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. */
 17struct 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 */
 31int 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 */
 73static 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 */
 92int 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);
146out:
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 */
161void 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
170retry:
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". */
193LIST_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 */
202static 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 */
219static 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 */
242int 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);
278out:
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 */
297static 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 */
343static 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 */
382static 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 */
403int 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);
421out:
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 */
438static 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 */
462struct 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);
491out:
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 */
503static 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 */
522struct 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);
584out:
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 */
613static 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	}
684out:
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 */
701int 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	/*
726	 * Get symlink's pathname of program, but fallback to realpath if
727	 * symlink's pathname does not exist or symlink's pathname refers
728	 * to proc filesystem (e.g. /dev/fd/<num> or /proc/self/fd/<num> ).
729	 */
730	exename.name = tomoyo_realpath_nofollow(original_name);
731	if (exename.name && !strncmp(exename.name, "proc:/", 6)) {
732		kfree(exename.name);
733		exename.name = NULL;
734	}
735	if (!exename.name) {
736		exename.name = tomoyo_realpath_from_path(&bprm->file->f_path);
737		if (!exename.name)
738			goto out;
739	}
740	tomoyo_fill_path_info(&exename);
741retry:
742	/* Check 'aggregator' directive. */
743	{
744		struct tomoyo_aggregator *ptr;
745		struct list_head *list =
746			&old_domain->ns->policy_list[TOMOYO_ID_AGGREGATOR];
747
748		/* Check 'aggregator' directive. */
749		candidate = &exename;
750		list_for_each_entry_rcu(ptr, list, head.list,
751					srcu_read_lock_held(&tomoyo_ss)) {
752			if (ptr->head.is_deleted ||
753			    !tomoyo_path_matches_pattern(&exename,
754							 ptr->original_name))
755				continue;
756			candidate = ptr->aggregated_name;
757			break;
758		}
759	}
760
761	/* Check execute permission. */
762	retval = tomoyo_execute_permission(&ee->r, candidate);
763	if (retval == TOMOYO_RETRY_REQUEST)
764		goto retry;
765	if (retval < 0)
766		goto out;
767	/*
768	 * To be able to specify domainnames with wildcards, use the
769	 * pathname specified in the policy (which may contain
770	 * wildcard) rather than the pathname passed to execve()
771	 * (which never contains wildcard).
772	 */
773	if (ee->r.param.path.matched_path)
774		candidate = ee->r.param.path.matched_path;
775
776	/*
777	 * Check for domain transition preference if "file execute" matched.
778	 * If preference is given, make execve() fail if domain transition
779	 * has failed, for domain transition preference should be used with
780	 * destination domain defined.
781	 */
782	if (ee->transition) {
783		const char *domainname = ee->transition->name;
784
785		reject_on_transition_failure = true;
786		if (!strcmp(domainname, "keep"))
787			goto force_keep_domain;
788		if (!strcmp(domainname, "child"))
789			goto force_child_domain;
790		if (!strcmp(domainname, "reset"))
791			goto force_reset_domain;
792		if (!strcmp(domainname, "initialize"))
793			goto force_initialize_domain;
794		if (!strcmp(domainname, "parent")) {
795			char *cp;
796
797			strscpy(ee->tmp, old_domain->domainname->name, TOMOYO_EXEC_TMPSIZE);
798			cp = strrchr(ee->tmp, ' ');
799			if (cp)
800				*cp = '\0';
801		} else if (*domainname == '<')
802			strscpy(ee->tmp, domainname, TOMOYO_EXEC_TMPSIZE);
803		else
804			snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
805				 old_domain->domainname->name, domainname);
806		goto force_jump_domain;
807	}
808	/*
809	 * No domain transition preference specified.
810	 * Calculate domain to transit to.
811	 */
812	switch (tomoyo_transition_type(old_domain->ns, old_domain->domainname,
813				       candidate)) {
814	case TOMOYO_TRANSITION_CONTROL_RESET:
815force_reset_domain:
816		/* Transit to the root of specified namespace. */
817		snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "<%s>",
818			 candidate->name);
819		/*
820		 * Make execve() fail if domain transition across namespaces
821		 * has failed.
