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TOMOYO Linux Cross Reference
Linux/security/tomoyo/audit.c

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  1 /*
  2  * security/tomoyo/audit.c
  3  *
  4  * Copyright (C) 2005-2011  NTT DATA CORPORATION
  5  */
  6 
  7 #include "common.h"
  8 #include <linux/slab.h>
  9 
 10 /**
 11  * tomoyo_print_bprm - Print "struct linux_binprm" for auditing.
 12  *
 13  * @bprm: Pointer to "struct linux_binprm".
 14  * @dump: Pointer to "struct tomoyo_page_dump".
 15  *
 16  * Returns the contents of @bprm on success, NULL otherwise.
 17  *
 18  * This function uses kzalloc(), so caller must kfree() if this function
 19  * didn't return NULL.
 20  */
 21 static char *tomoyo_print_bprm(struct linux_binprm *bprm,
 22                                struct tomoyo_page_dump *dump)
 23 {
 24         static const int tomoyo_buffer_len = 4096 * 2;
 25         char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS);
 26         char *cp;
 27         char *last_start;
 28         int len;
 29         unsigned long pos = bprm->p;
 30         int offset = pos % PAGE_SIZE;
 31         int argv_count = bprm->argc;
 32         int envp_count = bprm->envc;
 33         bool truncated = false;
 34         if (!buffer)
 35                 return NULL;
 36         len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ ");
 37         cp = buffer + len;
 38         if (!argv_count) {
 39                 memmove(cp, "} envp[]={ ", 11);
 40                 cp += 11;
 41         }
 42         last_start = cp;
 43         while (argv_count || envp_count) {
 44                 if (!tomoyo_dump_page(bprm, pos, dump))
 45                         goto out;
 46                 pos += PAGE_SIZE - offset;
 47                 /* Read. */
 48                 while (offset < PAGE_SIZE) {
 49                         const char *kaddr = dump->data;
 50                         const unsigned char c = kaddr[offset++];
 51                         if (cp == last_start)
 52                                 *cp++ = '"';
 53                         if (cp >= buffer + tomoyo_buffer_len - 32) {
 54                                 /* Reserve some room for "..." string. */
 55                                 truncated = true;
 56                         } else if (c == '\\') {
 57                                 *cp++ = '\\';
 58                                 *cp++ = '\\';
 59                         } else if (c > ' ' && c < 127) {
 60                                 *cp++ = c;
 61                         } else if (!c) {
 62                                 *cp++ = '"';
 63                                 *cp++ = ' ';
 64                                 last_start = cp;
 65                         } else {
 66                                 *cp++ = '\\';
 67                                 *cp++ = (c >> 6) + '';
 68                                 *cp++ = ((c >> 3) & 7) + '';
 69                                 *cp++ = (c & 7) + '';
 70                         }
 71                         if (c)
 72                                 continue;
 73                         if (argv_count) {
 74                                 if (--argv_count == 0) {
 75                                         if (truncated) {
 76                                                 cp = last_start;
 77                                                 memmove(cp, "... ", 4);
 78                                                 cp += 4;
 79                                         }
 80                                         memmove(cp, "} envp[]={ ", 11);
 81                                         cp += 11;
 82                                         last_start = cp;
 83                                         truncated = false;
 84                                 }
 85                         } else if (envp_count) {
 86                                 if (--envp_count == 0) {
 87                                         if (truncated) {
 88                                                 cp = last_start;
 89                                                 memmove(cp, "... ", 4);
 90                                                 cp += 4;
 91                                         }
 92                                 }
 93                         }
 94                         if (!argv_count && !envp_count)
 95                                 break;
 96                 }
 97                 offset = 0;
 98         }
 99         *cp++ = '}';
100         *cp = '\0';
101         return buffer;
102 out:
103         snprintf(buffer, tomoyo_buffer_len - 1,
104                  "argv[]={ ... } envp[]= { ... }");
105         return buffer;
106 }
107 
108 /**
109  * tomoyo_filetype - Get string representation of file type.
110  *
111  * @mode: Mode value for stat().
112  *
113  * Returns file type string.
