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ipv4: fix validate_source for VRF setup 

David reported breakages of VRF scenarios due to the
commit 6e617de84e ("net: avoid a full fib lookup when rp_filter is
disabled."): the local addresses based test is too strict when VRFs
are in place.

With this change we fall-back to a full lookup when custom fib rules
are in place; so that we address the VRF use case and possibly other
similar issues in non trivial setups.

v1 -> v2:
 - fix build breakage when CONFIG_IP_MULTIPLE_TABLES is not defined,
   reported by the kbuild test robot

Reported-by: David Ahern <dsahern@gmail.com>
Fixes: 6e617de84e ("net: avoid a full fib lookup when rp_filter is disabled.")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2017-10-31 14:32:38 +01:00 committed by David S. Miller
parent dc82673f0c
commit 032a480202
1 changed files with 15 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
net/ipv4/fib_frontend.c
View File

@ -73,6 +73,11 @@ fail:
fib_free_table(main_table);
return -ENOMEM;
}
static bool fib4_has_custom_rules(struct net *net)
{
return false;
}
#else
struct fib_table *fib_new_table(struct net *net, u32 id)
@ -128,6 +133,11 @@ struct fib_table *fib_get_table(struct net *net, u32 id)
}
return NULL;
}
static bool fib4_has_custom_rules(struct net *net)
{
return net->ipv4.fib_has_custom_rules;
}
#endif /* CONFIG_IP_MULTIPLE_TABLES */
static void fib_replace_table(struct net *net, struct fib_table *old,
@ -405,10 +415,12 @@ int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
(dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
if (IN_DEV_ACCEPT_LOCAL(idev))
goto ok;
/* if no local routes are added from user space we can check
* for local addresses looking-up the ifaddr table
/* with custom local routes in place, checking local addresses
* only will be too optimistic, with custom rules, checking
* local addresses only can be too strict, e.g. due to vrf
*/
if (net->ipv4.fib_has_custom_local_routes)
if (net->ipv4.fib_has_custom_local_routes ||
fib4_has_custom_rules(net))
goto full_check;
if (inet_lookup_ifaddr_rcu(net, src))
return -EINVAL;