[mirror_ubuntu-hirsute-kernel.git] / net / sched / em_ipt.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/sched/em_ipt.c IPtables matches Ematch
 *
 * (c) 2018 Eyal Birger <eyal.birger@gmail.com>
 */

#include <linux/gfp.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/tc_ematch/tc_em_ipt.h>
#include <linux/netfilter.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <net/pkt_cls.h>

struct em_ipt_match {
	const struct xt_match *match;
	u32 hook;
	u8 nfproto;
	u8 match_data[0] __aligned(8);
};

struct em_ipt_xt_match {
	char *match_name;
	int (*validate_match_data)(struct nlattr **tb, u8 mrev);
};

static const struct nla_policy em_ipt_policy[TCA_EM_IPT_MAX + 1] = {
	[TCA_EM_IPT_MATCH_NAME]		= { .type = NLA_STRING,
					    .len = XT_EXTENSION_MAXNAMELEN },
	[TCA_EM_IPT_MATCH_REVISION]	= { .type = NLA_U8 },
	[TCA_EM_IPT_HOOK]		= { .type = NLA_U32 },
	[TCA_EM_IPT_NFPROTO]		= { .type = NLA_U8 },
	[TCA_EM_IPT_MATCH_DATA]		= { .type = NLA_UNSPEC },
};

static int check_match(struct net *net, struct em_ipt_match *im, int mdata_len)
{
	struct xt_mtchk_param mtpar = {};
	union {
		struct ipt_entry e4;
		struct ip6t_entry e6;
	} e = {};

	mtpar.net	= net;
	mtpar.table	= "filter";
	mtpar.hook_mask	= 1 << im->hook;
	mtpar.family	= im->match->family;
	mtpar.match	= im->match;
	mtpar.entryinfo = &e;
	mtpar.matchinfo	= (void *)im->match_data;
	return xt_check_match(&mtpar, mdata_len, 0, 0);
}

static int policy_validate_match_data(struct nlattr **tb, u8 mrev)
{
	if (mrev != 0) {
		pr_err("only policy match revision 0 supported");
		return -EINVAL;
	}

	if (nla_get_u32(tb[TCA_EM_IPT_HOOK]) != NF_INET_PRE_ROUTING) {
		pr_err("policy can only be matched on NF_INET_PRE_ROUTING");
		return -EINVAL;
	}

	return 0;
}

static const struct em_ipt_xt_match em_ipt_xt_matches[] = {
	{
		.match_name = "policy",
		.validate_match_data = policy_validate_match_data
	},
	{}
};

static struct xt_match *get_xt_match(struct nlattr **tb)
{
	const struct em_ipt_xt_match *m;
	struct nlattr *mname_attr;
	u8 nfproto, mrev = 0;
	int ret;

	mname_attr = tb[TCA_EM_IPT_MATCH_NAME];
	for (m = em_ipt_xt_matches; m->match_name; m++) {
		if (!nla_strcmp(mname_attr, m->match_name))
			break;
	}

	if (!m->match_name) {
		pr_err("Unsupported xt match");
		return ERR_PTR(-EINVAL);
	}

	if (tb[TCA_EM_IPT_MATCH_REVISION])
		mrev = nla_get_u8(tb[TCA_EM_IPT_MATCH_REVISION]);

	ret = m->validate_match_data(tb, mrev);
	if (ret < 0)
		return ERR_PTR(ret);

	nfproto = nla_get_u8(tb[TCA_EM_IPT_NFPROTO]);
	return xt_request_find_match(nfproto, m->match_name, mrev);
}

static int em_ipt_change(struct net *net, void *data, int data_len,
			 struct tcf_ematch *em)
{
	struct nlattr *tb[TCA_EM_IPT_MAX + 1];
	struct em_ipt_match *im = NULL;
	struct xt_match *match;
	int mdata_len, ret;
	u8 nfproto;

	ret = nla_parse_deprecated(tb, TCA_EM_IPT_MAX, data, data_len,
				   em_ipt_policy, NULL);
	if (ret < 0)
		return ret;

