1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
  4 * Copyright (c) 2012-2014 Pablo Neira Ayuso <pablo@netfilter.org>
  5 *
  6 * Development of this code funded by Astaro AG (http://www.astaro.com/)
  7 */
  8
  9#include <linux/audit.h>
 10#include <linux/kernel.h>
 11#include <linux/init.h>
 12#include <linux/module.h>
 13#include <linux/netlink.h>
 14#include <linux/netfilter.h>
 15#include <linux/netfilter/nf_tables.h>
 16#include <net/ipv6.h>
 17#include <net/ip.h>
 18#include <net/netfilter/nf_tables.h>
 19#include <net/netfilter/nf_log.h>
 20#include <linux/netdevice.h>
 21
 22static const char *nft_log_null_prefix = "";
 23
 24struct nft_log {
 25	struct nf_loginfo	loginfo;
 26	char			*prefix;
 27};
 28
 29static bool audit_ip4(struct audit_buffer *ab, struct sk_buff *skb)
 30{
 31	struct iphdr _iph;
 32	const struct iphdr *ih;
 33
 34	ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_iph), &_iph);
 35	if (!ih)
 36		return false;
 37
 38	audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu",
 39			 &ih->saddr, &ih->daddr, ih->protocol);
 40
 41	return true;
 42}
 43
 44static bool audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
 45{
 46	struct ipv6hdr _ip6h;
 47	const struct ipv6hdr *ih;
 48	u8 nexthdr;
 49	__be16 frag_off;
 50
 51	ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
 52	if (!ih)
 53		return false;
 54
 55	nexthdr = ih->nexthdr;
 56	ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), &nexthdr, &frag_off);
 57
 58	audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
 59			 &ih->saddr, &ih->daddr, nexthdr);
 60
 61	return true;
 62}
 63
 64static void nft_log_eval_audit(const struct nft_pktinfo *pkt)
 65{
 66	struct sk_buff *skb = pkt->skb;
 67	struct audit_buffer *ab;
 68	int fam = -1;
 69
 70	if (!audit_enabled)
 71		return;
 72
 73	ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
 74	if (!ab)
 75		return;
 76
 77	audit_log_format(ab, "mark=%#x", skb->mark);
 78
 79	switch (nft_pf(pkt)) {
 80	case NFPROTO_BRIDGE:
 81		switch (eth_hdr(skb)->h_proto) {
 82		case htons(ETH_P_IP):
 83			fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
 84			break;
 85		case htons(ETH_P_IPV6):
 86			fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
 87			break;
 88		}
 89		break;
 90	case NFPROTO_IPV4:
 91		fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
 92		break;
 93	case NFPROTO_IPV6:
 94		fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
 95		break;
 96	}
 97
 98	if (fam == -1)
 99		audit_log_format(ab, " saddr=? daddr=? proto=-1");
100
101	audit_log_end(ab);
102}
103
104static void nft_log_eval(const struct nft_expr *expr,
105			 struct nft_regs *regs,
106			 const struct nft_pktinfo *pkt)
107{
108	const struct nft_log *priv = nft_expr_priv(expr);
109
110	if (priv->loginfo.type == NF_LOG_TYPE_LOG &&
111	    priv->loginfo.u.log.level == NFT_LOGLEVEL_AUDIT) {
112		nft_log_eval_audit(pkt);
113		return;
114	}
115
116	nf_log_packet(nft_net(pkt), nft_pf(pkt), nft_hook(pkt), pkt->skb,
117		      nft_in(pkt), nft_out(pkt), &priv->loginfo, "%s",
118		      priv->prefix);
119}
120
121static const struct nla_policy nft_log_policy[NFTA_LOG_MAX + 1] = {
122	[NFTA_LOG_GROUP]	= { .type = NLA_U16 },
123	[NFTA_LOG_PREFIX]	= { .type = NLA_STRING,
124				    .len = NF_LOG_PREFIXLEN - 1 },
125	[NFTA_LOG_SNAPLEN]	= { .type = NLA_U32 },
126	[NFTA_LOG_QTHRESHOLD]	= { .type = NLA_U16 },
127	[NFTA_LOG_LEVEL]	= { .type = NLA_U32 },
128	[NFTA_LOG_FLAGS]	= { .type = NLA_U32 },
129};
130
131static int nft_log_init(const struct nft_ctx *ctx,
132			const struct nft_expr *expr,
133			const struct nlattr * const tb[])
134{
135	struct nft_log *priv = nft_expr_priv(expr);
136	struct nf_loginfo *li = &priv->loginfo;
137	const struct nlattr *nla;
138	int err;
139
140	li->type = NF_LOG_TYPE_LOG;
141	if (tb[NFTA_LOG_LEVEL] != NULL &&
142	    tb[NFTA_LOG_GROUP] != NULL)
143		return -EINVAL;
144	if (tb[NFTA_LOG_GROUP] != NULL) {
145		li->type = NF_LOG_TYPE_ULOG;
146		if (tb[NFTA_LOG_FLAGS] != NULL)
147			return -EINVAL;
148	}
149
150	nla = tb[NFTA_LOG_PREFIX];
151	if (nla != NULL) {
