Merge tag 'docs-5.12' of git://git.lwn.net/linux
[linux-2.6-microblaze.git] / security / tomoyo / domain.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * security/tomoyo/domain.c
4  *
5  * Copyright (C) 2005-2011  NTT DATA CORPORATION
6  */
7
8 #include "common.h"
9
10 #include <linux/binfmts.h>
11 #include <linux/slab.h>
12 #include <linux/rculist.h>
13
14 /* Variables definitions.*/
15
16 /* The initial domain. */
17 struct tomoyo_domain_info tomoyo_kernel_domain;
18
19 /**
20  * tomoyo_update_policy - Update an entry for exception policy.
21  *
22  * @new_entry:       Pointer to "struct tomoyo_acl_info".
23  * @size:            Size of @new_entry in bytes.
24  * @param:           Pointer to "struct tomoyo_acl_param".
25  * @check_duplicate: Callback function to find duplicated entry.
26  *
27  * Returns 0 on success, negative value otherwise.
28  *
29  * Caller holds tomoyo_read_lock().
30  */
31 int tomoyo_update_policy(struct tomoyo_acl_head *new_entry, const int size,
32                          struct tomoyo_acl_param *param,
33                          bool (*check_duplicate)(const struct tomoyo_acl_head
34                                                  *,
35                                                  const struct tomoyo_acl_head
36                                                  *))
37 {
38         int error = param->is_delete ? -ENOENT : -ENOMEM;
39         struct tomoyo_acl_head *entry;
40         struct list_head *list = param->list;
41
42         if (mutex_lock_interruptible(&tomoyo_policy_lock))
43                 return -ENOMEM;
44         list_for_each_entry_rcu(entry, list, list,
45                                 srcu_read_lock_held(&tomoyo_ss)) {
46                 if (entry->is_deleted == TOMOYO_GC_IN_PROGRESS)
47                         continue;
48                 if (!check_duplicate(entry, new_entry))
49                         continue;
50                 entry->is_deleted = param->is_delete;
51                 error = 0;
52                 break;
53         }
54         if (error && !param->is_delete) {
55                 entry = tomoyo_commit_ok(new_entry, size);
56                 if (entry) {
57                         list_add_tail_rcu(&entry->list, list);
58                         error = 0;
59                 }
60         }
61         mutex_unlock(&tomoyo_policy_lock);
62         return error;
63 }
64
65 /**
66  * tomoyo_same_acl_head - Check for duplicated "struct tomoyo_acl_info" entry.
67  *
68  * @a: Pointer to "struct tomoyo_acl_info".
69  * @b: Pointer to "struct tomoyo_acl_info".
70  *
71  * Returns true if @a == @b, false otherwise.
72  */
73 static inline bool tomoyo_same_acl_head(const struct tomoyo_acl_info *a,
74                                         const struct tomoyo_acl_info *b)
75 {
76         return a->type == b->type && a->cond == b->cond;
77 }
78
79 /**
80  * tomoyo_update_domain - Update an entry for domain policy.
81  *
82  * @new_entry:       Pointer to "struct tomoyo_acl_info".
83  * @size:            Size of @new_entry in bytes.
84  * @param:           Pointer to "struct tomoyo_acl_param".
85  * @check_duplicate: Callback function to find duplicated entry.
86  * @merge_duplicate: Callback function to merge duplicated entry.
87  *
88  * Returns 0 on success, negative value otherwise.
89  *
90  * Caller holds tomoyo_read_lock().
91  */
92 int tomoyo_update_domain(struct tomoyo_acl_info *new_entry, const int size,
93                          struct tomoyo_acl_param *param,
94                          bool (*check_duplicate)(const struct tomoyo_acl_info
95                                                  *,
96                                                  const struct tomoyo_acl_info
97                                                  *),
98                          bool (*merge_duplicate)(struct tomoyo_acl_info *,
99                                                  struct tomoyo_acl_info *,
100                                                  const bool))
101 {
102         const bool is_delete = param->is_delete;
103         int error = is_delete ? -ENOENT : -ENOMEM;
104         struct tomoyo_acl_info *entry;
105         struct list_head * const list = param->list;
106
107         if (param->data[0]) {
108                 new_entry->cond = tomoyo_get_condition(param);
109                 if (!new_entry->cond)
110                         return -EINVAL;
111                 /*
112                  * Domain transition preference is allowed for only
113                  * "file execute" entries.
