linux/net/sched/cls_matchall.c

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/*
* net/sched/cls_matchll.c Match-all classifier
*
* Copyright (c) 2016 Jiri Pirko <jiri@mellanox.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <net/sch_generic.h>
#include <net/pkt_cls.h>
struct cls_mall_head {
struct tcf_exts exts;
struct tcf_result res;
u32 handle;
u32 flags;
unsigned int in_hw_count;
struct tc_matchall_pcnt __percpu *pf;
struct rcu_work rwork;
};
static int mall_classify(struct sk_buff *skb, const struct tcf_proto *tp,
struct tcf_result *res)
{
struct cls_mall_head *head = rcu_dereference_bh(tp->root);
if (tc_skip_sw(head->flags))
return -1;
net/sched: cls_matchall: fix crash when used with classful qdisc this script, edited from Linux Advanced Routing and Traffic Control guide tc q a dev en0 root handle 1: htb default a tc c a dev en0 parent 1: classid 1:1 htb rate 6mbit burst 15k tc c a dev en0 parent 1:1 classid 1:a htb rate 5mbit ceil 6mbit burst 15k tc c a dev en0 parent 1:1 classid 1:b htb rate 1mbit ceil 6mbit burst 15k tc f a dev en0 parent 1:0 prio 1 $clsname $clsargs classid 1:b ping $address -c1 tc -s c s dev en0 classifies traffic to 1:b or 1:a, depending on whether the packet matches or not the pattern $clsargs of filter $clsname. However, when $clsname is 'matchall', a systematic crash can be observed in htb_classify(). HTB and classful qdiscs don't assign initial value to struct tcf_result, but then they expect it to contain valid values after filters have been run. Thus, current 'matchall' ignores the TCA_MATCHALL_CLASSID attribute, configured by user, and makes HTB (and classful qdiscs) dereference random pointers. By assigning head->res to *res in mall_classify(), before the actions are invoked, we fix this crash and enable TCA_MATCHALL_CLASSID functionality, that had no effect on 'matchall' classifier since its first introduction. BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1460213 Reported-by: Jiri Benc <jbenc@redhat.com> Fixes: b87f7936a932 ("net/sched: introduce Match-all classifier") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Acked-by: Yotam Gigi <yotamg@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-16 20:02:21 +08:00
*res = head->res;
__this_cpu_inc(head->pf->rhit);
return tcf_exts_exec(skb, &head->exts, res);
}
static int mall_init(struct tcf_proto *tp)
{
return 0;
}
static void __mall_destroy(struct cls_mall_head *head)
{
tcf_exts_destroy(&head->exts);
tcf_exts_put_net(&head->exts);
free_percpu(head->pf);
kfree(head);
}
static void mall_destroy_work(struct work_struct *work)
{
struct cls_mall_head *head = container_of(to_rcu_work(work),
struct cls_mall_head,
rwork);
rtnl_lock();
__mall_destroy(head);
rtnl_unlock();
}
static void mall_destroy_hw_filter(struct tcf_proto *tp,
struct cls_mall_head *head,
unsigned long cookie,
struct netlink_ext_ack *extack)
{
struct tc_cls_matchall_offload cls_mall = {};
struct tcf_block *block = tp->chain->block;
tc_cls_common_offload_init(&cls_mall.common, tp, head->flags, extack);
cls_mall.command = TC_CLSMATCHALL_DESTROY;
cls_mall.cookie = cookie;
tc_setup_cb_call(block, TC_SETUP_CLSMATCHALL, &cls_mall, false);
tcf_block_offload_dec(block, &head->flags);
}
static int mall_replace_hw_filter(struct tcf_proto *tp,
struct cls_mall_head *head,
unsigned long cookie,
struct netlink_ext_ack *extack)
{
struct tc_cls_matchall_offload cls_mall = {};
struct tcf_block *block = tp->chain->block;
bool skip_sw = tc_skip_sw(head->flags);
int err;
tc_cls_common_offload_init(&cls_mall.common, tp, head->flags, extack);
cls_mall.command = TC_CLSMATCHALL_REPLACE;
cls_mall.exts = &head->exts;
cls_mall.cookie = cookie;
