CRED: Use creds in file structs
[linux-3.10.git] / net / ipv6 / netfilter / ip6t_LOG.c
1 /*
2  * This is a module which is used for logging packets.
3  */
4
5 /* (C) 2001 Jan Rekorajski <baggins@pld.org.pl>
6  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12
13 #include <linux/module.h>
14 #include <linux/moduleparam.h>
15 #include <linux/skbuff.h>
16 #include <linux/if_arp.h>
17 #include <linux/ip.h>
18 #include <linux/spinlock.h>
19 #include <linux/icmpv6.h>
20 #include <net/udp.h>
21 #include <net/tcp.h>
22 #include <net/ipv6.h>
23 #include <linux/netfilter.h>
24 #include <linux/netfilter/x_tables.h>
25 #include <linux/netfilter_ipv6/ip6_tables.h>
26 #include <net/netfilter/nf_log.h>
27
28 MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
29 MODULE_DESCRIPTION("Xtables: IPv6 packet logging to syslog");
30 MODULE_LICENSE("GPL");
31
32 struct in_device;
33 #include <net/route.h>
34 #include <linux/netfilter_ipv6/ip6t_LOG.h>
35
36 /* Use lock to serialize, so printks don't overlap */
37 static DEFINE_SPINLOCK(log_lock);
38
39 /* One level of recursion won't kill us */
40 static void dump_packet(const struct nf_loginfo *info,
41                         const struct sk_buff *skb, unsigned int ip6hoff,
42                         int recurse)
43 {
44         u_int8_t currenthdr;
45         int fragment;
46         struct ipv6hdr _ip6h;
47         const struct ipv6hdr *ih;
48         unsigned int ptr;
49         unsigned int hdrlen = 0;
50         unsigned int logflags;
51
52         if (info->type == NF_LOG_TYPE_LOG)
53                 logflags = info->u.log.logflags;
54         else
55                 logflags = NF_LOG_MASK;
56
57         ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
58         if (ih == NULL) {
59                 printk("TRUNCATED");
60                 return;
61         }
62
63         /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
64         printk("SRC=" NIP6_FMT " DST=" NIP6_FMT " ", NIP6(ih->saddr), NIP6(ih->daddr));
65
66         /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
67         printk("LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
68                ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
69                (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
70                ih->hop_limit,
71                (ntohl(*(__be32 *)ih) & 0x000fffff));
72
73         fragment = 0;
74         ptr = ip6hoff + sizeof(struct ipv6hdr);
75         currenthdr = ih->nexthdr;
76         while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
77                 struct ipv6_opt_hdr _hdr;
78                 const struct ipv6_opt_hdr *hp;
79
80                 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
81                 if (hp == NULL) {
82                         printk("TRUNCATED");
83                         return;
84                 }
85
86                 /* Max length: 48 "OPT (...) " */
87                 if (logflags & IP6T_LOG_IPOPT)
88                         printk("OPT ( ");
89
90                 switch (currenthdr) {
91                 case IPPROTO_FRAGMENT: {
92                         struct frag_hdr _fhdr;
93                         const struct frag_hdr *fh;
94
95                         printk("FRAG:");
96                         fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
97                                                 &_fhdr);
98                         if (fh == NULL) {
99                                 printk("TRUNCATED ");
100                                 return;
101                         }
102
103                         /* Max length: 6 "65535 " */
104                         printk("%u ", ntohs(fh->frag_off) & 0xFFF8);
105
106                         /* Max length: 11 "INCOMPLETE " */
107                         if (fh->frag_off & htons(0x0001))
108                                 printk("INCOMPLETE ");
109
110                         printk("ID:%08x ", ntohl(fh->identification));
111
112                         if (ntohs(fh->frag_off) & 0xFFF8)
113                                 fragment = 1;
114
115                         hdrlen = 8;
116
117                         break;
118                 }
119                 case IPPROTO_DSTOPTS:
120                 case IPPROTO_ROUTING:
121                 case IPPROTO_HOPOPTS:
122                         if (fragment) {
123                                 if (logflags & IP6T_LOG_IPOPT)
124                                         printk(")");
125                                 return;
126                         }
127                         hdrlen = ipv6_optlen(hp);
128                         break;
129                 /* Max Length */
130                 case IPPROTO_AH:
131                         if (logflags & IP6T_LOG_IPOPT) {
132                                 struct ip_auth_hdr _ahdr;
133                                 const struct ip_auth_hdr *ah;
134
135                                 /* Max length: 3 "AH " */
136                                 printk("AH ");
137
