From patchwork Wed May 10 20:35:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 13237240 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4FBD3C77B7C for ; Wed, 10 May 2023 20:38:34 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pwqY4-0005DB-Hy; Wed, 10 May 2023 16:36:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pwqY2-0005AL-7I for qemu-devel@nongnu.org; Wed, 10 May 2023 16:36:30 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pwqY0-0003K1-NI for qemu-devel@nongnu.org; Wed, 10 May 2023 16:36:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683750988; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yD72QprueAbSuOWgAgRWxGGjAq16e84Rapg38+Z4Z9g=; b=bETM0KMpmzVo6VU7kKFbKFFv8SB0tp0wUTr0d7TFej0UxY7c3L7z+u1PqnfM5pCtOpTzPm s1DcidBlPX6IWygTAonCwAHRjPem7oxoTcw+0CTXuRvr5G5JCHu1AxCRnm9tu66CH48q5i xh2Xqjab127ibE+K5AW9vtDBWENhZiU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-668-1rq3FXV4NSSEq79QdghG2A-1; Wed, 10 May 2023 16:36:24 -0400 X-MC-Unique: 1rq3FXV4NSSEq79QdghG2A-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8E90880067D; Wed, 10 May 2023 20:36:24 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.148]) by smtp.corp.redhat.com (Postfix) with ESMTP id E13431121314; Wed, 10 May 2023 20:36:22 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, hreitz@redhat.com, stefanha@redhat.com, f.ebner@proxmox.com, qemu-devel@nongnu.org Subject: [PATCH 2/8] block/export: Fix null pointer dereference in error path Date: Wed, 10 May 2023 22:35:55 +0200 Message-Id: <20230510203601.418015-3-kwolf@redhat.com> In-Reply-To: <20230510203601.418015-1-kwolf@redhat.com> References: <20230510203601.418015-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org There are some error paths in blk_exp_add() that jump to 'fail:' before 'exp' is even created. So we can't just unconditionally access exp->blk. Add a NULL check, and switch from exp->blk to blk, which is available earlier, just to be extra sure that we really cover all cases where BlockDevOps could have been set for it (in practice, this only happens in drv->create() today, so this part of the change isn't strictly necessary). Fixes: de79b52604e43fdeba6cee4f5af600b62169f2d2 Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake Tested-by: Eric Blake --- block/export/export.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/block/export/export.c b/block/export/export.c index 62c7c22d45..a5c8f42f53 100644 --- a/block/export/export.c +++ b/block/export/export.c @@ -192,8 +192,10 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) return exp; fail: - blk_set_dev_ops(exp->blk, NULL, NULL); - blk_unref(blk); + if (blk) { + blk_set_dev_ops(blk, NULL, NULL); + blk_unref(blk); + } aio_context_release(ctx); if (exp) { g_free(exp->id);