From patchwork Thu Jan 3 22:43:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Ignatov X-Patchwork-Id: 1020535 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="EeGWvBZO"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43W2yZ6f2fz9s3l for ; Fri, 4 Jan 2019 09:43:50 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728599AbfACWnq (ORCPT ); Thu, 3 Jan 2019 17:43:46 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:47184 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728419AbfACWnp (ORCPT ); Thu, 3 Jan 2019 17:43:45 -0500 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x03McG9N016479 for ; Thu, 3 Jan 2019 14:43:44 -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=PgCUcg7wkhB1gzzrfuJa8/odhpKA49sA0FQX5jIZfyw=; b=EeGWvBZOG0WO9dtclCBoRBajcE9wK0z5KuvCQE/c8fU/zPc0pZdaoc1abEaCYprzfoY5 1aeT8rgRfveRFLnSNdJdko4RJS2UJ18/y5QMEUa1Dhud/iONfSxEtrxkncwBDTclgYde fHaCONYj6L+D12QzhaCijsP7mHzd5t8V8Ug= Received: from maileast.thefacebook.com ([199.201.65.23]) by mx0a-00082601.pphosted.com with ESMTP id 2psrk8gj59-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Thu, 03 Jan 2019 14:43:44 -0800 Received: from mx-out.facebook.com (2620:10d:c0a1:3::13) by mail.thefacebook.com (2620:10d:c021:18::173) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1531.3; Thu, 3 Jan 2019 14:43:43 -0800 Received: by dev082.prn2.facebook.com (Postfix, from userid 572249) id 3A19B3702B1F; Thu, 3 Jan 2019 14:43:42 -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 1/2] bpf: Fix [::] -> [::1] rewrite in sys_sendmsg Date: Thu, 3 Jan 2019 14:43:19 -0800 Message-ID: <7646d8f6f0b7ba8206d2dc8625cbcb5bb33f9523.1546554049.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=2019-01-03_10:, , 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..cd563f985e1a 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;