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 40A15C43387 for ; Fri, 11 Jan 2019 15:02:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1055E20874 for ; Fri, 11 Jan 2019 15:02:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547218953; bh=BWj9Uzie4zntXf30fEXtv/uevnWFL2Z3AdZv80+j1V4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Uta265uwEpe1YKRNxL8WmIPNxMGyrymiRC0m/4HNFAWYkkPmcpYBQWFK/nT+sTsx6 EYj2S+YNf22tjWBqvja7GDkgF0XJVgr4FhNt+IvWbi2H9sBWLGOyayqkuJ0CF4If55 +NwvDQywHZ802Oa8o7cFR7BikjQppqAal6B/srCc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389187AbfAKOba (ORCPT ); Fri, 11 Jan 2019 09:31:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:48522 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388733AbfAKO3a (ORCPT ); Fri, 11 Jan 2019 09:29:30 -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 AB6632063F; Fri, 11 Jan 2019 14:29:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547216970; bh=BWj9Uzie4zntXf30fEXtv/uevnWFL2Z3AdZv80+j1V4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Kgwb4dMwrDYAZoOYS8YFNiniCH4Pe9ziffFk4zehE+BccTT6uTGbTRWXrqWI5uXGA tJPiIrth5+JguXp4ZVO+QkAmsuj+Qlo9tOLnrxfOpHlY6n37m8SamFJNhjsepC7/wn a3OGcNY3Bg/0SM8B+LAHIdSwXjr7pOku7D3lTMyg= 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 4.9 56/63] 9p/net: put a lower bound on msize Date: Fri, 11 Jan 2019 15:14:59 +0100 Message-Id: <20190111131054.634039809@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190111131046.387528003@linuxfoundation.org> References: <20190111131046.387528003@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.9-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 @@ -156,6 +156,12 @@ 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: @@ -972,10 +978,18 @@ 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; @@ -1040,6 +1054,13 @@ 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;