114                  */
115                 if (new_entry->cond->transit &&
116                     !(new_entry->type == TOMOYO_TYPE_PATH_ACL &&
117                       container_of(new_entry, struct tomoyo_path_acl, head)
118                       ->perm == 1 << TOMOYO_TYPE_EXECUTE))
119                         goto out;
120         }
121         if (mutex_lock_interruptible(&tomoyo_policy_lock))
122                 goto out;
123         list_for_each_entry_rcu(entry, list, list,
124                                 srcu_read_lock_held(&tomoyo_ss)) {
125                 if (entry->is_deleted == TOMOYO_GC_IN_PROGRESS)
126                         continue;
127                 if (!tomoyo_same_acl_head(entry, new_entry) ||
128                     !check_duplicate(entry, new_entry))
129                         continue;
130                 if (merge_duplicate)
131                         entry->is_deleted = merge_duplicate(entry, new_entry,
132                                                             is_delete);
133                 else
134                         entry->is_deleted = is_delete;
135                 error = 0;
136                 break;
137         }
138         if (error && !is_delete) {
139                 entry = tomoyo_commit_ok(new_entry, size);
140                 if (entry) {
141                         list_add_tail_rcu(&entry->list, list);
142                         error = 0;
143                 }
144         }
145         mutex_unlock(&tomoyo_policy_lock);
146 out:
147         tomoyo_put_condition(new_entry->cond);
148         return error;
149 }
150
151 /**
152  * tomoyo_check_acl - Do permission check.
153  *
154  * @r:           Pointer to "struct tomoyo_request_info".
155  * @check_entry: Callback function to check type specific parameters.
156  *
157  * Returns 0 on success, negative value otherwise.
158  *
159  * Caller holds tomoyo_read_lock().
160  */
161 void tomoyo_check_acl(struct tomoyo_request_info *r,
162                       bool (*check_entry)(struct tomoyo_request_info *,
163                                           const struct tomoyo_acl_info *))
164 {
165         const struct tomoyo_domain_info *domain = r->domain;
166         struct tomoyo_acl_info *ptr;
167         const struct list_head *list = &domain->acl_info_list;
168         u16 i = 0;
169
170 retry:
171         list_for_each_entry_rcu(ptr, list, list,
172                                 srcu_read_lock_held(&tomoyo_ss)) {
173                 if (ptr->is_deleted || ptr->type != r->param_type)
174                         continue;
175                 if (!check_entry(r, ptr))
176                         continue;
177                 if (!tomoyo_condition(r, ptr->cond))
178                         continue;
179                 r->matched_acl = ptr;
180                 r->granted = true;
181                 return;
182         }
183         for (; i < TOMOYO_MAX_ACL_GROUPS; i++) {
184                 if (!test_bit(i, domain->group))
185                         continue;
186                 list = &domain->ns->acl_group[i++];
187                 goto retry;
188         }
189         r->granted = false;
190 }
191
192 /* The list for "struct tomoyo_domain_info". */
193 LIST_HEAD(tomoyo_domain_list);
194
195 /**
196  * tomoyo_last_word - Get last component of a domainname.
197  *
198  * @name: Domainname to check.
199  *
200  * Returns the last word of @domainname.
201  */
202 static const char *tomoyo_last_word(const char *name)
203 {
204         const char *cp = strrchr(name, ' ');
205
206         if (cp)
207                 return cp + 1;
208         return name;
209 }
210
211 /**
212  * tomoyo_same_transition_control - Check for duplicated "struct tomoyo_transition_control" entry.
213  *
214  * @a: Pointer to "struct tomoyo_acl_head".
215  * @b: Pointer to "struct tomoyo_acl_head".
216  *
217  * Returns true if @a == @b, false otherwise.
218  */
219 static bool tomoyo_same_transition_control(const struct tomoyo_acl_head *a,
220                                            const struct tomoyo_acl_head *b)
221 {
222         const struct tomoyo_transition_control *p1 = container_of(a,
223                                                                   typeof(*p1),
224                                                                   head);
225         const struct tomoyo_transition_control *p2 = container_of(b,
226                                                                   typeof(*p2),
227                                                                   head);
228
229         return p1->type == p2->type && p1->is_last_name == p2->is_last_name
230                 && p1->domainname == p2->domainname
231                 && p1->program == p2->program;
232 }
233
234 /**
235  * tomoyo_write_transition_control - Write "struct tomoyo_transition_control" list.
