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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 54C96C282CA for ; Wed, 13 Feb 2019 02:37:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 244E1222CA for ; Wed, 13 Feb 2019 02:37:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550025455; bh=qQHn/cPbskFkR/KCb+yN8S0xGLXYeY96wswNr8pghiA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=o6nvqC9huRCET2AO4iB3XWT2PJWZUBR/gFHaCDQG4wSJbOi6JJjSD6HcC7V3aA6x2 Y2jnQL1OVwTD7J4KzP9zpa9SFr4jCjiLREnzFBkiceeWWQxUiic7uhO6eYe5UMd5wz BEcqnaNpNS/yRK5FtJybWsRmCci2hrT5zd+CKrLU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732798AbfBMChd (ORCPT ); Tue, 12 Feb 2019 21:37:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:41058 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388317AbfBMChc (ORCPT ); Tue, 12 Feb 2019 21:37:32 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 61FD7222C2; Wed, 13 Feb 2019 02:37:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550025451; bh=qQHn/cPbskFkR/KCb+yN8S0xGLXYeY96wswNr8pghiA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZTFS58aT1R3EdhiGzLd11JE2azOti4gRMwyOXKu7doWrmzJl0w07dHeRVSQMgg0+I sfe31s0BZaPiY2WHZhsFC7LC5o29vfBFayd5Hp9D+5q/bZdfsHTM9cpwPh6h1V3ysz 5jReCEYh8veHE4dQ9wU8qlCB1LmhW+EwUPztU4+Q= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andrey Ignatov , Alexei Starovoitov , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 24/83] bpf: Fix [::] -> [::1] rewrite in sys_sendmsg Date: Tue, 12 Feb 2019 21:36:02 -0500 Message-Id: <20190213023701.20286-24-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190213023701.20286-1-sashal@kernel.org> References: <20190213023701.20286-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Andrey Ignatov [ Upstream commit e8e36984080b55ac5e57bdb09a5b570f2fc8e963 ] sys_sendmsg has supported unspecified destination IPv6 (wildcard) for unconnected UDP sockets since 876c7f41. When [::] is passed by user as destination, sys_sendmsg rewrites it with [::1] to be consistent with BSD (see "BSD'ism" comment in the code). This didn't work when cgroup-bpf was enabled though since the rewrite [::] -> [::1] happened before passing control to cgroup-bpf block where fl6.daddr was updated with passed by user sockaddr_in6.sin6_addr (that might or might not be changed by BPF program). That way if user passed [::] as dst IPv6 it was first rewritten with [::1] by original code from 876c7f41, but then rewritten back with [::] by cgroup-bpf block. It happened even when BPF_CGROUP_UDP6_SENDMSG program was not present (CONFIG_CGROUP_BPF=y was enough). The fix is to apply BSD'ism after cgroup-bpf block so that [::] is replaced with [::1] no matter where it came from: passed by user to sys_sendmsg or set by BPF_CGROUP_UDP6_SENDMSG program. Fixes: 1cedee13d25a ("bpf: Hooks for sys_sendmsg") Reported-by: Nitin Rawat Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- net/ipv6/udp.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 76ba2f34ef6b..cab8b2b647f9 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1322,10 +1322,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) ipc6.opt = opt; fl6.flowi6_proto = sk->sk_protocol; - if (!ipv6_addr_any(daddr)) - fl6.daddr = *daddr; - else - fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ + fl6.daddr = *daddr; if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr)) fl6.saddr = np->saddr; fl6.fl6_sport = inet->inet_sport; @@ -1353,6 +1350,9 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) } } + if (ipv6_addr_any(&fl6.daddr)) + fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ + final_p = fl6_update_dst(&fl6, opt, &final); if (final_p) connected = false; -- 2.19.1