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_find_get(int pf,enum nf_log_type type)154 int nf_logger_find_get(int pf, enum nf_log_type type)
155 {
156 struct nf_logger *logger;
157 int ret = -ENOENT;
158
159 if (pf == NFPROTO_INET) {
160 ret = nf_logger_find_get(NFPROTO_IPV4, type);
161 if (ret < 0)
162 return ret;
163
164 ret = nf_logger_find_get(NFPROTO_IPV6, type);
165 if (ret < 0) {
166 nf_logger_put(NFPROTO_IPV4, type);
167 return ret;
168 }
169
170 return 0;
171 }
172
173 rcu_read_lock();
174 logger = rcu_dereference(loggers[pf][type]);
175 if (logger == NULL)
176 goto out;
177
178 if (try_module_get(logger->me))
179 ret = 0;
180 out:
181 rcu_read_unlock();
182 return ret;
183 }
184 EXPORT_SYMBOL_GPL(nf_logger_find_get);
185
nf_logger_put(int pf,enum nf_log_type type)186 void nf_logger_put(int pf, enum nf_log_type type)
187 {
188 struct nf_logger *logger;
189
190 if (pf == NFPROTO_INET) {
191 nf_logger_put(NFPROTO_IPV4, type);
192 nf_logger_put(NFPROTO_IPV6, type);
193 return;
194 }
195
196 rcu_read_lock();
197 logger = rcu_dereference(loggers[pf][type]);
198 if (!logger)
199 WARN_ON_ONCE(1);
200 else
201 module_put(logger->me);
202 rcu_read_unlock();
203 }
204 EXPORT_SYMBOL_GPL(nf_logger_put);
205
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,...)206 void nf_log_packet(struct net *net,
207 u_int8_t pf,
208 unsigned int hooknum,
209 const struct sk_buff *skb,
210 const struct net_device *in,
211 const struct net_device *out,
212 const struct nf_loginfo *loginfo,
213 const char *fmt, ...)
214 {
215 va_list args;
216 char prefix[NF_LOG_PREFIXLEN];
217 const struct nf_logger *logger;
218
219 rcu_read_lock();
220 if (loginfo != NULL)
221 logger = rcu_dereference(loggers[pf][loginfo->type]);
222 else
223 logger = rcu_dereference(net->nf.nf_loggers[pf]);
224
225 if (logger) {
226 va_start(args, fmt);
227 vsnprintf(prefix, sizeof(prefix), fmt, args);
228 va_end(args);
229 logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
230 }
231 rcu_read_unlock();
232 }
233 EXPORT_SYMBOL(nf_log_packet);
234
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,...)235 void nf_log_trace(struct net *net,
236 u_int8_t pf,
237 unsigned int hooknum,
238 const struct sk_buff *skb,
239 const struct net_device *in,
240 const struct net_device *out,
241 const struct nf_loginfo *loginfo, const char *fmt, ...)
242 {
243 va_list args;
244 char prefix[NF_LOG_PREFIXLEN];
245 const struct nf_logger *logger;
246
247 rcu_read_lock();
248 logger = rcu_dereference(net->nf.nf_loggers[pf]);
249 if (logger) {
250 va_start(args, fmt);
251 vsnprintf(prefix, sizeof(prefix), fmt, args);
252 va_end(args);
253 logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
254 }
255 rcu_read_unlock();
256 }
257 EXPORT_SYMBOL(nf_log_trace);
258
259 #define S_SIZE (1024 - (sizeof(unsigned int) + 1))
260
261 struct nf_log_buf {
262 unsigned int count;
263 char buf[S_SIZE + 1];
264 };
265 static struct nf_log_buf emergency, *emergency_ptr = &emergency;
266
nf_log_buf_add(struct nf_log_buf * m,const char * f,...)267 __printf(2, 3) int nf_log_buf_add(struct nf_log_buf *m, const char *f, ...)
