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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                        current_uid(), current_gid(), current_euid(),
172                        current_egid(), current_suid(), current_sgid(),
173                        current_fsuid(), current_fsgid());
174         if (!obj)
175                 goto no_obj_info;
176         if (!obj->validate_done) {
177                 tomoyo_get_attributes(obj);
178                 obj->validate_done = true;
179         }
180         for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
181                 struct tomoyo_mini_stat *stat;
182                 unsigned int dev;
183                 umode_t mode;
184                 if (!obj->stat_valid[i])
185                         continue;
186                 stat = &obj->stat[i];
187                 dev = stat->dev;
188                 mode = stat->mode;
189                 if (i & 1) {
190                         pos += snprintf(buffer + pos,
191                                         tomoyo_buffer_len - 1 - pos,
192                                         " path%u.parent={ uid=%u gid=%u "
193                                         "ino=%lu perm=0%o }", (i >> 1) + 1,
194                                         stat->uid, stat->gid, (unsigned long)
195                                         stat->ino, stat->mode & S_IALLUGO);
196                         continue;
197                 }
198                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
199                                 " path%u={ uid=%u gid=%u ino=%lu major=%u"
200                                 " minor=%u perm=0%o type=%s", (i >> 1) + 1,
201                                 stat->uid, stat->gid, (unsigned long)
202                                 stat->ino, MAJOR(dev), MINOR(dev),
203                                 mode & S_IALLUGO, tomoyo_filetype(mode));
204                 if (S_ISCHR(mode) || S_ISBLK(mode)) {
205                         dev = stat->rdev;
206                         pos += snprintf(buffer + pos,
207                                         tomoyo_buffer_len - 1 - pos,
208                                         " dev_major=%u dev_minor=%u",
209                                         MAJOR(dev), MINOR(dev));
210                 }
211                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
212                                 " }");
213         }
214 no_obj_info:
215         if (pos < tomoyo_buffer_len - 1)
216                 return buffer;
217         kfree(buffer);
218         return NULL;
219 }
220 
221 /**
222  * tomoyo_init_log - Allocate buffer for audit logs.
223  *
224  * @r:    Pointer to "struct tomoyo_request_info".
225  * @len:  Buffer size needed for @fmt and @args.
226  * @fmt:  The printf()'s format string.
227  * @args: va_list structure for @fmt.
228  *
229  * Returns pointer to allocated memory.
230  *
231  * This function uses kzalloc(), so caller must kfree() if this function
232  * didn't return NULL.
233  */
234 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
235                       va_list args)
236 {
237         char *buf = NULL;
238         char *bprm_info = NULL;
239         const char *header = NULL;
240         char *realpath = NULL;
241         const char *symlink = NULL;
242         int pos;
243         const char *domainname = r->domain->domainname->name;
244         header = tomoyo_print_header(r);
245         if (!header)
246                 return NULL;
247         /* +10 is for '\n' etc. and '\0'. */
248         len += strlen(domainname) + strlen(header) + 10;
249         if (r->ee) {
250                 struct file *file = r->ee->bprm->file;
251                 realpath = tomoyo_realpath_from_path(&file->f_path);
252                 bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
253                 if (!realpath || !bprm_info)
254                         goto out;
255                 /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
256                 len += strlen(realpath) + 80 + strlen(bprm_info);
257         } else if (r->obj && r->obj->symlink_target) {
258                 symlink = r->obj->symlink_target->name;
259                 /* +18 is for " symlink.target=\"%s\"" */
260                 len += 18 + strlen(symlink);
261         }
262         len = tomoyo_round2(len);
263         buf = kzalloc(len, GFP_NOFS);
264         if (!buf)
265                 goto out;
266         len--;
267         pos = snprintf(buf, len, "%s", header);
268         if (realpath) {
269                 struct linux_binprm *bprm = r->ee->bprm;
270                 pos += snprintf(buf + pos, len - pos,
271                                 " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
272                                 realpath, bprm->argc, bprm->envc, bprm_info);
273         } else if (symlink)
274                 pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
275                                 symlink);
276         pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
277         vsnprintf(buf + pos, len - pos, fmt, args);
278 out:
279         kfree(realpath);
280         kfree(bprm_info);
281         kfree(header);
282         return buf;
283 }
284 
285 /* Wait queue for /sys/kernel/security/tomoyo/audit. */
286 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
287 
288 /* Structure for audit log. */
289 struct tomoyo_log {
290         struct list_head list;
291         char *log;
292         int size;
293 };
294 
295 /* The list for "struct tomoyo_log". */
296 static LIST_HEAD(tomoyo_log);
297 
298 /* Lock for "struct list_head tomoyo_log". */
299 static DEFINE_SPINLOCK(tomoyo_log_lock);
300 
301 /* Length of "stuct list_head tomoyo_log". */
302 static unsigned int tomoyo_log_count;
303 
304 /**
305  * tomoyo_get_audit - Get audit mode.
