Hi, 2017-05-18 21:22 GMT+09:00 <gregkh@xxxxxxxxxxxxxxxxxxx>: > > > This is a note to let you know that I've just added the patch titled > > net/ipv6: add sysctl option accept_ra_min_hop_limit > > to the 3.18-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > net-ipv6-add-sysctl-option-accept_ra_min_hop_limit.patch > and it can be found in the queue-3.18 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. > > > From 8013d1d7eafb0589ca766db6b74026f76b7f5cb4 Mon Sep 17 00:00:00 2001 > From: Hangbin Liu <liuhangbin@xxxxxxxxx> > Date: Thu, 30 Jul 2015 14:28:42 +0800 > Subject: net/ipv6: add sysctl option accept_ra_min_hop_limit > > From: Hangbin Liu <liuhangbin@xxxxxxxxx> > > 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@xxxxxxxxx> > Acked-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@xxxxxxxxxxxxxxxx> > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> > Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > --- > 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(-) > > --- a/Documentation/networking/ip-sysctl.txt > +++ b/Documentation/networking/ip-sysctl.txt > @@ -1256,6 +1256,14 @@ accept_ra_from_local - BOOLEAN > disabled if accept_ra_from_local is disabled > on a specific interface. > > +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. > > --- 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; > --- a/include/uapi/linux/ipv6.h > +++ b/include/uapi/linux/ipv6.h > @@ -164,6 +164,7 @@ enum { > DEVCONF_MLDV2_UNSOLICITED_REPORT_INTERVAL, > DEVCONF_SUPPRESS_FRAG_NDISC, > DEVCONF_ACCEPT_RA_FROM_LOCAL, > + DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT, > DEVCONF_MAX > }; > Please do not do this. This is not compatible with current linus-tree. >From Linux 4.11: DEVCONF_SUPPRESS_FRAG_NDISC, DEVCONF_ACCEPT_RA_FROM_LOCAL, DEVCONF_USE_OPTIMISTIC, DEVCONF_ACCEPT_RA_MTU, DEVCONF_STABLE_SECRET, DEVCONF_USE_OIF_ADDRS_ONLY, DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT, DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN, // snip --yoshfuji