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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3A88C433EF for ; Tue, 14 Jun 2022 02:24:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354264AbiFNCY4 (ORCPT ); Mon, 13 Jun 2022 22:24:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353628AbiFNCWq (ORCPT ); Mon, 13 Jun 2022 22:22:46 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B407E369CB; Mon, 13 Jun 2022 19:10:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E54FDB8168A; Tue, 14 Jun 2022 02:10:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C7C17C36AFE; Tue, 14 Jun 2022 02:10:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655172615; bh=ELWPu2WsVA7XBvgFySoXF2QkOya+kpglczV7K/lrUXA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u7D9cLeyCqX21DF1yqR+uaHolFXe8Sn+jnxUVxM0yNIe7IATyqbmoF2b4GFKOZ4eo 7XLFDDtPPtKjc9V719X5vfLtz/Gr8fO5Mm9isiTz0S8/DFEGx2NS0ZMrgQsMHsR6Db OX2exzpc1HbdANE38Qnl9UnF04qbcNCOBEG7k5CHeUZ2zgDtPyDxZiMEmFtOcmjV4P n3xS6OynaaivB+dSNswYxSENGM1XGZP2NhLNZTko/JMwvnYvEs76fdFWSRI+8qR13x TdxD5P+P0S5+UJZmIKnH5GwafUP/fDL6ucBrQjumaAoIQQww6UiovRwnh0+WTcPgGL VJk+krvnC5TwQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Wang Yufen , Jakub Kicinski , Sasha Levin , davem@davemloft.net, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 16/18] ipv6: Fix signed integer overflow in l2tp_ip6_sendmsg Date: Mon, 13 Jun 2022 22:09:39 -0400 Message-Id: <20220614020941.1100702-16-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220614020941.1100702-1-sashal@kernel.org> References: <20220614020941.1100702-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Wang Yufen [ Upstream commit f638a84afef3dfe10554c51820c16e39a278c915 ] When len >= INT_MAX - transhdrlen, ulen = len + transhdrlen will be overflow. To fix, we can follow what udpv6 does and subtract the transhdrlen from the max. Signed-off-by: Wang Yufen Link: https://lore.kernel.org/r/20220607120028.845916-2-wangyufen@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/l2tp/l2tp_ip6.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c index 2ff25c445b82..9dae10d8880c 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -519,14 +519,15 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) struct ipcm6_cookie ipc6; int addr_len = msg->msg_namelen; int transhdrlen = 4; /* zero session-id */ - int ulen = len + transhdrlen; + int ulen; int err; /* Rough check on arithmetic overflow, better check is made in ip6_append_data(). */ - if (len > INT_MAX) + if (len > INT_MAX - transhdrlen) return -EMSGSIZE; + ulen = len + transhdrlen; /* Mirror BSD error message compatibility */ if (msg->msg_flags & MSG_OOB) -- 2.35.1