net: Fix "ip rule delete table 256"

[ Upstream commit 13eb2ab2d33c57ebddc57437a7d341995fc9138c ]

When trying to delete a table >= 256 using iproute2 the local table
will be deleted.
The table id is specified as a netlink attribute when it needs more then
8 bits and iproute2 then sets the table field to RT_TABLE_UNSPEC (0).
Preconditions to matching the table id in the rule delete code
doesn't seem to take the "table id in netlink attribute" into condition
so the frh_get_table helper function never gets to do its job when
matching against current rule.
Use the helper function twice instead of peaking at the table value directly.

Originally reported at: http://bugs.debian.org/724783

Reported-by: Nicolas HICHER <nhicher@avencall.com>
Signed-off-by: Andreas Henriksson <andreas@fatal.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index c02e63c..c0c21b1 100644 (file)
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -443,7 +443,8 @@ static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
                if (frh->action && (frh->action != rule->action))
                        continue;
 
-               if (frh->table && (frh_get_table(frh, tb) != rule->table))
+               if (frh_get_table(frh, tb) &&
+                   (frh_get_table(frh, tb) != rule->table))
                        continue;
 
                if (tb[FRA_PRIORITY] &&