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=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 A78E8C43387 for ; Fri, 11 Jan 2019 14:40:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 79D3C2133F for ; Fri, 11 Jan 2019 14:40:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547217631; bh=UOdzwU+SPY92oRjHbsCbeqtGlHkhSteNjOpf+XoZmeI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gpFqb+91pI8me8ad6ZP6EmztSeoGW6JKJc7p+FLaJksgWdVdZXdCr4/+eD+CNRM42 ngWpjcUFZ18lz5eZIs1oaubKEGOH1nd5KlH2lN7pRN+g5YVqhWEsEkFIVOveJ9W94G SFjQPY4ZX4tzb5Fe/qf+CZOQ9hPFRex32aFccSVI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391237AbfAKOka (ORCPT ); Fri, 11 Jan 2019 09:40:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:33062 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391207AbfAKOk2 (ORCPT ); Fri, 11 Jan 2019 09:40:28 -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 B8308206B6; Fri, 11 Jan 2019 14:40:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547217628; bh=UOdzwU+SPY92oRjHbsCbeqtGlHkhSteNjOpf+XoZmeI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=btpBoXUp3PYeZ2/aomEruqQhflwtm/rDSpThjf1SdtTlNtBDQGz9pTW8BuRX93TQR QPgStjtl3HBL+bdkK4YdoAyH4CTbqibVRPx+vIyoEFa+YSaHlxd+2tEDHhb0cXPnRH Z32HD2WifyT7rjxaaf4an20oFsu/m88nF9U2siRg= 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 4.19 131/148] 9p/net: put a lower bound on msize Date: Fri, 11 Jan 2019 15:15:09 +0100 Message-Id: <20190111131119.509618306@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190111131114.337122649@linuxfoundation.org> References: <20190111131114.337122649@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 4.19-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: @@ -993,10 +999,18 @@ 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; @@ -1055,6 +1069,13 @@ 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;