Commit 3c9e9f73 authored Mar 12, 2015 by Alexander Duyck Committed by David S. Miller Mar 12, 2015

fib_trie: Avoid NULL pointer if local table is not allocated



The function fib_unmerge assumed the local table had already been
allocated.  If that is not the case however when custom rules are applied
then this can result in a NULL pointer dereference.

In order to prevent this we must check the value of the local table pointer
and if it is NULL simply return 0 as there is no local table to separate
from the main.

Fixes: 0ddcf43d ("ipv4: FIB Local/MAIN table collapse")
Reported-by: Madhu Challa <challa@noironetworks.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 80f1d68c

net/ipv4/fib_frontend.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -156,9 +156,12 @@ int fib_unmerge(struct net *net)
		{
		struct fib_table old, new;

		/* attempt to fetch local table if it has been allocated */
		old = fib_get_table(net, RT_TABLE_LOCAL);
		new = fib_trie_unmerge(old);
		if (!old)
		return 0;

		new = fib_trie_unmerge(old);
		if (!new)
		return -ENOMEM;