236  *
237  * @param: Pointer to "struct tomoyo_acl_param".
238  * @type:  Type of this entry.
239  *
240  * Returns 0 on success, negative value otherwise.
241  */
242 int tomoyo_write_transition_control(struct tomoyo_acl_param *param,
243                                     const u8 type)
244 {
245         struct tomoyo_transition_control e = { .type = type };
246         int error = param->is_delete ? -ENOENT : -ENOMEM;
247         char *program = param->data;
248         char *domainname = strstr(program, " from ");
249
250         if (domainname) {
251                 *domainname = '\0';
252                 domainname += 6;
253         } else if (type == TOMOYO_TRANSITION_CONTROL_NO_KEEP ||
254                    type == TOMOYO_TRANSITION_CONTROL_KEEP) {
255                 domainname = program;
256                 program = NULL;
257         }
258         if (program && strcmp(program, "any")) {
259                 if (!tomoyo_correct_path(program))
260                         return -EINVAL;
261                 e.program = tomoyo_get_name(program);
262                 if (!e.program)
263                         goto out;
264         }
265         if (domainname && strcmp(domainname, "any")) {
266                 if (!tomoyo_correct_domain(domainname)) {
267                         if (!tomoyo_correct_path(domainname))
268                                 goto out;
269                         e.is_last_name = true;
270                 }
271                 e.domainname = tomoyo_get_name(domainname);
272                 if (!e.domainname)
273                         goto out;
274         }
275         param->list = &param->ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
276         error = tomoyo_update_policy(&e.head, sizeof(e), param,
277                                      tomoyo_same_transition_control);
278 out:
279         tomoyo_put_name(e.domainname);
280         tomoyo_put_name(e.program);
281         return error;
282 }
283
284 /**
285  * tomoyo_scan_transition - Try to find specific domain transition type.
286  *
287  * @list:       Pointer to "struct list_head".
288  * @domainname: The name of current domain.
289  * @program:    The name of requested program.
290  * @last_name:  The last component of @domainname.
291  * @type:       One of values in "enum tomoyo_transition_type".
292  *
293  * Returns true if found one, false otherwise.
294  *
295  * Caller holds tomoyo_read_lock().
296  */
297 static inline bool tomoyo_scan_transition
298 (const struct list_head *list, const struct tomoyo_path_info *domainname,
299  const struct tomoyo_path_info *program, const char *last_name,
300  const enum tomoyo_transition_type type)
301 {
302         const struct tomoyo_transition_control *ptr;
303
304         list_for_each_entry_rcu(ptr, list, head.list,
305                                 srcu_read_lock_held(&tomoyo_ss)) {
306                 if (ptr->head.is_deleted || ptr->type != type)
307                         continue;
308                 if (ptr->domainname) {
309                         if (!ptr->is_last_name) {
310                                 if (ptr->domainname != domainname)
311                                         continue;
312                         } else {
313                                 /*
314                                  * Use direct strcmp() since this is
315                                  * unlikely used.
316                                  */
317                                 if (strcmp(ptr->domainname->name, last_name))
318                                         continue;
319                         }
320                 }
321                 if (ptr->program && tomoyo_pathcmp(ptr->program, program))
322                         continue;
323                 return true;
324         }
325         return false;
326 }
327
328 /**
329  * tomoyo_transition_type - Get domain transition type.
330  *
331  * @ns:         Pointer to "struct tomoyo_policy_namespace".
332  * @domainname: The name of current domain.
333  * @program:    The name of requested program.
334  *
335  * Returns TOMOYO_TRANSITION_CONTROL_TRANSIT if executing @program causes
336  * domain transition across namespaces, TOMOYO_TRANSITION_CONTROL_INITIALIZE if
337  * executing @program reinitializes domain transition within that namespace,
338  * TOMOYO_TRANSITION_CONTROL_KEEP if executing @program stays at @domainname ,
339  * others otherwise.
340  *
341  * Caller holds tomoyo_read_lock().