268 {
269 va_list args;
270 int len;
271
272 if (likely(m->count < S_SIZE)) {
273 va_start(args, f);
274 len = vsnprintf(m->buf + m->count, S_SIZE - m->count, f, args);
275 va_end(args);
276 if (likely(m->count + len < S_SIZE)) {
277 m->count += len;
278 return 0;
279 }
280 }
281 m->count = S_SIZE;
282 printk_once(KERN_ERR KBUILD_MODNAME " please increase S_SIZE\n");
283 return -1;
284 }
285 EXPORT_SYMBOL_GPL(nf_log_buf_add);
286
nf_log_buf_open(void)287 struct nf_log_buf *nf_log_buf_open(void)
288 {
289 struct nf_log_buf *m = kmalloc(sizeof(*m), GFP_ATOMIC);
290
291 if (unlikely(!m)) {
292 local_bh_disable();
293 do {
294 m = xchg(&emergency_ptr, NULL);
295 } while (!m);
296 }
297 m->count = 0;
298 return m;
299 }
300 EXPORT_SYMBOL_GPL(nf_log_buf_open);
301
nf_log_buf_close(struct nf_log_buf * m)302 void nf_log_buf_close(struct nf_log_buf *m)
303 {
304 m->buf[m->count] = 0;
305 printk("%s\n", m->buf);
306
307 if (likely(m != &emergency))
308 kfree(m);
309 else {
310 emergency_ptr = m;
311 local_bh_enable();
312 }
313 }
314 EXPORT_SYMBOL_GPL(nf_log_buf_close);
315
316 #ifdef CONFIG_PROC_FS
seq_start(struct seq_file * seq,loff_t * pos)317 static void *seq_start(struct seq_file *seq, loff_t *pos)
318 {
319 struct net *net = seq_file_net(seq);
320
321 mutex_lock(&nf_log_mutex);
322
323 if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
324 return NULL;
325
326 return pos;
327 }
328
seq_next(struct seq_file * s,void * v,loff_t * pos)329 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
330 {
331 struct net *net = seq_file_net(s);
332
333 (*pos)++;
334
335 if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
336 return NULL;
337
338 return pos;
339 }
340
seq_stop(struct seq_file * s,void * v)341 static void seq_stop(struct seq_file *s, void *v)
342 {
343 mutex_unlock(&nf_log_mutex);
344 }
345
seq_show(struct seq_file * s,void * v)346 static int seq_show(struct seq_file *s, void *v)
347 {
348 loff_t *pos = v;
349 const struct nf_logger *logger;
350 int i;
351 struct net *net = seq_file_net(s);
352
353 logger = nft_log_dereference(net->nf.nf_loggers[*pos]);
354
355 if (!logger)
356 seq_printf(s, "%2lld NONE (", *pos);
357 else
358 seq_printf(s, "%2lld %s (", *pos, logger->name);
359
360 if (seq_has_overflowed(s))
361 return -ENOSPC;
362
363 for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
364 if (loggers[*pos][i] == NULL)
365 continue;
366
367 logger = nft_log_dereference(loggers[*pos][i]);
368 seq_puts(s, logger->name);
369 if (i == 0 && loggers[*pos][i + 1] != NULL)
370 seq_puts(s, ",");
371
372 if (seq_has_overflowed(s))
373 return -ENOSPC;
374 }
375
376 seq_puts(s, ")\n");
377
378 if (seq_has_overflowed(s))
379 return -ENOSPC;
380 return 0;
381 }
382
383 static const struct seq_operations nflog_seq_ops = {
384 .start = seq_start,
385 .next = seq_next,
386 .stop = seq_stop,
387 .show = seq_show,
388 };
389 #endif /* PROC_FS */
390
391 #ifdef CONFIG_SYSCTL
392 static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
393 static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
394 static struct ctl_table_header *nf_log_sysctl_fhdr;
395
396 static struct ctl_table nf_log_sysctl_ftable[] = {
397 {
398 .procname = "nf_log_all_netns",
399 .data = &sysctl_nf_log_all_netns,
400 .maxlen = sizeof(sysctl_nf_log_all_netns),
401 .mode = 0644,
402 .proc_handler = proc_dointvec,
403 },
404 { }
405 };
406
nf_log_proc_dostring(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)407 static int nf_log_proc_dostring(struct ctl_table *table, int write,
408 void *buffer, size_t *lenp, loff_t *ppos)
409 {
410 const struct nf_logger *logger;
411 char buf[NFLOGGER_NAME_LEN];
412 int r = 0;
413 int tindex = (unsigned long)table->extra1;
414 struct net *net = table->extra2;
415
416 if (write) {
417 struct ctl_table tmp = *table;
418
419 /* proc_dostring() can append to existing strings, so we need to
420 * initialize it as an empty string.
