[PATCH] [IPV6] remove sysctl accept_source_route

[PATCH] [IPV6] remove sysctl accept_source_route

[Eldad Zack]

The only place where the accpet_source_route flag is checked is when we
are processing the type 2 routing header. In that case we only allow it if
it (1) has only segments left = 1 and (2) if it matches our home address,
which is the behavior required by RFC 6275 (see sections 8.5, 11.3.3), and
it doesn't make sense to block rh2 when we're a mobile node.

Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
---
 include/linux/ipv6.h |    2 --
 net/ipv6/addrconf.c  |   10 ----------
 net/ipv6/exthdrs.c   |    6 ------
 3 files changed, 18 deletions(-)

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 8260ef7..a77c6fe 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -162,7 +162,6 @@ struct ipv6_devconf {
 #endif
 #endif
 	__s32		proxy_ndp;
-	__s32		accept_source_route;
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 	__s32		optimistic_dad;
 #endif
@@ -208,7 +207,6 @@ enum {
 	DEVCONF_ACCEPT_RA_RT_INFO_MAX_PLEN,
 	DEVCONF_PROXY_NDP,
 	DEVCONF_OPTIMISTIC_DAD,
-	DEVCONF_ACCEPT_SOURCE_ROUTE,
 	DEVCONF_MC_FORWARDING,
 	DEVCONF_DISABLE_IPV6,
 	DEVCONF_ACCEPT_DAD,
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index e3b3421..bca2acf 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -194,7 +194,6 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
 #endif
 #endif
 	.proxy_ndp		= 0,
-	.accept_source_route	= 0,	/* we do not accept RH0 by default. */
 	.disable_ipv6		= 0,
 	.accept_dad		= 1,
 };
@@ -228,7 +227,6 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
 #endif
 #endif
 	.proxy_ndp		= 0,
-	.accept_source_route	= 0,	/* we do not accept RH0 by default. */
 	.disable_ipv6		= 0,
 	.accept_dad		= 1,
 };
@@ -3905,7 +3903,6 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
 #endif
 #endif
 	array[DEVCONF_PROXY_NDP] = cnf->proxy_ndp;
-	array[DEVCONF_ACCEPT_SOURCE_ROUTE] = cnf->accept_source_route;
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 	array[DEVCONF_OPTIMISTIC_DAD] = cnf->optimistic_dad;
 #endif
@@ -4535,13 +4532,6 @@ static struct addrconf_sysctl_table
 			.mode		= 0644,
 			.proc_handler	= proc_dointvec,
 		},
-		{
-			.procname	= "accept_source_route",
-			.data		= &ipv6_devconf.accept_source_route,
-			.maxlen		= sizeof(int),
-			.mode		= 0644,
-			.proc_handler	= proc_dointvec,
-		},
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 		{
 			.procname       = "optimistic_dad",
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index aa0a51e..597cf2a 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -337,12 +337,8 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
 	struct ipv6_rt_hdr *hdr;
 	struct rt0_hdr *rthdr;
 	struct net *net = dev_net(skb->dev);
-	int accept_source_route = net->ipv6.devconf_all->accept_source_route;
 
 	idev = __in6_dev_get(skb->dev);
-	if (idev && accept_source_route > idev->cnf.accept_source_route)
-		accept_source_route = idev->cnf.accept_source_route;
-
 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
 				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
@@ -393,8 +389,6 @@ looped_back:
 	switch (hdr->type) {
 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 	case IPV6_SRCRT_TYPE_2:
-		if (accept_source_route < 0)
-			goto unknown_rh;
 		/* Silently discard invalid RTH type 2 */
 		if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 			IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
-- 
1.7.10

Re: [PATCH] [IPV6] remove sysctl accept_source_route

[David Miller]

From: Eldad Zack <eldad@fogrefinery.com>
Date: Sun, 29 Apr 2012 12:37:10 +0200

> The only place where the accpet_source_route flag is checked is when we
> are processing the type 2 routing header. In that case we only allow it if
> it (1) has only segments left = 1 and (2) if it matches our home address,
> which is the behavior required by RFC 6275 (see sections 8.5, 11.3.3), and
> it doesn't make sense to block rh2 when we're a mobile node.
> 
> Signed-off-by: Eldad Zack <eldad@fogrefinery.com>

Considering commits:

commit c382bb9d32a55029fb13b118858e25908fab4617
Author: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Date:   Tue Jul 10 22:47:58 2007 -0700

    [IPV6]: Restore semantics of Routing Header processing.
    
    The "fix" for emerging security threat was overkill and it broke
    basic semantic of IPv6 routing header processing.  We should assume
    RT0 (or even RT2, depends on configuration) as "unknown" RH type so
    that we
    - silently ignore the routing header if segleft == 0
    - send ICMPv6 Parameter Problem message back to the sender,
      otherwise.
    
    Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
    Signed-off-by: David S. Miller <davem@davemloft.net>

and:

commit bb4dbf9e61d0801927e7df2569bb3dd8287ea301
Author: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Date:   Tue Jul 10 22:55:49 2007 -0700

    [IPV6]: Do not send RH0 anymore.
    
    Based on <draft-ietf-ipv6-deprecate-rh0-00.txt>.
    
    Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
    Signed-off-by: David S. Miller <davem@davemloft.net>

the current behavior seems very much intentional.

Secondly, we cannot just delete sysctls like this, if someone
depends upon whatever current behavior is we will break them.

Therefore, on either account, I cannot apply this patch.

Sorry.