342  */
343 static enum tomoyo_transition_type tomoyo_transition_type
344 (const struct tomoyo_policy_namespace *ns,
345  const struct tomoyo_path_info *domainname,
346  const struct tomoyo_path_info *program)
347 {
348         const char *last_name = tomoyo_last_word(domainname->name);
349         enum tomoyo_transition_type type = TOMOYO_TRANSITION_CONTROL_NO_RESET;
350
351         while (type < TOMOYO_MAX_TRANSITION_TYPE) {
352                 const struct list_head * const list =
353                         &ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
354
355                 if (!tomoyo_scan_transition(list, domainname, program,
356                                             last_name, type)) {
357                         type++;
358                         continue;
359                 }
360                 if (type != TOMOYO_TRANSITION_CONTROL_NO_RESET &&
361                     type != TOMOYO_TRANSITION_CONTROL_NO_INITIALIZE)
362                         break;
363                 /*
364                  * Do not check for reset_domain if no_reset_domain matched.
365                  * Do not check for initialize_domain if no_initialize_domain
366                  * matched.
367                  */
368                 type++;
369                 type++;
370         }
371         return type;
372 }
373
374 /**
375  * tomoyo_same_aggregator - Check for duplicated "struct tomoyo_aggregator" entry.
376  *
377  * @a: Pointer to "struct tomoyo_acl_head".
378  * @b: Pointer to "struct tomoyo_acl_head".
379  *
380  * Returns true if @a == @b, false otherwise.
381  */
382 static bool tomoyo_same_aggregator(const struct tomoyo_acl_head *a,
383                                    const struct tomoyo_acl_head *b)
384 {
385         const struct tomoyo_aggregator *p1 = container_of(a, typeof(*p1),
386                                                           head);
387         const struct tomoyo_aggregator *p2 = container_of(b, typeof(*p2),
388                                                           head);
389
390         return p1->original_name == p2->original_name &&
391                 p1->aggregated_name == p2->aggregated_name;
392 }
393
394 /**
395  * tomoyo_write_aggregator - Write "struct tomoyo_aggregator" list.
396  *
397  * @param: Pointer to "struct tomoyo_acl_param".
398  *
399  * Returns 0 on success, negative value otherwise.
400  *
401  * Caller holds tomoyo_read_lock().
402  */
403 int tomoyo_write_aggregator(struct tomoyo_acl_param *param)
404 {
405         struct tomoyo_aggregator e = { };
406         int error = param->is_delete ? -ENOENT : -ENOMEM;
407         const char *original_name = tomoyo_read_token(param);
408         const char *aggregated_name = tomoyo_read_token(param);
409
410         if (!tomoyo_correct_word(original_name) ||
411             !tomoyo_correct_path(aggregated_name))
412                 return -EINVAL;
413         e.original_name = tomoyo_get_name(original_name);
414         e.aggregated_name = tomoyo_get_name(aggregated_name);
415         if (!e.original_name || !e.aggregated_name ||
416             e.aggregated_name->is_patterned) /* No patterns allowed. */
417                 goto out;
418         param->list = &param->ns->policy_list[TOMOYO_ID_AGGREGATOR];
419         error = tomoyo_update_policy(&e.head, sizeof(e), param,
420                                      tomoyo_same_aggregator);
421 out:
422         tomoyo_put_name(e.original_name);
423         tomoyo_put_name(e.aggregated_name);
424         return error;
425 }
426
427 /**
428  * tomoyo_find_namespace - Find specified namespace.
429  *
430  * @name: Name of namespace to find.
431  * @len:  Length of @name.
432  *
433  * Returns pointer to "struct tomoyo_policy_namespace" if found,
434  * NULL otherwise.
435  *
436  * Caller holds tomoyo_read_lock().
437  */
438 static struct tomoyo_policy_namespace *tomoyo_find_namespace
439 (const char *name, const unsigned int len)
440 {
441         struct tomoyo_policy_namespace *ns;
442
443         list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) {
444                 if (strncmp(name, ns->name, len) ||
445                     (name[len] && name[len] != ' '))
446                         continue;
447                 return ns;
448         }
449         return NULL;
450 }
451
452 /**
453  * tomoyo_assign_namespace - Create a new namespace.
454  *
455  * @domainname: Name of namespace to create.
456  *
457  * Returns pointer to "struct tomoyo_policy_namespace" on success,
458  * NULL otherwise.
459  *
460  * Caller holds tomoyo_read_lock().
