xref: /linux/security/tomoyo/util.c (revision 4b132aacb0768ac1e652cf517097ea6f237214b9) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * security/tomoyo/util.c
4  *
5  * Copyright (C) 2005-2011  NTT DATA CORPORATION
6  */
7 
8 #include <linux/slab.h>
9 #include <linux/rculist.h>
10 
11 #include "common.h"
12 
13 /* Lock for protecting policy. */
14 DEFINE_MUTEX(tomoyo_policy_lock);
15 
16 /* Has /sbin/init started? */
17 bool tomoyo_policy_loaded;
18 
19 /*
20  * Mapping table from "enum tomoyo_mac_index" to
21  * "enum tomoyo_mac_category_index".
22  */
23 const u8 tomoyo_index2category[TOMOYO_MAX_MAC_INDEX] = {
24 	/* CONFIG::file group */
25 	[TOMOYO_MAC_FILE_EXECUTE]    = TOMOYO_MAC_CATEGORY_FILE,
26 	[TOMOYO_MAC_FILE_OPEN]       = TOMOYO_MAC_CATEGORY_FILE,
27 	[TOMOYO_MAC_FILE_CREATE]     = TOMOYO_MAC_CATEGORY_FILE,
28 	[TOMOYO_MAC_FILE_UNLINK]     = TOMOYO_MAC_CATEGORY_FILE,
29 	[TOMOYO_MAC_FILE_GETATTR]    = TOMOYO_MAC_CATEGORY_FILE,
30 	[TOMOYO_MAC_FILE_MKDIR]      = TOMOYO_MAC_CATEGORY_FILE,
31 	[TOMOYO_MAC_FILE_RMDIR]      = TOMOYO_MAC_CATEGORY_FILE,
32 	[TOMOYO_MAC_FILE_MKFIFO]     = TOMOYO_MAC_CATEGORY_FILE,
33 	[TOMOYO_MAC_FILE_MKSOCK]     = TOMOYO_MAC_CATEGORY_FILE,
34 	[TOMOYO_MAC_FILE_TRUNCATE]   = TOMOYO_MAC_CATEGORY_FILE,
35 	[TOMOYO_MAC_FILE_SYMLINK]    = TOMOYO_MAC_CATEGORY_FILE,
36 	[TOMOYO_MAC_FILE_MKBLOCK]    = TOMOYO_MAC_CATEGORY_FILE,
37 	[TOMOYO_MAC_FILE_MKCHAR]     = TOMOYO_MAC_CATEGORY_FILE,
38 	[TOMOYO_MAC_FILE_LINK]       = TOMOYO_MAC_CATEGORY_FILE,
39 	[TOMOYO_MAC_FILE_RENAME]     = TOMOYO_MAC_CATEGORY_FILE,
40 	[TOMOYO_MAC_FILE_CHMOD]      = TOMOYO_MAC_CATEGORY_FILE,
41 	[TOMOYO_MAC_FILE_CHOWN]      = TOMOYO_MAC_CATEGORY_FILE,
42 	[TOMOYO_MAC_FILE_CHGRP]      = TOMOYO_MAC_CATEGORY_FILE,
43 	[TOMOYO_MAC_FILE_IOCTL]      = TOMOYO_MAC_CATEGORY_FILE,
44 	[TOMOYO_MAC_FILE_CHROOT]     = TOMOYO_MAC_CATEGORY_FILE,
45 	[TOMOYO_MAC_FILE_MOUNT]      = TOMOYO_MAC_CATEGORY_FILE,
46 	[TOMOYO_MAC_FILE_UMOUNT]     = TOMOYO_MAC_CATEGORY_FILE,
47 	[TOMOYO_MAC_FILE_PIVOT_ROOT] = TOMOYO_MAC_CATEGORY_FILE,
48 	/* CONFIG::network group */
49 	[TOMOYO_MAC_NETWORK_INET_STREAM_BIND]       =
50 	TOMOYO_MAC_CATEGORY_NETWORK,
51 	[TOMOYO_MAC_NETWORK_INET_STREAM_LISTEN]     =
52 	TOMOYO_MAC_CATEGORY_NETWORK,
53 	[TOMOYO_MAC_NETWORK_INET_STREAM_CONNECT]    =
54 	TOMOYO_MAC_CATEGORY_NETWORK,
55 	[TOMOYO_MAC_NETWORK_INET_DGRAM_BIND]        =
56 	TOMOYO_MAC_CATEGORY_NETWORK,