152		priv->prefix = kmalloc(nla_len(nla) + 1, GFP_KERNEL);
153		if (priv->prefix == NULL)
154			return -ENOMEM;
155		nla_strlcpy(priv->prefix, nla, nla_len(nla) + 1);
156	} else {
157		priv->prefix = (char *)nft_log_null_prefix;
158	}
159
160	switch (li->type) {
161	case NF_LOG_TYPE_LOG:
162		if (tb[NFTA_LOG_LEVEL] != NULL) {
163			li->u.log.level =
164				ntohl(nla_get_be32(tb[NFTA_LOG_LEVEL]));
165		} else {
166			li->u.log.level = NFT_LOGLEVEL_WARNING;
167		}
168		if (li->u.log.level > NFT_LOGLEVEL_AUDIT) {
169			err = -EINVAL;
170			goto err1;
171		}
172
173		if (tb[NFTA_LOG_FLAGS] != NULL) {
174			li->u.log.logflags =
175				ntohl(nla_get_be32(tb[NFTA_LOG_FLAGS]));
176			if (li->u.log.logflags & ~NF_LOG_MASK) {
177				err = -EINVAL;
178				goto err1;
179			}
180		}
181		break;
182	case NF_LOG_TYPE_ULOG:
183		li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
184		if (tb[NFTA_LOG_SNAPLEN] != NULL) {
185			li->u.ulog.flags |= NF_LOG_F_COPY_LEN;
186			li->u.ulog.copy_len =
187				ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
188		}
189		if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
190			li->u.ulog.qthreshold =
191				ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
192		}
193		break;
194	}
195
196	if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
197		return 0;
198
199	err = nf_logger_find_get(ctx->family, li->type);
200	if (err < 0)
201		goto err1;
202
203	return 0;
204
205err1:
206	if (priv->prefix != nft_log_null_prefix)
207		kfree(priv->prefix);
208	return err;
209}
210
211static void nft_log_destroy(const struct nft_ctx *ctx,
212			    const struct nft_expr *expr)
213{
214	struct nft_log *priv = nft_expr_priv(expr);
215	struct nf_loginfo *li = &priv->loginfo;
216
217	if (priv->prefix != nft_log_null_prefix)
218		kfree(priv->prefix);
219
220	if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
221		return;
222
223	nf_logger_put(ctx->family, li->type);
224}
225
226static int nft_log_dump(struct sk_buff *skb, const struct nft_expr *expr)
227{
228	const struct nft_log *priv = nft_expr_priv(expr);
229	const struct nf_loginfo *li = &priv->loginfo;
230
231	if (priv->prefix != nft_log_null_prefix)
232		if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
233			goto nla_put_failure;
234	switch (li->type) {
235	case NF_LOG_TYPE_LOG:
236		if (nla_put_be32(skb, NFTA_LOG_LEVEL, htonl(li->u.log.level)))
237			goto nla_put_failure;
238
239		if (li->u.log.logflags) {
240			if (nla_put_be32(skb, NFTA_LOG_FLAGS,
241					 htonl(li->u.log.logflags)))
242				goto nla_put_failure;
243		}
244		break;
245	case NF_LOG_TYPE_ULOG:
246		if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
247			goto nla_put_failure;
248
249		if (li->u.ulog.flags & NF_LOG_F_COPY_LEN) {
250			if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
251					 htonl(li->u.ulog.copy_len)))
252				goto nla_put_failure;
253		}
254		if (li->u.ulog.qthreshold) {
255			if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
256					 htons(li->u.ulog.qthreshold)))
257				goto nla_put_failure;
258		}
259		break;
260	}
261	return 0;
262
263nla_put_failure:
264	return -1;
265}
266
267static struct nft_expr_type nft_log_type;
268static const struct nft_expr_ops nft_log_ops = {
269	.type		= &nft_log_type,
270	.size		= NFT_EXPR_SIZE(sizeof(struct nft_log)),
271	.eval		= nft_log_eval,
272	.init		= nft_log_init,
273	.destroy	= nft_log_destroy,
274	.dump		= nft_log_dump,
275};
276
277static struct nft_expr_type nft_log_type __read_mostly = {
278	.name		= "log",
279	.ops		= &nft_log_ops,
280	.policy		= nft_log_policy,
281	.maxattr	= NFTA_LOG_MAX,
282	.owner		= THIS_MODULE,
283};
284
285static int __init nft_log_module_init(void)
286{
287	return nft_register_expr(&nft_log_type);
288}
289
290static void __exit nft_log_module_exit(void)
291{
292	nft_unregister_expr(&nft_log_type);
293}
294
295module_init(nft_log_module_init);
296module_exit(nft_log_module_exit);
297
298MODULE_LICENSE("GPL");
299MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
300MODULE_ALIAS_NFT_EXPR("log");
301MODULE_DESCRIPTION("Netfilter nf_tables log module");