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ipv6: fib6_rules should return exact return value

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With the addition of the suppress operation
(7764a45a8f ("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>
This commit is contained in:
Hannes Frederic Sowa 2013-08-01 08:54:47 +02:00 committed by David S. Miller
parent 378307217e
commit 46b3a42190
1 changed files with 11 additions and 3 deletions
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14
net/ipv6/fib6_rules.c
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@ -55,26 +55,33 @@ static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
struct fib6_table *table; struct fib6_table *table;
struct net *net = rule->fr_net; struct net *net = rule->fr_net;
pol_lookup_t lookup = arg->lookup_ptr; pol_lookup_t lookup = arg->lookup_ptr;
int err = 0;
switch (rule->action) { switch (rule->action) {
case FR_ACT_TO_TBL: case FR_ACT_TO_TBL:
break; break;
case FR_ACT_UNREACHABLE: case FR_ACT_UNREACHABLE:
err = -ENETUNREACH;
rt = net->ipv6.ip6_null_entry; rt = net->ipv6.ip6_null_entry;
goto discard_pkt; goto discard_pkt;
default: default:
case FR_ACT_BLACKHOLE: case FR_ACT_BLACKHOLE:
err = -EINVAL;
rt = net->ipv6.ip6_blk_hole_entry; rt = net->ipv6.ip6_blk_hole_entry;
goto discard_pkt; goto discard_pkt;
case FR_ACT_PROHIBIT: case FR_ACT_PROHIBIT:
err = -EACCES;
rt = net->ipv6.ip6_prohibit_entry; rt = net->ipv6.ip6_prohibit_entry;
goto discard_pkt; goto discard_pkt;
} }
table = fib6_get_table(net, rule->table); table = fib6_get_table(net, rule->table);
if (table) if (!table) {
rt = lookup(net, table, flp6, flags); err = -EAGAIN;
goto out;
}
rt = lookup(net, table, flp6, flags);
if (rt != net->ipv6.ip6_null_entry) { if (rt != net->ipv6.ip6_null_entry) {
struct fib6_rule *r = (struct fib6_rule *)rule; struct fib6_rule *r = (struct fib6_rule *)rule;
@ -101,6 +108,7 @@ static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
} }
again: again:
ip6_rt_put(rt); ip6_rt_put(rt);
err = -EAGAIN;
rt = NULL; rt = NULL;
goto out; goto out;
@ -108,7 +116,7 @@ discard_pkt:
dst_hold(&rt->dst); dst_hold(&rt->dst);
out: out:
arg->result = rt; arg->result = rt;
return rt == NULL ? -EAGAIN : 0; return err;
} }
static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)