[3.16.y-ckt stable] Patch "net/ipv6: add sysctl option accept_ra_min_hop_limit" has been added to the 3.16.y-ckt tree
YOSHIFUJI Hideaki/吉藤英明
hideaki.yoshifuji at miraclelinux.com
Tue Mar 22 11:02:28 UTC 2016
Hi,
Luis Henriques wrote:
> This is a note to let you know that I have just added a patch titled
>
> net/ipv6: add sysctl option accept_ra_min_hop_limit
>
> to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
> which can be found at:
>
> http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue
>
> This patch is scheduled to be released in version 3.16.7-ckt26.
>
> If you, or anyone else, feels it should not be added to this tree, please
> reply to this email.
>
> For more information about the 3.16.y-ckt tree, see
> https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
>
> Thanks.
> -Luis
>
> ---8<------------------------------------------------------------
>
> From dafdd3bb2296d4b70703c0bdb725f3265064ba4a Mon Sep 17 00:00:00 2001
> From: Hangbin Liu <liuhangbin at gmail.com>
> Date: Thu, 30 Jul 2015 14:28:42 +0800
> Subject: net/ipv6: add sysctl option accept_ra_min_hop_limit
>
> 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 <liuhangbin at gmail.com>
> Acked-by: YOSHIFUJI Hideaki <hideaki.yoshifuji at miraclelinux.com>
> Signed-off-by: David S. Miller <davem at davemloft.net>
> [ luis: backported to 3.16: adjusted context ]
> Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
> ---
> 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 ab42c95f9985..36aa39eee48f 100644
> --- a/Documentation/networking/ip-sysctl.txt
> +++ b/Documentation/networking/ip-sysctl.txt
> @@ -1210,6 +1210,14 @@ 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 f3d5d11b8871..9cc2240d7e52 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 593b0e32d956..f1d321427905 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,
Please add followings:
__DEVCONF_ACCEPT_RA_FROM_LOCAL,
__DEVCONF_USE_OPTIMISTIC,
__DEVCONF_ACCEPT_RA_MTU,
__DEVCONF_STABLE_SECRET,
__DEVCONF_USE_OIF_ADDRS_ONLY,
Otherwise
> + DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT,
has different value than the value we have in mainline.
--yoshfuji
> DEVCONF_MAX
> };
>
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 75630e173adf..405575f9ae77 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -186,6 +186,7 @@ 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,
> @@ -222,6 +223,7 @@ 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,
> @@ -4294,6 +4296,7 @@ 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;
> @@ -5079,6 +5082,13 @@ 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 e2eb53c719dc..577338204863 100644
> --- a/net/ipv6/ndisc.c
> +++ b/net/ipv6/ndisc.c
> @@ -1189,18 +1189,16 @@ 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:
>
--
吉藤英明 <hideaki.yoshifuji at miraclelinux.com>
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