From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: Stefan Tomanek <stefan.tomanek@wertarbyte.de>,
netdev@vger.kernel.org, Andrew Collins <bsderandrew@gmail.com>
Subject: Re: [PATCH] fib_rules: add .suppress operation
Date: Sat, 27 Jul 2013 08:08:02 +0200 [thread overview]
Message-ID: <20130727060802.GD20273@order.stressinduktion.org> (raw)
In-Reply-To: <20130726170556.GA11434@order.stressinduktion.org>
On Fri, Jul 26, 2013 at 07:05:56PM +0200, Hannes Frederic Sowa wrote:
> On Fri, Jul 26, 2013 at 12:46:57PM +0200, Stefan Tomanek wrote:
> > if (err != -EAGAIN) {
> > + if (ops->suppress && ops->suppress(rule, arg)) {
> > + continue;
> > + }
We need to make sure route lookup succeeded:
if (!err && ops->suppress && ops->suppress(rule, arg))
> > +static int fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) {
> > + struct rt6_info *rt = (struct rt6_info *) arg->result;
> > + /*
> > + * do not accept result if the route does
> > + * not meet the required prefix length
> > + */
> > + if (rt->rt6i_dst.plen < rule->table_prefixlen_min) {
> > + return 1;
> > + }
> > + return 0;
> > +}
>
> Urks, fib6_rule_action is broken. The switch (rule->action) does update the rt
> entry but does not signal the correct error code to stop iterating the rules
> in case it finds a blackhole, prohibit etc. action (it always signals
> -EAGAIN).
I have to take back that fib6_rule_action is broken, it just showes some
unwanted side effects in this constalation.
> A change in this logic could have impact to your patch as I currently
> don't know how the null handling of arg->result will turn out. IPv6 does not
> preinitialize arg->result as IPv4 does.
>
> I am looking for a solution.
This compile-only-tested patch would make the error reporting consistent
with its ipv4 counterpart. arg->result should only be NULL iff the
function returns -EAGAIN. So we are clean here.
(It seems this patch also fixes a potential nullptr dereference.)
diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index 2e1a432..4c8bac7 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -55,26 +55,33 @@ static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
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 @@ static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
}
again:
ip6_rt_put(rt);
+ err = -EAGAIN;
rt = NULL;
goto out;
@@ -108,7 +116,7 @@ discard_pkt:
dst_hold(&rt->dst);
out:
arg->result = rt;
- return rt == NULL ? -EAGAIN : 0;
+ return err;
}
next prev parent reply other threads:[~2013-07-27 6:08 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-23 22:02 [PATCH] fib_rules: add minimum prefix length Stefan Tomanek
2013-07-23 22:38 ` Stephen Hemminger
2013-07-23 22:52 ` Stefan Tomanek
2013-07-24 2:14 ` Hannes Frederic Sowa
2013-07-24 7:57 ` Stefan Tomanek
2013-07-25 16:29 ` Stefan Tomanek
2013-07-25 17:43 ` [PATCH] fib_rules/fib6rules: " Stefan Tomanek
2013-07-25 18:17 ` [PATCH] fib_rules: " Hannes Frederic Sowa
2013-07-25 18:28 ` Stefan Tomanek
2013-07-25 21:46 ` Andrew Collins
2013-07-25 22:11 ` Stefan Tomanek
2013-07-26 10:46 ` [PATCH] fib_rules: add .suppress operation Stefan Tomanek
2013-07-26 17:05 ` Hannes Frederic Sowa
2013-07-27 6:08 ` Hannes Frederic Sowa [this message]
2013-07-27 6:26 ` Hannes Frederic Sowa
2013-07-27 7:07 ` Hannes Frederic Sowa
2013-07-27 10:21 ` Stefan Tomanek
2013-07-27 15:10 ` Hannes Frederic Sowa
2013-07-28 10:36 ` Stefan Tomanek
2013-07-30 6:52 ` [PATCH v2 1/2] fib6_rules: make error handling consistent with IPv4 Stefan Tomanek
2013-07-30 6:53 ` [PATCH v2 2/2] fib_rules: add .suppress operation Stefan Tomanek
2013-07-30 7:03 ` David Miller
2013-07-30 7:23 ` Stefan Tomanek
2013-07-30 7:34 ` David Miller
2013-07-30 7:46 ` [PATCH v3] " Stefan Tomanek
2013-07-31 22:13 ` David Miller
2013-08-01 0:24 ` Stefan Tomanek
2013-08-01 0:26 ` David Miller
2013-08-01 0:17 ` [PATCH v4] " Stefan Tomanek
2013-08-01 0:27 ` David Miller
2013-08-01 1:26 ` Stefan Tomanek
2013-08-01 5:35 ` Hannes Frederic Sowa
2013-07-26 10:54 ` [PATCH] fib_rules: add minimum prefix length Stefan Tomanek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20130727060802.GD20273@order.stressinduktion.org \
--to=hannes@stressinduktion.org \
--cc=bsderandrew@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=stefan.tomanek@wertarbyte.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).