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 | |
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(s1: str_logger, s2: log->name, strlen(log->name))) |
39 | return log; |
40 | } |
41 | |
42 | return NULL; |
43 | } |
44 | |
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(lock: &nf_log_mutex); |
58 | |
59 | return 0; |
60 | } |
61 | EXPORT_SYMBOL(nf_log_set); |
62 | |
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(lock: &nf_log_mutex); |
75 | } |
76 | EXPORT_SYMBOL(nf_log_unset); |
77 | |
78 | /* return EEXIST if the same logger is registered, 0 on success. */ |
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(lock: &nf_log_mutex); |
108 | return ret; |
109 | } |
110 | EXPORT_SYMBOL(nf_log_register); |
111 | |
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(lock: &nf_log_mutex); |
124 | synchronize_rcu(); |
125 | } |
126 | EXPORT_SYMBOL(nf_log_unregister); |
127 | |
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, str_logger: logger->name) == NULL) { |
135 | mutex_unlock(lock: &nf_log_mutex); |
136 | return -ENOENT; |
137 | } |
138 | rcu_assign_pointer(net->nf.nf_loggers[pf], logger); |
139 | mutex_unlock(lock: &nf_log_mutex); |
140 | return 0; |
141 | } |
142 | EXPORT_SYMBOL(nf_log_bind_pf); |
143 | |
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(lock: &nf_log_mutex); |
151 | } |
152 | EXPORT_SYMBOL(nf_log_unbind_pf); |
153 | |
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(pf: NFPROTO_IPV4, type); |
161 | if (ret < 0) |
162 | return ret; |
163 | |
164 | ret = nf_logger_find_get(pf: NFPROTO_IPV6, type); |
165 | if (ret < 0) { |
166 | nf_logger_put(pf: 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(module: logger->me)) |
179 | ret = 0; |
180 | out: |
181 | rcu_read_unlock(); |
182 | return ret; |
183 | } |
184 | EXPORT_SYMBOL_GPL(nf_logger_find_get); |
185 | |
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(pf: NFPROTO_IPV4, type); |
192 | nf_logger_put(pf: NFPROTO_IPV6, type); |
193 | return; |
194 | } |
195 | |
196 | BUG_ON(loggers[pf][type] == NULL); |
197 | |
198 | rcu_read_lock(); |
199 | logger = rcu_dereference(loggers[pf][type]); |
200 | module_put(module: logger->me); |
201 | rcu_read_unlock(); |
202 | } |
203 | EXPORT_SYMBOL_GPL(nf_logger_put); |
204 | |
205 | void nf_log_packet(struct net *net, |
206 | u_int8_t pf, |
207 | unsigned int hooknum, |
208 | const struct sk_buff *skb, |
209 | const struct net_device *in, |
210 | const struct net_device *out, |
211 | const struct nf_loginfo *loginfo, |
212 | const char *fmt, ...) |
213 | { |
214 | va_list args; |
215 | char prefix[NF_LOG_PREFIXLEN]; |
216 | const struct nf_logger *logger; |
217 | |
218 | rcu_read_lock(); |
219 | if (loginfo != NULL) |
220 | logger = rcu_dereference(loggers[pf][loginfo->type]); |
221 | else |
222 | logger = rcu_dereference(net->nf.nf_loggers[pf]); |
223 | |
224 | if (logger) { |
225 | va_start(args, fmt); |
226 | vsnprintf(buf: prefix, size: sizeof(prefix), fmt, args); |
227 | va_end(args); |
228 | logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix); |
229 | } |
230 | rcu_read_unlock(); |
231 | } |
232 | EXPORT_SYMBOL(nf_log_packet); |
233 | |
234 | void nf_log_trace(struct net *net, |
235 | u_int8_t pf, |
236 | unsigned int hooknum, |
