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TOMOYO Linux Cross Reference
Linux/net/netfilter/nf_log.c

Version: ~ [ linux-5.7 ] ~ [ linux-5.6.15 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.43 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.125 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.182 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.225 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.225 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.84 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 #include <linux/kernel.h>
  2 #include <linux/init.h>
  3 #include <linux/module.h>
  4 #include <linux/proc_fs.h>
  5 #include <linux/skbuff.h>
  6 #include <linux/netfilter.h>
  7 #include <linux/seq_file.h>
  8 #include <net/protocol.h>
  9 #include <net/netfilter/nf_log.h>
 10 
 11 #include "nf_internals.h"
 12 
 13 /* Internal logging interface, which relies on the real
 14    LOG target modules */
 15 
 16 #define NF_LOG_PREFIXLEN                128
 17 #define NFLOGGER_NAME_LEN               64
 18 
 19 static struct nf_logger __rcu *loggers[NFPROTO_NUMPROTO][NF_LOG_TYPE_MAX] __read_mostly;
 20 static DEFINE_MUTEX(nf_log_mutex);
 21 
 22 static struct nf_logger *__find_logger(int pf, const char *str_logger)
 23 {
 24         struct nf_logger *log;
 25         int i;
 26 
 27         for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
 28                 if (loggers[pf][i] == NULL)
 29                         continue;
 30 
 31                 log = rcu_dereference_protected(loggers[pf][i],
 32                                                 lockdep_is_held(&nf_log_mutex));
 33                 if (!strnicmp(str_logger, log->name, strlen(log->name)))
 34                         return log;
 35         }
 36 
 37         return NULL;
 38 }
 39 
 40 void nf_log_set(struct net *net, u_int8_t pf, const struct nf_logger *logger)
 41 {
 42         const struct nf_logger *log;
 43 
 44         if (pf == NFPROTO_UNSPEC)
 45                 return;
 46 
 47         mutex_lock(&nf_log_mutex);
 48         log = rcu_dereference_protected(net->nf.nf_loggers[pf],
 49                                         lockdep_is_held(&nf_log_mutex));
 50         if (log == NULL)
 51                 rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
 52 
 53         mutex_unlock(&nf_log_mutex);
 54 }
 55 EXPORT_SYMBOL(nf_log_set);
 56 
 57 void nf_log_unset(struct net *net, const struct nf_logger *logger)
 58 {
 59         int i;
 60         const struct nf_logger *log;
 61 
 62         mutex_lock(&nf_log_mutex);
 63         for (i = 0; i < NFPROTO_NUMPROTO; i++) {
 64                 log = rcu_dereference_protected(net->nf.nf_loggers[i],
 65                                 lockdep_is_held(&nf_log_mutex));
 66                 if (log == logger)
 67                         RCU_INIT_POINTER(net->nf.nf_loggers[i], NULL);
 68         }
 69         mutex_unlock(&nf_log_mutex);
 70         synchronize_rcu();
 71 }
 72 EXPORT_SYMBOL(nf_log_unset);
 73 
 74 /* return EEXIST if the same logger is registered, 0 on success. */
 75 int nf_log_register(u_int8_t pf, struct nf_logger *logger)
 76 {
 77         int i;
 78 
 79         if (pf >= ARRAY_SIZE(init_net.nf.nf_loggers))
 80                 return -EINVAL;
 81 
 82         mutex_lock(&nf_log_mutex);
 83 
 84         if (pf == NFPROTO_UNSPEC) {
 85                 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
 86                         rcu_assign_pointer(loggers[i][logger->type], logger);
 87         } else {
 88                 /* register at end of list to honor first register win */
 89                 rcu_assign_pointer(loggers[pf][logger->type], logger);
 90         }
 91 
 92         mutex_unlock(&nf_log_mutex);
 93 
 94         return 0;
 95 }
 96 EXPORT_SYMBOL(nf_log_register);
 97 