	if (!tb[TCA_EM_IPT_HOOK] || !tb[TCA_EM_IPT_MATCH_NAME] ||
	    !tb[TCA_EM_IPT_MATCH_DATA] || !tb[TCA_EM_IPT_NFPROTO])
		return -EINVAL;

	nfproto = nla_get_u8(tb[TCA_EM_IPT_NFPROTO]);
	switch (nfproto) {
	case NFPROTO_IPV4:
	case NFPROTO_IPV6:
		break;
	default:
		return -EINVAL;
	}

	match = get_xt_match(tb);
	if (IS_ERR(match)) {
		pr_err("unable to load match\n");
		return PTR_ERR(match);
	}

	mdata_len = XT_ALIGN(nla_len(tb[TCA_EM_IPT_MATCH_DATA]));
	im = kzalloc(sizeof(*im) + mdata_len, GFP_KERNEL);
	if (!im) {
		ret = -ENOMEM;
		goto err;
	}

	im->match = match;
	im->hook = nla_get_u32(tb[TCA_EM_IPT_HOOK]);
	im->nfproto = nfproto;
	nla_memcpy(im->match_data, tb[TCA_EM_IPT_MATCH_DATA], mdata_len);

	ret = check_match(net, im, mdata_len);
	if (ret)
		goto err;

	em->datalen = sizeof(*im) + mdata_len;
	em->data = (unsigned long)im;
	return 0;

err:
	kfree(im);
	module_put(match->me);
	return ret;
}

static void em_ipt_destroy(struct tcf_ematch *em)
{
	struct em_ipt_match *im = (void *)em->data;

	if (!im)
		return;

	if (im->match->destroy) {
		struct xt_mtdtor_param par = {
			.net = em->net,
			.match = im->match,
			.matchinfo = im->match_data,
			.family = im->match->family
		};
		im->match->destroy(&par);
	}
	module_put(im->match->me);
	kfree((void *)im);
}

static int em_ipt_match(struct sk_buff *skb, struct tcf_ematch *em,
			struct tcf_pkt_info *info)
{
	const struct em_ipt_match *im = (const void *)em->data;
	struct xt_action_param acpar = {};
	struct net_device *indev = NULL;
	u8 nfproto = im->match->family;
	struct nf_hook_state state;
	int ret;

	switch (tc_skb_protocol(skb)) {
	case htons(ETH_P_IP):
		if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
			return 0;
		if (nfproto == NFPROTO_UNSPEC)
			nfproto = NFPROTO_IPV4;
		break;
	case htons(ETH_P_IPV6):
		if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
			return 0;
		if (nfproto == NFPROTO_UNSPEC)
			nfproto = NFPROTO_IPV6;
		break;
	default:
		return 0;
	}

	rcu_read_lock();

	if (skb->skb_iif)
		indev = dev_get_by_index_rcu(em->net, skb->skb_iif);

	nf_hook_state_init(&state, im->hook, nfproto,
			   indev ?: skb->dev, skb->dev, NULL, em->net, NULL);

	acpar.match = im->match;
	acpar.matchinfo = im->match_data;
	acpar.state = &state;

	ret = im->match->match(skb, &acpar);

	rcu_read_unlock();
	return ret;
}

static int em_ipt_dump(struct sk_buff *skb, struct tcf_ematch *em)
{
	struct em_ipt_match *im = (void *)em->data;

	if (nla_put_string(skb, TCA_EM_IPT_MATCH_NAME, im->match->name) < 0)
		return -EMSGSIZE;
	if (nla_put_u32(skb, TCA_EM_IPT_HOOK, im->hook) < 0)
		return -EMSGSIZE;
	if (nla_put_u8(skb, TCA_EM_IPT_MATCH_REVISION, im->match->revision) < 0)
		return -EMSGSIZE;
	if (nla_put_u8(skb, TCA_EM_IPT_NFPROTO, im->nfproto) < 0)
		return -EMSGSIZE;
	if (nla_put(skb, TCA_EM_IPT_MATCH_DATA,
		    im->match->usersize ?: im->match->matchsize,
		    im->match_data) < 0)
		return -EMSGSIZE;

