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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 35977C5CFE7 for ; Mon, 9 Jul 2018 22:43:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8CB3208DB for ; Mon, 9 Jul 2018 22:43:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="S+TOk0yy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D8CB3208DB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933609AbeGIWnc (ORCPT ); Mon, 9 Jul 2018 18:43:32 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:35229 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933166AbeGIWn3 (ORCPT ); Mon, 9 Jul 2018 18:43:29 -0400 Received: by mail-wm0-f65.google.com with SMTP id v3-v6so18712485wmh.0; Mon, 09 Jul 2018 15:43:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=ZLf0WhIai3jR7LvewS2sDfi0QvlUsjMwaqVya5bupjA=; b=S+TOk0yyJVSelmSXtkY1uEyLdvkygtz2leArNxBYb8H0vewtQQZ0aFStqDv08seaxx fV+0GPELKminioVz7Z5tYSFb21MDLnucJ0mLbg/RjnQj+yXG9w7+dVMQMuJby+wLoCP+ WNqtd9RO38J7bILN6o9m6haq4S7Yo9NK6MUt2dIkJAjgyc+g3BcElC4FRWdf1LsyzGVS 1C2WxtcNHxY0ERXd5zoRrNxhflOoI2OriOe207M6qXuQdf2yjOOzdxdufmGOGMSLS4EJ FvRfp25arwUfVMF+FMS74jAQVTObWlH0XXxxGycCXnoTH2l5OKoUqx9VkNkuN6LVWXD5 DTMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=ZLf0WhIai3jR7LvewS2sDfi0QvlUsjMwaqVya5bupjA=; b=Nj6vzl73Ci8UjzuTcjaRydm1yXDsttNNfyDuk97CmjtWHSwOD+8Cvid7a7T6SFtsjZ r7sJU/DyFx3LQ/lgguHinVVFzZLPzmhYDrib0NCn/W21JRhN3IfUEH7RJoWOs8ztmGkI 46UKlwTgHkCpsqBDAIt/9xeeFa9Ll+3bYH99vcLkaiUTvSbMG6bY8hs1olizJxG0FzoT y3GmGPz20Dz7YAMih3kg2Pj0zcz4Vd2gEV+Wn5pcjYlQPt8hwIrzhADezAYsSqs/VJ7W m8Db+BBdocMJb5HnHkAnKgjLGoGYUTMAR4WLb36vPd6KQBxGECeVjziNurKCHWRchfZM F6ww== X-Gm-Message-State: APt69E0iGanOJdzgfCsvlq4QLzGni6OIz4j73B64x6MfWD7bxVTDxjVe /MvxXjJ+ePQbFoB1cirGo4U= X-Google-Smtp-Source: AAOMgpf966P86xkzpodjFQhlzsN6o+iVyNwYW878dxWqIExxtuqeQmmPGWAhxjldNbB9oR0CS2GNQg== X-Received: by 2002:a1c:b801:: with SMTP id i1-v6mr12727238wmf.30.1531176208116; Mon, 09 Jul 2018 15:43:28 -0700 (PDT) Received: from localhost.localdomain ([185.175.214.210]) by smtp.gmail.com with ESMTPSA id o21-v6sm17480482wmg.28.2018.07.09.15.43.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 09 Jul 2018 15:43:26 -0700 (PDT) From: Tomas Bortoli To: ericvh@gmail.com, rminnich@sandia.gov, lucho@ionkov.net Cc: davem@davemloft.net, v9fs-developer@lists.sourceforge.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller@googlegroups.com, Tomas Bortoli Subject: [V9fs-developer] [PATCH] p9_check_errors() validate PDU length Date: Tue, 10 Jul 2018 00:43:23 +0200 Message-Id: <20180709224323.20597-1-tomasbortoli@gmail.com> X-Mailer: git-send-email 2.11.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org p9_check_errors() does not validate the size of the PDU read in p9_parse_header(). Any size can be passed, provoking out-of-bound reads. Signed-off-by: Tomas Bortoli Reported-by: syzbot+65c6b72f284a39d416b4@syzkaller.appspotmail.com --- As suggested by Dominique: https://lkml.org/lkml/2018/7/9/688 Such check is not enough as it will prevent to read more than how it has been allocated but it won't prevent to read more than how it has been read So this patch will require some more changes to prevent bad sizes. net/9p/client.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/9p/client.c b/net/9p/client.c index 40f7c47f2f74..5b161b576b8a 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -520,10 +520,13 @@ EXPORT_SYMBOL(p9_parse_header); static int p9_check_errors(struct p9_client *c, struct p9_req_t *req) { int8_t type; + int32_t size; int err; int ecode; - err = p9_parse_header(req->rc, NULL, &type, NULL, 0); + err = p9_parse_header(req->rc, &size, &type, NULL, 0); + if (size > req->rc->capacity) + return -EINVAL; /* * dump the response from server * This should be after check errors which poplulate pdu_fcall. -- 2.11.0