kernel_optimize_test/net/sched/act_connmark.c
Etienne Noss 52491c7607 act_connmark: avoid crashing on malformed nlattrs with null parms
tcf_connmark_init does not check in its configuration if TCA_CONNMARK_PARMS
is set, resulting in a null pointer dereference when trying to access it.

[501099.043007] BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
[501099.043039] IP: [<ffffffffc10c60fb>] tcf_connmark_init+0x8b/0x180 [act_connmark]
...
[501099.044334] Call Trace:
[501099.044345]  [<ffffffffa47270e8>] ? tcf_action_init_1+0x198/0x1b0
[501099.044363]  [<ffffffffa47271b0>] ? tcf_action_init+0xb0/0x120
[501099.044380]  [<ffffffffa47250a4>] ? tcf_exts_validate+0xc4/0x110
[501099.044398]  [<ffffffffc0f5fa97>] ? u32_set_parms+0xa7/0x270 [cls_u32]
[501099.044417]  [<ffffffffc0f60bf0>] ? u32_change+0x680/0x87b [cls_u32]
[501099.044436]  [<ffffffffa4725d1d>] ? tc_ctl_tfilter+0x4dd/0x8a0
[501099.044454]  [<ffffffffa44a23a1>] ? security_capable+0x41/0x60
[501099.044471]  [<ffffffffa470ca01>] ? rtnetlink_rcv_msg+0xe1/0x220
[501099.044490]  [<ffffffffa470c920>] ? rtnl_newlink+0x870/0x870
[501099.044507]  [<ffffffffa472cc61>] ? netlink_rcv_skb+0xa1/0xc0
[501099.044524]  [<ffffffffa47073f4>] ? rtnetlink_rcv+0x24/0x30
[501099.044541]  [<ffffffffa472c634>] ? netlink_unicast+0x184/0x230
[501099.044558]  [<ffffffffa472c9d8>] ? netlink_sendmsg+0x2f8/0x3b0
[501099.044576]  [<ffffffffa46d8880>] ? sock_sendmsg+0x30/0x40
[501099.044592]  [<ffffffffa46d8e03>] ? SYSC_sendto+0xd3/0x150
[501099.044608]  [<ffffffffa425fda1>] ? __do_page_fault+0x2d1/0x510
[501099.044626]  [<ffffffffa47fbd7b>] ? system_call_fast_compare_end+0xc/0x9b

Fixes: 22a5dc0e5e ("net: sched: Introduce connmark action")
Signed-off-by: Étienne Noss <etienne.noss@wifirst.fr>
Signed-off-by: Victorien Molle <victorien.molle@wifirst.fr>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-12 23:32:41 -07:00

