[IPV4] fib_trie: fix duplicated route issue

http://bugzilla.kernel.org/show_bug.cgi?id=9493

The fib allows making identical routes with 'ip route replace'.
This patch makes the fib return -EEXIST if replacement would cause duplication.

Signed-off-by: Joonwoo Park <joonwpark81@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 8d8c2915e064..1010b469d7d3 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1214,6 +1214,9 @@ static int fn_trie_insert(struct fib_table *tb, struct fib_config *cfg)
                         struct fib_info *fi_drop;
                         u8 state;
 
+                        if (fi->fib_treeref > 1)
+                                goto out;
+
                         err = -ENOBUFS;
                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
                         if (new_fa == NULL)