57 	[TOMOYO_MAC_NETWORK_INET_DGRAM_SEND]        =
58 	TOMOYO_MAC_CATEGORY_NETWORK,
59 	[TOMOYO_MAC_NETWORK_INET_RAW_BIND]          =
60 	TOMOYO_MAC_CATEGORY_NETWORK,
61 	[TOMOYO_MAC_NETWORK_INET_RAW_SEND]          =
62 	TOMOYO_MAC_CATEGORY_NETWORK,
63 	[TOMOYO_MAC_NETWORK_UNIX_STREAM_BIND]       =
64 	TOMOYO_MAC_CATEGORY_NETWORK,
65 	[TOMOYO_MAC_NETWORK_UNIX_STREAM_LISTEN]     =
66 	TOMOYO_MAC_CATEGORY_NETWORK,
67 	[TOMOYO_MAC_NETWORK_UNIX_STREAM_CONNECT]    =
68 	TOMOYO_MAC_CATEGORY_NETWORK,
69 	[TOMOYO_MAC_NETWORK_UNIX_DGRAM_BIND]        =
70 	TOMOYO_MAC_CATEGORY_NETWORK,
71 	[TOMOYO_MAC_NETWORK_UNIX_DGRAM_SEND]        =
72 	TOMOYO_MAC_CATEGORY_NETWORK,
73 	[TOMOYO_MAC_NETWORK_UNIX_SEQPACKET_BIND]    =
74 	TOMOYO_MAC_CATEGORY_NETWORK,
75 	[TOMOYO_MAC_NETWORK_UNIX_SEQPACKET_LISTEN]  =
76 	TOMOYO_MAC_CATEGORY_NETWORK,
77 	[TOMOYO_MAC_NETWORK_UNIX_SEQPACKET_CONNECT] =
78 	TOMOYO_MAC_CATEGORY_NETWORK,
79 	/* CONFIG::misc group */
80 	[TOMOYO_MAC_ENVIRON]         = TOMOYO_MAC_CATEGORY_MISC,
81 };
82 
83 /**
84  * tomoyo_convert_time - Convert time_t to YYYY/MM/DD hh/mm/ss.
85  *
86  * @time64: Seconds since 1970/01/01 00:00:00.
87  * @stamp:  Pointer to "struct tomoyo_time".
88  *
89  * Returns nothing.
90  */
91 void tomoyo_convert_time(time64_t time64, struct tomoyo_time *stamp)
92 {
93 	struct tm tm;
94 
95 	time64_to_tm(time64, 0, &tm);
96 	stamp->sec = tm.tm_sec;
97 	stamp->min = tm.tm_min;
98 	stamp->hour = tm.tm_hour;
99 	stamp->day = tm.tm_mday;
100 	stamp->month = tm.tm_mon + 1;
101 	stamp->year = tm.tm_year + 1900;
102 }
103 
104 /**
105  * tomoyo_permstr - Find permission keywords.
106  *
107  * @string: String representation for permissions in foo/bar/buz format.
108  * @keyword: Keyword to find from @string/
109  *
110  * Returns true if @keyword was found in @string, false otherwise.
111  *
112  * This function assumes that strncmp(w1, w2, strlen(w1)) != 0 if w1 != w2.
113  */
114 bool tomoyo_permstr(const char *string, const char *keyword)
115 {
116 	const char *cp = strstr(string, keyword);
117 
118 	if (cp)
119 		return cp == string || *(cp - 1) == '/';
120 	return false;
121 }
122 
123 /**
124  * tomoyo_read_token - Read a word from a line.
125  *
126  * @param: Pointer to "struct tomoyo_acl_param".
127  *
128  * Returns a word on success, "" otherwise.
129  *
130  * To allow the caller to skip NULL check, this function returns "" rather than
131  * NULL if there is no more words to read.