421 */
422 buf[0] = '\0';
423 tmp.data = buf;
424 r = proc_dostring(&tmp, write, buffer, lenp, ppos);
425 if (r)
426 return r;
427
428 if (!strcmp(buf, "NONE")) {
429 nf_log_unbind_pf(net, tindex);
430 return 0;
431 }
432 mutex_lock(&nf_log_mutex);
433 logger = __find_logger(tindex, buf);
434 if (logger == NULL) {
435 mutex_unlock(&nf_log_mutex);
436 return -ENOENT;
437 }
438 rcu_assign_pointer(net->nf.nf_loggers[tindex], logger);
439 mutex_unlock(&nf_log_mutex);
440 } else {
441 struct ctl_table tmp = *table;
442
443 tmp.data = buf;
444 mutex_lock(&nf_log_mutex);
445 logger = nft_log_dereference(net->nf.nf_loggers[tindex]);
446 if (!logger)
447 strscpy(buf, "NONE", sizeof(buf));
448 else
449 strscpy(buf, logger->name, sizeof(buf));
450 mutex_unlock(&nf_log_mutex);
451 r = proc_dostring(&tmp, write, buffer, lenp, ppos);
452 }
453
454 return r;
455 }
456
netfilter_log_sysctl_init(struct net * net)457 static int netfilter_log_sysctl_init(struct net *net)
458 {
459 int i;
460 struct ctl_table *table;
461
462 table = nf_log_sysctl_table;
463 if (!net_eq(net, &init_net)) {
464 table = kmemdup(nf_log_sysctl_table,
465 sizeof(nf_log_sysctl_table),
466 GFP_KERNEL);
467 if (!table)
468 goto err_alloc;
469 } else {
470 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
471 snprintf(nf_log_sysctl_fnames[i],
472 3, "%d", i);
473 nf_log_sysctl_table[i].procname =
474 nf_log_sysctl_fnames[i];
475 nf_log_sysctl_table[i].maxlen = NFLOGGER_NAME_LEN;
476 nf_log_sysctl_table[i].mode = 0644;
477 nf_log_sysctl_table[i].proc_handler =
478 nf_log_proc_dostring;
479 nf_log_sysctl_table[i].extra1 =
480 (void *)(unsigned long) i;
481 }
482 nf_log_sysctl_fhdr = register_net_sysctl(net, "net/netfilter",
483 nf_log_sysctl_ftable);
484 if (!nf_log_sysctl_fhdr)
485 goto err_freg;
486 }
487
488 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
489 table[i].extra2 = net;
490
491 net->nf.nf_log_dir_header = register_net_sysctl_sz(net,
492 "net/netfilter/nf_log",
493 table,
494 ARRAY_SIZE(nf_log_sysctl_table));
495 if (!net->nf.nf_log_dir_header)
496 goto err_reg;
497
498 return 0;
499
500 err_reg:
501 if (!net_eq(net, &init_net))
502 kfree(table);
503 else
504 unregister_net_sysctl_table(nf_log_sysctl_fhdr);
505 err_freg:
506 err_alloc:
507 return -ENOMEM;
508 }
509
netfilter_log_sysctl_exit(struct net * net)510 static void netfilter_log_sysctl_exit(struct net *net)
511 {
512 struct ctl_table *table;
513
514 table = net->nf.nf_log_dir_header->ctl_table_arg;
515 unregister_net_sysctl_table(net->nf.nf_log_dir_header);
516 if (!net_eq(net, &init_net))
517 kfree(table);
518 else
519 unregister_net_sysctl_table(nf_log_sysctl_fhdr);
520 }
521 #else
netfilter_log_sysctl_init(struct net * net)522 static int netfilter_log_sysctl_init(struct net *net)
523 {
524 return 0;
525 }
526
netfilter_log_sysctl_exit(struct net * net)527 static void netfilter_log_sysctl_exit(struct net *net)
528 {
529 }
530 #endif /* CONFIG_SYSCTL */
531
nf_log_net_init(struct net * net)532 static int __net_init nf_log_net_init(struct net *net)
533 {
534 int ret = -ENOMEM;
535
536 #ifdef CONFIG_PROC_FS
537 if (!proc_create_net("nf_log", 0444, net->nf.proc_netfilter,
538 &nflog_seq_ops, sizeof(struct seq_net_private)))
539 return ret;
540 #endif
541 ret = netfilter_log_sysctl_init(net);
542 if (ret < 0)
543 goto out_sysctl;
544
545 return 0;
546
547 out_sysctl:
548 #ifdef CONFIG_PROC_FS
549 remove_proc_entry("nf_log", net->nf.proc_netfilter);
550 #endif
551 return ret;
552 }
553
nf_log_net_exit(struct net * net)554 static void __net_exit nf_log_net_exit(struct net *net)
555 {
556 netfilter_log_sysctl_exit(net);
557 #ifdef CONFIG_PROC_FS
558 remove_proc_entry("nf_log", net->nf.proc_netfilter);
559 #endif
560 }
561
562 static struct pernet_operations nf_log_net_ops = {
563 .init = nf_log_net_init,
564 .exit = nf_log_net_exit,
565 };
566
netfilter_log_init(void)567 int __init netfilter_log_init(void)
568 {
569 return register_pernet_subsys(&nf_log_net_ops);
570 }
571