path: root/net/mpls
diff options
authorRobert Shearman <rshearma@brocade.com>2015-12-10 19:30:49 +0000
committerDavid S. Miller <davem@davemloft.net>2015-12-12 00:43:44 -0500
commit72dcac96c7f8320caf80dfaa559331174060a1ce (patch)
tree6ebf1a477b7f842038fb96ade44df2a500d10653 /net/mpls
parenta3e948e83a302c63f196512e253067ded6bbc832 (diff)
mpls: don't dump RTA_VIA attribute if not specified
The problem seen is that when adding a route with a nexthop with no via address specified, iproute2 generates bogus output: # ip -f mpls route add 100 dev lo # ip -f mpls route list 100 via inet dev lo The reason for this is that the kernel generates an RTA_VIA attribute with the family set to AF_INET, but the via address data having zero length. The cause of family being AF_INET is that on route insert cfg->rc_via_table is left set to 0, which just happens to be NEIGH_ARP_TABLE which is then translated into AF_INET. iproute2 doesn't validate the length prior to printing and so prints garbage. Although it could be fixed to do the validation, I would argue that AF_INET addresses should always be exactly 4 bytes so the kernel is really giving userspace bogus data. Therefore, avoid generating the RTA_VIA attribute when dumping the route if the via address wasn't specified on add/modify. This is indicated by NEIGH_ARP_TABLE and a zero via address length - if the user specified a via address the address length would have been validated such that it was 4 bytes. Although this is a change in behaviour that is visible to userspace, I believe that what was generated before was invalid and as such userspace wouldn't be expecting it. Signed-off-by: Robert Shearman <rshearma@brocade.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/mpls')
1 files changed, 6 insertions, 2 deletions
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 3be29cb1f658..ac1c116abaac 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -1235,7 +1235,9 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
nla_put_labels(skb, RTA_NEWDST, nh->nh_labels,
goto nla_put_failure;
- if (nla_put_via(skb, nh->nh_via_table, mpls_nh_via(rt, nh),
+ if ((nh->nh_via_table != NEIGH_ARP_TABLE ||
+ nh->nh_via_alen != 0) &&
+ nla_put_via(skb, nh->nh_via_table, mpls_nh_via(rt, nh),
goto nla_put_failure;
dev = rtnl_dereference(nh->nh_dev);
@@ -1323,7 +1325,9 @@ static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
if (nh->nh_dev)
payload += nla_total_size(4); /* RTA_OIF */
- payload += nla_total_size(2 + nh->nh_via_alen); /* RTA_VIA */
+ if (nh->nh_via_table != NEIGH_ARP_TABLE ||
+ nh->nh_via_alen != 0) /* RTA_VIA */
+ payload += nla_total_size(2 + nh->nh_via_alen);
if (nh->nh_labels) /* RTA_NEWDST */
payload += nla_total_size(nh->nh_labels * 4);
} else {