1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/kernel.h>
3 #include <linux/init.h>
4 #include <linux/module.h>
5 #include <linux/proc_fs.h>
6 #include <linux/skbuff.h>
7 #include <linux/netfilter.h>
8 #include <linux/seq_file.h>
9 #include <net/protocol.h>
10 #include <net/netfilter/nf_log.h>
11
12 #include "nf_internals.h"
13
14 /* Internal logging interface, which relies on the real
15 LOG target modules */
16
17 #define NFLOGGER_NAME_LEN 64
18
19 int sysctl_nf_log_all_netns __read_mostly;
20 EXPORT_SYMBOL(sysctl_nf_log_all_netns);
21
22 static struct nf_logger __rcu *loggers[NFPROTO_NUMPROTO][NF_LOG_TYPE_MAX] __read_mostly;
23 static DEFINE_MUTEX(nf_log_mutex);
24
25 #define nft_log_dereference(logger) \
26 rcu_dereference_protected(logger, lockdep_is_held(&nf_log_mutex))
27
__find_logger(int pf,const char * str_logger)28 static struct nf_logger *__find_logger(int pf, const char *str_logger)
29 {
30 struct nf_logger *log;
31 int i;
32
33 for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
34 if (loggers[pf][i] == NULL)
35 continue;
36
37 log = nft_log_dereference(loggers[pf][i]);
38 if (!strncasecmp(str_logger, log->name, strlen(log->name)))
39 return log;
40 }
41
42 return NULL;
43 }
44
nf_log_set(struct net * net,u_int8_t pf,const struct nf_logger * logger)45 int nf_log_set(struct net *net, u_int8_t pf, const struct nf_logger *logger)
46 {
47 const struct nf_logger *log;
48
49 if (pf == NFPROTO_UNSPEC || pf >= ARRAY_SIZE(net->nf.nf_loggers))
50 return -EOPNOTSUPP;
51
52 mutex_lock(&nf_log_mutex);
53 log = nft_log_dereference(net->nf.nf_loggers[pf]);
54 if (log == NULL)
55 rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
56
57 mutex_unlock(&nf_log_mutex);
58
59 return 0;
60 }
61 EXPORT_SYMBOL(nf_log_set);
62
nf_log_unset(struct net * net,const struct nf_logger * logger)63 void nf_log_unset(struct net *net, const struct nf_logger *logger)
64 {
65 int i;
66 const struct nf_logger *log;
67
68 mutex_lock(&nf_log_mutex);
69 for (i = 0; i < NFPROTO_NUMPROTO; i++) {
70 log = nft_log_dereference(net->nf.nf_loggers[i]);
71 if (log == logger)
72 RCU_INIT_POINTER(net->nf.nf_loggers[i], NULL);
73 }
74 mutex_unlock(&nf_log_mutex);
75 }
76 EXPORT_SYMBOL(nf_log_unset);
77
78 /* return EEXIST if the same logger is registered, 0 on success. */
nf_log_register(u_int8_t pf,struct nf_logger * logger)79 int nf_log_register(u_int8_t pf, struct nf_logger *logger)
80 {
81 int i;
82 int ret = 0;
83
84 if (pf >= ARRAY_SIZE(init_net.nf.nf_loggers))
85 return -EINVAL;
86
87 mutex_lock(&nf_log_mutex);
88
89 if (pf == NFPROTO_UNSPEC) {
90 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
91 if (rcu_access_pointer(loggers[i][logger->type])) {
92 ret = -EEXIST;
93 goto unlock;
94 }
95 }
96 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
97 rcu_assign_pointer(loggers[i][logger->type], logger);
98 } else {
99 if (rcu_access_pointer(loggers[pf][logger->type])) {
100 ret = -EEXIST;
101 goto unlock;
102 }
103 rcu_assign_pointer(loggers[pf][logger->type], logger);
104 }
105
106 unlock:
107 mutex_unlock(&nf_log_mutex);
108 return ret;
109 }
110 EXPORT_SYMBOL(nf_log_register);
111
nf_log_unregister(struct nf_logger * logger)112 void nf_log_unregister(struct nf_logger *logger)
