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=unavailable 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 EB5A7C5B57D for ; Tue, 2 Jul 2019 08:14:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB33D206A2 for ; Tue, 2 Jul 2019 08:14:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562055283; bh=S+DIEFDqaSmUJzNhm1v6tI65Wx7tRIHzy5KPod8TXuk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=r+JcEa0aFTSkFzCi6rjFSy+CnnboOqVaqqJN37CbUBSlBq9k74TneeEK2FBT5olIU xL9s3+vqnu1xl4y2VRTWxmB7WUU/v0Zagv6zWIGen+kp1LZ8z79i4k/F3K8lo9o+K9 GHxitErmjTcrYFspO6kbLp4k7YpLrBLm1Lel+dHU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728009AbfGBIFw (ORCPT ); Tue, 2 Jul 2019 04:05:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:52112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728005AbfGBIFw (ORCPT ); Tue, 2 Jul 2019 04:05:52 -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 DE13121479; Tue, 2 Jul 2019 08:05:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562054751; bh=S+DIEFDqaSmUJzNhm1v6tI65Wx7tRIHzy5KPod8TXuk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=O6jY+/ntDCuvr3ultDbUmfg0KQyP9N0pEzF11KgNQlDOOPF0Phbx2/R2s81o9VLVO 4KYdMhgeSeqQyED0e/pnYdk7Ac03VWidvRqxXYIRVnh+L7mQV3dHpa9v+ivJhbNct6 VDrqS+HbtoK2h6e+mv0hfEnxTN6fPv+zNtzqRIi0= 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 4.19 07/72] 9p/xen: fix check for xenbus_read error in front_probe Date: Tue, 2 Jul 2019 10:01:08 +0200 Message-Id: <20190702080124.947283085@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190702080124.564652899@linuxfoundation.org> References: <20190702080124.564652899@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 c2d54ac76bfd..843cb823d9b9 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -391,8 +391,8 @@ 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