114  */
115 static inline const char *tomoyo_filetype(const umode_t mode)
116 {
117         switch (mode & S_IFMT) {
118         case S_IFREG:
119         case 0:
120                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
121         case S_IFDIR:
122                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
123         case S_IFLNK:
124                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
125         case S_IFIFO:
126                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
127         case S_IFSOCK:
128                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
129         case S_IFBLK:
130                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
131         case S_IFCHR:
132                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
133         }
134         return "unknown"; /* This should not happen. */
135 }
136 
137 /**
138  * tomoyo_print_header - Get header line of audit log.
139  *
140  * @r: Pointer to "struct tomoyo_request_info".
141  *
142  * Returns string representation.
143  *
144  * This function uses kmalloc(), so caller must kfree() if this function
145  * didn't return NULL.
146  */
147 static char *tomoyo_print_header(struct tomoyo_request_info *r)
148 {
149         struct tomoyo_time stamp;
150         const pid_t gpid = task_pid_nr(current);
151         struct tomoyo_obj_info *obj = r->obj;
152         static const int tomoyo_buffer_len = 4096;
153         char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
154         int pos;
155         u8 i;
156         if (!buffer)
157                 return NULL;
158         {
159                 struct timeval tv;
160                 do_gettimeofday(&tv);
161                 tomoyo_convert_time(tv.tv_sec, &stamp);
162         }
163         pos = snprintf(buffer, tomoyo_buffer_len - 1,
164                        "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "
165                        "granted=%s (global-pid=%u) task={ pid=%u ppid=%u "
166                        "uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u "
167                        "fsuid=%u fsgid=%u }", stamp.year, stamp.month,
168                        stamp.day, stamp.hour, stamp.min, stamp.sec, r->profile,
169                        tomoyo_mode[r->mode], tomoyo_yesno(r->granted), gpid,
170                        tomoyo_sys_getpid(), tomoyo_sys_getppid(),
171                        from_kuid(&init_user_ns, current_uid()),
172                        from_kgid(&init_user_ns, current_gid()),
173                        from_kuid(&init_user_ns, current_euid()),
174                        from_kgid(&init_user_ns, current_egid()),
175                        from_kuid(&init_user_ns, current_suid()),
176                        from_kgid(&init_user_ns, current_sgid()),
177                        from_kuid(&init_user_ns, current_fsuid()),
178                        from_kgid(&init_user_ns, current_fsgid()));
179         if (!obj)
180                 goto no_obj_info;
181         if (!obj->validate_done) {
182                 tomoyo_get_attributes(obj);
183                 obj->validate_done = true;
184         }
185         for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
186                 struct tomoyo_mini_stat *stat;
187                 unsigned int dev;
188                 umode_t mode;
189                 if (!obj->stat_valid[i])
190                         continue;
191                 stat = &obj->stat[i];
192                 dev = stat->dev;
193                 mode = stat->mode;
194                 if (i & 1) {
195                         pos += snprintf(buffer + pos,
196                                         tomoyo_buffer_len - 1 - pos,
197                                         " path%u.parent={ uid=%u gid=%u "
198                                         "ino=%lu perm=0%o }", (i >> 1) + 1,
199                                         from_kuid(&init_user_ns, stat->uid),
200                                         from_kgid(&init_user_ns, stat->gid),
201                                         (unsigned long)stat->ino,
202                                         stat->mode & S_IALLUGO);
203                         continue;
204                 }
205                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
206                                 " path%u={ uid=%u gid=%u ino=%lu major=%u"
207                                 " minor=%u perm=0%o type=%s", (i >> 1) + 1,
208                                 from_kuid(&init_user_ns, stat->uid),
209                                 from_kgid(&init_user_ns, stat->gid),
210                                 (unsigned long)stat->ino,
211                                 MAJOR(dev), MINOR(dev),
212                                 mode & S_IALLUGO, tomoyo_filetype(mode));
213                 if (S_ISCHR(mode) || S_ISBLK(mode)) {
214                         dev = stat->rdev;
215                         pos += snprintf(buffer + pos,
216                                         tomoyo_buffer_len - 1 - pos,
217                                         " dev_major=%u dev_minor=%u",
218                                         MAJOR(dev), MINOR(dev));
219                 }
220                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
221                                 " }");
222         }
223 no_obj_info:
224         if (pos < tomoyo_buffer_len - 1)
225                 return buffer;
226         kfree(buffer);
227         return NULL;
228 }
229 
230 /**
231  * tomoyo_init_log - Allocate buffer for audit logs.
