1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9 #include <linux/module.h>
10 #include <linux/spinlock.h>
11 #include <linux/skbuff.h>
12 #include <linux/if_arp.h>
13 #include <linux/ip.h>
14 #include <net/ipv6.h>
15 #include <net/icmp.h>
16 #include <net/udp.h>
17 #include <net/tcp.h>
18 #include <net/route.h>
19
20 #include <linux/netfilter.h>
21 #include <linux/netfilter/xt_LOG.h>
22 #include <net/netfilter/nf_log.h>
23
24 static struct nf_loginfo default_loginfo = {
25 .type = NF_LOG_TYPE_LOG,
26 .u = {
27 .log = {
28 .level = 5,
29 .logflags = NF_LOG_MASK,
30 },
31 },
32 };
33
34 /* One level of recursion won't kill us */
dump_ipv4_packet(struct nf_log_buf * m,const struct nf_loginfo * info,const struct sk_buff * skb,unsigned int iphoff)35 static void dump_ipv4_packet(struct nf_log_buf *m,
36 const struct nf_loginfo *info,
37 const struct sk_buff *skb, unsigned int iphoff)
38 {
39 struct iphdr _iph;
40 const struct iphdr *ih;
41 unsigned int logflags;
42
43 if (info->type == NF_LOG_TYPE_LOG)
44 logflags = info->u.log.logflags;
45 else
46 logflags = NF_LOG_MASK;
47
48 ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
49 if (ih == NULL) {
50 nf_log_buf_add(m, "TRUNCATED");
51 return;
52 }
53
54 /* Important fields:
55 * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
56 /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
57 nf_log_buf_add(m, "SRC=%pI4 DST=%pI4 ", &ih->saddr, &ih->daddr);
58
59 /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
60 nf_log_buf_add(m, "LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
61 ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
62 ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));
63
64 /* Max length: 6 "CE DF MF " */
65 if (ntohs(ih->frag_off) & IP_CE)
66 nf_log_buf_add(m, "CE ");
67 if (ntohs(ih->frag_off) & IP_DF)
68 nf_log_buf_add(m, "DF ");
69 if (ntohs(ih->frag_off) & IP_MF)
70 nf_log_buf_add(m, "MF ");
71
72 /* Max length: 11 "FRAG:65535 " */
73 if (ntohs(ih->frag_off) & IP_OFFSET)
74 nf_log_buf_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
75
76 if ((logflags & XT_LOG_IPOPT) &&
77 ih->ihl * 4 > sizeof(struct iphdr)) {
78 const unsigned char *op;
79 unsigned char _opt[4 * 15 - sizeof(struct iphdr)];
80 unsigned int i, optsize;
81
82 optsize = ih->ihl * 4 - sizeof(struct iphdr);
83 op = skb_header_pointer(skb, iphoff+sizeof(_iph),
84 optsize, _opt);
85 if (op == NULL) {
86 nf_log_buf_add(m, "TRUNCATED");
87 return;
88 }
89
90 /* Max length: 127 "OPT (" 15*4*2chars ") " */
91 nf_log_buf_add(m, "OPT (");
92 for (i = 0; i < optsize; i++)
93 nf_log_buf_add(m, "%02X", op[i]);
94 nf_log_buf_add(m, ") ");
95 }
96
97 switch (ih->protocol) {
98 case IPPROTO_TCP:
99 if (nf_log_dump_tcp_header(m, skb, ih->protocol,
100 ntohs(ih->frag_off) & IP_OFFSET,
101 iphoff+ih->ihl*4, logflags))
102 return;
103 break;
104 case IPPROTO_UDP:
105 case IPPROTO_UDPLITE:
106 if (nf_log_dump_udp_header(m, skb, ih->protocol,
107 ntohs(ih->frag_off) & IP_OFFSET,
108 iphoff+ih->ihl*4))
109 return;
110 break;
111 case IPPROTO_ICMP: {
112 struct icmphdr _icmph;
113 const struct icmphdr *ich;
114 static const size_t required_len[NR_ICMP_TYPES+1]
115 = { [ICMP_ECHOREPLY] = 4,
116 [ICMP_DEST_UNREACH]
117 = 8 + sizeof(struct iphdr),
118 [ICMP_SOURCE_QUENCH]
119 = 8 + sizeof(struct iphdr),
120 [ICMP_REDIRECT]
121 = 8 + sizeof(struct iphdr),
122 [ICMP_ECHO] = 4,
123 [ICMP_TIME_EXCEEDED]
124 = 8 + sizeof(struct iphdr),
125 [ICMP_PARAMETERPROB]
126 = 8 + sizeof(struct iphdr),
127 [ICMP_TIMESTAMP] = 20,
128 [ICMP_TIMESTAMPREPLY] = 20,
129 [ICMP_ADDRESS] = 12,
130 [ICMP_ADDRESSREPLY] = 12 };
131
132 /* Max length: 11 "PROTO=ICMP " */