	return 0;
}

static struct tcf_ematch_ops em_ipt_ops = {
	.kind	  = TCF_EM_IPT,
	.change	  = em_ipt_change,
	.destroy  = em_ipt_destroy,
	.match	  = em_ipt_match,
	.dump	  = em_ipt_dump,
	.owner	  = THIS_MODULE,
	.link	  = LIST_HEAD_INIT(em_ipt_ops.link)
};

static int __init init_em_ipt(void)
{
	return tcf_em_register(&em_ipt_ops);
}

static void __exit exit_em_ipt(void)
{
	tcf_em_unregister(&em_ipt_ops);
}

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Eyal Birger <eyal.birger@gmail.com>");
MODULE_DESCRIPTION("TC extended match for IPtables matches");

module_init(init_em_ipt);
module_exit(exit_em_ipt);

MODULE_ALIAS_TCF_EMATCH(TCF_EM_IPT);
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
ccc007e4 EB	2	/*
	3	* net/sched/em_ipt.c IPtables matches Ematch
	4	*
	5	* (c) 2018 Eyal Birger <eyal.birger@gmail.com>
ccc007e4 EB	6	*/
	7
	8	#include <linux/gfp.h>
	9	#include <linux/module.h>
	10	#include <linux/types.h>
	11	#include <linux/kernel.h>
	12	#include <linux/string.h>
	13	#include <linux/skbuff.h>
	14	#include <linux/tc_ematch/tc_em_ipt.h>
	15	#include <linux/netfilter.h>
	16	#include <linux/netfilter/x_tables.h>
	17	#include <linux/netfilter_ipv4/ip_tables.h>
	18	#include <linux/netfilter_ipv6/ip6_tables.h>
	19	#include <net/pkt_cls.h>
	20
	21	struct em_ipt_match {
	22	const struct xt_match *match;
	23	u32 hook;
ba3d24d4	24	u8 nfproto;
ccc007e4 EB	25	u8 match_data[0] __aligned(8);
	26	};
	27
	28	struct em_ipt_xt_match {
	29	char *match_name;
	30	int (validate_match_data)(struct nlattr *tb, u8 mrev);
	31	};
	32
	33	static const struct nla_policy em_ipt_policy[TCA_EM_IPT_MAX + 1] = {
	34	[TCA_EM_IPT_MATCH_NAME] = { .type = NLA_STRING,
	35	.len = XT_EXTENSION_MAXNAMELEN },
	36	[TCA_EM_IPT_MATCH_REVISION] = { .type = NLA_U8 },
	37	[TCA_EM_IPT_HOOK] = { .type = NLA_U32 },
	38	[TCA_EM_IPT_NFPROTO] = { .type = NLA_U8 },
	39	[TCA_EM_IPT_MATCH_DATA] = { .type = NLA_UNSPEC },
	40	};
	41
	42	static int check_match(struct net net, struct em_ipt_match im, int mdata_len)
	43	{
	44	struct xt_mtchk_param mtpar = {};
	45	union {
	46	struct ipt_entry e4;
	47	struct ip6t_entry e6;
	48	} e = {};
	49
	50	mtpar.net = net;
	51	mtpar.table = "filter";
	52	mtpar.hook_mask = 1 << im->hook;
	53	mtpar.family = im->match->family;
	54	mtpar.match = im->match;
	55	mtpar.entryinfo = &e;
	56	mtpar.matchinfo = (void *)im->match_data;
	57	return xt_check_match(&mtpar, mdata_len, 0, 0);
	58	}
	59
	60	static int policy_validate_match_data(struct nlattr **tb, u8 mrev)
	61	{
	62	if (mrev != 0) {
	63	pr_err("only policy match revision 0 supported");
	64	return -EINVAL;
	65	}
	66
	67	if (nla_get_u32(tb[TCA_EM_IPT_HOOK]) != NF_INET_PRE_ROUTING) {
	68	pr_err("policy can only be matched on NF_INET_PRE_ROUTING");
	69	return -EINVAL;
	70	}
	71
	72	return 0;
	73	}
	74
	75	static const struct em_ipt_xt_match em_ipt_xt_matches[] = {