243 lines
5.9 KiB
C

/*
* net/sched/act_connmark.c netfilter connmark retriever action
* skb mark is over-written
*
* Copyright (c) 2011 Felix Fietkau <nbd@openwrt.org>
*
* 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/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/pkt_cls.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/act_api.h>
#include <uapi/linux/tc_act/tc_connmark.h>
#include <net/tc_act/tc_connmark.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_zones.h>
#define CONNMARK_TAB_MASK 3
static unsigned int connmark_net_id;
static struct tc_action_ops act_connmark_ops;
static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
const struct nf_conntrack_tuple_hash *thash;
struct nf_conntrack_tuple tuple;
enum ip_conntrack_info ctinfo;
struct tcf_connmark_info *ca = to_connmark(a);
struct nf_conntrack_zone zone;
struct nf_conn *c;
int proto;
spin_lock(&ca->tcf_lock);
tcf_lastuse_update(&ca->tcf_tm);
bstats_update(&ca->tcf_bstats, skb);
if (skb->protocol == htons(ETH_P_IP)) {
if (skb->len < sizeof(struct iphdr))
goto out;
proto = NFPROTO_IPV4;
} else if (skb->protocol == htons(ETH_P_IPV6)) {
if (skb->len < sizeof(struct ipv6hdr))
goto out;
proto = NFPROTO_IPV6;
} else {
goto out;
}
c = nf_ct_get(skb, &ctinfo);
if (c) {
skb->mark = c->mark;
/* using overlimits stats to count how many packets marked */
ca->tcf_qstats.overlimits++;
goto out;
}
if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
proto, ca->net, &tuple))
goto out;
zone.id = ca->zone;
zone.dir = NF_CT_DEFAULT_ZONE_DIR;
thash = nf_conntrack_find_get(ca->net, &zone, &tuple);
if (!thash)
goto out;
c = nf_ct_tuplehash_to_ctrack(thash);
/* using overlimits stats to count how many packets marked */
ca->tcf_qstats.overlimits++;
skb->mark = c->mark;
nf_ct_put(c);
out:
spin_unlock(&ca->tcf_lock);
return ca->tcf_action;
}
static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
[TCA_CONNMARK_PARMS] = { .len = sizeof(struct tc_connmark) },
};
static int tcf_connmark_init(struct net *net, struct nlattr *nla,
struct nlattr *est, struct tc_action **a,
int ovr, int bind)
{
struct tc_action_net *tn = net_generic(net, connmark_net_id);
struct nlattr *tb[TCA_CONNMARK_MAX + 1];
struct tcf_connmark_info *ci;
struct tc_connmark *parm;
int ret = 0;
if (!nla)
return -EINVAL;
ret = nla_parse_nested(tb, TCA_CONNMARK_MAX, nla, connmark_policy);
if (ret < 0)
return ret;
if (!tb[TCA_CONNMARK_PARMS])
return -EINVAL;
parm = nla_data(tb[TCA_CONNMARK_PARMS]);
if (!tcf_hash_check(tn, parm->index, a, bind)) {
ret = tcf_hash_create(tn, parm->index, est, a,
&act_connmark_ops, bind, false);
if (ret)
return ret;
ci = to_connmark(*a);
ci->tcf_action = parm->action;
ci->net = net;
ci->zone = parm->zone;
tcf_hash_insert(tn, *a);
ret = ACT_P_CREATED;
} else {
ci = to_connmark(*a);
if (bind)
return 0;
tcf_hash_release(*a, bind);
if (!ovr)
return -EEXIST;
/* replacing action and zone */
ci->tcf_action = parm->action;
ci->zone = parm->zone;
}
return ret;
}
static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
int bind, int ref)
{
unsigned char *b = skb_tail_pointer(skb);
struct tcf_connmark_info *ci = to_connmark(a);
struct tc_connmark opt = {
.index = ci->tcf_index,
.refcnt = ci->tcf_refcnt - ref,
.bindcnt = ci->tcf_bindcnt - bind,
.action = ci->tcf_action,
.zone = ci->zone,
};
struct tcf_t t;
if (nla_put(skb, TCA_CONNMARK_PARMS, sizeof(opt), &opt))
goto nla_put_failure;
tcf_tm_dump(&t, &ci->tcf_tm);
if (nla_put_64bit(skb, TCA_CONNMARK_TM, sizeof(t), &t,
TCA_CONNMARK_PAD))
goto nla_put_failure;
return skb->len;
nla_put_failure:
nlmsg_trim(skb, b);
return -1;
}
static int tcf_connmark_walker(struct net *net, struct sk_buff *skb,
struct netlink_callback *cb, int type,
const struct tc_action_ops *ops)
{
struct tc_action_net *tn = net_generic(net, connmark_net_id);
return tcf_generic_walker(tn, skb, cb, type, ops);
}
static int tcf_connmark_search(struct net *net, struct tc_action **a, u32 index)
{
struct tc_action_net *tn = net_generic(net, connmark_net_id);
return tcf_hash_search(tn, a, index);
}
static struct tc_action_ops act_connmark_ops = {
.kind = "connmark",
.type = TCA_ACT_CONNMARK,
.owner = THIS_MODULE,
.act = tcf_connmark,
.dump = tcf_connmark_dump,
.init = tcf_connmark_init,
.walk = tcf_connmark_walker,
.lookup = tcf_connmark_search,
.size = sizeof(struct tcf_connmark_info),
};
static __net_init int connmark_init_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, connmark_net_id);
return tc_action_net_init(tn, &act_connmark_ops, CONNMARK_TAB_MASK);
}
static void __net_exit connmark_exit_net(struct net *net)
{
struct tc_action_net *tn = net_generic(net, connmark_net_id);
tc_action_net_exit(tn);
}
static struct pernet_operations connmark_net_ops = {
.init = connmark_init_net,
.exit = connmark_exit_net,
.id = &connmark_net_id,
.size = sizeof(struct tc_action_net),
};
static int __init connmark_init_module(void)
{
return tcf_register_action(&act_connmark_ops, &connmark_net_ops);
}
static void __exit connmark_cleanup_module(void)
{
tcf_unregister_action(&act_connmark_ops, &connmark_net_ops);
}
module_init(connmark_init_module);
module_exit(connmark_cleanup_module);
MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
MODULE_DESCRIPTION("Connection tracking mark restoring");
MODULE_LICENSE("GPL");