822		 */
823		reject_on_transition_failure = true;
824		break;
825	case TOMOYO_TRANSITION_CONTROL_INITIALIZE:
826force_initialize_domain:
827		/* Transit to the child of current namespace's root. */
828		snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
829			 old_domain->ns->name, candidate->name);
830		break;
831	case TOMOYO_TRANSITION_CONTROL_KEEP:
832force_keep_domain:
833		/* Keep current domain. */
834		domain = old_domain;
835		break;
836	default:
837		if (old_domain == &tomoyo_kernel_domain &&
838		    !tomoyo_policy_loaded) {
839			/*
840			 * Needn't to transit from kernel domain before
841			 * starting /sbin/init. But transit from kernel domain
842			 * if executing initializers because they might start
843			 * before /sbin/init.
844			 */
845			domain = old_domain;
846			break;
847		}
848force_child_domain:
849		/* Normal domain transition. */
850		snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
851			 old_domain->domainname->name, candidate->name);
852		break;
853	}
854force_jump_domain:
855	if (!domain)
856		domain = tomoyo_assign_domain(ee->tmp, true);
857	if (domain)
858		retval = 0;
859	else if (reject_on_transition_failure) {
860		pr_warn("ERROR: Domain '%s' not ready.\n", ee->tmp);
861		retval = -ENOMEM;
862	} else if (ee->r.mode == TOMOYO_CONFIG_ENFORCING)
863		retval = -ENOMEM;
864	else {
865		retval = 0;
866		if (!old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED]) {
867			old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED] = true;
868			ee->r.granted = false;
869			tomoyo_write_log(&ee->r, "%s", tomoyo_dif
870					 [TOMOYO_DIF_TRANSITION_FAILED]);
871			pr_warn("ERROR: Domain '%s' not defined.\n", ee->tmp);
872		}
873	}
874 out:
875	if (!domain)
876		domain = old_domain;
877	/* Update reference count on "struct tomoyo_domain_info". */
878	{
879		struct tomoyo_task *s = tomoyo_task(current);
880
881		s->old_domain_info = s->domain_info;
882		s->domain_info = domain;
883		atomic_inc(&domain->users);
884	}
885	kfree(exename.name);
886	if (!retval) {
887		ee->r.domain = domain;
888		retval = tomoyo_environ(ee);
889	}
890	kfree(ee->tmp);
891	kfree(ee->dump.data);
892	kfree(ee);
893	return retval;
894}
895
896/**
897 * tomoyo_dump_page - Dump a page to buffer.
898 *
899 * @bprm: Pointer to "struct linux_binprm".
900 * @pos:  Location to dump.
901 * @dump: Pointer to "struct tomoyo_page_dump".
902 *
903 * Returns true on success, false otherwise.
904 */
905bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
906		      struct tomoyo_page_dump *dump)
907{
908	struct page *page;
909#ifdef CONFIG_MMU
910	int ret;
911#endif
912
913	/* dump->data is released by tomoyo_find_next_domain(). */
914	if (!dump->data) {
915		dump->data = kzalloc(PAGE_SIZE, GFP_NOFS);
916		if (!dump->data)
917			return false;
918	}
919	/* Same with get_arg_page(bprm, pos, 0) in fs/exec.c */
920#ifdef CONFIG_MMU
921	/*
922	 * This is called at execve() time in order to dig around
923	 * in the argv/environment of the new process
924	 * (represented by bprm).
925	 */
926	mmap_read_lock(bprm->mm);
927	ret = get_user_pages_remote(bprm->mm, pos, 1,
928				    FOLL_FORCE, &page, NULL);
929	mmap_read_unlock(bprm->mm);
930	if (ret <= 0)
931		return false;
932#else
933	page = bprm->page[pos / PAGE_SIZE];
934#endif
935	if (page != dump->page) {
936		const unsigned int offset = pos % PAGE_SIZE;
937		char *kaddr = kmap_local_page(page);
938
939		dump->page = page;
940		memcpy(dump->data + offset, kaddr + offset,
941		       PAGE_SIZE - offset);
942		kunmap_local(kaddr);
943	}
944	/* Same with put_arg_page(page) in fs/exec.c */
945#ifdef CONFIG_MMU
946	put_page(page);
947#endif
948	return true;
949}