err = tc_setup_cb_call(block, TC_SETUP_CLSMATCHALL, &cls_mall, skip_sw);
if (err < 0) {
mall_destroy_hw_filter(tp, head, cookie, NULL);
return err;
} else if (err > 0) {
head->in_hw_count = err;
tcf_block_offload_inc(block, &head->flags);
}
if (skip_sw && !(head->flags & TCA_CLS_FLAGS_IN_HW))
return -EINVAL;
return 0;
}
static void mall_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
{
struct cls_mall_head *head = rtnl_dereference(tp->root);
if (!head)
return;
tcf_unbind_filter(tp, &head->res);
if (!tc_skip_hw(head->flags))
mall_destroy_hw_filter(tp, head, (unsigned long) head, extack);
if (tcf_exts_get_net(&head->exts))
tcf_queue_work(&head->rwork, mall_destroy_work);
else
__mall_destroy(head);
}
static void *mall_get(struct tcf_proto *tp, u32 handle)
{
return NULL;
}
static const struct nla_policy mall_policy[TCA_MATCHALL_MAX + 1] = {
[TCA_MATCHALL_UNSPEC] = { .type = NLA_UNSPEC },
[TCA_MATCHALL_CLASSID] = { .type = NLA_U32 },
};
static int mall_set_parms(struct net *net, struct tcf_proto *tp,
struct cls_mall_head *head,
unsigned long base, struct nlattr **tb,
struct nlattr *est, bool ovr,
struct netlink_ext_ack *extack)
{
int err;
err = tcf_exts_validate(net, tp, tb, est, &head->exts, ovr, extack);
if (err < 0)
return err;
if (tb[TCA_MATCHALL_CLASSID]) {
head->res.classid = nla_get_u32(tb[TCA_MATCHALL_CLASSID]);
tcf_bind_filter(tp, &head->res, base);
}
return 0;
}
static int mall_change(struct net *net, struct sk_buff *in_skb,
struct tcf_proto *tp, unsigned long base,
u32 handle, struct nlattr **tca,
void **arg, bool ovr, struct netlink_ext_ack *extack)
{
struct cls_mall_head *head = rtnl_dereference(tp->root);
struct nlattr *tb[TCA_MATCHALL_MAX + 1];
struct cls_mall_head *new;
u32 flags = 0;
int err;
if (!tca[TCA_OPTIONS])
return -EINVAL;
if (head)
return -EEXIST;
err = nla_parse_nested(tb, TCA_MATCHALL_MAX, tca[TCA_OPTIONS],
mall_policy, NULL);
if (err < 0)
return err;
if (tb[TCA_MATCHALL_FLAGS]) {
flags = nla_get_u32(tb[TCA_MATCHALL_FLAGS]);
if (!tc_flags_valid(flags))
return -EINVAL;
}
new = kzalloc(sizeof(*new), GFP_KERNEL);
if (!new)
return -ENOBUFS;
err = tcf_exts_init(&new->exts, TCA_MATCHALL_ACT, 0);
if (err)
goto err_exts_init;
if (!handle)
handle = 1;
new->handle = handle;
new->flags = flags;
new->pf = alloc_percpu(struct tc_matchall_pcnt);
if (!new->pf) {
err = -ENOMEM;
goto err_alloc_percpu;
}
err = mall_set_parms(net, tp, new, base, tb, tca[TCA_RATE], ovr,
extack);
if (err)
goto err_set_parms;
if (!tc_skip_hw(new->flags)) {
err = mall_replace_hw_filter(tp, new, (unsigned long)new,
extack);
if (err)
goto err_replace_hw_filter;
}
if (!tc_in_hw(new->flags))
new->flags |= TCA_CLS_FLAGS_NOT_IN_HW;
*arg = head;
rcu_assign_pointer(tp->root, new);
return 0;
err_replace_hw_filter:
err_set_parms:
free_percpu(new->pf);
err_alloc_percpu:
tcf_exts_destroy(&new->exts);
err_exts_init:
kfree(new);
return err;
}
static int mall_delete(struct tcf_proto *tp, void *arg, bool *last,
struct netlink_ext_ack *extack)
{
return -EOPNOTSUPP;
}
static void mall_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
struct cls_mall_head *head = rtnl_dereference(tp->root);
if (arg->count < arg->skip)
goto skip;
if (arg->fn(tp, head, arg) < 0)
arg->stop = 1;
skip:
arg->count++;
}
static int mall_reoffload(struct tcf_proto *tp, bool add, tc_setup_cb_t *cb,
void *cb_priv, struct netlink_ext_ack *extack)
{
struct cls_mall_head *head = rtnl_dereference(tp->root);
struct tc_cls_matchall_offload cls_mall = {};
struct tcf_block *block = tp->chain->block;
int err;
if (tc_skip_hw(head->flags))
return 0;
tc_cls_common_offload_init(&cls_mall.common, tp, head->flags, extack);
cls_mall.command = add ?