461  */
462 struct tomoyo_policy_namespace *tomoyo_assign_namespace(const char *domainname)
463 {
464         struct tomoyo_policy_namespace *ptr;
465         struct tomoyo_policy_namespace *entry;
466         const char *cp = domainname;
467         unsigned int len = 0;
468
469         while (*cp && *cp++ != ' ')
470                 len++;
471         ptr = tomoyo_find_namespace(domainname, len);
472         if (ptr)
473                 return ptr;
474         if (len >= TOMOYO_EXEC_TMPSIZE - 10 || !tomoyo_domain_def(domainname))
475                 return NULL;
476         entry = kzalloc(sizeof(*entry) + len + 1, GFP_NOFS | __GFP_NOWARN);
477         if (mutex_lock_interruptible(&tomoyo_policy_lock))
478                 goto out;
479         ptr = tomoyo_find_namespace(domainname, len);
480         if (!ptr && tomoyo_memory_ok(entry)) {
481                 char *name = (char *) (entry + 1);
482
483                 ptr = entry;
484                 memmove(name, domainname, len);
485                 name[len] = '\0';
486                 entry->name = name;
487                 tomoyo_init_policy_namespace(entry);
488                 entry = NULL;
489         }
490         mutex_unlock(&tomoyo_policy_lock);
491 out:
492         kfree(entry);
493         return ptr;
494 }
495
496 /**
497  * tomoyo_namespace_jump - Check for namespace jump.
498  *
499  * @domainname: Name of domain.
500  *
501  * Returns true if namespace differs, false otherwise.
502  */
503 static bool tomoyo_namespace_jump(const char *domainname)
504 {
505         const char *namespace = tomoyo_current_namespace()->name;
506         const int len = strlen(namespace);
507
508         return strncmp(domainname, namespace, len) ||
509                 (domainname[len] && domainname[len] != ' ');
510 }
511
512 /**
513  * tomoyo_assign_domain - Create a domain or a namespace.
514  *
515  * @domainname: The name of domain.
516  * @transit:    True if transit to domain found or created.
517  *
518  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
519  *
520  * Caller holds tomoyo_read_lock().
521  */
522 struct tomoyo_domain_info *tomoyo_assign_domain(const char *domainname,
523                                                 const bool transit)
524 {
525         struct tomoyo_domain_info e = { };
526         struct tomoyo_domain_info *entry = tomoyo_find_domain(domainname);
527         bool created = false;
528
529         if (entry) {
530                 if (transit) {
531                         /*
532                          * Since namespace is created at runtime, profiles may
533                          * not be created by the moment the process transits to
534                          * that domain. Do not perform domain transition if
535                          * profile for that domain is not yet created.
536                          */
537                         if (tomoyo_policy_loaded &&
538                             !entry->ns->profile_ptr[entry->profile])
539                                 return NULL;
540                 }
541                 return entry;
542         }
543         /* Requested domain does not exist. */
544         /* Don't create requested domain if domainname is invalid. */
545         if (strlen(domainname) >= TOMOYO_EXEC_TMPSIZE - 10 ||
546             !tomoyo_correct_domain(domainname))
547                 return NULL;
548         /*
549          * Since definition of profiles and acl_groups may differ across
550          * namespaces, do not inherit "use_profile" and "use_group" settings
551          * by automatically creating requested domain upon domain transition.
552          */
553         if (transit && tomoyo_namespace_jump(domainname))
554                 return NULL;
555         e.ns = tomoyo_assign_namespace(domainname);
556         if (!e.ns)
557                 return NULL;
558         /*
559          * "use_profile" and "use_group" settings for automatically created
560          * domains are inherited from current domain. These are 0 for manually
561          * created domains.
562          */
563         if (transit) {
564                 const struct tomoyo_domain_info *domain = tomoyo_domain();
565
566                 e.profile = domain->profile;
567                 memcpy(e.group, domain->group, sizeof(e.group));
568         }
569         e.domainname = tomoyo_get_name(domainname);
570         if (!e.domainname)
571                 return NULL;
572         if (mutex_lock_interruptible(&tomoyo_policy_lock))
573                 goto out;
574         entry = tomoyo_find_domain(domainname);
575         if (!entry) {
576                 entry = tomoyo_commit_ok(&e, sizeof(e));
577                 if (entry) {
578                         INIT_LIST_HEAD(&entry->acl_info_list);
579                         list_add_tail_rcu(&entry->list, &tomoyo_domain_list);
580                         created = true;
581                 }
582         }
583         mutex_unlock(&tomoyo_policy_lock);
584 out:
585         tomoyo_put_name(e.domainname);
586         if (entry && transit) {
587                 if (created) {
588                         struct tomoyo_request_info r;
589                         int i;
590
591                         tomoyo_init_request_info(&r, entry,
592                                                  TOMOYO_MAC_FILE_EXECUTE);
593                         r.granted = false;
594                         tomoyo_write_log(&r, "use_profile %u\n",
595                                          entry->profile);
596                         for (i = 0; i < TOMOYO_MAX_ACL_GROUPS; i++)
597                                 if (test_bit(i, entry->group))
598                                         tomoyo_write_log(&r, "use_group %u\n",
599                                                          i);
600                         tomoyo_update_stat(TOMOYO_STAT_POLICY_UPDATES);
601                 }
602         }
603         return entry;
604 }
605
606 /**
607  * tomoyo_environ - Check permission for environment variable names.