138                                 if (fragment) {
139                                         printk(")");
140                                         return;
141                                 }
142
143                                 ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
144                                                         &_ahdr);
145                                 if (ah == NULL) {
146                                         /*
147                                          * Max length: 26 "INCOMPLETE [65535
148                                          *  bytes] )"
149                                          */
150                                         printk("INCOMPLETE [%u bytes] )",
151                                                skb->len - ptr);
152                                         return;
153                                 }
154
155                                 /* Length: 15 "SPI=0xF1234567 */
156                                 printk("SPI=0x%x ", ntohl(ah->spi));
157
158                         }
159
160                         hdrlen = (hp->hdrlen+2)<<2;
161                         break;
162                 case IPPROTO_ESP:
163                         if (logflags & IP6T_LOG_IPOPT) {
164                                 struct ip_esp_hdr _esph;
165                                 const struct ip_esp_hdr *eh;
166
167                                 /* Max length: 4 "ESP " */
168                                 printk("ESP ");
169
170                                 if (fragment) {
171                                         printk(")");
172                                         return;
173                                 }
174
175                                 /*
176                                  * Max length: 26 "INCOMPLETE [65535 bytes] )"
177                                  */
178                                 eh = skb_header_pointer(skb, ptr, sizeof(_esph),
179                                                         &_esph);
180                                 if (eh == NULL) {
181                                         printk("INCOMPLETE [%u bytes] )",
182                                                skb->len - ptr);
183                                         return;
184                                 }
185
186                                 /* Length: 16 "SPI=0xF1234567 )" */
187                                 printk("SPI=0x%x )", ntohl(eh->spi) );
188
189                         }
190                         return;
191                 default:
192                         /* Max length: 20 "Unknown Ext Hdr 255" */
193                         printk("Unknown Ext Hdr %u", currenthdr);
194                         return;
195                 }
196                 if (logflags & IP6T_LOG_IPOPT)
197                         printk(") ");
198
199                 currenthdr = hp->nexthdr;
200                 ptr += hdrlen;
201         }
202
203         switch (currenthdr) {
204         case IPPROTO_TCP: {
205                 struct tcphdr _tcph;
206                 const struct tcphdr *th;
207
208                 /* Max length: 10 "PROTO=TCP " */
209                 printk("PROTO=TCP ");
210
211                 if (fragment)
212                         break;
213
214                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
215                 th = skb_header_pointer(skb, ptr, sizeof(_tcph), &_tcph);
216                 if (th == NULL) {
217                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
218                         return;
219                 }
220
221                 /* Max length: 20 "SPT=65535 DPT=65535 " */
222                 printk("SPT=%u DPT=%u ",
223                        ntohs(th->source), ntohs(th->dest));
224                 /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
225                 if (logflags & IP6T_LOG_TCPSEQ)
226                         printk("SEQ=%u ACK=%u ",
227                                ntohl(th->seq), ntohl(th->ack_seq));
228                 /* Max length: 13 "WINDOW=65535 " */
229                 printk("WINDOW=%u ", ntohs(th->window));
230                 /* Max length: 9 "RES=0x3C " */
231                 printk("RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
232                 /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
233                 if (th->cwr)
234                         printk("CWR ");
235                 if (th->ece)
236                         printk("ECE ");
237                 if (th->urg)
238                         printk("URG ");
239                 if (th->ack)
240                         printk("ACK ");
241                 if (th->psh)
242                         printk("PSH ");
243                 if (th->rst)
244                         printk("RST ");
245                 if (th->syn)
246                         printk("SYN ");
247                 if (th->fin)
248                         printk("FIN ");
249                 /* Max length: 11 "URGP=65535 " */
250                 printk("URGP=%u ", ntohs(th->urg_ptr));