132  */
133 char *tomoyo_read_token(struct tomoyo_acl_param *param)
134 {
135 	char *pos = param->data;
136 	char *del = strchr(pos, ' ');
137 
138 	if (del)
139 		*del++ = '\0';
140 	else
141 		del = pos + strlen(pos);
142 	param->data = del;
143 	return pos;
144 }
145 
146 static bool tomoyo_correct_path2(const char *filename, const size_t len);
147 
148 /**
149  * tomoyo_get_domainname - Read a domainname from a line.
150  *
151  * @param: Pointer to "struct tomoyo_acl_param".
152  *
153  * Returns a domainname on success, NULL otherwise.
154  */
155 const struct tomoyo_path_info *tomoyo_get_domainname
156 (struct tomoyo_acl_param *param)
157 {
158 	char *start = param->data;
159 	char *pos = start;
160 
161 	while (*pos) {
162 		if (*pos++ != ' ' ||
163 		    tomoyo_correct_path2(pos, strchrnul(pos, ' ') - pos))
164 			continue;
165 		*(pos - 1) = '\0';
166 		break;
167 	}
168 	param->data = pos;
169 	if (tomoyo_correct_domain(start))
170 		return tomoyo_get_name(start);
171 	return NULL;
172 }
173 
174 /**
175  * tomoyo_parse_ulong - Parse an "unsigned long" value.
176  *
177  * @result: Pointer to "unsigned long".
178  * @str:    Pointer to string to parse.
179  *
180  * Returns one of values in "enum tomoyo_value_type".
181  *
182  * The @src is updated to point the first character after the value
183  * on success.
184  */
185 u8 tomoyo_parse_ulong(unsigned long *result, char **str)
186 {
187 	const char *cp = *str;
188 	char *ep;
189 	int base = 10;
190 
191 	if (*cp == '0') {
192 		char c = *(cp + 1);
193 
194 		if (c == 'x' || c == 'X') {
195 			base = 16;
196 			cp += 2;
197 		} else if (c >= '0' && c <= '7') {
198 			base = 8;
199 			cp++;
200 		}
201 	}
202 	*result = simple_strtoul(cp, &ep, base);
203 	if (cp == ep)
204 		return TOMOYO_VALUE_TYPE_INVALID;
205 	*str = ep;
206 	switch (base) {
207 	case 16:
208 		return TOMOYO_VALUE_TYPE_HEXADECIMAL;
209 	case 8:
210 		return TOMOYO_VALUE_TYPE_OCTAL;
211 	default:
212 		return TOMOYO_VALUE_TYPE_DECIMAL;
213 	}
214 }
215 
216 /**
217  * tomoyo_print_ulong - Print an "unsigned long" value.
218  *
219  * @buffer:     Pointer to buffer.
220  * @buffer_len: Size of @buffer.
221  * @value:      An "unsigned long" value.
222  * @type:       Type of @value.
223  *
224  * Returns nothing.
225  */
226 void tomoyo_print_ulong(char *buffer, const int buffer_len,
227 			const unsigned long value, const u8 type)
228 {
229 	if (type == TOMOYO_VALUE_TYPE_DECIMAL)
230 		snprintf(buffer, buffer_len, "%lu", value);
231 	else if (type == TOMOYO_VALUE_TYPE_OCTAL)
232 		snprintf(buffer, buffer_len, "0%lo", value);
233 	else if (type == TOMOYO_VALUE_TYPE_HEXADECIMAL)
234 		snprintf(buffer, buffer_len, "0x%lX", value);
235 	else
236 		snprintf(buffer, buffer_len, "type(%u)", type);
237 }
238 
239 /**
240  * tomoyo_parse_name_union - Parse a tomoyo_name_union.
241  *
242  * @param: Pointer to "struct tomoyo_acl_param".
243  * @ptr:   Pointer to "struct tomoyo_name_union".
244  *
245  * Returns true on success, false otherwise.
246  */
247 bool tomoyo_parse_name_union(struct tomoyo_acl_param *param,
248 			     struct tomoyo_name_union *ptr)
249 {
250 	char *filename;
251 
252 	if (param->data[0] == '@') {
253 		param->data++;
254 		ptr->group = tomoyo_get_group(param, TOMOYO_PATH_GROUP);
255 		return ptr->group != NULL;
256 	}
257 	filename = tomoyo_read_token(param);
258 	if (!tomoyo_correct_word(filename))
259 		return false;
260 	ptr->filename = tomoyo_get_name(filename);
261 	return ptr->filename != NULL;
262 }
263 
264 /**
265  * tomoyo_parse_number_union - Parse a tomoyo_number_union.
