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=-10.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 22F90C43387 for ; Fri, 11 Jan 2019 14:43:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E9C21206B6 for ; Fri, 11 Jan 2019 14:43:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547217803; bh=J7MLIe9kx4UhEAnsTbN4LubRtANRoAQSk+fo99/988w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lwdbLWqbSLjOVzYQ7NPgjvBgXSVk+FFZpr8v7fhuszcoGp15VnVIb2AlHKTjINEqa eUEF82mIpF7hyVWZsv1x/y0zlxA0UsGqYbMNgavTkLRgcySkQm3updhfWA/YRp2GMm hnv4rUGQQZ7avVI3PuFt+aAXdMEZe4gZ9Y5B+Xx4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391387AbfAKOnV (ORCPT ); Fri, 11 Jan 2019 09:43:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:36164 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391057AbfAKOnR (ORCPT ); Fri, 11 Jan 2019 09:43:17 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 2B1642184A; Fri, 11 Jan 2019 14:43:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547217796; bh=J7MLIe9kx4UhEAnsTbN4LubRtANRoAQSk+fo99/988w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jW81x+d8mkoxjhOEcmHBdGJPTV+x9k816IPVQ/71jaj05TkLgvoezDgj0MUTgc46Y zmco15uoeaU9tJUcCb0fvkivFtK5C+Ay9VPAUiS5sXU7KNzkmVFfpkbT2tMJV/b21d ApgQZoOszBHEdpFlmFRyAJgohGXykq6MEDmfDiH0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+0c1d61e4db7db94102ca@syzkaller.appspotmail.com, Dominique Martinet , Eric Van Hensbergen , Latchesar Ionkov Subject: [PATCH 4.20 45/65] 9p/net: put a lower bound on msize Date: Fri, 11 Jan 2019 15:15:31 +0100 Message-Id: <20190111131102.537703599@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190111131055.331350141@linuxfoundation.org> References: <20190111131055.331350141@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dominique Martinet commit 574d356b7a02c7e1b01a1d9cba8a26b3c2888f45 upstream. If the requested msize is too small (either from command line argument or from the server version reply), we won't get any work done. If it's *really* too small, nothing will work, and this got caught by syzbot recently (on a new kmem_cache_create_usercopy() call) Just set a minimum msize to 4k in both code paths, until someone complains they have a use-case for a smaller msize. We need to check in both mount option and server reply individually because the msize for the first version request would be unchecked with just a global check on clnt->msize. Link: http://lkml.kernel.org/r/1541407968-31350-1-git-send-email-asmadeus@codewreck.org Reported-by: syzbot+0c1d61e4db7db94102ca@syzkaller.appspotmail.com Signed-off-by: Dominique Martinet Cc: Eric Van Hensbergen Cc: Latchesar Ionkov Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- net/9p/client.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) --- a/net/9p/client.c +++ b/net/9p/client.c @@ -181,6 +181,12 @@ static int parse_opts(char *opts, struct ret = r; continue; } + if (option < 4096) { + p9_debug(P9_DEBUG_ERROR, + "msize should be at least 4k\n"); + ret = -EINVAL; + continue; + } clnt->msize = option; break; case Opt_trans: @@ -983,10 +989,18 @@ static int p9_client_version(struct p9_c else if (!strncmp(version, "9P2000", 6)) c->proto_version = p9_proto_legacy; else { + p9_debug(P9_DEBUG_ERROR, + "server returned an unknown version: %s\n", version); err = -EREMOTEIO; goto error; } + if (msize < 4096) { + p9_debug(P9_DEBUG_ERROR, + "server returned a msize < 4096: %d\n", msize); + err = -EREMOTEIO; + goto error; + } if (msize < c->msize) c->msize = msize; @@ -1043,6 +1057,13 @@ struct p9_client *p9_client_create(const if (clnt->msize > clnt->trans_mod->maxsize) clnt->msize = clnt->trans_mod->maxsize; + if (clnt->msize < 4096) { + p9_debug(P9_DEBUG_ERROR, + "Please specify a msize of at least 4k\n"); + err = -EINVAL; + goto free_client; + } + err = p9_client_version(clnt); if (err) goto close_trans;