From patchwork Tue Apr 13 13:39:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 12200559 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=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 9842BC433B4 for ; Tue, 13 Apr 2021 13:43:23 +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 53ABE610FC for ; Tue, 13 Apr 2021 13:43:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 53ABE610FC 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]:44100 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lWJK6-0005hA-Ex for qemu-devel@archiver.kernel.org; Tue, 13 Apr 2021 09:43:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51628) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lWJGZ-0003Yw-W5 for qemu-devel@nongnu.org; Tue, 13 Apr 2021 09:39:44 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:41795) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lWJGY-0005VQ-HT for qemu-devel@nongnu.org; Tue, 13 Apr 2021 09:39:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618321181; 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=2SoxoYVPStABLgBvBamkLSFv17gsk6VRl6mPBexslps=; b=OiJidPEU1xum5ExA5pqwIpa8A+TrVpe+UGXKvSc1Nwwl4iG3xZ05YuPa4mf6dUJL9fNpWh Kpz0NJSUdBC/H+FxdyBkSxqsuztIiESJi+8OyU9Nfk88pQe54gPvfAp+9CjtvD6StGN3Vy 8v14nEYzvsmXmf7gtYy8FiOJi3tDkVI= 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-494-Xw9GQ4xCOQOCWBdI0EjXOg-1; Tue, 13 Apr 2021 09:39:08 -0400 X-MC-Unique: Xw9GQ4xCOQOCWBdI0EjXOg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CB83284B9AB; Tue, 13 Apr 2021 13:39:07 +0000 (UTC) Received: from localhost (ovpn-114-55.ams2.redhat.com [10.36.114.55]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 70E9D6062F; Tue, 13 Apr 2021 13:39:07 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PULL 1/1] block/nbd: fix possible use after free of s->connect_thread Date: Tue, 13 Apr 2021 15:39:03 +0200 Message-Id: <20210413133903.545695-2-mreitz@redhat.com> In-Reply-To: <20210413133903.545695-1-mreitz@redhat.com> References: <20210413133903.545695-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: Kevin Wolf , Peter Maydell , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Vladimir Sementsov-Ogievskiy If on nbd_close() we detach the thread (in nbd_co_establish_connection_cancel() thr->state becomes CONNECT_THREAD_RUNNING_DETACHED), after that point we should not use s->connect_thread (which is set to NULL), as running thread may free it at any time. Still nbd_co_establish_connection() does exactly this: it saves s->connect_thread to local variable (just for better code style) and use it even after yield point, when thread may be already detached. Fix that. Also check thr to be non-NULL on nbd_co_establish_connection() start for safety. After this patch "case CONNECT_THREAD_RUNNING_DETACHED" becomes impossible in the second switch in nbd_co_establish_connection(). Still, don't add extra abort() just before the release. If it somehow possible to reach this "case:" it won't hurt. Anyway, good refactoring of all this reconnect mess will come soon. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20210406155114.1057355-1-vsementsov@virtuozzo.com> Reviewed-by: Roman Kagan Signed-off-by: Max Reitz --- block/nbd.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/block/nbd.c b/block/nbd.c index c26dc5a54f..1d4668d42d 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -443,6 +443,11 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp) BDRVNBDState *s = bs->opaque; NBDConnectThread *thr = s->connect_thread; + if (!thr) { + /* detached */ + return -1; + } + qemu_mutex_lock(&thr->mutex); switch (thr->state) { @@ -486,6 +491,12 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp) s->wait_connect = true; qemu_coroutine_yield(); + if (!s->connect_thread) { + /* detached */ + return -1; + } + assert(thr == s->connect_thread); + qemu_mutex_lock(&thr->mutex); switch (thr->state) {