[PATCH 4.9 23/59] ipv4: Do not allow MAIN to be alias for new LOCAL w/ custom rules

From: Greg Kroah-Hartman
Date: Fri Jan 13 2017 - 07:05:07 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>


[ 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@xxxxxxxxxx>
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/fib_frontend.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -85,7 +85,7 @@ struct fib_table *fib_new_table(struct n
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);