266  *
267  * @param: Pointer to "struct tomoyo_acl_param".
268  * @ptr:   Pointer to "struct tomoyo_number_union".
269  *
270  * Returns true on success, false otherwise.
271  */
272 bool tomoyo_parse_number_union(struct tomoyo_acl_param *param,
273 			       struct tomoyo_number_union *ptr)
274 {
275 	char *data;
276 	u8 type;
277 	unsigned long v;
278 
279 	memset(ptr, 0, sizeof(*ptr));
280 	if (param->data[0] == '@') {
281 		param->data++;
282 		ptr->group = tomoyo_get_group(param, TOMOYO_NUMBER_GROUP);
283 		return ptr->group != NULL;
284 	}
285 	data = tomoyo_read_token(param);
286 	type = tomoyo_parse_ulong(&v, &data);
287 	if (type == TOMOYO_VALUE_TYPE_INVALID)
288 		return false;
289 	ptr->values[0] = v;
290 	ptr->value_type[0] = type;
291 	if (!*data) {
292 		ptr->values[1] = v;
293 		ptr->value_type[1] = type;
294 		return true;
295 	}
296 	if (*data++ != '-')
297 		return false;
298 	type = tomoyo_parse_ulong(&v, &data);
299 	if (type == TOMOYO_VALUE_TYPE_INVALID || *data || ptr->values[0] > v)
300 		return false;
301 	ptr->values[1] = v;
302 	ptr->value_type[1] = type;
303 	return true;
304 }
305 
306 /**
307  * tomoyo_byte_range - Check whether the string is a \ooo style octal value.
308  *
309  * @str: Pointer to the string.
310  *
311  * Returns true if @str is a \ooo style octal value, false otherwise.
312  *
313  * TOMOYO uses \ooo style representation for 0x01 - 0x20 and 0x7F - 0xFF.
314  * This function verifies that \ooo is in valid range.
315  */
316 static inline bool tomoyo_byte_range(const char *str)
317 {
318 	return *str >= '0' && *str++ <= '3' &&
319 		*str >= '0' && *str++ <= '7' &&
320 		*str >= '0' && *str <= '7';
321 }
322 
323 /**
324  * tomoyo_alphabet_char - Check whether the character is an alphabet.
325  *
326  * @c: The character to check.
327  *
328  * Returns true if @c is an alphabet character, false otherwise.
329  */
330 static inline bool tomoyo_alphabet_char(const char c)
331 {
332 	return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
333 }
334 
335 /**
336  * tomoyo_make_byte - Make byte value from three octal characters.
337  *
338  * @c1: The first character.
339  * @c2: The second character.
340  * @c3: The third character.
341  *
342  * Returns byte value.
343  */
344 static inline u8 tomoyo_make_byte(const u8 c1, const u8 c2, const u8 c3)
345 {
346 	return ((c1 - '0') << 6) + ((c2 - '0') << 3) + (c3 - '0');
347 }
348 
349 /**
350  * tomoyo_valid - Check whether the character is a valid char.
351  *
352  * @c: The character to check.
353  *
354  * Returns true if @c is a valid character, false otherwise.
355  */
356 static inline bool tomoyo_valid(const unsigned char c)
357 {
358 	return c > ' ' && c < 127;
359 }
360 
361 /**
362  * tomoyo_invalid - Check whether the character is an invalid char.
363  *
364  * @c: The character to check.
365  *
366  * Returns true if @c is an invalid character, false otherwise.
367  */
368 static inline bool tomoyo_invalid(const unsigned char c)
369 {
370 	return c && (c <= ' ' || c >= 127);
371 }
372 
373 /**
374  * tomoyo_str_starts - Check whether the given string starts with the given keyword.
375  *
376  * @src:  Pointer to pointer to the string.
377  * @find: Pointer to the keyword.
378  *
379  * Returns true if @src starts with @find, false otherwise.
380  *
381  * The @src is updated to point the first character after the @find
382  * if @src starts with @find.
