ipv6: fib6_rules should return exact return value
With the addition of the suppress operation
(7764a45a8f1fe74d4f7d301eaca2e558e7e2831a ("fib_rules: add .suppress
operation") we rely on accurate error reporting of the fib_rules.actions.
fib6_rule_action always returned -EAGAIN in case we could not find a
matching route and 0 if a rule was matched. This also included a match
for blackhole or prohibited rule actions which could get suppressed by
the new logic.
So adapt fib6_rule_action to always return the correct error code as
its counterpart fib4_rule_action does. This also fixes a possiblity of
nullptr-deref where we don't find a table, thus rt == NULL. Because
the condition rt != ip6_null_entry still holdes it seems we could later
get a nullptr bug on dereference rt->dst.
v2:
a) Fixed a brain fart in the commit msg (the rule => a table, etc). No
changes to the patch.
Cc: Stefan Tomanek <stefan.tomanek@wertarbyte.de>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index e64e6a5..554a4fb 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -55,26 +55,33 @@
struct fib6_table *table;
struct net *net = rule->fr_net;
pol_lookup_t lookup = arg->lookup_ptr;
+ int err = 0;
switch (rule->action) {
case FR_ACT_TO_TBL:
break;
case FR_ACT_UNREACHABLE:
+ err = -ENETUNREACH;
rt = net->ipv6.ip6_null_entry;
goto discard_pkt;
default:
case FR_ACT_BLACKHOLE:
+ err = -EINVAL;
rt = net->ipv6.ip6_blk_hole_entry;
goto discard_pkt;
case FR_ACT_PROHIBIT:
+ err = -EACCES;
rt = net->ipv6.ip6_prohibit_entry;
goto discard_pkt;
}
table = fib6_get_table(net, rule->table);
- if (table)
- rt = lookup(net, table, flp6, flags);
+ if (!table) {
+ err = -EAGAIN;
+ goto out;
+ }
+ rt = lookup(net, table, flp6, flags);
if (rt != net->ipv6.ip6_null_entry) {
struct fib6_rule *r = (struct fib6_rule *)rule;
@@ -101,6 +108,7 @@
}
again:
ip6_rt_put(rt);
+ err = -EAGAIN;
rt = NULL;
goto out;
@@ -108,7 +116,7 @@
dst_hold(&rt->dst);
out:
arg->result = rt;
- return rt == NULL ? -EAGAIN : 0;
+ return err;
}
static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)