ipv4: Do not allow MAIN to be alias for new LOCAL w/ custom rules

In the case of custom rules being present we need to handle the case of the
LOCAL table being intialized after the new rule has been added.  To address
that I am adding a new check so that we can make certain we don't use an
alias of MAIN for LOCAL when allocating a new table.

Fixes: 0ddcf43d5d4a ("ipv4: FIB Local/MAIN table collapse")
Reported-by: Oliver Brunel <jjk@jjacky.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 3ff8938893ec85311012b55a27de10d9368b50f1..eae0332b0e8c1f861ce629ed9ce3ddc45802a6b8 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -85,7 +85,7 @@ struct fib_table *fib_new_table(struct net *net, u32 id)
        if (tb)
                return tb;
 
-       if (id == RT_TABLE_LOCAL)
+       if (id == RT_TABLE_LOCAL && !net->ipv4.fib_has_custom_rules)
                alias = fib_new_table(net, RT_TABLE_MAIN);
 
        tb = fib_trie_table(id, alias);