608  *
609  * @ee: Pointer to "struct tomoyo_execve".
610  *
611  * Returns 0 on success, negative value otherwise.
612  */
613 static int tomoyo_environ(struct tomoyo_execve *ee)
614 {
615         struct tomoyo_request_info *r = &ee->r;
616         struct linux_binprm *bprm = ee->bprm;
617         /* env_page.data is allocated by tomoyo_dump_page(). */
618         struct tomoyo_page_dump env_page = { };
619         char *arg_ptr; /* Size is TOMOYO_EXEC_TMPSIZE bytes */
620         int arg_len = 0;
621         unsigned long pos = bprm->p;
622         int offset = pos % PAGE_SIZE;
623         int argv_count = bprm->argc;
624         int envp_count = bprm->envc;
625         int error = -ENOMEM;
626
627         ee->r.type = TOMOYO_MAC_ENVIRON;
628         ee->r.profile = r->domain->profile;
629         ee->r.mode = tomoyo_get_mode(r->domain->ns, ee->r.profile,
630                                      TOMOYO_MAC_ENVIRON);
631         if (!r->mode || !envp_count)
632                 return 0;
633         arg_ptr = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
634         if (!arg_ptr)
635                 goto out;
636         while (error == -ENOMEM) {
637                 if (!tomoyo_dump_page(bprm, pos, &env_page))
638                         goto out;
639                 pos += PAGE_SIZE - offset;
640                 /* Read. */
641                 while (argv_count && offset < PAGE_SIZE) {
642                         if (!env_page.data[offset++])
643                                 argv_count--;
644                 }
645                 if (argv_count) {
646                         offset = 0;
647                         continue;
648                 }
649                 while (offset < PAGE_SIZE) {
650                         const unsigned char c = env_page.data[offset++];
651
652                         if (c && arg_len < TOMOYO_EXEC_TMPSIZE - 10) {
653                                 if (c == '=') {
654                                         arg_ptr[arg_len++] = '\0';
655                                 } else if (c == '\\') {
656                                         arg_ptr[arg_len++] = '\\';
657                                         arg_ptr[arg_len++] = '\\';
658                                 } else if (c > ' ' && c < 127) {
659                                         arg_ptr[arg_len++] = c;
660                                 } else {
661                                         arg_ptr[arg_len++] = '\\';
662                                         arg_ptr[arg_len++] = (c >> 6) + '0';
663                                         arg_ptr[arg_len++]
664                                                 = ((c >> 3) & 7) + '0';
665                                         arg_ptr[arg_len++] = (c & 7) + '0';
666                                 }
667                         } else {
668                                 arg_ptr[arg_len] = '\0';
669                         }
670                         if (c)
671                                 continue;
672                         if (tomoyo_env_perm(r, arg_ptr)) {
673                                 error = -EPERM;
674                                 break;
675                         }
676                         if (!--envp_count) {
677                                 error = 0;
678                                 break;
679                         }
680                         arg_len = 0;
681                 }
682                 offset = 0;
683         }
684 out:
685         if (r->mode != TOMOYO_CONFIG_ENFORCING)
686                 error = 0;
687         kfree(env_page.data);
688         kfree(arg_ptr);
689         return error;
690 }
691
692 /**
693  * tomoyo_find_next_domain - Find a domain.
694  *
695  * @bprm: Pointer to "struct linux_binprm".
696  *
697  * Returns 0 on success, negative value otherwise.
698  *
699  * Caller holds tomoyo_read_lock().
