diff options
| author | Wei Wang <weiwan@google.com> | 2017-10-06 21:06:09 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-10-07 22:22:58 +0200 |
| commit | 17ecf590b3cba19d9ecb410e340aa78128382abb (patch) | |
| tree | 4e7110008039b7e656e34f8b098ee0650c831af7 | |
| parent | ipv6: check fn->leaf before it is used (diff) | |
| download | linux-17ecf590b3cba19d9ecb410e340aa78128382abb.tar.xz linux-17ecf590b3cba19d9ecb410e340aa78128382abb.zip | |
ipv6: add key length check into rt6_select()
After rwlock is replaced with rcu and spinlock, fib6_lookup() could
potentially return an intermediate node if other thread is doing
fib6_del() on a route which is the only route on the node so that
fib6_repair_tree() will be called on this node and potentially assigns
fn->leaf to the its child's fn->leaf.
In order to detect this situation in rt6_select(), we have to check if
fn->fn_bit is consistent with the key length stored in the route. And
depending on if the fn is in the subtree or not, the key is either
rt->rt6i_dst or rt->rt6i_src.
If any inconsistency is found, that means the node no longer holds valid
routes in it. So net->ipv6.ip6_null_entry is returned.
Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv6/route.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 05dc450af441..24b80f43bbfb 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -755,6 +755,7 @@ static struct rt6_info *rt6_select(struct net *net, struct fib6_node *fn, struct rt6_info *leaf = fn->leaf; struct rt6_info *match, *rt0; bool do_rr = false; + int key_plen; if (!leaf) return net->ipv6.ip6_null_entry; @@ -763,6 +764,19 @@ static struct rt6_info *rt6_select(struct net *net, struct fib6_node *fn, if (!rt0) fn->rr_ptr = rt0 = leaf; + /* Double check to make sure fn is not an intermediate node + * and fn->leaf does not points to its child's leaf + * (This might happen if all routes under fn are deleted from + * the tree and fib6_repair_tree() is called on the node.) + */ + key_plen = rt0->rt6i_dst.plen; +#ifdef CONFIG_IPV6_SUBTREES + if (rt0->rt6i_src.plen) + key_plen = rt0->rt6i_src.plen; +#endif + if (fn->fn_bit != key_plen) + return net->ipv6.ip6_null_entry; + match = find_rr_leaf(fn, leaf, rt0, rt0->rt6i_metric, oif, strict, &do_rr); |