383  */
384 bool tomoyo_str_starts(char **src, const char *find)
385 {
386 	const int len = strlen(find);
387 	char *tmp = *src;
388 
389 	if (strncmp(tmp, find, len))
390 		return false;
391 	tmp += len;
392 	*src = tmp;
393 	return true;
394 }
395 
396 /**
397  * tomoyo_normalize_line - Format string.
398  *
399  * @buffer: The line to normalize.
400  *
401  * Leading and trailing whitespaces are removed.
402  * Multiple whitespaces are packed into single space.
403  *
404  * Returns nothing.
405  */
406 void tomoyo_normalize_line(unsigned char *buffer)
407 {
408 	unsigned char *sp = buffer;
409 	unsigned char *dp = buffer;
410 	bool first = true;
411 
412 	while (tomoyo_invalid(*sp))
413 		sp++;
414 	while (*sp) {
415 		if (!first)
416 			*dp++ = ' ';
417 		first = false;
418 		while (tomoyo_valid(*sp))
419 			*dp++ = *sp++;
420 		while (tomoyo_invalid(*sp))
421 			sp++;
422 	}
423 	*dp = '\0';
424 }
425 
426 /**
427  * tomoyo_correct_word2 - Validate a string.
428  *
429  * @string: The string to check. Maybe non-'\0'-terminated.
430  * @len:    Length of @string.
431  *
432  * Check whether the given string follows the naming rules.
433  * Returns true if @string follows the naming rules, false otherwise.
434  */
435 static bool tomoyo_correct_word2(const char *string, size_t len)
436 {
437 	u8 recursion = 20;
438 	const char *const start = string;
439 	bool in_repetition = false;
440 
441 	if (!len)
442 		goto out;
443 	while (len--) {
444 		unsigned char c = *string++;
445 
446 		if (c == '\\') {
447 			if (!len--)
448 				goto out;
449 			c = *string++;
450 			if (c >= '0' && c <= '3') {
451 				unsigned char d;
452 				unsigned char e;
453 
454 				if (!len-- || !len--)
455 					goto out;
456 				d = *string++;
457 				e = *string++;
458 				if (d < '0' || d > '7' || e < '0' || e > '7')
459 					goto out;
460 				c = tomoyo_make_byte(c, d, e);
461 				if (c <= ' ' || c >= 127)
462 					continue;
463 				goto out;
464 			}
465 			switch (c) {
466 			case '\\':  /* "\\" */
467 			case '+':   /* "\+" */
468 			case '?':   /* "\?" */
469 			case 'x':   /* "\x" */
470 			case 'a':   /* "\a" */
471 			case '-':   /* "\-" */
472 				continue;
473 			}
474 			if (!recursion--)
475 				goto out;
476 			switch (c) {
477 			case '*':   /* "\*" */
478 			case '@':   /* "\@" */
479 			case '$':   /* "\$" */
480 			case 'X':   /* "\X" */
481 			case 'A':   /* "\A" */
482 				continue;
483 			case '{':   /* "/\{" */
484 				if (string - 3 < start || *(string - 3) != '/')
485 					goto out;
486 				in_repetition = true;
487 				continue;
488 			case '}':   /* "\}/" */
489 				if (*string != '/')
490 					goto out;
491 				if (!in_repetition)
492 					goto out;
493 				in_repetition = false;
494 				continue;
495 			}
496 			goto out;
497 		} else if (in_repetition && c == '/') {
498 			goto out;
499 		} else if (c <= ' ' || c >= 127) {
500 			goto out;
501 		}
502 	}
503 	if (in_repetition)
504 		goto out;
505 	return true;
506  out:
507 	return false;
508 }
509 
510 /**
511  * tomoyo_correct_word - Validate a string.
512  *
513  * @string: The string to check.
514  *
515  * Check whether the given string follows the naming rules.
516  * Returns true if @string follows the naming rules, false otherwise.
517  */
518 bool tomoyo_correct_word(const char *string)
519 {
520 	return tomoyo_correct_word2(string, strlen(string));
521 }
522 
523 /**
524  * tomoyo_correct_path2 - Check whether the given pathname follows the naming rules.
525  *
526  * @filename: The pathname to check.
527  * @len:      Length of @filename.
528  *
529  * Returns true if @filename follows the naming rules, false otherwise.