237 | const struct sk_buff *skb, |
238 | const struct net_device *in, |
239 | const struct net_device *out, |
240 | const struct nf_loginfo *loginfo, const char *fmt, ...) |
241 | { |
242 | va_list args; |
243 | char prefix[NF_LOG_PREFIXLEN]; |
244 | const struct nf_logger *logger; |
245 | |
246 | rcu_read_lock(); |
247 | logger = rcu_dereference(net->nf.nf_loggers[pf]); |
248 | if (logger) { |
249 | va_start(args, fmt); |
250 | vsnprintf(buf: prefix, size: sizeof(prefix), fmt, args); |
251 | va_end(args); |
252 | logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix); |
253 | } |
254 | rcu_read_unlock(); |
255 | } |
256 | EXPORT_SYMBOL(nf_log_trace); |
257 | |
258 | #define S_SIZE (1024 - (sizeof(unsigned int) + 1)) |
259 | |
260 | struct nf_log_buf { |
261 | unsigned int count; |
262 | char buf[S_SIZE + 1]; |
263 | }; |
264 | static struct nf_log_buf emergency, *emergency_ptr = &emergency; |
265 | |
266 | __printf(2, 3) int nf_log_buf_add(struct nf_log_buf *m, const char *f, ...) |
267 | { |
268 | va_list args; |
269 | int len; |
270 | |
271 | if (likely(m->count < S_SIZE)) { |
272 | va_start(args, f); |
273 | len = vsnprintf(buf: m->buf + m->count, S_SIZE - m->count, fmt: f, args); |
274 | va_end(args); |
275 | if (likely(m->count + len < S_SIZE)) { |
276 | m->count += len; |
277 | return 0; |
278 | } |
279 | } |
280 | m->count = S_SIZE; |
281 | printk_once(KERN_ERR KBUILD_MODNAME " please increase S_SIZE\n" ); |
282 | return -1; |
283 | } |
284 | EXPORT_SYMBOL_GPL(nf_log_buf_add); |
285 | |
286 | struct nf_log_buf *nf_log_buf_open(void) |
287 | { |
288 | struct nf_log_buf *m = kmalloc(size: sizeof(*m), GFP_ATOMIC); |
289 | |
290 | if (unlikely(!m)) { |
291 | local_bh_disable(); |
292 | do { |
293 | m = xchg(&emergency_ptr, NULL); |
294 | } while (!m); |
295 | } |
296 | m->count = 0; |
297 | return m; |
298 | } |
299 | EXPORT_SYMBOL_GPL(nf_log_buf_open); |
300 | |
301 | void nf_log_buf_close(struct nf_log_buf *m) |
302 | { |
303 | m->buf[m->count] = 0; |
304 | printk("%s\n" , m->buf); |
305 | |
306 | if (likely(m != &emergency)) |
307 | kfree(objp: m); |
308 | else { |
309 | emergency_ptr = m; |
310 | local_bh_enable(); |
311 | } |
312 | } |
313 | EXPORT_SYMBOL_GPL(nf_log_buf_close); |
314 | |
315 | #ifdef CONFIG_PROC_FS |
316 | static void *seq_start(struct seq_file *seq, loff_t *pos) |
317 | { |
318 | struct net *net = seq_file_net(seq); |
319 | |
320 | mutex_lock(&nf_log_mutex); |
321 | |
322 | if (*pos >= ARRAY_SIZE(net->nf.nf_loggers)) |
323 | return NULL; |
324 | |
325 | return pos; |
326 | } |
327 | |
328 | static void *seq_next(struct seq_file *s, void *v, loff_t *pos) |
329 | { |
330 | struct net *net = seq_file_net(seq: s); |
331 | |
332 | (*pos)++; |
333 | |
334 | if (*pos >= ARRAY_SIZE(net->nf.nf_loggers)) |
335 | return NULL; |
336 | |
337 | return pos; |
338 | } |
339 | |
340 | static void seq_stop(struct seq_file *s, void *v) |
341 | { |
342 | mutex_unlock(lock: &nf_log_mutex); |
343 | } |
344 | |
345 | static int seq_show(struct seq_file *s, void *v) |
346 | { |
347 | loff_t *pos = v; |
348 | const struct nf_logger *logger; |
349 | int i; |
350 | struct net *net = seq_file_net(seq: s); |
351 | |
352 | logger = nft_log_dereference(net->nf.nf_loggers[*pos]); |
353 | |
