From patchwork Tue Dec 22 22:23:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 346887 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 4C6C3C433DB for ; Tue, 22 Dec 2020 22:25:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1DE61239A4 for ; Tue, 22 Dec 2020 22:25:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727868AbgLVWYp (ORCPT ); Tue, 22 Dec 2020 17:24:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726329AbgLVWYp (ORCPT ); Tue, 22 Dec 2020 17:24:45 -0500 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF3A0C0613D6; Tue, 22 Dec 2020 14:24:04 -0800 (PST) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1krq4Z-0001tv-6e; Tue, 22 Dec 2020 23:24:03 +0100 From: Florian Westphal To: Cc: , torvalds@linux-foundation.org, syzkaller-bugs@googlegroups.com, Florian Westphal , syzbot+e86f7c428c8c50db65b4@syzkaller.appspotmail.com Subject: [PATCH nf] netfilter: xt_RATEEST: reject non-null terminated string from userspace Date: Tue, 22 Dec 2020 23:23:56 +0100 Message-Id: <20201222222356.22645-1-fw@strlen.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <000000000000fcbe0705b70e9bd9@google.com> References: <000000000000fcbe0705b70e9bd9@google.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org syzbot reports: detected buffer overflow in strlen [..] Call Trace: strlen include/linux/string.h:325 [inline] strlcpy include/linux/string.h:348 [inline] xt_rateest_tg_checkentry+0x2a5/0x6b0 net/netfilter/xt_RATEEST.c:143 strlcpy assumes src is a c-string. Check info->name before its used. Reported-by: syzbot+e86f7c428c8c50db65b4@syzkaller.appspotmail.com Fixes: 5859034d7eb8793 ("[NETFILTER]: x_tables: add RATEEST target") Signed-off-by: Florian Westphal --- RATEEST test in iptables.git still passes, syzbot repro setsockopt fails with -ENAMETOOLONG. diff --git a/net/netfilter/xt_RATEEST.c b/net/netfilter/xt_RATEEST.c index 37253d399c6b..0d5c422f8745 100644 --- a/net/netfilter/xt_RATEEST.c +++ b/net/netfilter/xt_RATEEST.c @@ -115,6 +115,9 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) } cfg; int ret; + if (strnlen(info->name, sizeof(est->name)) >= sizeof(est->name)) + return -ENAMETOOLONG; + net_get_random_once(&jhash_rnd, sizeof(jhash_rnd)); mutex_lock(&xn->hash_lock);