530  */
531 static bool tomoyo_correct_path2(const char *filename, const size_t len)
532 {
533 	const char *cp1 = memchr(filename, '/', len);
534 	const char *cp2 = memchr(filename, '.', len);
535 
536 	return cp1 && (!cp2 || (cp1 < cp2)) && tomoyo_correct_word2(filename, len);
537 }
538 
539 /**
540  * tomoyo_correct_path - Validate a pathname.
541  *
542  * @filename: The pathname to check.
543  *
544  * Check whether the given pathname follows the naming rules.
545  * Returns true if @filename follows the naming rules, false otherwise.
546  */
547 bool tomoyo_correct_path(const char *filename)
548 {
549 	return tomoyo_correct_path2(filename, strlen(filename));
550 }
551 
552 /**
553  * tomoyo_correct_domain - Check whether the given domainname follows the naming rules.
554  *
555  * @domainname: The domainname to check.
556  *
557  * Returns true if @domainname follows the naming rules, false otherwise.
558  */
559 bool tomoyo_correct_domain(const unsigned char *domainname)
560 {
561 	if (!domainname || !tomoyo_domain_def(domainname))
562 		return false;
563 	domainname = strchr(domainname, ' ');
564 	if (!domainname++)
565 		return true;
566 	while (1) {
567 		const unsigned char *cp = strchr(domainname, ' ');
568 
569 		if (!cp)
570 			break;
571 		if (!tomoyo_correct_path2(domainname, cp - domainname))
572 			return false;
573 		domainname = cp + 1;
574 	}
575 	return tomoyo_correct_path(domainname);
576 }
577 
578 /**
579  * tomoyo_domain_def - Check whether the given token can be a domainname.
580  *
581  * @buffer: The token to check.
582  *
583  * Returns true if @buffer possibly be a domainname, false otherwise.
584  */
585 bool tomoyo_domain_def(const unsigned char *buffer)
586 {
587 	const unsigned char *cp;
588 	int len;
589 
590 	if (*buffer != '<')
591 		return false;
592 	cp = strchr(buffer, ' ');
593 	if (!cp)
594 		len = strlen(buffer);
595 	else
596 		len = cp - buffer;
597 	if (buffer[len - 1] != '>' ||
598 	    !tomoyo_correct_word2(buffer + 1, len - 2))
599 		return false;
600 	return true;
601 }
602 
603 /**
604  * tomoyo_find_domain - Find a domain by the given name.
605  *
606  * @domainname: The domainname to find.
607  *
608  * Returns pointer to "struct tomoyo_domain_info" if found, NULL otherwise.
609  *
610  * Caller holds tomoyo_read_lock().
611  */
612 struct tomoyo_domain_info *tomoyo_find_domain(const char *domainname)
613 {
614 	struct tomoyo_domain_info *domain;
615 	struct tomoyo_path_info name;
616 
617 	name.name = domainname;
618 	tomoyo_fill_path_info(&name);
619 	list_for_each_entry_rcu(domain, &tomoyo_domain_list, list,
620 				srcu_read_lock_held(&tomoyo_ss)) {
621 		if (!domain->is_deleted &&
622 		    !tomoyo_pathcmp(&name, domain->domainname))
623 			return domain;
624 	}
625 	return NULL;
626 }
627 
628 /**
629  * tomoyo_const_part_length - Evaluate the initial length without a pattern in a token.
630  *
631  * @filename: The string to evaluate.
632  *
633  * Returns the initial length without a pattern in @filename.
634  */
635 static int tomoyo_const_part_length(const char *filename)
636 {
637 	char c;
638 	int len = 0;
639 
640 	if (!filename)
641 		return 0;
642 	while ((c = *filename++) != '\0') {
643 		if (c != '\\') {
644 			len++;
645 			continue;
646 		}
647 		c = *filename++;
648 		switch (c) {
649 		case '\\':  /* "\\" */
650 			len += 2;
651 			continue;
652 		case '0':   /* "\ooo" */
653 		case '1':
654 		case '2':
655 		case '3':
656 			c = *filename++;
657 			if (c < '0' || c > '7')
658 				break;
659 			c = *filename++;
660 			if (c < '0' || c > '7')
661 				break;
662 			len += 4;
663 			continue;
664 		}
665 		break;
666 	}
667 	return len;
668 }
669 
670 /**
671  * tomoyo_fill_path_info - Fill in "struct tomoyo_path_info" members.