TC_CLSMATCHALL_REPLACE : TC_CLSMATCHALL_DESTROY;
cls_mall.exts = &head->exts;
cls_mall.cookie = (unsigned long)head;
err = cb(TC_SETUP_CLSMATCHALL, &cls_mall, cb_priv);
if (err) {
if (add && tc_skip_sw(head->flags))
return err;
return 0;
}
tc_cls_offload_cnt_update(block, &head->in_hw_count, &head->flags, add);
return 0;
}
static int mall_dump(struct net *net, struct tcf_proto *tp, void *fh,
struct sk_buff *skb, struct tcmsg *t)
{
struct tc_matchall_pcnt gpf = {};
struct cls_mall_head *head = fh;
struct nlattr *nest;
int cpu;
if (!head)
return skb->len;
t->tcm_handle = head->handle;
nest = nla_nest_start(skb, TCA_OPTIONS);
if (!nest)
goto nla_put_failure;
if (head->res.classid &&
nla_put_u32(skb, TCA_MATCHALL_CLASSID, head->res.classid))
goto nla_put_failure;
if (head->flags && nla_put_u32(skb, TCA_MATCHALL_FLAGS, head->flags))
goto nla_put_failure;
for_each_possible_cpu(cpu) {
struct tc_matchall_pcnt *pf = per_cpu_ptr(head->pf, cpu);
gpf.rhit += pf->rhit;
}
if (nla_put_64bit(skb, TCA_MATCHALL_PCNT,
sizeof(struct tc_matchall_pcnt),
&gpf, TCA_MATCHALL_PAD))
goto nla_put_failure;
if (tcf_exts_dump(skb, &head->exts))
goto nla_put_failure;
nla_nest_end(skb, nest);
if (tcf_exts_dump_stats(skb, &head->exts) < 0)
goto nla_put_failure;
return skb->len;
nla_put_failure:
nla_nest_cancel(skb, nest);
return -1;
}
static void mall_bind_class(void *fh, u32 classid, unsigned long cl)
{
struct cls_mall_head *head = fh;
if (head && head->res.classid == classid)
head->res.class = cl;
}
static struct tcf_proto_ops cls_mall_ops __read_mostly = {
.kind = "matchall",
.classify = mall_classify,
.init = mall_init,
.destroy = mall_destroy,
.get = mall_get,
.change = mall_change,
.delete = mall_delete,
.walk = mall_walk,
.reoffload = mall_reoffload,
.dump = mall_dump,
.bind_class = mall_bind_class,
.owner = THIS_MODULE,
};
static int __init cls_mall_init(void)
{
return register_tcf_proto_ops(&cls_mall_ops);
}
static void __exit cls_mall_exit(void)
{
unregister_tcf_proto_ops(&cls_mall_ops);
}
module_init(cls_mall_init);
module_exit(cls_mall_exit);
MODULE_AUTHOR("Jiri Pirko <jiri@mellanox.com>");
MODULE_DESCRIPTION("Match-all classifier");
MODULE_LICENSE("GPL v2");