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 047F3C433EF for ; Tue, 14 Jun 2022 02:23:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354386AbiFNCXH (ORCPT ); Mon, 13 Jun 2022 22:23:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353823AbiFNCQ7 (ORCPT ); Mon, 13 Jun 2022 22:16:59 -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 1A7F23E5F7; Mon, 13 Jun 2022 19:09:39 -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 3FA38B816B3; Tue, 14 Jun 2022 02:09:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0091C341C6; Tue, 14 Jun 2022 02:09:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655172576; bh=/JxTVNZQgird5HD+oKTweiMNeN6rCY5i+EHHudwkku8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uHT95jC1Xss4NC9zEP422EFg5jKgllgijzuTYNmlKflbjE1jt5hoWYGZ9QBwx5ArA 09BmfKYM/xtPCfHsI4hr9b8/pacHIIO4oiFAWDbVQms2CcFt2DVJoz7MO/Jrq/TYTC b+EXsXy1hducxp088zCly0edNOZR6upIqxU9wwxE1gx/gxP4cbjZtgn/8/Ju2jAd4S INaKyoV6Tzbk38z7U+WPzUgsG2hNYvHFIBraY8lgkqwIbVJv5hhxtUJaAvSBWuAyu0 UzuFmw7kU6Dx2LGvpXaXsgRLvgL7DnkwNl3ig0OGm10CGw8+GeYoc+zN26CN50LCDa x586X9WToYbJg== 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 5.4 21/23] ipv6: Fix signed integer overflow in l2tp_ip6_sendmsg Date: Mon, 13 Jun 2022 22:08:57 -0400 Message-Id: <20220614020900.1100401-21-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220614020900.1100401-1-sashal@kernel.org> References: <20220614020900.1100401-1-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: linux-kernel@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 0fa694bd3f6a..23e9ce985ed6 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -515,14 +515,15 @@ 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