113 {
114 const struct nf_logger *log;
115 int i;
116
117 mutex_lock(&nf_log_mutex);
118 for (i = 0; i < NFPROTO_NUMPROTO; i++) {
119 log = nft_log_dereference(loggers[i][logger->type]);
120 if (log == logger)
121 RCU_INIT_POINTER(loggers[i][logger->type], NULL);
122 }
123 mutex_unlock(&nf_log_mutex);
124 synchronize_rcu();
125 }
126 EXPORT_SYMBOL(nf_log_unregister);
127
nf_log_bind_pf(struct net * net,u_int8_t pf,const struct nf_logger * logger)128 int nf_log_bind_pf(struct net *net, u_int8_t pf,
129 const struct nf_logger *logger)
130 {
131 if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
132 return -EINVAL;
133 mutex_lock(&nf_log_mutex);
134 if (__find_logger(pf, logger->name) == NULL) {
135 mutex_unlock(&nf_log_mutex);
136 return -ENOENT;
137 }
138 rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
139 mutex_unlock(&nf_log_mutex);
140 return 0;
141 }
142 EXPORT_SYMBOL(nf_log_bind_pf);
143
nf_log_unbind_pf(struct net * net,u_int8_t pf)144 void nf_log_unbind_pf(struct net *net, u_int8_t pf)
145 {
146 if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
147 return;
148 mutex_lock(&nf_log_mutex);
149 RCU_INIT_POINTER(net->nf.nf_loggers[pf], NULL);
150 mutex_unlock(&nf_log_mutex);
151 }
152 EXPORT_SYMBOL(nf_log_unbind_pf);
153
nf_logger_request_module(int pf,enum nf_log_type type)154 void nf_logger_request_module(int pf, enum nf_log_type type)
155 {
156 if (loggers[pf][type] == NULL)
157 request_module("nf-logger-%u-%u", pf, type);
158 }
159 EXPORT_SYMBOL_GPL(nf_logger_request_module);
160
nf_logger_find_get(int pf,enum nf_log_type type)161 int nf_logger_find_get(int pf, enum nf_log_type type)
162 {
163 struct nf_logger *logger;
164 int ret = -ENOENT;
165
166 if (pf == NFPROTO_INET) {
167 ret = nf_logger_find_get(NFPROTO_IPV4, type);
168 if (ret < 0)
169 return ret;
170
171 ret = nf_logger_find_get(NFPROTO_IPV6, type);
172 if (ret < 0) {
173 nf_logger_put(NFPROTO_IPV4, type);
174 return ret;
175 }
176
177 return 0;
178 }
179
180 if (rcu_access_pointer(loggers[pf][type]) == NULL)
181 request_module("nf-logger-%u-%u", pf, type);
182
183 rcu_read_lock();
184 logger = rcu_dereference(loggers[pf][type]);
185 if (logger == NULL)
186 goto out;
187
188 if (try_module_get(logger->me))
189 ret = 0;
190 out:
191 rcu_read_unlock();
192 return ret;
193 }
194 EXPORT_SYMBOL_GPL(nf_logger_find_get);
195
nf_logger_put(int pf,enum nf_log_type type)196 void nf_logger_put(int pf, enum nf_log_type type)
197 {
198 struct nf_logger *logger;
199
200 if (pf == NFPROTO_INET) {
201 nf_logger_put(NFPROTO_IPV4, type);
202 nf_logger_put(NFPROTO_IPV6, type);
203 return;
204 }
205
206 BUG_ON(loggers[pf][type] == NULL);
207
208 rcu_read_lock();
209 logger = rcu_dereference(loggers[pf][type]);
210 module_put(logger->me);
211 rcu_read_unlock();
212 }
213 EXPORT_SYMBOL_GPL(nf_logger_put);
214
nf_log_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 * fmt,...)215 void nf_log_packet(struct net *net,
216 u_int8_t pf,
217 unsigned int hooknum,
218 const struct sk_buff *skb,
219 const struct net_device *in,
220 const struct net_device *out,
221 const struct nf_loginfo *loginfo,
222 const char *fmt, ...)