 98 void nf_log_unregister(struct nf_logger *logger)
 99 {
100         int i;
101 
102         mutex_lock(&nf_log_mutex);
103         for (i = 0; i < NFPROTO_NUMPROTO; i++)
104                 RCU_INIT_POINTER(loggers[i][logger->type], NULL);
105         mutex_unlock(&nf_log_mutex);
106 }
107 EXPORT_SYMBOL(nf_log_unregister);
108 
109 int nf_log_bind_pf(struct net *net, u_int8_t pf,
110                    const struct nf_logger *logger)
111 {
112         if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
113                 return -EINVAL;
114         mutex_lock(&nf_log_mutex);
115         if (__find_logger(pf, logger->name) == NULL) {
116                 mutex_unlock(&nf_log_mutex);
117                 return -ENOENT;
118         }
119         rcu_assign_pointer(net->nf.nf_loggers[pf], logger);
120         mutex_unlock(&nf_log_mutex);
121         return 0;
122 }
123 EXPORT_SYMBOL(nf_log_bind_pf);
124 
125 void nf_log_unbind_pf(struct net *net, u_int8_t pf)
126 {
127         if (pf >= ARRAY_SIZE(net->nf.nf_loggers))
128                 return;
129         mutex_lock(&nf_log_mutex);
130         RCU_INIT_POINTER(net->nf.nf_loggers[pf], NULL);
131         mutex_unlock(&nf_log_mutex);
132 }
133 EXPORT_SYMBOL(nf_log_unbind_pf);
134 
135 void nf_logger_request_module(int pf, enum nf_log_type type)
136 {
137         if (loggers[pf][type] == NULL)
138                 request_module("nf-logger-%u-%u", pf, type);
139 }
140 EXPORT_SYMBOL_GPL(nf_logger_request_module);
141 
142 int nf_logger_find_get(int pf, enum nf_log_type type)
143 {
144         struct nf_logger *logger;
145         int ret = -ENOENT;
146 
147         logger = loggers[pf][type];
148         if (logger == NULL)
149                 request_module("nf-logger-%u-%u", pf, type);
150 
151         rcu_read_lock();
152         logger = rcu_dereference(loggers[pf][type]);
153         if (logger == NULL)
154                 goto out;
155 
156         if (logger && try_module_get(logger->me))
157                 ret = 0;
158 out:
159         rcu_read_unlock();
160         return ret;
161 }
162 EXPORT_SYMBOL_GPL(nf_logger_find_get);
163 
164 void nf_logger_put(int pf, enum nf_log_type type)
165 {
166         struct nf_logger *logger;
167 
168         BUG_ON(loggers[pf][type] == NULL);
169 
170         rcu_read_lock();
171         logger = rcu_dereference(loggers[pf][type]);
172         module_put(logger->me);
173         rcu_read_unlock();
174 }
175 EXPORT_SYMBOL_GPL(nf_logger_put);
176 
177 void nf_log_packet(struct net *net,
178                    u_int8_t pf,
179                    unsigned int hooknum,
180                    const struct sk_buff *skb,
181                    const struct net_device *in,
182                    const struct net_device *out,
183                    const struct nf_loginfo *loginfo,
184                    const char *fmt, ...)
185 {
186         va_list args;
187         char prefix[NF_LOG_PREFIXLEN];
188         const struct nf_logger *logger;
189 
190         rcu_read_lock();
191         if (loginfo != NULL)
192                 logger = rcu_dereference(loggers[pf][loginfo->type]);
193         else
194                 logger = rcu_dereference(net->nf.nf_loggers[pf]);
195 
196         if (logger) {
197                 va_start(args, fmt);
198                 vsnprintf(prefix, sizeof(prefix), fmt, args);
199                 va_end(args);
200                 logger->logfn(net, pf, hooknum, skb, in, out, loginfo, prefix);
201         }
202         rcu_read_unlock();
203 }
204 EXPORT_SYMBOL(nf_log_packet);
205 
206 #define S_SIZE (1024 - (sizeof(unsigned int) + 1))
207 
208 struct nf_log_buf {
209         unsigned int    count;
210         char            buf[S_SIZE + 1];
211 };
212 static struct nf_log_buf emergency, *emergency_ptr = &emergency;
213 
214 __printf(2, 3) int nf_log_buf_add(struct nf_log_buf *m, const char *f, ...)
