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(str_logger, 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(&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(&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(&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(&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, 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); 143 144 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); 153 154 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); 160 161 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); 195 196 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); 214 215 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); 243 244 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; 275 276 __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); 295 296 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); 310 311 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 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 } 337 338 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 } 349 350 static void seq_stop(struct seq_file *s, void *v) 351 { 352 mutex_unlock(&nf_log_mutex); 353 } 354 355 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 }; 415 416 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 } 465 466 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 } 517 518 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 530 static int netfilter_log_sysctl_init(struct net *net) 531 { 532 return 0; 533 } 534 535 static void netfilter_log_sysctl_exit(struct net *net) 536 { 537 } 538 #endif /* CONFIG_SYSCTL */ 539 540 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 } 561 562 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 }; 574 575 int __init netfilter_log_init(void) 576 { 577 return register_pernet_subsys(&nf_log_net_ops); 578 } 579