223 {
224 va_list args;
225 char prefix[NF_LOG_PREFIXLEN];
226 const struct nf_logger *logger;
227
228 rcu_read_lock();
229 if (loginfo != NULL)
230 logger = rcu_dereference(loggers[pf][loginfo->type]);
231 else
232 logger = rcu_dereference(net->nf.nf_loggers[pf]);
233
234 if (logger) {
235 va_start(args, fmt);
236 vsnprintf(prefix, sizeof(prefix), fmt, args);
237 va_end(args);
238 logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
239 }
240 rcu_read_unlock();
241 }
242 EXPORT_SYMBOL(nf_log_packet);
243
nf_log_trace(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 * fmt,...)244 void nf_log_trace(struct net *net,
245 u_int8_t pf,
246 unsigned int hooknum,
247 const struct sk_buff *skb,
248 const struct net_device *in,
249 const struct net_device *out,
250 const struct nf_loginfo *loginfo, const char *fmt, ...)
251 {
252 va_list args;
253 char prefix[NF_LOG_PREFIXLEN];
254 const struct nf_logger *logger;
255
256 rcu_read_lock();
257 logger = rcu_dereference(net->nf.nf_loggers[pf]);
258 if (logger) {
259 va_start(args, fmt);
260 vsnprintf(prefix, sizeof(prefix), fmt, args);
261 va_end(args);
262 logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
263 }
264 rcu_read_unlock();
265 }
266 EXPORT_SYMBOL(nf_log_trace);
267
268 #define S_SIZE (1024 - (sizeof(unsigned int) + 1))
269
270 struct nf_log_buf {
271 unsigned int count;
272 char buf[S_SIZE + 1];
273 };
274 static struct nf_log_buf emergency, *emergency_ptr = &emergency;
275
nf_log_buf_add(struct nf_log_buf * m,const char * f,...)276 __printf(2, 3) int nf_log_buf_add(struct nf_log_buf *m, const char *f, ...)
277 {
278 va_list args;
279 int len;
280
281 if (likely(m->count < S_SIZE)) {
282 va_start(args, f);
283 len = vsnprintf(m->buf + m->count, S_SIZE - m->count, f, args);
284 va_end(args);
285 if (likely(m->count + len < S_SIZE)) {
286 m->count += len;
287 return 0;
288 }
289 }
290 m->count = S_SIZE;
291 printk_once(KERN_ERR KBUILD_MODNAME " please increase S_SIZE\n");
292 return -1;
293 }
294 EXPORT_SYMBOL_GPL(nf_log_buf_add);
295
nf_log_buf_open(void)296 struct nf_log_buf *nf_log_buf_open(void)
297 {
298 struct nf_log_buf *m = kmalloc(sizeof(*m), GFP_ATOMIC);
299
300 if (unlikely(!m)) {
301 local_bh_disable();
302 do {
303 m = xchg(&emergency_ptr, NULL);
304 } while (!m);
305 }
306 m->count = 0;
307 return m;
308 }
309 EXPORT_SYMBOL_GPL(nf_log_buf_open);
310
nf_log_buf_close(struct nf_log_buf * m)311 void nf_log_buf_close(struct nf_log_buf *m)
312 {
313 m->buf[m->count] = 0;
314 printk("%s\n", m->buf);
315
316 if (likely(m != &emergency))
317 kfree(m);
318 else {
319 emergency_ptr = m;
320 local_bh_enable();
321 }
322 }
323 EXPORT_SYMBOL_GPL(nf_log_buf_close);
324
325 #ifdef CONFIG_PROC_FS
seq_start(struct seq_file * seq,loff_t * pos)326 static void *seq_start(struct seq_file *seq, loff_t *pos)
327 {
328 struct net *net = seq_file_net(seq);
329
330 mutex_lock(&nf_log_mutex);
331
332 if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
333 return NULL;
334
335 return pos;
336 }
337
seq_next(struct seq_file * s,void * v,loff_t * pos)338 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
339 {
340 struct net *net = seq_file_net(s);