354 | if (!logger) |
355 | seq_printf(m: s, fmt: "%2lld NONE (" , *pos); |
356 | else |
357 | seq_printf(m: s, fmt: "%2lld %s (" , *pos, logger->name); |
358 | |
359 | if (seq_has_overflowed(m: s)) |
360 | return -ENOSPC; |
361 | |
362 | for (i = 0; i < NF_LOG_TYPE_MAX; i++) { |
363 | if (loggers[*pos][i] == NULL) |
364 | continue; |
365 | |
366 | logger = nft_log_dereference(loggers[*pos][i]); |
367 | seq_puts(m: s, s: logger->name); |
368 | if (i == 0 && loggers[*pos][i + 1] != NULL) |
369 | seq_puts(m: s, s: "," ); |
370 | |
371 | if (seq_has_overflowed(m: s)) |
372 | return -ENOSPC; |
373 | } |
374 | |
375 | seq_puts(m: s, s: ")\n" ); |
376 | |
377 | if (seq_has_overflowed(m: s)) |
378 | return -ENOSPC; |
379 | return 0; |
380 | } |
381 | |
382 | static const struct seq_operations nflog_seq_ops = { |
383 | .start = seq_start, |
384 | .next = seq_next, |
385 | .stop = seq_stop, |
386 | .show = seq_show, |
387 | }; |
388 | #endif /* PROC_FS */ |
389 | |
390 | #ifdef CONFIG_SYSCTL |
391 | static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3]; |
392 | static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1]; |
393 | static struct ctl_table_header *nf_log_sysctl_fhdr; |
394 | |
395 | static struct ctl_table nf_log_sysctl_ftable[] = { |
396 | { |
397 | .procname = "nf_log_all_netns" , |
398 | .data = &sysctl_nf_log_all_netns, |
399 | .maxlen = sizeof(sysctl_nf_log_all_netns), |
400 | .mode = 0644, |
401 | .proc_handler = proc_dointvec, |
402 | }, |
403 | { } |
404 | }; |
405 | |
406 | static int nf_log_proc_dostring(struct ctl_table *table, int write, |
407 | void *buffer, size_t *lenp, loff_t *ppos) |
408 | { |
409 | const struct nf_logger *logger; |
410 | char buf[NFLOGGER_NAME_LEN]; |
411 | int r = 0; |
412 | int tindex = (unsigned long)table->extra1; |
413 | struct net *net = table->extra2; |
414 | |
415 | if (write) { |
416 | struct ctl_table tmp = *table; |
417 | |
418 | /* proc_dostring() can append to existing strings, so we need to |
419 | * initialize it as an empty string. |
420 | */ |
421 | buf[0] = '\0'; |
422 | tmp.data = buf; |
423 | r = proc_dostring(&tmp, write, buffer, lenp, ppos); |
424 | if (r) |
425 | return r; |
426 | |
427 | if (!strcmp(buf, "NONE" )) { |
428 | nf_log_unbind_pf(net, tindex); |
429 | return 0; |
430 | } |
431 | mutex_lock(&nf_log_mutex); |
432 | logger = __find_logger(pf: tindex, str_logger: buf); |
433 | if (logger == NULL) { |
434 | mutex_unlock(lock: &nf_log_mutex); |
435 | return -ENOENT; |
436 | } |
437 | rcu_assign_pointer(net->nf.nf_loggers[tindex], logger); |
438 | mutex_unlock(lock: &nf_log_mutex); |
439 | } else { |
440 | struct ctl_table tmp = *table; |
441 | |
442 | tmp.data = buf; |
443 | mutex_lock(&nf_log_mutex); |
444 | logger = nft_log_dereference(net->nf.nf_loggers[tindex]); |
445 | if (!logger) |
446 | strscpy(p: buf, q: "NONE" , size: sizeof(buf)); |
447 | else |
448 | strscpy(p: buf, q: logger->name, size: sizeof(buf)); |
449 | mutex_unlock(lock: &nf_log_mutex); |
450 | r = proc_dostring(&tmp, write, buffer, lenp, ppos); |
451 | } |
452 | |
453 | return r; |
454 | } |
455 | |
456 | static int netfilter_log_sysctl_init(struct net *net) |
457 | { |
458 | int i; |
459 | struct ctl_table *table; |
460 | |
461 | table = nf_log_sysctl_table; |
462 | if (!net_eq(net1: net, net2: &init_net)) { |
463 | table = kmemdup(p: nf_log_sysctl_table, |
464 | size: sizeof(nf_log_sysctl_table), |
465 | GFP_KERNEL); |
466 | if (!table) |
467 | goto err_alloc; |
468 | } else { |
469 | for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) { |
470 | snprintf(buf: nf_log_sysctl_fnames[i], |
471 | size: 3, fmt: "%d" , i); |
472 | nf_log_sysctl_table[i].procname = |
473 | nf_log_sysctl_fnames[i]; |
474 | nf_log_sysctl_table[i].maxlen = NFLOGGER_NAME_LEN; |
475 | nf_log_sysctl_table[i].mode = 0644; |
476 | nf_log_sysctl_table[i].proc_handler = |
477 | nf_log_proc_dostring; |
478 | nf_log_sysctl_table[i].extra1 = |
479 | (void *)(unsigned long) i; |
480 | } |
481 | nf_log_sysctl_fhdr = register_net_sysctl(net, "net/netfilter" , |
482 | nf_log_sysctl_ftable); |
483 | if (!nf_log_sysctl_fhdr) |
484 | goto err_freg; |
485 | } |
486 | |
487 | for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) |
488 | table[i].extra2 = net; |
489 | |
490 | net->nf.nf_log_dir_header = register_net_sysctl_sz(net, |
491 | path: "net/netfilter/nf_log" , |
492 | table, |
493 | ARRAY_SIZE(nf_log_sysctl_table)); |
494 | if (!net->nf.nf_log_dir_header) |
495 | goto err_reg; |
496 | |
497 | return 0; |
498 | |
499 | err_reg: |
500 | if (!net_eq(net1: net, net2: &init_net)) |
501 | kfree(objp: table); |
502 | else |
503 | unregister_net_sysctl_table(header: nf_log_sysctl_fhdr); |
504 | err_freg: |
505 | err_alloc: |
506 | return -ENOMEM; |
507 | } |
508 | |
509 | static void netfilter_log_sysctl_exit(struct net *net) |
510 | { |
511 | struct ctl_table *table; |
512 | |
513 | table = net->nf.nf_log_dir_header->ctl_table_arg; |
514 | unregister_net_sysctl_table(header: net->nf.nf_log_dir_header); |
515 | if (!net_eq(net1: net, net2: &init_net)) |
516 | kfree(objp: table); |
517 | else |
518 | unregister_net_sysctl_table(header: nf_log_sysctl_fhdr); |
519 | } |
520 | #else |
521 | static int netfilter_log_sysctl_init(struct net *net) |
522 | { |
523 | return 0; |
524 | } |
525 | |
526 | static void netfilter_log_sysctl_exit(struct net *net) |
527 | { |
528 | } |
529 | #endif /* CONFIG_SYSCTL */ |
530 | |
531 | static int __net_init nf_log_net_init(struct net *net) |
532 | { |
533 | int ret = -ENOMEM; |
534 | |
535 | #ifdef CONFIG_PROC_FS |
536 | if (!proc_create_net("nf_log" , 0444, net->nf.proc_netfilter, |
537 | &nflog_seq_ops, sizeof(struct seq_net_private))) |
538 | return ret; |
539 | #endif |
540 | ret = netfilter_log_sysctl_init(net); |
541 | if (ret < 0) |
542 | goto out_sysctl; |
543 | |
544 | return 0; |
545 | |
546 | out_sysctl: |
547 | #ifdef CONFIG_PROC_FS |
548 | remove_proc_entry("nf_log" , net->nf.proc_netfilter); |
549 | #endif |
550 | return ret; |
551 | } |
552 | |
553 | static void __net_exit nf_log_net_exit(struct net *net) |
554 | { |
555 | netfilter_log_sysctl_exit(net); |
556 | #ifdef CONFIG_PROC_FS |
557 | remove_proc_entry("nf_log" , net->nf.proc_netfilter); |
558 | #endif |
559 | } |
560 | |
561 | static struct pernet_operations nf_log_net_ops = { |
562 | .init = nf_log_net_init, |
563 | .exit = nf_log_net_exit, |
564 | }; |
565 | |
566 | int __init netfilter_log_init(void) |
567 | { |
568 | return register_pernet_subsys(&nf_log_net_ops); |
569 | } |
570 | |