From patchwork Wed Mar 9 23:14:09 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 595475 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 1368E140909; Thu, 10 Mar 2016 10:19:47 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1adnOJ-0005n4-MR; Wed, 09 Mar 2016 23:19:43 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1adnNd-0005FA-Ub for kernel-team@lists.ubuntu.com; Wed, 09 Mar 2016 23:19:01 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1adnNd-0002sk-Fs; Wed, 09 Mar 2016 23:19:01 +0000 Received: from kamal by fourier with local (Exim 4.86) (envelope-from ) id 1adnNa-0004CZ-RI; Wed, 09 Mar 2016 15:18:58 -0800 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.13.y-ckt 122/138] net/ipv6: add sysctl option accept_ra_min_hop_limit Date: Wed, 9 Mar 2016 15:14:09 -0800 Message-Id: <1457565265-15195-123-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1457565265-15195-1-git-send-email-kamal@canonical.com> References: <1457565265-15195-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Cc: Kamal Mostafa , "David S . Miller" , Hangbin Liu X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.13.11-ckt36 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Hangbin Liu commit 8013d1d7eafb0589ca766db6b74026f76b7f5cb4 upstream. Commit 6fd99094de2b ("ipv6: Don't reduce hop limit for an interface") disabled accept hop limit from RA if it is smaller than the current hop limit for security stuff. But this behavior kind of break the RFC definition. RFC 4861, 6.3.4. Processing Received Router Advertisements A Router Advertisement field (e.g., Cur Hop Limit, Reachable Time, and Retrans Timer) may contain a value denoting that it is unspecified. In such cases, the parameter should be ignored and the host should continue using whatever value it is already using. If the received Cur Hop Limit value is non-zero, the host SHOULD set its CurHopLimit variable to the received value. So add sysctl option accept_ra_min_hop_limit to let user choose the minimum hop limit value they can accept from RA. And set default to 1 to meet RFC standards. Signed-off-by: Hangbin Liu Acked-by: YOSHIFUJI Hideaki Signed-off-by: David S. Miller [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques Signed-off-by: Kamal Mostafa --- Documentation/networking/ip-sysctl.txt | 8 ++++++++ include/linux/ipv6.h | 1 + include/uapi/linux/ipv6.h | 1 + net/ipv6/addrconf.c | 10 ++++++++++ net/ipv6/ndisc.c | 16 +++++++--------- 5 files changed, 27 insertions(+), 9 deletions(-) diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index b4be7fd..9a11e8d 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1143,6 +1143,14 @@ accept_ra_defrtr - BOOLEAN Functional default: enabled if accept_ra is enabled. disabled if accept_ra is disabled. +accept_ra_min_hop_limit - INTEGER + Minimum hop limit Information in Router Advertisement. + + Hop limit Information in Router Advertisement less than this + variable shall be ignored. + + Default: 1 + accept_ra_pinfo - BOOLEAN Learn Prefix Information in Router Advertisement. diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index c56c350..dc80edd 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -29,6 +29,7 @@ struct ipv6_devconf { __s32 max_desync_factor; __s32 max_addresses; __s32 accept_ra_defrtr; + __s32 accept_ra_min_hop_limit; __s32 accept_ra_pinfo; #ifdef CONFIG_IPV6_ROUTER_PREF __s32 accept_ra_rtr_pref; diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index 593b0e3..f1d3214 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -163,6 +163,7 @@ enum { DEVCONF_MLDV1_UNSOLICITED_REPORT_INTERVAL, DEVCONF_MLDV2_UNSOLICITED_REPORT_INTERVAL, DEVCONF_SUPPRESS_FRAG_NDISC, + DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT, DEVCONF_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 2be400d..dd8b55b 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -184,6 +184,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .max_desync_factor = MAX_DESYNC_FACTOR, .max_addresses = IPV6_MAX_ADDRESSES, .accept_ra_defrtr = 1, + .accept_ra_min_hop_limit= 1, .accept_ra_pinfo = 1, #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1, @@ -220,6 +221,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .max_desync_factor = MAX_DESYNC_FACTOR, .max_addresses = IPV6_MAX_ADDRESSES, .accept_ra_defrtr = 1, + .accept_ra_min_hop_limit= 1, .accept_ra_pinfo = 1, #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1, @@ -4125,6 +4127,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_MAX_DESYNC_FACTOR] = cnf->max_desync_factor; array[DEVCONF_MAX_ADDRESSES] = cnf->max_addresses; array[DEVCONF_ACCEPT_RA_DEFRTR] = cnf->accept_ra_defrtr; + array[DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT] = cnf->accept_ra_min_hop_limit; array[DEVCONF_ACCEPT_RA_PINFO] = cnf->accept_ra_pinfo; #ifdef CONFIG_IPV6_ROUTER_PREF array[DEVCONF_ACCEPT_RA_RTR_PREF] = cnf->accept_ra_rtr_pref; @@ -4864,6 +4867,13 @@ static struct addrconf_sysctl_table .proc_handler = proc_dointvec, }, { + .procname = "accept_ra_min_hop_limit", + .data = &ipv6_devconf.accept_ra_min_hop_limit, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { .procname = "accept_ra_pinfo", .data = &ipv6_devconf.accept_ra_pinfo, .maxlen = sizeof(int), diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index ac0bbe8..4e62e51 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1190,18 +1190,16 @@ static void ndisc_router_discovery(struct sk_buff *skb) if (rt) rt6_set_expires(rt, jiffies + (HZ * lifetime)); - if (ra_msg->icmph.icmp6_hop_limit) { - /* Only set hop_limit on the interface if it is higher than - * the current hop_limit. - */ - if (in6_dev->cnf.hop_limit < ra_msg->icmph.icmp6_hop_limit) { + if (in6_dev->cnf.accept_ra_min_hop_limit < 256 && + ra_msg->icmph.icmp6_hop_limit) { + if (in6_dev->cnf.accept_ra_min_hop_limit <= ra_msg->icmph.icmp6_hop_limit) { in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit; + if (rt) + dst_metric_set(&rt->dst, RTAX_HOPLIMIT, + ra_msg->icmph.icmp6_hop_limit); } else { - ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than current\n"); + ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than minimum\n"); } - if (rt) - dst_metric_set(&rt->dst, RTAX_HOPLIMIT, - ra_msg->icmph.icmp6_hop_limit); } skip_defrtr: