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

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * security/tomoyo/audit.c
  4  *
  5  * Copyright (C) 2005-2011  NTT DATA CORPORATION
  6  */
  7 
  8 #include "common.h"
  9 #include <linux/slab.h>
 10 
 11 /**
 12  * tomoyo_print_bprm - Print "struct linux_binprm" for auditing.
 13  *
 14  * @bprm: Pointer to "struct linux_binprm".
 15  * @dump: Pointer to "struct tomoyo_page_dump".
 16  *
 17  * Returns the contents of @bprm on success, NULL otherwise.
 18  *
 19  * This function uses kzalloc(), so caller must kfree() if this function
 20  * didn't return NULL.
 21  */
 22 static char *tomoyo_print_bprm(struct linux_binprm *bprm,
 23                                struct tomoyo_page_dump *dump)
 24 {
 25         static const int tomoyo_buffer_len = 4096 * 2;
 26         char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS);
 27         char *cp;
 28         char *last_start;
 29         int len;
 30         unsigned long pos = bprm->p;
 31         int offset = pos % PAGE_SIZE;
 32         int argv_count = bprm->argc;
 33         int envp_count = bprm->envc;
 34         bool truncated = false;
 35 
 36         if (!buffer)
 37                 return NULL;
 38         len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ ");
 39         cp = buffer + len;
 40         if (!argv_count) {
 41                 memmove(cp, "} envp[]={ ", 11);
 42                 cp += 11;
 43         }
 44         last_start = cp;
 45         while (argv_count || envp_count) {
 46                 if (!tomoyo_dump_page(bprm, pos, dump))
 47                         goto out;
 48                 pos += PAGE_SIZE - offset;
 49                 /* Read. */
 50                 while (offset < PAGE_SIZE) {
 51                         const char *kaddr = dump->data;
 52                         const unsigned char c = kaddr[offset++];
 53 
 54                         if (cp == last_start)
 55                                 *cp++ = '"';
 56                         if (cp >= buffer + tomoyo_buffer_len - 32) {
 57                                 /* Reserve some room for "..." string. */
 58                                 truncated = true;
 59                         } else if (c == '\\') {
 60                                 *cp++ = '\\';
 61                                 *cp++ = '\\';
 62                         } else if (c > ' ' && c < 127) {
 63                                 *cp++ = c;
 64                         } else if (!c) {
 65                                 *cp++ = '"';
 66                                 *cp++ = ' ';
 67                                 last_start = cp;
 68                         } else {
 69                                 *cp++ = '\\';
 70                                 *cp++ = (c >> 6) + '';
 71                                 *cp++ = ((c >> 3) & 7) + '';
 72                                 *cp++ = (c & 7) + '';
 73                         }
 74                         if (c)
 75                                 continue;
 76                         if (argv_count) {
 77                                 if (--argv_count == 0) {
 78                                         if (truncated) {
 79                                                 cp = last_start;
 80                                                 memmove(cp, "... ", 4);
 81                                                 cp += 4;
 82                                         }
 83                                         memmove(cp, "} envp[]={ ", 11);
 84                                         cp += 11;
 85                                         last_start = cp;
 86                                         truncated = false;
 87                                 }
 88                         } else if (envp_count) {
 89                                 if (--envp_count == 0) {
 90                                         if (truncated) {
 91                                                 cp = last_start;
 92                                                 memmove(cp, "... ", 4);
 93                                                 cp += 4;
 94                                         }
 95                                 }
 96                         }
 97                         if (!argv_count && !envp_count)
 98                                 break;
 99                 }
100                 offset = 0;
101         }
102         *cp++ = '}';
103         *cp = '\0';
104         return buffer;
105 out:
106         snprintf(buffer, tomoyo_buffer_len - 1,
107                  "argv[]={ ... } envp[]= { ... }");
108         return buffer;
109 }
110 
111 /**
112  * tomoyo_filetype - Get string representation of file type.
113  *
114  * @mode: Mode value for stat().
115  *
116  * Returns file type string.
117  */
118 static inline const char *tomoyo_filetype(const umode_t mode)
119 {
120         switch (mode & S_IFMT) {
121         case S_IFREG:
122         case 0:
123                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
124         case S_IFDIR:
125                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
126         case S_IFLNK:
127                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
128         case S_IFIFO:
129                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
130         case S_IFSOCK:
131                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
132         case S_IFBLK:
133                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
134         case S_IFCHR:
135                 return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
136         }
137         return "unknown"; /* This should not happen. */
138 }
139 
140 /**
141  * tomoyo_print_header - Get header line of audit log.
142  *
143  * @r: Pointer to "struct tomoyo_request_info".
144  *
145  * Returns string representation.
146  *
147  * This function uses kmalloc(), so caller must kfree() if this function
148  * didn't return NULL.
149  */
150 static char *tomoyo_print_header(struct tomoyo_request_info *r)
151 {
152         struct tomoyo_time stamp;
153         const pid_t gpid = task_pid_nr(current);
154         struct tomoyo_obj_info *obj = r->obj;
155         static const int tomoyo_buffer_len = 4096;
156         char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
157         int pos;
158         u8 i;
159 
160         if (!buffer)
161                 return NULL;
162 
163         tomoyo_convert_time(ktime_get_real_seconds(), &stamp);
164 
165         pos = snprintf(buffer, tomoyo_buffer_len - 1,
166                        "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s granted=%s (global-pid=%u) task={ pid=%u ppid=%u uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u fsuid=%u fsgid=%u }",
167                        stamp.year, stamp.month, stamp.day, stamp.hour,
168                        stamp.min, stamp.sec, r->profile, tomoyo_mode[r->mode],
169                        tomoyo_yesno(r->granted), gpid, tomoyo_sys_getpid(),
170                        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 
190                 if (!obj->stat_valid[i])
191                         continue;
192                 stat = &obj->stat[i];
193                 dev = stat->dev;
194                 mode = stat->mode;
195                 if (i & 1) {
196                         pos += snprintf(buffer + pos,
197                                         tomoyo_buffer_len - 1 - pos,
198                                         " path%u.parent={ uid=%u gid=%u ino=%lu perm=0%o }",
199                                         (i >> 1) + 1,
200                                         from_kuid(&init_user_ns, stat->uid),
201                                         from_kgid(&init_user_ns, stat->gid),
202                                         (unsigned long)stat->ino,
203                                         stat->mode & S_IALLUGO);
204                         continue;
205                 }
206                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
207                                 " path%u={ uid=%u gid=%u ino=%lu major=%u minor=%u perm=0%o type=%s",
208                                 (i >> 1) + 1,
209                                 from_kuid(&init_user_ns, stat->uid),
210                                 from_kgid(&init_user_ns, stat->gid),
211                                 (unsigned long)stat->ino,
212                                 MAJOR(dev), MINOR(dev),
213                                 mode & S_IALLUGO, tomoyo_filetype(mode));
214                 if (S_ISCHR(mode) || S_ISBLK(mode)) {
215                         dev = stat->rdev;
216                         pos += snprintf(buffer + pos,
217                                         tomoyo_buffer_len - 1 - pos,
218                                         " dev_major=%u dev_minor=%u",
219                                         MAJOR(dev), MINOR(dev));
220                 }
221                 pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
222                                 " }");
223         }
224 no_obj_info:
225         if (pos < tomoyo_buffer_len - 1)
226                 return buffer;
227         kfree(buffer);
228         return NULL;
229 }
230 
231 /**
232  * tomoyo_init_log - Allocate buffer for audit logs.
233  *
234  * @r:    Pointer to "struct tomoyo_request_info".
235  * @len:  Buffer size needed for @fmt and @args.
236  * @fmt:  The printf()'s format string.
237  * @args: va_list structure for @fmt.
238  *
239  * Returns pointer to allocated memory.
240  *
241  * This function uses kzalloc(), so caller must kfree() if this function
242  * didn't return NULL.
243  */
244 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
245                       va_list args)
246 {
247         char *buf = NULL;
248         char *bprm_info = NULL;
249         const char *header = NULL;
250         char *realpath = NULL;
251         const char *symlink = NULL;
252         int pos;
253         const char *domainname = r->domain->domainname->name;
254 
255         header = tomoyo_print_header(r);
256         if (!header)
257                 return NULL;
258         /* +10 is for '\n' etc. and '\0'. */
259         len += strlen(domainname) + strlen(header) + 10;
260         if (r->ee) {
261                 struct file *file = r->ee->bprm->file;
262 
263                 realpath = tomoyo_realpath_from_path(&file->f_path);
264                 bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
265                 if (!realpath || !bprm_info)
266                         goto out;
267                 /* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
268                 len += strlen(realpath) + 80 + strlen(bprm_info);
269         } else if (r->obj && r->obj->symlink_target) {
270                 symlink = r->obj->symlink_target->name;
271                 /* +18 is for " symlink.target=\"%s\"" */
272                 len += 18 + strlen(symlink);
273         }
274         len = tomoyo_round2(len);
275         buf = kzalloc(len, GFP_NOFS);
276         if (!buf)
277                 goto out;
278         len--;
279         pos = snprintf(buf, len, "%s", header);
280         if (realpath) {
281                 struct linux_binprm *bprm = r->ee->bprm;
282 
283                 pos += snprintf(buf + pos, len - pos,
284                                 " exec={ realpath=\"%s\" argc=%d envc=%d %s }",
285                                 realpath, bprm->argc, bprm->envc, bprm_info);
286         } else if (symlink)
287                 pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
288                                 symlink);
289         pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
290         vsnprintf(buf + pos, len - pos, fmt, args);
291 out:
292         kfree(realpath);
293         kfree(bprm_info);
294         kfree(header);
295         return buf;
296 }
297 
298 /* Wait queue for /sys/kernel/security/tomoyo/audit. */
299 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
300 
301 /* Structure for audit log. */
302 struct tomoyo_log {
303         struct list_head list;
304         char *log;
305         int size;
306 };
307 
308 /* The list for "struct tomoyo_log". */
309 static LIST_HEAD(tomoyo_log);
310 
311 /* Lock for "struct list_head tomoyo_log". */
312 static DEFINE_SPINLOCK(tomoyo_log_lock);
313 
314 /* Length of "stuct list_head tomoyo_log". */
315 static unsigned int tomoyo_log_count;
316 
317 /**
318  * tomoyo_get_audit - Get audit mode.