133 nf_log_buf_add(m, "PROTO=ICMP ");
134
135 if (ntohs(ih->frag_off) & IP_OFFSET)
136 break;
137
138 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
139 ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
140 sizeof(_icmph), &_icmph);
141 if (ich == NULL) {
142 nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
143 skb->len - iphoff - ih->ihl*4);
144 break;
145 }
146
147 /* Max length: 18 "TYPE=255 CODE=255 " */
148 nf_log_buf_add(m, "TYPE=%u CODE=%u ", ich->type, ich->code);
149
150 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
151 if (ich->type <= NR_ICMP_TYPES &&
152 required_len[ich->type] &&
153 skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
154 nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
155 skb->len - iphoff - ih->ihl*4);
156 break;
157 }
158
159 switch (ich->type) {
160 case ICMP_ECHOREPLY:
161 case ICMP_ECHO:
162 /* Max length: 19 "ID=65535 SEQ=65535 " */
163 nf_log_buf_add(m, "ID=%u SEQ=%u ",
164 ntohs(ich->un.echo.id),
165 ntohs(ich->un.echo.sequence));
166 break;
167
168 case ICMP_PARAMETERPROB:
169 /* Max length: 14 "PARAMETER=255 " */
170 nf_log_buf_add(m, "PARAMETER=%u ",
171 ntohl(ich->un.gateway) >> 24);
172 break;
173 case ICMP_REDIRECT:
174 /* Max length: 24 "GATEWAY=255.255.255.255 " */
175 nf_log_buf_add(m, "GATEWAY=%pI4 ", &ich->un.gateway);
176 /* Fall through */
177 case ICMP_DEST_UNREACH:
178 case ICMP_SOURCE_QUENCH:
179 case ICMP_TIME_EXCEEDED:
180 /* Max length: 3+maxlen */
181 if (!iphoff) { /* Only recurse once. */
182 nf_log_buf_add(m, "[");
183 dump_ipv4_packet(m, info, skb,
184 iphoff + ih->ihl*4+sizeof(_icmph));
185 nf_log_buf_add(m, "] ");
186 }
187
188 /* Max length: 10 "MTU=65535 " */
189 if (ich->type == ICMP_DEST_UNREACH &&
190 ich->code == ICMP_FRAG_NEEDED) {
191 nf_log_buf_add(m, "MTU=%u ",
192 ntohs(ich->un.frag.mtu));
193 }
194 }
195 break;
196 }
197 /* Max Length */
198 case IPPROTO_AH: {
199 struct ip_auth_hdr _ahdr;
200 const struct ip_auth_hdr *ah;
201
202 if (ntohs(ih->frag_off) & IP_OFFSET)
203 break;
204
205 /* Max length: 9 "PROTO=AH " */
206 nf_log_buf_add(m, "PROTO=AH ");
207
208 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
209 ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
210 sizeof(_ahdr), &_ahdr);
211 if (ah == NULL) {
212 nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
213 skb->len - iphoff - ih->ihl*4);
214 break;
215 }
216
217 /* Length: 15 "SPI=0xF1234567 " */
218 nf_log_buf_add(m, "SPI=0x%x ", ntohl(ah->spi));
219 break;
220 }
221 case IPPROTO_ESP: {
222 struct ip_esp_hdr _esph;
223 const struct ip_esp_hdr *eh;
224
225 /* Max length: 10 "PROTO=ESP " */
226 nf_log_buf_add(m, "PROTO=ESP ");
227
228 if (ntohs(ih->frag_off) & IP_OFFSET)
229 break;
230
231 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
232 eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
233 sizeof(_esph), &_esph);
234 if (eh == NULL) {
235 nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
236 skb->len - iphoff - ih->ihl*4);
237 break;
238 }
239
240 /* Length: 15 "SPI=0xF1234567 " */
241 nf_log_buf_add(m, "SPI=0x%x ", ntohl(eh->spi));
242 break;
243 }
244 /* Max length: 10 "PROTO 255 " */
245 default:
246 nf_log_buf_add(m, "PROTO=%u ", ih->protocol);
247 }
248
249 /* Max length: 15 "UID=4294967295 " */
250 if ((logflags & XT_LOG_UID) && !iphoff)
251 nf_log_dump_sk_uid_gid(m, skb->sk);
252
253 /* Max length: 16 "MARK=0xFFFFFFFF " */
254 if (!iphoff && skb->mark)
255 nf_log_buf_add(m, "MARK=0x%x ", skb->mark);
256
257 /* Proto Max log string length */
258 /* IP: 40+46+6+11+127 = 230 */
259 /* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */
260 /* UDP: 10+max(25,20) = 35 */
261 /* UDPLITE: 14+max(25,20) = 39 */
