On 18 May 2017 at 18:35, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > On Thu, May 18, 2017 at 09:39:12PM +0900, 吉藤英明 wrote: >> 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, > > Oh, nice catch. I'll go drop this. > > Amit, can you send the _correct_ patch? Looks like Google messed up on > their backport :) Hi, Thanks for catching this. Please drop this one. This is not an AOSP backport, I just didn't think this one through. Regards, Amit Pundir > > thanks, > > greg k-h