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| author | Robert Shearman <rshearma@brocade.com> | 2015-12-10 20:30:49 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-12-12 06:43:44 +0100 |
| commit | 72dcac96c7f8320caf80dfaa559331174060a1ce (patch) | |
| tree | 6ebf1a477b7f842038fb96ade44df2a500d10653 /net/mpls | |
| parent | mpls: validate L2 via address length (diff) | |
| download | linux-72dcac96c7f8320caf80dfaa559331174060a1ce.tar.xz linux-72dcac96c7f8320caf80dfaa559331174060a1ce.zip | |
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 0.0.8.0 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')
| -rw-r--r-- | net/mpls/af_mpls.c | 8 |
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, nh->nh_label)) 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), nh->nh_via_alen)) 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 { |