700  */
701 int tomoyo_find_next_domain(struct linux_binprm *bprm)
702 {
703         struct tomoyo_domain_info *old_domain = tomoyo_domain();
704         struct tomoyo_domain_info *domain = NULL;
705         const char *original_name = bprm->filename;
706         int retval = -ENOMEM;
707         bool reject_on_transition_failure = false;
708         const struct tomoyo_path_info *candidate;
709         struct tomoyo_path_info exename;
710         struct tomoyo_execve *ee = kzalloc(sizeof(*ee), GFP_NOFS);
711
712         if (!ee)
713                 return -ENOMEM;
714         ee->tmp = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
715         if (!ee->tmp) {
716                 kfree(ee);
717                 return -ENOMEM;
718         }
719         /* ee->dump->data is allocated by tomoyo_dump_page(). */
720         tomoyo_init_request_info(&ee->r, NULL, TOMOYO_MAC_FILE_EXECUTE);
721         ee->r.ee = ee;
722         ee->bprm = bprm;
723         ee->r.obj = &ee->obj;
724         ee->obj.path1 = bprm->file->f_path;
725         /* Get symlink's pathname of program. */
726         retval = -ENOENT;
727         exename.name = tomoyo_realpath_nofollow(original_name);
728         if (!exename.name)
729                 goto out;
730         tomoyo_fill_path_info(&exename);
731 retry:
732         /* Check 'aggregator' directive. */
733         {
734                 struct tomoyo_aggregator *ptr;
735                 struct list_head *list =
736                         &old_domain->ns->policy_list[TOMOYO_ID_AGGREGATOR];
737
738                 /* Check 'aggregator' directive. */
739                 candidate = &exename;
740                 list_for_each_entry_rcu(ptr, list, head.list,
741                                         srcu_read_lock_held(&tomoyo_ss)) {
742                         if (ptr->head.is_deleted ||
743                             !tomoyo_path_matches_pattern(&exename,
744                                                          ptr->original_name))
745                                 continue;
746                         candidate = ptr->aggregated_name;
747                         break;
748                 }
749         }
750
751         /* Check execute permission. */
752         retval = tomoyo_execute_permission(&ee->r, candidate);
753         if (retval == TOMOYO_RETRY_REQUEST)
754                 goto retry;
755         if (retval < 0)
756                 goto out;
757         /*
758          * To be able to specify domainnames with wildcards, use the
759          * pathname specified in the policy (which may contain
760          * wildcard) rather than the pathname passed to execve()
761          * (which never contains wildcard).
762          */
763         if (ee->r.param.path.matched_path)
764                 candidate = ee->r.param.path.matched_path;
765
766         /*
767          * Check for domain transition preference if "file execute" matched.
768          * If preference is given, make execve() fail if domain transition
769          * has failed, for domain transition preference should be used with
770          * destination domain defined.
771          */
772         if (ee->transition) {
773                 const char *domainname = ee->transition->name;
774
775                 reject_on_transition_failure = true;
776                 if (!strcmp(domainname, "keep"))
777                         goto force_keep_domain;
778                 if (!strcmp(domainname, "child"))
779                         goto force_child_domain;
780                 if (!strcmp(domainname, "reset"))
781                         goto force_reset_domain;
782                 if (!strcmp(domainname, "initialize"))
783                         goto force_initialize_domain;
784                 if (!strcmp(domainname, "parent")) {
785                         char *cp;
786
787                         strncpy(ee->tmp, old_domain->domainname->name,
788                                 TOMOYO_EXEC_TMPSIZE - 1);
789                         cp = strrchr(ee->tmp, ' ');
790                         if (cp)
791                                 *cp = '\0';
792                 } else if (*domainname == '<')
793                         strncpy(ee->tmp, domainname, TOMOYO_EXEC_TMPSIZE - 1);
794                 else
795                         snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
796                                  old_domain->domainname->name, domainname);
797                 goto force_jump_domain;
798         }
799         /*
800          * No domain transition preference specified.
801          * Calculate domain to transit to.
802          */
803         switch (tomoyo_transition_type(old_domain->ns, old_domain->domainname,
804                                        candidate)) {
805         case TOMOYO_TRANSITION_CONTROL_RESET:
806 force_reset_domain:
807                 /* Transit to the root of specified namespace. */
808                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "<%s>",
809                          candidate->name);
810                 /*
811                  * Make execve() fail if domain transition across namespaces
812                  * has failed.