	76	{
	77	.match_name = "policy",
	78	.validate_match_data = policy_validate_match_data
	79	},
	80	{}
	81	};
	82
	83	static struct xt_match get_xt_match(struct nlattr *tb)
	84	{
	85	const struct em_ipt_xt_match *m;
	86	struct nlattr *mname_attr;
	87	u8 nfproto, mrev = 0;
	88	int ret;
89
90	mname_attr = tb[TCA_EM_IPT_MATCH_NAME];
91	for (m = em_ipt_xt_matches; m->match_name; m++) {
92	if (!nla_strcmp(mname_attr, m->match_name))
93	break;
94	}
95
96	if (!m->match_name) {
97	pr_err("Unsupported xt match");
98	return ERR_PTR(-EINVAL);
99	}
100
101	if (tb[TCA_EM_IPT_MATCH_REVISION])
102	mrev = nla_get_u8(tb[TCA_EM_IPT_MATCH_REVISION]);
103
104	ret = m->validate_match_data(tb, mrev);
105	if (ret < 0)
106	return ERR_PTR(ret);
107
108	nfproto = nla_get_u8(tb[TCA_EM_IPT_NFPROTO]);
109	return xt_request_find_match(nfproto, m->match_name, mrev);
110	}
111
112	static int em_ipt_change(struct net net, void data, int data_len,
113	struct tcf_ematch *em)
114	{
115	struct nlattr *tb[TCA_EM_IPT_MAX + 1];
116	struct em_ipt_match *im = NULL;
117	struct xt_match *match;
118	int mdata_len, ret;
ba3d24d4	119	u8 nfproto;
ccc007e4	120
8cb08174 JB	121	ret = nla_parse_deprecated(tb, TCA_EM_IPT_MAX, data, data_len,
8cb08174 JB	122	em_ipt_policy, NULL);
ccc007e4 EB	123	if (ret < 0)
	124	return ret;
	125
	126	if (!tb[TCA_EM_IPT_HOOK] \|\| !tb[TCA_EM_IPT_MATCH_NAME] \|\|
	127	!tb[TCA_EM_IPT_MATCH_DATA] \|\| !tb[TCA_EM_IPT_NFPROTO])
	128	return -EINVAL;
	129
ba3d24d4 NA	130	nfproto = nla_get_u8(tb[TCA_EM_IPT_NFPROTO]);
	131	switch (nfproto) {
	132	case NFPROTO_IPV4:
	133	case NFPROTO_IPV6:
	134	break;
	135	default:
	136	return -EINVAL;
	137	}
	138
ccc007e4 EB	139	match = get_xt_match(tb);
	140	if (IS_ERR(match)) {
	141	pr_err("unable to load match\n");
	142	return PTR_ERR(match);
	143	}
	144
	145	mdata_len = XT_ALIGN(nla_len(tb[TCA_EM_IPT_MATCH_DATA]));
	146	im = kzalloc(sizeof(*im) + mdata_len, GFP_KERNEL);
	147	if (!im) {
	148	ret = -ENOMEM;
	149	goto err;
	150	}
	151
	152	im->match = match;
	153	im->hook = nla_get_u32(tb[TCA_EM_IPT_HOOK]);
ba3d24d4	154	im->nfproto = nfproto;
ccc007e4 EB	155	nla_memcpy(im->match_data, tb[TCA_EM_IPT_MATCH_DATA], mdata_len);
	156
	157	ret = check_match(net, im, mdata_len);
	158	if (ret)
	159	goto err;
	160
	161	em->datalen = sizeof(*im) + mdata_len;
	162	em->data = (unsigned long)im;
	163	return 0;
	164
	165	err:
	166	kfree(im);
	167	module_put(match->me);
	168	return ret;
	169	}
	170
	171	static void em_ipt_destroy(struct tcf_ematch *em)
	172	{
	173	struct em_ipt_match im = (void )em->data;
	174
	175	if (!im)
	176	return;
	177
	178	if (im->match->destroy) {
	179	struct xt_mtdtor_param par = {
	180	.net = em->net,
	181	.match = im->match,
	182	.matchinfo = im->match_data,
	183	.family = im->match->family
	184	};
	185	im->match->destroy(&par);
	186	}