232  *
233  * @r:    Pointer to "struct tomoyo_request_info".
234  * @len:  Buffer size needed for @fmt and @args.
235  * @fmt:  The printf()'s format string.
236  * @args: va_list structure for @fmt.
237  *
238  * Returns pointer to allocated memory.
239  *
240  * This function uses kzalloc(), so caller must kfree() if this function
241  * didn't return NULL.
242  */
243 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
244                       va_list args)
245 {
246         char *buf = NULL;
247         char *bprm_info = NULL;
248         const char *header = NULL;
249         char *realpath = NULL;
250         const char *symlink = NULL;
251         int pos;
252         const char *domainname = r->domain->domainname->name;
253         header = tomoyo_print_header(r);
254         if (!header)
255                 return NULL;
256         /* +10 is for '\n' etc. and '\0'. */
257         len += strlen(domainname) + strlen(header) + 10;
258         if (r->ee) {
259                 struct file *file = r->ee->bprm->file;
260                 realpath = tomoyo_realpath_from_path(&file->f_path);
261                 bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
262                 if (!realpath || !bprm_info)
263                         goto out;
264                 /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
265                 len += strlen(realpath) + 80 + strlen(bprm_info);
266         } else if (r->obj && r->obj->symlink_target) {
267                 symlink = r->obj->symlink_target->name;
268                 /* +18 is for " symlink.target=\"%s\"" */
269                 len += 18 + strlen(symlink);
270         }
271         len = tomoyo_round2(len);
272         buf = kzalloc(len, GFP_NOFS);
273         if (!buf)
274                 goto out;
275         len--;
276         pos = snprintf(buf, len, "%s", header);
277         if (realpath) {
278                 struct linux_binprm *bprm = r->ee->bprm;
279                 pos += snprintf(buf + pos, len - pos,
280                                 " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
281                                 realpath, bprm->argc, bprm->envc, bprm_info);
282         } else if (symlink)
283                 pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
284                                 symlink);
285         pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
286         vsnprintf(buf + pos, len - pos, fmt, args);
287 out:
288         kfree(realpath);
289         kfree(bprm_info);
290         kfree(header);
291         return buf;
292 }
293 
294 /* Wait queue for /sys/kernel/security/tomoyo/audit. */
295 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
296 
297 /* Structure for audit log. */
298 struct tomoyo_log {
299         struct list_head list;
300         char *log;
301         int size;
302 };
303 
304 /* The list for "struct tomoyo_log". */
305 static LIST_HEAD(tomoyo_log);
306 
307 /* Lock for "struct list_head tomoyo_log". */
308 static DEFINE_SPINLOCK(tomoyo_log_lock);
309 
310 /* Length of "stuct list_head tomoyo_log". */
311 static unsigned int tomoyo_log_count;
312 
313 /**
314  * tomoyo_get_audit - Get audit mode.
315  *
316  * @ns:          Pointer to "struct tomoyo_policy_namespace".
317  * @profile:     Profile number.
318  * @index:       Index number of functionality.
319  * @is_granted:  True if granted log, false otherwise.
320  *
321  * Returns true if this request should be audited, false otherwise.
322  */
323 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
324                              const u8 profile, const u8 index,
325                              const struct tomoyo_acl_info *matched_acl,
326                              const bool is_granted)
327 {
328         u8 mode;
329         const u8 category = tomoyo_index2category[index] +
330                 TOMOYO_MAX_MAC_INDEX;
331         struct tomoyo_profile *p;
332         if (!tomoyo_policy_loaded)
333                 return false;
334         p = tomoyo_profile(ns, profile);
335         if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
336                 return false;
337         if (is_granted && matched_acl && matched_acl->cond &&
338             matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
339                 return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
340         mode = p->config[index];
341         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
342                 mode = p->config[category];
343         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
344                 mode = p->default_config;
345         if (is_granted)
346                 return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
347         return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
348 }
349 
350 /**
351  * tomoyo_write_log2 - Write an audit log.