319  *
320  * @ns:          Pointer to "struct tomoyo_policy_namespace".
321  * @profile:     Profile number.
322  * @index:       Index number of functionality.
323  * @is_granted:  True if granted log, false otherwise.
324  *
325  * Returns true if this request should be audited, false otherwise.
326  */
327 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
328                              const u8 profile, const u8 index,
329                              const struct tomoyo_acl_info *matched_acl,
330                              const bool is_granted)
331 {
332         u8 mode;
333         const u8 category = tomoyo_index2category[index] +
334                 TOMOYO_MAX_MAC_INDEX;
335         struct tomoyo_profile *p;
336 
337         if (!tomoyo_policy_loaded)
338                 return false;
339         p = tomoyo_profile(ns, profile);
340         if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
341                 return false;
342         if (is_granted && matched_acl && matched_acl->cond &&
343             matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
344                 return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
345         mode = p->config[index];
346         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
347                 mode = p->config[category];
348         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
349                 mode = p->default_config;
350         if (is_granted)
351                 return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
352         return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
353 }
354 
355 /**
356  * tomoyo_write_log2 - Write an audit log.
357  *
358  * @r:    Pointer to "struct tomoyo_request_info".
359  * @len:  Buffer size needed for @fmt and @args.
360  * @fmt:  The printf()'s format string.
361  * @args: va_list structure for @fmt.
362  *
363  * Returns nothing.
364  */
365 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
366                        va_list args)
367 {
368         char *buf;
369         struct tomoyo_log *entry;
370         bool quota_exceeded = false;
371 
372         if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
373                               r->matched_acl, r->granted))
374                 goto out;
375         buf = tomoyo_init_log(r, len, fmt, args);
376         if (!buf)
377                 goto out;
378         entry = kzalloc(sizeof(*entry), GFP_NOFS);
379         if (!entry) {
380                 kfree(buf);
381                 goto out;
382         }
383         entry->log = buf;
384         len = tomoyo_round2(strlen(buf) + 1);
385         /*
386          * The entry->size is used for memory quota checks.
387          * Don't go beyond strlen(entry->log).
388          */
389         entry->size = len + tomoyo_round2(sizeof(*entry));
390         spin_lock(&tomoyo_log_lock);
391         if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
392             tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
393             tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
394                 quota_exceeded = true;
395         } else {
396                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
397                 list_add_tail(&entry->list, &tomoyo_log);
398                 tomoyo_log_count++;
399         }
400         spin_unlock(&tomoyo_log_lock);
401         if (quota_exceeded) {
402                 kfree(buf);
403                 kfree(entry);
404                 goto out;
405         }
406         wake_up(&tomoyo_log_wait);
407 out:
408         return;
409 }
410 
411 /**
412  * tomoyo_write_log - Write an audit log.
413  *
414  * @r:   Pointer to "struct tomoyo_request_info".
415  * @fmt: The printf()'s format string, followed by parameters.
416  *
417  * Returns nothing.
418  */
419 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
420 {
421         va_list args;
422         int len;
423 
424         va_start(args, fmt);
425         len = vsnprintf((char *) &len, 1, fmt, args) + 1;
426         va_end(args);
427         va_start(args, fmt);
428         tomoyo_write_log2(r, len, fmt, args);
429         va_end(args);
430 }
431 
432 /**
433  * tomoyo_read_log - Read an audit log.
434  *
435  * @head: Pointer to "struct tomoyo_io_buffer".
436  *
437  * Returns nothing.
438  */
439 void tomoyo_read_log(struct tomoyo_io_buffer *head)
440 {
441         struct tomoyo_log *ptr = NULL;
442 
443         if (head->r.w_pos)
444                 return;
445         kfree(head->read_buf);
446         head->read_buf = NULL;
447         spin_lock(&tomoyo_log_lock);
448         if (!list_empty(&tomoyo_log)) {
449                 ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
450                 list_del(&ptr->list);
451                 tomoyo_log_count--;
452                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
453         }
454         spin_unlock(&tomoyo_log_lock);
455         if (ptr) {
456                 head->read_buf = ptr->log;
457                 head->r.w[head->r.w_pos++] = head->read_buf;
458                 kfree(ptr);
459         }
460 }
461 
462 /**
463  * tomoyo_poll_log - Wait for an audit log.
464  *
465  * @file: Pointer to "struct file".
466  * @wait: Pointer to "poll_table". Maybe NULL.
467  *
468  * Returns EPOLLIN | EPOLLRDNORM when ready to read an audit log.
469  */
470 __poll_t tomoyo_poll_log(struct file *file, poll_table *wait)
471 {
472         if (tomoyo_log_count)
473                 return EPOLLIN | EPOLLRDNORM;
474         poll_wait(file, &tomoyo_log_wait, wait);
475         if (tomoyo_log_count)
476                 return EPOLLIN | EPOLLRDNORM;
477         return 0;
478 }
479 

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