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_modprobe(struct net *net, enum nf_log_type t)
132{
133	switch (t) {
134	case NF_LOG_TYPE_LOG:
135		return nft_request_module(net, "%s", "nf_log_syslog");
136	case NF_LOG_TYPE_ULOG:
137		return nft_request_module(net, "%s", "nfnetlink_log");
138	case NF_LOG_TYPE_MAX:
139		break;
140	}
141
142	return -ENOENT;
143}
144
145static int nft_log_init(const struct nft_ctx *ctx,
146			const struct nft_expr *expr,
147			const struct nlattr * const tb[])
148{
149	struct nft_log *priv = nft_expr_priv(expr);
150	struct nf_loginfo *li = &priv->loginfo;
151	const struct nlattr *nla;
152	int err;
153
154	li->type = NF_LOG_TYPE_LOG;
155	if (tb[NFTA_LOG_LEVEL] != NULL &&
156	    tb[NFTA_LOG_GROUP] != NULL)
157		return -EINVAL;
158	if (tb[NFTA_LOG_GROUP] != NULL) {
159		li->type = NF_LOG_TYPE_ULOG;
160		if (tb[NFTA_LOG_FLAGS] != NULL)
161			return -EINVAL;
162	}
163
164	nla = tb[NFTA_LOG_PREFIX];
165	if (nla != NULL) {
166		priv->prefix = kmalloc(nla_len(nla) + 1, GFP_KERNEL);
167		if (priv->prefix == NULL)
168			return -ENOMEM;
169		nla_strscpy(priv->prefix, nla, nla_len(nla) + 1);
170	} else {
171		priv->prefix = (char *)nft_log_null_prefix;
172	}
173
174	switch (li->type) {
175	case NF_LOG_TYPE_LOG:
176		if (tb[NFTA_LOG_LEVEL] != NULL) {
177			li->u.log.level =
178				ntohl(nla_get_be32(tb[NFTA_LOG_LEVEL]));
179		} else {
180			li->u.log.level = NFT_LOGLEVEL_WARNING;
181		}
182		if (li->u.log.level > NFT_LOGLEVEL_AUDIT) {
183			err = -EINVAL;
184			goto err1;
185		}
186
187		if (tb[NFTA_LOG_FLAGS] != NULL) {
188			li->u.log.logflags =
189				ntohl(nla_get_be32(tb[NFTA_LOG_FLAGS]));
190			if (li->u.log.logflags & ~NF_LOG_MASK) {
191				err = -EINVAL;
192				goto err1;
193			}
194		}
195		break;
196	case NF_LOG_TYPE_ULOG:
197		li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
198		if (tb[NFTA_LOG_SNAPLEN] != NULL) {
199			li->u.ulog.flags |= NF_LOG_F_COPY_LEN;
200			li->u.ulog.copy_len =
201				ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
202		}
203		if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
204			li->u.ulog.qthreshold =
205				ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
206		}
207		break;
208	}
209
210	if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
211		return 0;
212
213	err = nf_logger_find_get(ctx->family, li->type);
214	if (err < 0) {
215		if (nft_log_modprobe(ctx->net, li->type) == -EAGAIN)
216			err = -EAGAIN;
217
218		goto err1;
219	}
220
221	return 0;
222
223err1:
224	if (priv->prefix != nft_log_null_prefix)
225		kfree(priv->prefix);
226	return err;
227}
228
229static void nft_log_destroy(const struct nft_ctx *ctx,
230			    const struct nft_expr *expr)
231{
232	struct nft_log *priv = nft_expr_priv(expr);
233	struct nf_loginfo *li = &priv->loginfo;
234
235	if (priv->prefix != nft_log_null_prefix)
236		kfree(priv->prefix);
237
238	if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
239		return;
240
241	nf_logger_put(ctx->family, li->type);
242}
243
244static int nft_log_dump(struct sk_buff *skb, const struct nft_expr *expr)
245{
246	const struct nft_log *priv = nft_expr_priv(expr);
247	const struct nf_loginfo *li = &priv->loginfo;
248
249	if (priv->prefix != nft_log_null_prefix)
250		if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
251			goto nla_put_failure;
252	switch (li->type) {
253	case NF_LOG_TYPE_LOG:
254		if (nla_put_be32(skb, NFTA_LOG_LEVEL, htonl(li->u.log.level)))
255			goto nla_put_failure;
256
257		if (li->u.log.logflags) {
258			if (nla_put_be32(skb, NFTA_LOG_FLAGS,
259					 htonl(li->u.log.logflags)))
260				goto nla_put_failure;
261		}
262		break;
263	case NF_LOG_TYPE_ULOG:
264		if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
265			goto nla_put_failure;
266
267		if (li->u.ulog.flags & NF_LOG_F_COPY_LEN) {
268			if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
269					 htonl(li->u.ulog.copy_len)))
270				goto nla_put_failure;
271		}
272		if (li->u.ulog.qthreshold) {
273			if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
274					 htons(li->u.ulog.qthreshold)))
275				goto nla_put_failure;
276		}
277		break;
278	}
279	return 0;
280
281nla_put_failure:
282	return -1;
283}
284
285static struct nft_expr_type nft_log_type;
286static const struct nft_expr_ops nft_log_ops = {
287	.type		= &nft_log_type,
288	.size		= NFT_EXPR_SIZE(sizeof(struct nft_log)),
289	.eval		= nft_log_eval,
290	.init		= nft_log_init,
291	.destroy	= nft_log_destroy,
292	.dump		= nft_log_dump,
293};
294
295static struct nft_expr_type nft_log_type __read_mostly = {
296	.name		= "log",
297	.ops		= &nft_log_ops,
298	.policy		= nft_log_policy,
299	.maxattr	= NFTA_LOG_MAX,
300	.owner		= THIS_MODULE,
301};
302
303static int __init nft_log_module_init(void)
304{
305	return nft_register_expr(&nft_log_type);
306}
307
308static void __exit nft_log_module_exit(void)
309{
310	nft_unregister_expr(&nft_log_type);
311}
312
313module_init(nft_log_module_init);
314module_exit(nft_log_module_exit);
315
316MODULE_LICENSE("GPL");
317MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
318MODULE_ALIAS_NFT_EXPR("log");
319MODULE_DESCRIPTION("Netfilter nf_tables log module");