251
252                 if ((logflags & IP6T_LOG_TCPOPT)
253                     && th->doff * 4 > sizeof(struct tcphdr)) {
254                         u_int8_t _opt[60 - sizeof(struct tcphdr)];
255                         const u_int8_t *op;
256                         unsigned int i;
257                         unsigned int optsize = th->doff * 4
258                                                - sizeof(struct tcphdr);
259
260                         op = skb_header_pointer(skb,
261                                                 ptr + sizeof(struct tcphdr),
262                                                 optsize, _opt);
263                         if (op == NULL) {
264                                 printk("OPT (TRUNCATED)");
265                                 return;
266                         }
267
268                         /* Max length: 127 "OPT (" 15*4*2chars ") " */
269                         printk("OPT (");
270                         for (i =0; i < optsize; i++)
271                                 printk("%02X", op[i]);
272                         printk(") ");
273                 }
274                 break;
275         }
276         case IPPROTO_UDP:
277         case IPPROTO_UDPLITE: {
278                 struct udphdr _udph;
279                 const struct udphdr *uh;
280
281                 if (currenthdr == IPPROTO_UDP)
282                         /* Max length: 10 "PROTO=UDP "     */
283                         printk("PROTO=UDP " );
284                 else    /* Max length: 14 "PROTO=UDPLITE " */
285                         printk("PROTO=UDPLITE ");
286
287                 if (fragment)
288                         break;
289
290                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
291                 uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
292                 if (uh == NULL) {
293                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
294                         return;
295                 }
296
297                 /* Max length: 20 "SPT=65535 DPT=65535 " */
298                 printk("SPT=%u DPT=%u LEN=%u ",
299                        ntohs(uh->source), ntohs(uh->dest),
300                        ntohs(uh->len));
301                 break;
302         }
303         case IPPROTO_ICMPV6: {
304                 struct icmp6hdr _icmp6h;
305                 const struct icmp6hdr *ic;
306
307                 /* Max length: 13 "PROTO=ICMPv6 " */
308                 printk("PROTO=ICMPv6 ");
309
310                 if (fragment)
311                         break;
312
313                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
314                 ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
315                 if (ic == NULL) {
316                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
317                         return;
318                 }
319
320                 /* Max length: 18 "TYPE=255 CODE=255 " */
321                 printk("TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
322
323                 switch (ic->icmp6_type) {
324                 case ICMPV6_ECHO_REQUEST:
325                 case ICMPV6_ECHO_REPLY:
326                         /* Max length: 19 "ID=65535 SEQ=65535 " */
327                         printk("ID=%u SEQ=%u ",
328                                 ntohs(ic->icmp6_identifier),
329                                 ntohs(ic->icmp6_sequence));
330                         break;
331                 case ICMPV6_MGM_QUERY:
332                 case ICMPV6_MGM_REPORT:
333                 case ICMPV6_MGM_REDUCTION:
334                         break;
335
336                 case ICMPV6_PARAMPROB:
337                         /* Max length: 17 "POINTER=ffffffff " */
338                         printk("POINTER=%08x ", ntohl(ic->icmp6_pointer));
339                         /* Fall through */
340                 case ICMPV6_DEST_UNREACH:
341                 case ICMPV6_PKT_TOOBIG:
342                 case ICMPV6_TIME_EXCEED:
343                         /* Max length: 3+maxlen */
344                         if (recurse) {
345                                 printk("[");
346                                 dump_packet(info, skb, ptr + sizeof(_icmp6h),
347                                             0);
348                                 printk("] ");
349                         }
350
351                         /* Max length: 10 "MTU=65535 " */
352                         if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
353                                 printk("MTU=%u ", ntohl(ic->icmp6_mtu));
354                 }
355                 break;
356         }
357         /* Max length: 10 "PROTO=255 " */
358         default:
359                 printk("PROTO=%u ", currenthdr);
360         }
361
362         /* Max length: 15 "UID=4294967295 " */
363         if ((logflags & IP6T_LOG_UID) && recurse && skb->sk) {
364                 read_lock_bh(&skb->sk->sk_callback_lock);
365                 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
