead. The virtio-blk bug was found by Alexander Bulekov's fuzzing effort. I found t= he virtio-crypto bug through code inspection. Stefan Hajnoczi (3): util/iov: add iov_discard_undo() virtio-blk: undo destructive iov_discard_*() operations virtio-crypto: don't modify elem->in/out_sg include/hw/virtio/virtio-blk.h | 2 + include/qemu/iov.h | 23 +++++ hw/block/virtio-blk.c | 9 +- hw/virtio/virtio-crypto.c | 17 +++- tests/test-iov.c | 165 +++++++++++++++++++++++++++++++++ util/iov.c | 50 +++++++++- 6 files changed, 257 insertions(+), 9 deletions(-) --=20 2.26.2