306  *
307  * @ns:          Pointer to "struct tomoyo_policy_namespace".
308  * @profile:     Profile number.
309  * @index:       Index number of functionality.
310  * @is_granted:  True if granted log, false otherwise.
311  *
312  * Returns true if this request should be audited, false otherwise.
313  */
314 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
315                              const u8 profile, const u8 index,
316                              const struct tomoyo_acl_info *matched_acl,
317                              const bool is_granted)
318 {
319         u8 mode;
320         const u8 category = tomoyo_index2category[index] +
321                 TOMOYO_MAX_MAC_INDEX;
322         struct tomoyo_profile *p;
323         if (!tomoyo_policy_loaded)
324                 return false;
325         p = tomoyo_profile(ns, profile);
326         if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
327                 return false;
328         if (is_granted && matched_acl && matched_acl->cond &&
329             matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
330                 return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
331         mode = p->config[index];
332         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
333                 mode = p->config[category];
334         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
335                 mode = p->default_config;
336         if (is_granted)
337                 return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
338         return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
339 }
340 
341 /**
342  * tomoyo_write_log2 - Write an audit log.
343  *
344  * @r:    Pointer to "struct tomoyo_request_info".
345  * @len:  Buffer size needed for @fmt and @args.
346  * @fmt:  The printf()'s format string.
347  * @args: va_list structure for @fmt.
348  *
349  * Returns nothing.
350  */
351 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
352                        va_list args)
353 {
354         char *buf;
355         struct tomoyo_log *entry;
356         bool quota_exceeded = false;
357         if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
358                               r->matched_acl, r->granted))
359                 goto out;
360         buf = tomoyo_init_log(r, len, fmt, args);
361         if (!buf)
362                 goto out;
363         entry = kzalloc(sizeof(*entry), GFP_NOFS);
364         if (!entry) {
365                 kfree(buf);
366                 goto out;
367         }
368         entry->log = buf;
369         len = tomoyo_round2(strlen(buf) + 1);
370         /*
371          * The entry->size is used for memory quota checks.
372          * Don't go beyond strlen(entry->log).
373          */
374         entry->size = len + tomoyo_round2(sizeof(*entry));
375         spin_lock(&tomoyo_log_lock);
376         if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
377             tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
378             tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
379                 quota_exceeded = true;
380         } else {
381                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
382                 list_add_tail(&entry->list, &tomoyo_log);
383                 tomoyo_log_count++;
384         }
385         spin_unlock(&tomoyo_log_lock);
386         if (quota_exceeded) {
387                 kfree(buf);
388                 kfree(entry);
389                 goto out;
390         }
391         wake_up(&tomoyo_log_wait);
392 out:
393         return;
394 }
395 
396 /**
397  * tomoyo_write_log - Write an audit log.
398  *
399  * @r:   Pointer to "struct tomoyo_request_info".
400  * @fmt: The printf()'s format string, followed by parameters.
401  *
402  * Returns nothing.
403  */
404 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
405 {
406         va_list args;
407         int len;
408         va_start(args, fmt);
409         len = vsnprintf((char *) &len, 1, fmt, args) + 1;
410         va_end(args);
411         va_start(args, fmt);
412         tomoyo_write_log2(r, len, fmt, args);
413         va_end(args);
414 }
415 
416 /**
417  * tomoyo_read_log - Read an audit log.
418  *
419  * @head: Pointer to "struct tomoyo_io_buffer".
420  *
421  * Returns nothing.
422  */
423 void tomoyo_read_log(struct tomoyo_io_buffer *head)
424 {
425         struct tomoyo_log *ptr = NULL;
426         if (head->r.w_pos)
427                 return;
428         kfree(head->read_buf);
429         head->read_buf = NULL;
430         spin_lock(&tomoyo_log_lock);
431         if (!list_empty(&tomoyo_log)) {
432                 ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
433                 list_del(&ptr->list);
434                 tomoyo_log_count--;
435                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
436         }
437         spin_unlock(&tomoyo_log_lock);
438         if (ptr) {
439                 head->read_buf = ptr->log;
440                 head->r.w[head->r.w_pos++] = head->read_buf;
441                 kfree(ptr);
442         }
443 }
444 
445 /**
446  * tomoyo_poll_log - Wait for an audit log.
447  *
448  * @file: Pointer to "struct file".
449  * @wait: Pointer to "poll_table". Maybe NULL.
450  *
451  * Returns POLLIN | POLLRDNORM when ready to read an audit log.
452  */
453 unsigned int tomoyo_poll_log(struct file *file, poll_table *wait)
454 {
455         if (tomoyo_log_count)
456                 return POLLIN | POLLRDNORM;
457         poll_wait(file, &tomoyo_log_wait, wait);
458         if (tomoyo_log_count)
459                 return POLLIN | POLLRDNORM;
460         return 0;
461 }
462 

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