813                  */
814                 reject_on_transition_failure = true;
815                 break;
816         case TOMOYO_TRANSITION_CONTROL_INITIALIZE:
817 force_initialize_domain:
818                 /* Transit to the child of current namespace's root. */
819                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
820                          old_domain->ns->name, candidate->name);
821                 break;
822         case TOMOYO_TRANSITION_CONTROL_KEEP:
823 force_keep_domain:
824                 /* Keep current domain. */
825                 domain = old_domain;
826                 break;
827         default:
828                 if (old_domain == &tomoyo_kernel_domain &&
829                     !tomoyo_policy_loaded) {
830                         /*
831                          * Needn't to transit from kernel domain before
832                          * starting /sbin/init. But transit from kernel domain
833                          * if executing initializers because they might start
834                          * before /sbin/init.
835                          */
836                         domain = old_domain;
837                         break;
838                 }
839 force_child_domain:
840                 /* Normal domain transition. */
841                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
842                          old_domain->domainname->name, candidate->name);
843                 break;
844         }
845 force_jump_domain:
846         if (!domain)
847                 domain = tomoyo_assign_domain(ee->tmp, true);
848         if (domain)
849                 retval = 0;
850         else if (reject_on_transition_failure) {
851                 pr_warn("ERROR: Domain '%s' not ready.\n", ee->tmp);
852                 retval = -ENOMEM;
853         } else if (ee->r.mode == TOMOYO_CONFIG_ENFORCING)
854                 retval = -ENOMEM;
855         else {
856                 retval = 0;
857                 if (!old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED]) {
858                         old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED] = true;
859                         ee->r.granted = false;
860                         tomoyo_write_log(&ee->r, "%s", tomoyo_dif
861                                          [TOMOYO_DIF_TRANSITION_FAILED]);
862                         pr_warn("ERROR: Domain '%s' not defined.\n", ee->tmp);
863                 }
864         }
865  out:
866         if (!domain)
867                 domain = old_domain;
868         /* Update reference count on "struct tomoyo_domain_info". */
869         {
870                 struct tomoyo_task *s = tomoyo_task(current);
871
872                 s->old_domain_info = s->domain_info;
873                 s->domain_info = domain;
874                 atomic_inc(&domain->users);
875         }
876         kfree(exename.name);
877         if (!retval) {
878                 ee->r.domain = domain;
879                 retval = tomoyo_environ(ee);
880         }
881         kfree(ee->tmp);
882         kfree(ee->dump.data);
883         kfree(ee);
884         return retval;
885 }
886
887 /**
888  * tomoyo_dump_page - Dump a page to buffer.
889  *
890  * @bprm: Pointer to "struct linux_binprm".
891  * @pos:  Location to dump.
892  * @dump: Pointer to "struct tomoyo_page_dump".
893  *
894  * Returns true on success, false otherwise.
895  */
896 bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
897                       struct tomoyo_page_dump *dump)
898 {
899         struct page *page;
900
901         /* dump->data is released by tomoyo_find_next_domain(). */
902         if (!dump->data) {
903                 dump->data = kzalloc(PAGE_SIZE, GFP_NOFS);
904                 if (!dump->data)
905                         return false;
906         }
907         /* Same with get_arg_page(bprm, pos, 0) in fs/exec.c */
908 #ifdef CONFIG_MMU
909         /*
910          * This is called at execve() time in order to dig around
911          * in the argv/environment of the new proceess
912          * (represented by bprm).  'current' is the process doing
913          * the execve().
914          */
915         if (get_user_pages_remote(bprm->mm, pos, 1,
916                                 FOLL_FORCE, &page, NULL, NULL) <= 0)
917                 return false;
918 #else
919         page = bprm->page[pos / PAGE_SIZE];
920 #endif
921         if (page != dump->page) {
922                 const unsigned int offset = pos % PAGE_SIZE;
923                 /*
924                  * Maybe kmap()/kunmap() should be used here.
925                  * But remove_arg_zero() uses kmap_atomic()/kunmap_atomic().
926                  * So do I.
927                  */
928                 char *kaddr = kmap_atomic(page);
929
930                 dump->page = page;
931                 memcpy(dump->data + offset, kaddr + offset,
932                        PAGE_SIZE - offset);
933                 kunmap_atomic(kaddr);
934         }
935         /* Same with put_arg_page(page) in fs/exec.c */
936 #ifdef CONFIG_MMU
937         put_page(page);
938 #endif
939         return true;
940 }