341
342 (*pos)++;
343
344 if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
345 return NULL;
346
347 return pos;
348 }
349
seq_stop(struct seq_file * s,void * v)350 static void seq_stop(struct seq_file *s, void *v)
351 {
352 mutex_unlock(&nf_log_mutex);
353 }
354
seq_show(struct seq_file * s,void * v)355 static int seq_show(struct seq_file *s, void *v)
356 {
357 loff_t *pos = v;
358 const struct nf_logger *logger;
359 int i;
360 struct net *net = seq_file_net(s);
361
362 logger = nft_log_dereference(net->nf.nf_loggers[*pos]);
363
364 if (!logger)
365 seq_printf(s, "%2lld NONE (", *pos);
366 else
367 seq_printf(s, "%2lld %s (", *pos, logger->name);
368
369 if (seq_has_overflowed(s))
370 return -ENOSPC;
371
372 for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
373 if (loggers[*pos][i] == NULL)
374 continue;
375
376 logger = nft_log_dereference(loggers[*pos][i]);
377 seq_puts(s, logger->name);
378 if (i == 0 && loggers[*pos][i + 1] != NULL)
379 seq_puts(s, ",");
380
381 if (seq_has_overflowed(s))
382 return -ENOSPC;
383 }
384
385 seq_puts(s, ")\n");
386
387 if (seq_has_overflowed(s))
388 return -ENOSPC;
389 return 0;
390 }
391
392 static const struct seq_operations nflog_seq_ops = {
393 .start = seq_start,
394 .next = seq_next,
395 .stop = seq_stop,
396 .show = seq_show,
397 };
398 #endif /* PROC_FS */
399
400 #ifdef CONFIG_SYSCTL
401 static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
402 static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
403 static struct ctl_table_header *nf_log_sysctl_fhdr;
404
405 static struct ctl_table nf_log_sysctl_ftable[] = {
406 {
407 .procname = "nf_log_all_netns",
408 .data = &sysctl_nf_log_all_netns,
409 .maxlen = sizeof(sysctl_nf_log_all_netns),
410 .mode = 0644,
411 .proc_handler = proc_dointvec,
412 },
413 { }
414 };
415
nf_log_proc_dostring(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)416 static int nf_log_proc_dostring(struct ctl_table *table, int write,
417 void __user *buffer, size_t *lenp, loff_t *ppos)
418 {
419 const struct nf_logger *logger;
420 char buf[NFLOGGER_NAME_LEN];
421 int r = 0;
422 int tindex = (unsigned long)table->extra1;
423 struct net *net = table->extra2;
424
425 if (write) {
426 struct ctl_table tmp = *table;
427
428 /* proc_dostring() can append to existing strings, so we need to
429 * initialize it as an empty string.
430 */
431 buf[0] = '\0';
432 tmp.data = buf;
433 r = proc_dostring(&tmp, write, buffer, lenp, ppos);
434 if (r)
435 return r;
436
437 if (!strcmp(buf, "NONE")) {
438 nf_log_unbind_pf(net, tindex);
439 return 0;
440 }
441 mutex_lock(&nf_log_mutex);
442 logger = __find_logger(tindex, buf);
443 if (logger == NULL) {
444 mutex_unlock(&nf_log_mutex);
445 return -ENOENT;
446 }
447 rcu_assign_pointer(net->nf.nf_loggers[tindex], logger);
448 mutex_unlock(&nf_log_mutex);
449 } else {
450 struct ctl_table tmp = *table;
451
452 tmp.data = buf;
453 mutex_lock(&nf_log_mutex);
454 logger = nft_log_dereference(net->nf.nf_loggers[tindex]);
455 if (!logger)
456 strlcpy(buf, "NONE", sizeof(buf));
457 else
458 strlcpy(buf, logger->name, sizeof(buf));
459 mutex_unlock(&nf_log_mutex);
