From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 7E742C5B57D for ; Tue, 2 Jul 2019 08:09:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 540CB2184E for ; Tue, 2 Jul 2019 08:09:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562054981; bh=WCMlNoAaWy7lyvfHPVNNy6TiejNn2cuBrEzf5p3829w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eYVBbbyuli66DQ6xyzMZ9SK/ueoPzRl1787EAWHS6xO27Fc5dPdjzExpSw7qleNY2 kfac0eWffjep48qOvguoBZatXKJQuit0sBEi17OzFwmyNKWmTc1BgRI4IixlDJJADn goPJ+IHtI0cVEk1gkQTCwpuPoC/XlvZ3MaOeHiOA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728717AbfGBIJj (ORCPT ); Tue, 2 Jul 2019 04:09:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:57498 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728684AbfGBIJf (ORCPT ); Tue, 2 Jul 2019 04:09:35 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 459C92184B; Tue, 2 Jul 2019 08:09:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562054974; bh=WCMlNoAaWy7lyvfHPVNNy6TiejNn2cuBrEzf5p3829w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bDWoBpoZI5semSFjfC1O/iHdg91BrJludeUTzjppRtHsWYA6+2jHeKaXLGW8Cbolg RCAw/41AQHx9DzYdw1uCHFB3SchGZeIuUrxijf5cANP2GM/SBkLxrVEiRpyPxmL/7z mWGXpJmXL+hYZ+SPE0hSofle4p8HLJ0LNloPAM+o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dominique Martinet , Stefano Stabellini , Eric Van Hensbergen , Latchesar Ionkov , Sasha Levin Subject: [PATCH 4.14 08/43] 9p/xen: fix check for xenbus_read error in front_probe Date: Tue, 2 Jul 2019 10:01:48 +0200 Message-Id: <20190702080124.283355221@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190702080123.904399496@linuxfoundation.org> References: <20190702080123.904399496@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 2f9ad0ac947ccbe3ffe7c6229c9330f2a7755f64 ] If the xen bus exists but does not expose the proper interface, it is possible to get a non-zero length but still some error, leading to strcmp failing trying to load invalid memory addresses e.g. fffffffffffffffe. There is then no need to check length when there is no error, as the xenbus driver guarantees that the string is nul-terminated. Link: http://lkml.kernel.org/r/1534236007-10170-1-git-send-email-asmadeus@codewreck.org Signed-off-by: Dominique Martinet Reviewed-by: Stefano Stabellini Cc: Eric Van Hensbergen Cc: Latchesar Ionkov Signed-off-by: Sasha Levin --- net/9p/trans_xen.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c index c10bdf63eae7..389eb635ec2c 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -392,8 +392,8 @@ static int xen_9pfs_front_probe(struct xenbus_device *dev, unsigned int max_rings, max_ring_order, len = 0; versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len); - if (!len) - return -EINVAL; + if (IS_ERR(versions)) + return PTR_ERR(versions); if (strcmp(versions, "1")) { kfree(versions); return -EINVAL; -- 2.20.1