672  *
673  * @ptr: Pointer to "struct tomoyo_path_info" to fill in.
674  *
675  * The caller sets "struct tomoyo_path_info"->name.
676  */
677 void tomoyo_fill_path_info(struct tomoyo_path_info *ptr)
678 {
679 	const char *name = ptr->name;
680 	const int len = strlen(name);
681 
682 	ptr->const_len = tomoyo_const_part_length(name);
683 	ptr->is_dir = len && (name[len - 1] == '/');
684 	ptr->is_patterned = (ptr->const_len < len);
685 	ptr->hash = full_name_hash(NULL, name, len);
686 }
687 
688 /**
689  * tomoyo_file_matches_pattern2 - Pattern matching without '/' character and "\-" pattern.
690  *
691  * @filename:     The start of string to check.
692  * @filename_end: The end of string to check.
693  * @pattern:      The start of pattern to compare.
694  * @pattern_end:  The end of pattern to compare.
695  *
696  * Returns true if @filename matches @pattern, false otherwise.
697  */
698 static bool tomoyo_file_matches_pattern2(const char *filename,
699 					 const char *filename_end,
700 					 const char *pattern,
701 					 const char *pattern_end)
702 {
703 	while (filename < filename_end && pattern < pattern_end) {
704 		char c;
705 		int i;
706 		int j;
707 
708 		if (*pattern != '\\') {
709 			if (*filename++ != *pattern++)
710 				return false;
711 			continue;
712 		}
713 		c = *filename;
714 		pattern++;
715 		switch (*pattern) {
716 		case '?':
717 			if (c == '/') {
718 				return false;
719 			} else if (c == '\\') {
720 				if (filename[1] == '\\')
721 					filename++;
722 				else if (tomoyo_byte_range(filename + 1))
723 					filename += 3;
724 				else
725 					return false;
726 			}
727 			break;
728 		case '\\':
729 			if (c != '\\')
730 				return false;
731 			if (*++filename != '\\')
732 				return false;
733 			break;
734 		case '+':
735 			if (!isdigit(c))
736 				return false;
737 			break;
738 		case 'x':
739 			if (!isxdigit(c))
740 				return false;
741 			break;
742 		case 'a':
743 			if (!tomoyo_alphabet_char(c))
744 				return false;
745 			break;
746 		case '0':
747 		case '1':
748 		case '2':
749 		case '3':
750 			if (c == '\\' && tomoyo_byte_range(filename + 1)
751 			    && strncmp(filename + 1, pattern, 3) == 0) {
752 				filename += 3;
753 				pattern += 2;
754 				break;
755 			}
756 			return false; /* Not matched. */
757 		case '*':
758 		case '@':
759 			for (i = 0; i <= filename_end - filename; i++) {
760 				if (tomoyo_file_matches_pattern2(
761 						    filename + i, filename_end,
762 						    pattern + 1, pattern_end))
763 					return true;
764 				c = filename[i];
765 				if (c == '.' && *pattern == '@')
766 					break;
767 				if (c != '\\')
768 					continue;
769 				if (filename[i + 1] == '\\')
770 					i++;
771 				else if (tomoyo_byte_range(filename + i + 1))
772 					i += 3;
773 				else
774 					break; /* Bad pattern. */
775 			}
776 			return false; /* Not matched. */
777 		default:
778 			j = 0;
779 			c = *pattern;
780 			if (c == '$') {
781 				while (isdigit(filename[j]))
782 					j++;
783 			} else if (c == 'X') {
784 				while (isxdigit(filename[j]))
785 					j++;
786 			} else if (c == 'A') {
787 				while (tomoyo_alphabet_char(filename[j]))
788 					j++;
789 			}
790 			for (i = 1; i <= j; i++) {
791 				if (tomoyo_file_matches_pattern2(
792 						    filename + i, filename_end,
793 						    pattern + 1, pattern_end))
794 					return true;
795 			}
796 			return false; /* Not matched or bad pattern. */
797 		}
798 		filename++;
799 		pattern++;
800 	}
801 	while (*pattern == '\\' &&
802 	       (*(pattern + 1) == '*' || *(pattern + 1) == '@'))
803 		pattern += 2;
804 	return filename == filename_end && pattern == pattern_end;
805 }
806 
807 /**
808  * tomoyo_file_matches_pattern - Pattern matching without '/' character.
