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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");
320