	187	module_put(im->match->me);
	188	kfree((void *)im);
	189	}
	190
	191	static int em_ipt_match(struct sk_buff skb, struct tcf_ematch em,
	192	struct tcf_pkt_info *info)
	193	{
	194	const struct em_ipt_match im = (const void )em->data;
	195	struct xt_action_param acpar = {};
	196	struct net_device *indev = NULL;
f4c1c40c	197	u8 nfproto = im->match->family;
ccc007e4 EB	198	struct nf_hook_state state;
	199	int ret;
	200
9e10edd7 NA	201	switch (tc_skb_protocol(skb)) {
	202	case htons(ETH_P_IP):
	203	if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
	204	return 0;
f4c1c40c NA	205	if (nfproto == NFPROTO_UNSPEC)
f4c1c40c NA	206	nfproto = NFPROTO_IPV4;
9e10edd7 NA	207	break;
	208	case htons(ETH_P_IPV6):
	209	if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
	210	return 0;
f4c1c40c NA	211	if (nfproto == NFPROTO_UNSPEC)
f4c1c40c NA	212	nfproto = NFPROTO_IPV6;
9e10edd7 NA	213	break;
	214	default:
	215	return 0;
	216	}
	217
ccc007e4 EB	218	rcu_read_lock();
	219
	220	if (skb->skb_iif)
	221	indev = dev_get_by_index_rcu(em->net, skb->skb_iif);
	222
f4c1c40c	223	nf_hook_state_init(&state, im->hook, nfproto,
ccc007e4 EB	224	indev ?: skb->dev, skb->dev, NULL, em->net, NULL);
	225
	226	acpar.match = im->match;
	227	acpar.matchinfo = im->match_data;
	228	acpar.state = &state;
	229
	230	ret = im->match->match(skb, &acpar);
	231
	232	rcu_read_unlock();
	233	return ret;
	234	}
	235
	236	static int em_ipt_dump(struct sk_buff skb, struct tcf_ematch em)
	237	{
	238	struct em_ipt_match im = (void )em->data;
	239
	240	if (nla_put_string(skb, TCA_EM_IPT_MATCH_NAME, im->match->name) < 0)
	241	return -EMSGSIZE;
	242	if (nla_put_u32(skb, TCA_EM_IPT_HOOK, im->hook) < 0)
	243	return -EMSGSIZE;
	244	if (nla_put_u8(skb, TCA_EM_IPT_MATCH_REVISION, im->match->revision) < 0)
	245	return -EMSGSIZE;
ba3d24d4	246	if (nla_put_u8(skb, TCA_EM_IPT_NFPROTO, im->nfproto) < 0)
ccc007e4 EB	247	return -EMSGSIZE;
	248	if (nla_put(skb, TCA_EM_IPT_MATCH_DATA,
	249	im->match->usersize ?: im->match->matchsize,
	250	im->match_data) < 0)
	251	return -EMSGSIZE;
	252
	253	return 0;
	254	}
	255
	256	static struct tcf_ematch_ops em_ipt_ops = {
	257	.kind = TCF_EM_IPT,
	258	.change = em_ipt_change,
	259	.destroy = em_ipt_destroy,
	260	.match = em_ipt_match,
	261	.dump = em_ipt_dump,
	262	.owner = THIS_MODULE,
	263	.link = LIST_HEAD_INIT(em_ipt_ops.link)
	264	};
	265
	266	static int __init init_em_ipt(void)
	267	{
	268	return tcf_em_register(&em_ipt_ops);
	269	}
	270
	271	static void __exit exit_em_ipt(void)
	272	{
	273	tcf_em_unregister(&em_ipt_ops);
	274	}
	275
	276	MODULE_LICENSE("GPL");
	277	MODULE_AUTHOR("Eyal Birger <eyal.birger@gmail.com>");
	278	MODULE_DESCRIPTION("TC extended match for IPtables matches");
	279
	280	module_init(init_em_ipt);
	281	module_exit(exit_em_ipt);
	282
	283	MODULE_ALIAS_TCF_EMATCH(TCF_EM_IPT);