460 r = proc_dostring(&tmp, write, buffer, lenp, ppos);
461 }
462
463 return r;
464 }
465
netfilter_log_sysctl_init(struct net * net)466 static int netfilter_log_sysctl_init(struct net *net)
467 {
468 int i;
469 struct ctl_table *table;
470
471 table = nf_log_sysctl_table;
472 if (!net_eq(net, &init_net)) {
473 table = kmemdup(nf_log_sysctl_table,
474 sizeof(nf_log_sysctl_table),
475 GFP_KERNEL);
476 if (!table)
477 goto err_alloc;
478 } else {
479 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
480 snprintf(nf_log_sysctl_fnames[i],
481 3, "%d", i);
482 nf_log_sysctl_table[i].procname =
483 nf_log_sysctl_fnames[i];
484 nf_log_sysctl_table[i].maxlen = NFLOGGER_NAME_LEN;
485 nf_log_sysctl_table[i].mode = 0644;
486 nf_log_sysctl_table[i].proc_handler =
487 nf_log_proc_dostring;
488 nf_log_sysctl_table[i].extra1 =
489 (void *)(unsigned long) i;
490 }
491 nf_log_sysctl_fhdr = register_net_sysctl(net, "net/netfilter",
492 nf_log_sysctl_ftable);
493 if (!nf_log_sysctl_fhdr)
494 goto err_freg;
495 }
496
497 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
498 table[i].extra2 = net;
499
500 net->nf.nf_log_dir_header = register_net_sysctl(net,
501 "net/netfilter/nf_log",
502 table);
503 if (!net->nf.nf_log_dir_header)
504 goto err_reg;
505
506 return 0;
507
508 err_reg:
509 if (!net_eq(net, &init_net))
510 kfree(table);
511 else
512 unregister_net_sysctl_table(nf_log_sysctl_fhdr);
513 err_freg:
514 err_alloc:
515 return -ENOMEM;
516 }
517
netfilter_log_sysctl_exit(struct net * net)518 static void netfilter_log_sysctl_exit(struct net *net)
519 {
520 struct ctl_table *table;
521
522 table = net->nf.nf_log_dir_header->ctl_table_arg;
523 unregister_net_sysctl_table(net->nf.nf_log_dir_header);
524 if (!net_eq(net, &init_net))
525 kfree(table);
526 else
527 unregister_net_sysctl_table(nf_log_sysctl_fhdr);
528 }
529 #else
netfilter_log_sysctl_init(struct net * net)530 static int netfilter_log_sysctl_init(struct net *net)
531 {
532 return 0;
533 }
534
netfilter_log_sysctl_exit(struct net * net)535 static void netfilter_log_sysctl_exit(struct net *net)
536 {
537 }
538 #endif /* CONFIG_SYSCTL */
539
nf_log_net_init(struct net * net)540 static int __net_init nf_log_net_init(struct net *net)
541 {
542 int ret = -ENOMEM;
543
544 #ifdef CONFIG_PROC_FS
545 if (!proc_create_net("nf_log", 0444, net->nf.proc_netfilter,
546 &nflog_seq_ops, sizeof(struct seq_net_private)))
547 return ret;
548 #endif
549 ret = netfilter_log_sysctl_init(net);
550 if (ret < 0)
551 goto out_sysctl;
552
553 return 0;
554
555 out_sysctl:
556 #ifdef CONFIG_PROC_FS
557 remove_proc_entry("nf_log", net->nf.proc_netfilter);
558 #endif
559 return ret;
560 }
561
nf_log_net_exit(struct net * net)562 static void __net_exit nf_log_net_exit(struct net *net)
563 {
564 netfilter_log_sysctl_exit(net);
565 #ifdef CONFIG_PROC_FS
566 remove_proc_entry("nf_log", net->nf.proc_netfilter);
567 #endif
568 }
569
570 static struct pernet_operations nf_log_net_ops = {
571 .init = nf_log_net_init,
572 .exit = nf_log_net_exit,
573 };
574
netfilter_log_init(void)575 int __init netfilter_log_init(void)
576 {
577 return register_pernet_subsys(&nf_log_net_ops);
578 }
579