352  *
353  * @r:    Pointer to "struct tomoyo_request_info".
354  * @len:  Buffer size needed for @fmt and @args.
355  * @fmt:  The printf()'s format string.
356  * @args: va_list structure for @fmt.
357  *
358  * Returns nothing.
359  */
360 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
361                        va_list args)
362 {
363         char *buf;
364         struct tomoyo_log *entry;
365         bool quota_exceeded = false;
366         if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
367                               r->matched_acl, r->granted))
368                 goto out;
369         buf = tomoyo_init_log(r, len, fmt, args);
370         if (!buf)
371                 goto out;
372         entry = kzalloc(sizeof(*entry), GFP_NOFS);
373         if (!entry) {
374                 kfree(buf);
375                 goto out;
376         }
377         entry->log = buf;
378         len = tomoyo_round2(strlen(buf) + 1);
379         /*
380          * The entry->size is used for memory quota checks.
381          * Don't go beyond strlen(entry->log).
382          */
383         entry->size = len + tomoyo_round2(sizeof(*entry));
384         spin_lock(&tomoyo_log_lock);
385         if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
386             tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
387             tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
388                 quota_exceeded = true;
389         } else {
390                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
391                 list_add_tail(&entry->list, &tomoyo_log);
392                 tomoyo_log_count++;
393         }
394         spin_unlock(&tomoyo_log_lock);
395         if (quota_exceeded) {
396                 kfree(buf);
397                 kfree(entry);
398                 goto out;
399         }
400         wake_up(&tomoyo_log_wait);
401 out:
402         return;
403 }
404 
405 /**
406  * tomoyo_write_log - Write an audit log.
407  *
408  * @r:   Pointer to "struct tomoyo_request_info".
409  * @fmt: The printf()'s format string, followed by parameters.
410  *
411  * Returns nothing.
412  */
413 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
414 {
415         va_list args;
416         int len;
417         va_start(args, fmt);
418         len = vsnprintf((char *) &len, 1, fmt, args) + 1;
419         va_end(args);
420         va_start(args, fmt);
421         tomoyo_write_log2(r, len, fmt, args);
422         va_end(args);
423 }
424 
425 /**
426  * tomoyo_read_log - Read an audit log.
427  *
428  * @head: Pointer to "struct tomoyo_io_buffer".
429  *
430  * Returns nothing.
431  */
432 void tomoyo_read_log(struct tomoyo_io_buffer *head)
433 {
434         struct tomoyo_log *ptr = NULL;
435         if (head->r.w_pos)
436                 return;
437         kfree(head->read_buf);
438         head->read_buf = NULL;
439         spin_lock(&tomoyo_log_lock);
440         if (!list_empty(&tomoyo_log)) {
441                 ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
442                 list_del(&ptr->list);
443                 tomoyo_log_count--;
444                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
445         }
446         spin_unlock(&tomoyo_log_lock);
447         if (ptr) {
448                 head->read_buf = ptr->log;
449                 head->r.w[head->r.w_pos++] = head->read_buf;
450                 kfree(ptr);
451         }
452 }
453 
454 /**
455  * tomoyo_poll_log - Wait for an audit log.
456  *
457  * @file: Pointer to "struct file".
458  * @wait: Pointer to "poll_table". Maybe NULL.
459  *
460  * Returns POLLIN | POLLRDNORM when ready to read an audit log.
461  */
462 unsigned int tomoyo_poll_log(struct file *file, poll_table *wait)
463 {
464         if (tomoyo_log_count)
465                 return POLLIN | POLLRDNORM;
466         poll_wait(file, &tomoyo_log_wait, wait);
467         if (tomoyo_log_count)
468                 return POLLIN | POLLRDNORM;
469         return 0;
470 }
471 

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