215 {
216         va_list args;
217         int len;
218 
219         if (likely(m->count < S_SIZE)) {
220                 va_start(args, f);
221                 len = vsnprintf(m->buf + m->count, S_SIZE - m->count, f, args);
222                 va_end(args);
223                 if (likely(m->count + len < S_SIZE)) {
224                         m->count += len;
225                         return 0;
226                 }
227         }
228         m->count = S_SIZE;
229         printk_once(KERN_ERR KBUILD_MODNAME " please increase S_SIZE\n");
230         return -1;
231 }
232 EXPORT_SYMBOL_GPL(nf_log_buf_add);
233 
234 struct nf_log_buf *nf_log_buf_open(void)
235 {
236         struct nf_log_buf *m = kmalloc(sizeof(*m), GFP_ATOMIC);
237 
238         if (unlikely(!m)) {
239                 local_bh_disable();
240                 do {
241                         m = xchg(&emergency_ptr, NULL);
242                 } while (!m);
243         }
244         m->count = 0;
245         return m;
246 }
247 EXPORT_SYMBOL_GPL(nf_log_buf_open);
248 
249 void nf_log_buf_close(struct nf_log_buf *m)
250 {
251         m->buf[m->count] = 0;
252         printk("%s\n", m->buf);
253 
254         if (likely(m != &emergency))
255                 kfree(m);
256         else {
257                 emergency_ptr = m;
258                 local_bh_enable();
259         }
260 }
261 EXPORT_SYMBOL_GPL(nf_log_buf_close);
262 
263 #ifdef CONFIG_PROC_FS
264 static void *seq_start(struct seq_file *seq, loff_t *pos)
265 {
266         struct net *net = seq_file_net(seq);
267 
268         mutex_lock(&nf_log_mutex);
269 
270         if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
271                 return NULL;
272 
273         return pos;
274 }
275 
276 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
277 {
278         struct net *net = seq_file_net(s);
279 
280         (*pos)++;
281 
282         if (*pos >= ARRAY_SIZE(net->nf.nf_loggers))
283                 return NULL;
284 
285         return pos;
286 }
287 
288 static void seq_stop(struct seq_file *s, void *v)
289 {
290         mutex_unlock(&nf_log_mutex);
291 }
292 
293 static int seq_show(struct seq_file *s, void *v)
294 {
295         loff_t *pos = v;
296         const struct nf_logger *logger;
297         int i, ret;
298         struct net *net = seq_file_net(s);
299 
300         logger = rcu_dereference_protected(net->nf.nf_loggers[*pos],
301                                            lockdep_is_held(&nf_log_mutex));
302 
303         if (!logger)
304                 ret = seq_printf(s, "%2lld NONE (", *pos);
305         else
306                 ret = seq_printf(s, "%2lld %s (", *pos, logger->name);
307 
308         if (ret < 0)
309                 return ret;
310 
311         for (i = 0; i < NF_LOG_TYPE_MAX; i++) {
312                 if (loggers[*pos][i] == NULL)
313                         continue;
314 
315                 logger = rcu_dereference_protected(loggers[*pos][i],
316                                            lockdep_is_held(&nf_log_mutex));
317                 ret = seq_printf(s, "%s", logger->name);
318                 if (ret < 0)
319                         return ret;
320                 if (i == 0 && loggers[*pos][i + 1] != NULL) {
321                         ret = seq_printf(s, ",");
322                         if (ret < 0)
323                                 return ret;
324                 }
325         }
326 
327         return seq_printf(s, ")\n");
328 }
329 
330 static const struct seq_operations nflog_seq_ops = {
331         .start  = seq_start,
332         .next   = seq_next,
333         .stop   = seq_stop,
334         .show   = seq_show,
335 };
336 
337 static int nflog_open(struct inode *inode, struct file *file)
338 {
339         return seq_open_net(inode, file, &nflog_seq_ops,
340                             sizeof(struct seq_net_private));
341 }
342 
343 static const struct file_operations nflog_file_ops = {
344         .owner   = THIS_MODULE,
345         .open    = nflog_open,
346         .read    = seq_read,
347         .llseek  = seq_lseek,
348         .release = seq_release_net,
349 };
350 
351 
352 #endif /* PROC_FS */
353 
354 #ifdef CONFIG_SYSCTL
355 static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
356 static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
357 
358 static int nf_log_proc_dostring(struct ctl_table *table, int write,
359                          void __user *buffer, size_t *lenp, loff_t *ppos)
360 {
361         const struct nf_logger *logger;
362         char buf[NFLOGGER_NAME_LEN];
363         size_t size = *lenp;
364         int r = 0;
365         int tindex = (unsigned long)table->extra1;
366         struct net *net = current->nsproxy->net_ns;
367 
368         if (write) {
