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

[ Upstream commit 5350d54f6cd12eaff623e890744c79b700bd3f17 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 63566ec54794db8213c2c935d75c2ba32dd71d61..4e60dae86df576ade9cf604d810b3140bb072778 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);