From patchwork Fri Jan 4 09:07:07 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Ignatov X-Patchwork-Id: 1020644 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="Uz1rGovj"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43WJpP5Yt3z9s3l for ; Fri, 4 Jan 2019 20:07:41 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727280AbfADJHk (ORCPT ); Fri, 4 Jan 2019 04:07:40 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:49106 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726581AbfADJHj (ORCPT ); Fri, 4 Jan 2019 04:07:39 -0500 Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x048xAa0025852 for ; Fri, 4 Jan 2019 01:07:37 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=VvRuCMA9Ef6H3yarq3bdc6G+Gjzj4zy5sJmnXVzZWM4=; b=Uz1rGovjrlC36YY8tX+i3De91cKbUZr9Ki7oiqraCseBddVdaLh62QtaxnEQtZfFxuXm xdmL+/4iSWpZ5HqqAhlnJ/tGKDYexIe8pHMRqGxsA9riBErhNSaU3ogEF5zl28CmsL5m n8ziwYo0O9uAxiy90cIPJ58v4SBLPH7/Rvw= Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2pt2a00bua-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Fri, 04 Jan 2019 01:07:37 -0800 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::128) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1531.3; Fri, 4 Jan 2019 01:07:35 -0800 Received: by dev082.prn2.facebook.com (Postfix, from userid 572249) id 2ED74370314C; Fri, 4 Jan 2019 01:07:26 -0800 (PST) Smtp-Origin-Hostprefix: dev From: Andrey Ignatov Smtp-Origin-Hostname: dev082.prn2.facebook.com To: CC: Andrey Ignatov , , , , Smtp-Origin-Cluster: prn2c23 Subject: [PATCH bpf v2 1/2] bpf: Fix [::] -> [::1] rewrite in sys_sendmsg Date: Fri, 4 Jan 2019 01:07:07 -0800 Message-ID: <4b643c5b0807915434450da044db0786e86a9e57.1546592666.git.rdna@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-01-04_04:, , signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 --- 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 9cbf363172bd..7c3505006f8e 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1390,10 +1390,7 @@ 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; @@ -1421,6 +1418,9 @@ 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;