262 /* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
263 /* ESP: 10+max(25)+15 = 50 */
264 /* AH: 9+max(25)+15 = 49 */
265 /* unknown: 10 */
266
267 /* (ICMP allows recursion one level deep) */
268 /* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */
269 /* maxlen = 230+ 91 + 230 + 252 = 803 */
270 }
271
dump_ipv4_mac_header(struct nf_log_buf * m,const struct nf_loginfo * info,const struct sk_buff * skb)272 static void dump_ipv4_mac_header(struct nf_log_buf *m,
273 const struct nf_loginfo *info,
274 const struct sk_buff *skb)
275 {
276 struct net_device *dev = skb->dev;
277 unsigned int logflags = 0;
278
279 if (info->type == NF_LOG_TYPE_LOG)
280 logflags = info->u.log.logflags;
281
282 if (!(logflags & XT_LOG_MACDECODE))
283 goto fallback;
284
285 switch (dev->type) {
286 case ARPHRD_ETHER:
287 nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
288 eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
289 ntohs(eth_hdr(skb)->h_proto));
290 return;
291 default:
292 break;
293 }
294
295 fallback:
296 nf_log_buf_add(m, "MAC=");
297 if (dev->hard_header_len &&
298 skb->mac_header != skb->network_header) {
299 const unsigned char *p = skb_mac_header(skb);
300 unsigned int i;
301
302 nf_log_buf_add(m, "%02x", *p++);
303 for (i = 1; i < dev->hard_header_len; i++, p++)
304 nf_log_buf_add(m, ":%02x", *p);
305 }
306 nf_log_buf_add(m, " ");
307 }
308
nf_log_ip_packet(struct net * net,u_int8_t pf,unsigned int hooknum,const struct sk_buff * skb,const struct net_device * in,const struct net_device * out,const struct nf_loginfo * loginfo,const char * prefix)309 static void nf_log_ip_packet(struct net *net, u_int8_t pf,
310 unsigned int hooknum, const struct sk_buff *skb,
311 const struct net_device *in,
312 const struct net_device *out,
313 const struct nf_loginfo *loginfo,
314 const char *prefix)
315 {
316 struct nf_log_buf *m;
317
318 /* FIXME: Disabled from containers until syslog ns is supported */
319 if (!net_eq(net, &init_net))
320 return;
321
322 m = nf_log_buf_open();
323
324 if (!loginfo)
325 loginfo = &default_loginfo;
326
327 nf_log_dump_packet_common(m, pf, hooknum, skb, in,
328 out, loginfo, prefix);
329
330 if (in != NULL)
331 dump_ipv4_mac_header(m, loginfo, skb);
332
333 dump_ipv4_packet(m, loginfo, skb, 0);
334
335 nf_log_buf_close(m);
336 }
337
338 static struct nf_logger nf_ip_logger __read_mostly = {
339 .name = "nf_log_ipv4",
340 .type = NF_LOG_TYPE_LOG,
341 .logfn = nf_log_ip_packet,
342 .me = THIS_MODULE,
343 };
344
nf_log_ipv4_net_init(struct net * net)345 static int __net_init nf_log_ipv4_net_init(struct net *net)
346 {
347 nf_log_set(net, NFPROTO_IPV4, &nf_ip_logger);
348 return 0;
349 }
350
nf_log_ipv4_net_exit(struct net * net)351 static void __net_exit nf_log_ipv4_net_exit(struct net *net)
352 {
353 nf_log_unset(net, &nf_ip_logger);
354 }
355
356 static struct pernet_operations nf_log_ipv4_net_ops = {
357 .init = nf_log_ipv4_net_init,
358 .exit = nf_log_ipv4_net_exit,
359 };
360
nf_log_ipv4_init(void)361 static int __init nf_log_ipv4_init(void)
362 {
363 int ret;
364
365 ret = register_pernet_subsys(&nf_log_ipv4_net_ops);
366 if (ret < 0)
367 return ret;
368
369 nf_log_register(NFPROTO_IPV4, &nf_ip_logger);
370 return 0;
371 }
372
nf_log_ipv4_exit(void)373 static void __exit nf_log_ipv4_exit(void)
374 {
375 unregister_pernet_subsys(&nf_log_ipv4_net_ops);
376 nf_log_unregister(&nf_ip_logger);
377 }
378
379 module_init(nf_log_ipv4_init);
380 module_exit(nf_log_ipv4_exit);
381
382 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
383 MODULE_DESCRIPTION("Netfilter IPv4 packet logging");
384 MODULE_LICENSE("GPL");
385 MODULE_ALIAS_NF_LOGGER(AF_INET, 0);
386