366                         printk("UID=%u GID=%u ",
367                                 skb->sk->sk_socket->file->f_cred->fsuid,
368                                 skb->sk->sk_socket->file->f_cred->fsgid);
369                 read_unlock_bh(&skb->sk->sk_callback_lock);
370         }
371
372         /* Max length: 16 "MARK=0xFFFFFFFF " */
373         if (!recurse && skb->mark)
374                 printk("MARK=0x%x ", skb->mark);
375 }
376
377 static struct nf_loginfo default_loginfo = {
378         .type   = NF_LOG_TYPE_LOG,
379         .u = {
380                 .log = {
381                         .level    = 0,
382                         .logflags = NF_LOG_MASK,
383                 },
384         },
385 };
386
387 static void
388 ip6t_log_packet(u_int8_t pf,
389                 unsigned int hooknum,
390                 const struct sk_buff *skb,
391                 const struct net_device *in,
392                 const struct net_device *out,
393                 const struct nf_loginfo *loginfo,
394                 const char *prefix)
395 {
396         if (!loginfo)
397                 loginfo = &default_loginfo;
398
399         spin_lock_bh(&log_lock);
400         printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
401                 prefix,
402                 in ? in->name : "",
403                 out ? out->name : "");
404         if (in && !out) {
405                 unsigned int len;
406                 /* MAC logging for input chain only. */
407                 printk("MAC=");
408                 if (skb->dev && (len = skb->dev->hard_header_len) &&
409                     skb->mac_header != skb->network_header) {
410                         const unsigned char *p = skb_mac_header(skb);
411                         int i;
412
413                         if (skb->dev->type == ARPHRD_SIT &&
414                             (p -= ETH_HLEN) < skb->head)
415                                 p = NULL;
416
417                         if (p != NULL) {
418                                 for (i = 0; i < len; i++)
419                                         printk("%02x%s", p[i],
420                                                i == len - 1 ? "" : ":");
421                         }
422                         printk(" ");
423
424                         if (skb->dev->type == ARPHRD_SIT) {
425                                 const struct iphdr *iph =
426                                         (struct iphdr *)skb_mac_header(skb);
427                                 printk("TUNNEL=%u.%u.%u.%u->%u.%u.%u.%u ",
428                                        NIPQUAD(iph->saddr),
429                                        NIPQUAD(iph->daddr));
430                         }
431                 } else
432                         printk(" ");
433         }
434
435         dump_packet(loginfo, skb, skb_network_offset(skb), 1);
436         printk("\n");
437         spin_unlock_bh(&log_lock);
438 }
439
440 static unsigned int
441 log_tg6(struct sk_buff *skb, const struct xt_target_param *par)
442 {
443         const struct ip6t_log_info *loginfo = par->targinfo;
444         struct nf_loginfo li;
445
446         li.type = NF_LOG_TYPE_LOG;
447         li.u.log.level = loginfo->level;
448         li.u.log.logflags = loginfo->logflags;
449
450         ip6t_log_packet(NFPROTO_IPV6, par->hooknum, skb, par->in, par->out,
451                         &li, loginfo->prefix);
452         return XT_CONTINUE;
453 }
454
455
456 static bool log_tg6_check(const struct xt_tgchk_param *par)
457 {
458         const struct ip6t_log_info *loginfo = par->targinfo;
459
460         if (loginfo->level >= 8) {
461                 pr_debug("LOG: level %u >= 8\n", loginfo->level);
462                 return false;
463         }
464         if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
465                 pr_debug("LOG: prefix term %i\n",
466                          loginfo->prefix[sizeof(loginfo->prefix)-1]);
467                 return false;
468         }
469         return true;
470 }
471
472 static struct xt_target log_tg6_reg __read_mostly = {
473         .name           = "LOG",
474         .family         = NFPROTO_IPV6,
475         .target         = log_tg6,
476         .targetsize     = sizeof(struct ip6t_log_info),
477         .checkentry     = log_tg6_check,
478         .me             = THIS_MODULE,
479 };
480
481 static const struct nf_logger ip6t_logger = {
482         .name           = "ip6t_LOG",
483         .logfn          = &ip6t_log_packet,
484         .me             = THIS_MODULE,
485 };
486
487 static int __init log_tg6_init(void)
488 {
489         int ret;
490
491         ret = xt_register_target(&log_tg6_reg);
492         if (ret < 0)
493                 return ret;
494         nf_log_register(NFPROTO_IPV6, &ip6t_logger);
495         return 0;
496 }
497
498 static void __exit log_tg6_exit(void)
499 {
500         nf_log_unregister(&ip6t_logger);
501         xt_unregister_target(&log_tg6_reg);
502 }
503
504 module_init(log_tg6_init);
505 module_exit(log_tg6_exit);