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, offset: skb_network_offset(skb), len: sizeof(_iph), buffer: &_iph);
35 if (!ih)
36 return false;
37
38 audit_log_format(ab, fmt: " 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, offset: skb_network_offset(skb), len: sizeof(_ip6h), buffer: &_ip6h);
52 if (!ih)
53 return false;
54
55 nexthdr = ih->nexthdr;
56 ipv6_skip_exthdr(skb, start: skb_network_offset(skb) + sizeof(_ip6h), nexthdrp: &nexthdr, frag_offp: &frag_off);
57
58 audit_log_format(ab, fmt: " 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, fmt: "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, fmt: " 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(net: nft_net(pkt), pf: nft_pf(pkt), hooknum: nft_hook(pkt), skb: pkt->skb,
117 in: nft_in(pkt), out: nft_out(pkt), li: &priv->loginfo, fmt: "%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, fmt: "%s", "nf_log_syslog");
136 case NF_LOG_TYPE_ULOG:
137 return nft_request_module(net, fmt: "%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_ACCOUNT);
167 if (priv->prefix == NULL)
168 return -ENOMEM;
169 nla_strscpy(dst: priv->prefix, nla, dstsize: 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(pf: ctx->family, type: li->type);
214 if (err < 0) {
215 if (nft_log_modprobe(net: ctx->net, t: 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(objp: 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(objp: priv->prefix);
237
238 if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
239 return;
240
241 nf_logger_put(pf: ctx->family, type: li->type);
242}
243
244static int nft_log_dump(struct sk_buff *skb,
245 const struct nft_expr *expr, bool reset)
246{
247 const struct nft_log *priv = nft_expr_priv(expr);
248 const struct nf_loginfo *li = &priv->loginfo;
249
250 if (priv->prefix != nft_log_null_prefix)
251 if (nla_put_string(skb, attrtype: NFTA_LOG_PREFIX, str: priv->prefix))
252 goto nla_put_failure;
253 switch (li->type) {
254 case NF_LOG_TYPE_LOG:
255 if (nla_put_be32(skb, attrtype: NFTA_LOG_LEVEL, htonl(li->u.log.level)))
256 goto nla_put_failure;
257
258 if (li->u.log.logflags) {
259 if (nla_put_be32(skb, attrtype: NFTA_LOG_FLAGS,
260 htonl(li->u.log.logflags)))
261 goto nla_put_failure;
262 }
263 break;
264 case NF_LOG_TYPE_ULOG:
265 if (nla_put_be16(skb, attrtype: NFTA_LOG_GROUP, htons(li->u.ulog.group)))
266 goto nla_put_failure;
267
268 if (li->u.ulog.flags & NF_LOG_F_COPY_LEN) {
269 if (nla_put_be32(skb, attrtype: NFTA_LOG_SNAPLEN,
270 htonl(li->u.ulog.copy_len)))
271 goto nla_put_failure;
272 }
273 if (li->u.ulog.qthreshold) {
274 if (nla_put_be16(skb, attrtype: NFTA_LOG_QTHRESHOLD,
275 htons(li->u.ulog.qthreshold)))
276 goto nla_put_failure;
277 }
278 break;
279 }
280 return 0;
281
282nla_put_failure:
283 return -1;
284}
285
286static struct nft_expr_type nft_log_type;
287static const struct nft_expr_ops nft_log_ops = {
288 .type = &nft_log_type,
289 .size = NFT_EXPR_SIZE(sizeof(struct nft_log)),
290 .eval = nft_log_eval,
291 .init = nft_log_init,
292 .destroy = nft_log_destroy,
293 .dump = nft_log_dump,
294 .reduce = NFT_REDUCE_READONLY,
295};
296
297static struct nft_expr_type nft_log_type __read_mostly = {
298 .name = "log",
299 .ops = &nft_log_ops,
300 .policy = nft_log_policy,
301 .maxattr = NFTA_LOG_MAX,
302 .owner = THIS_MODULE,
303};
304
305static int __init nft_log_module_init(void)
306{
307 return nft_register_expr(&nft_log_type);
308}
309
310static void __exit nft_log_module_exit(void)
311{
312 nft_unregister_expr(&nft_log_type);
313}
314
315module_init(nft_log_module_init);
316module_exit(nft_log_module_exit);
317
318MODULE_LICENSE("GPL");
319MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
320MODULE_ALIAS_NFT_EXPR("log");
321MODULE_DESCRIPTION("Netfilter nf_tables log module");
322

source code of linux/net/netfilter/nft_log.c