369                 if (size > sizeof(buf))
370                         size = sizeof(buf);
371                 if (copy_from_user(buf, buffer, size))
372                         return -EFAULT;
373 
374                 if (!strcmp(buf, "NONE")) {
375                         nf_log_unbind_pf(net, tindex);
376                         return 0;
377                 }
378                 mutex_lock(&nf_log_mutex);
379                 logger = __find_logger(tindex, buf);
380                 if (logger == NULL) {
381                         mutex_unlock(&nf_log_mutex);
382                         return -ENOENT;
383                 }
384                 rcu_assign_pointer(net->nf.nf_loggers[tindex], logger);
385                 mutex_unlock(&nf_log_mutex);
386         } else {
387                 mutex_lock(&nf_log_mutex);
388                 logger = rcu_dereference_protected(net->nf.nf_loggers[tindex],
389                                                    lockdep_is_held(&nf_log_mutex));
390                 if (!logger)
391                         table->data = "NONE";
392                 else
393                         table->data = logger->name;
394                 r = proc_dostring(table, write, buffer, lenp, ppos);
395                 mutex_unlock(&nf_log_mutex);
396         }
397 
398         return r;
399 }
400 
401 static int netfilter_log_sysctl_init(struct net *net)
402 {
403         int i;
404         struct ctl_table *table;
405 
406         table = nf_log_sysctl_table;
407         if (!net_eq(net, &init_net)) {
408                 table = kmemdup(nf_log_sysctl_table,
409                                  sizeof(nf_log_sysctl_table),
410                                  GFP_KERNEL);
411                 if (!table)
412                         goto err_alloc;
413         } else {
414                 for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
415                         snprintf(nf_log_sysctl_fnames[i],
416                                  3, "%d", i);
417                         nf_log_sysctl_table[i].procname =
418                                 nf_log_sysctl_fnames[i];
419                         nf_log_sysctl_table[i].data = NULL;
420                         nf_log_sysctl_table[i].maxlen =
421                                 NFLOGGER_NAME_LEN * sizeof(char);
422                         nf_log_sysctl_table[i].mode = 0644;
423                         nf_log_sysctl_table[i].proc_handler =
424                                 nf_log_proc_dostring;
425                         nf_log_sysctl_table[i].extra1 =
426                                 (void *)(unsigned long) i;
427                 }
428         }
429 
430         net->nf.nf_log_dir_header = register_net_sysctl(net,
431                                                 "net/netfilter/nf_log",
432                                                 table);
433         if (!net->nf.nf_log_dir_header)
434                 goto err_reg;
435 
436         return 0;
437 
438 err_reg:
439         if (!net_eq(net, &init_net))
440                 kfree(table);
441 err_alloc:
442         return -ENOMEM;
443 }
444 
445 static void netfilter_log_sysctl_exit(struct net *net)
446 {
447         struct ctl_table *table;
448 
449         table = net->nf.nf_log_dir_header->ctl_table_arg;
450         unregister_net_sysctl_table(net->nf.nf_log_dir_header);
451         if (!net_eq(net, &init_net))
452                 kfree(table);
453 }
454 #else
455 static int netfilter_log_sysctl_init(struct net *net)
456 {
457         return 0;
458 }
459 
460 static void netfilter_log_sysctl_exit(struct net *net)
461 {
462 }
463 #endif /* CONFIG_SYSCTL */
464 
465 static int __net_init nf_log_net_init(struct net *net)
466 {
467         int ret = -ENOMEM;
468 
469 #ifdef CONFIG_PROC_FS
470         if (!proc_create("nf_log", S_IRUGO,
471                          net->nf.proc_netfilter, &nflog_file_ops))
472                 return ret;
473 #endif
474         ret = netfilter_log_sysctl_init(net);
475         if (ret < 0)
476                 goto out_sysctl;
477 
478         return 0;
479 
480 out_sysctl:
481 #ifdef CONFIG_PROC_FS
482         remove_proc_entry("nf_log", net->nf.proc_netfilter);
483 #endif
484         return ret;
485 }
486 
487 static void __net_exit nf_log_net_exit(struct net *net)
488 {
489         netfilter_log_sysctl_exit(net);
490 #ifdef CONFIG_PROC_FS
491         remove_proc_entry("nf_log", net->nf.proc_netfilter);
492 #endif
493 }
494 
495 static struct pernet_operations nf_log_net_ops = {
496         .init = nf_log_net_init,
497         .exit = nf_log_net_exit,
498 };
499 
500 int __init netfilter_log_init(void)
501 {
502         return register_pernet_subsys(&nf_log_net_ops);
503 }
504 

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