809  *
810  * @filename:     The start of string to check.
811  * @filename_end: The end of string to check.
812  * @pattern:      The start of pattern to compare.
813  * @pattern_end:  The end of pattern to compare.
814  *
815  * Returns true if @filename matches @pattern, false otherwise.
816  */
817 static bool tomoyo_file_matches_pattern(const char *filename,
818 					const char *filename_end,
819 					const char *pattern,
820 					const char *pattern_end)
821 {
822 	const char *pattern_start = pattern;
823 	bool first = true;
824 	bool result;
825 
826 	while (pattern < pattern_end - 1) {
827 		/* Split at "\-" pattern. */
828 		if (*pattern++ != '\\' || *pattern++ != '-')
829 			continue;
830 		result = tomoyo_file_matches_pattern2(filename,
831 						      filename_end,
832 						      pattern_start,
833 						      pattern - 2);
834 		if (first)
835 			result = !result;
836 		if (result)
837 			return false;
838 		first = false;
839 		pattern_start = pattern;
840 	}
841 	result = tomoyo_file_matches_pattern2(filename, filename_end,
842 					      pattern_start, pattern_end);
843 	return first ? result : !result;
844 }
845 
846 /**
847  * tomoyo_path_matches_pattern2 - Do pathname pattern matching.
848  *
849  * @f: The start of string to check.
850  * @p: The start of pattern to compare.
851  *
852  * Returns true if @f matches @p, false otherwise.
853  */
854 static bool tomoyo_path_matches_pattern2(const char *f, const char *p)
855 {
856 	const char *f_delimiter;
857 	const char *p_delimiter;
858 
859 	while (*f && *p) {
860 		f_delimiter = strchr(f, '/');
861 		if (!f_delimiter)
862 			f_delimiter = f + strlen(f);
863 		p_delimiter = strchr(p, '/');
864 		if (!p_delimiter)
865 			p_delimiter = p + strlen(p);
866 		if (*p == '\\' && *(p + 1) == '{')
867 			goto recursive;
868 		if (!tomoyo_file_matches_pattern(f, f_delimiter, p,
869 						 p_delimiter))
870 			return false;
871 		f = f_delimiter;
872 		if (*f)
873 			f++;
874 		p = p_delimiter;
875 		if (*p)
876 			p++;
877 	}
878 	/* Ignore trailing "\*" and "\@" in @pattern. */
879 	while (*p == '\\' &&
880 	       (*(p + 1) == '*' || *(p + 1) == '@'))
881 		p += 2;
882 	return !*f && !*p;
883  recursive:
884 	/*
885 	 * The "\{" pattern is permitted only after '/' character.
886 	 * This guarantees that below "*(p - 1)" is safe.
887 	 * Also, the "\}" pattern is permitted only before '/' character
888 	 * so that "\{" + "\}" pair will not break the "\-" operator.
889 	 */
890 	if (*(p - 1) != '/' || p_delimiter <= p + 3 || *p_delimiter != '/' ||
891 	    *(p_delimiter - 1) != '}' || *(p_delimiter - 2) != '\\')
892 		return false; /* Bad pattern. */
893 	do {
894 		/* Compare current component with pattern. */
895 		if (!tomoyo_file_matches_pattern(f, f_delimiter, p + 2,
896 						 p_delimiter - 2))
897 			break;
898 		/* Proceed to next component. */
899 		f = f_delimiter;
900 		if (!*f)
901 			break;
902 		f++;
903 		/* Continue comparison. */
904 		if (tomoyo_path_matches_pattern2(f, p_delimiter + 1))
905 			return true;
906 		f_delimiter = strchr(f, '/');
907 	} while (f_delimiter);
908 	return false; /* Not matched. */
909 }
910 
911 /**
912  * tomoyo_path_matches_pattern - Check whether the given filename matches the given pattern.
913  *
914  * @filename: The filename to check.
915  * @pattern:  The pattern to compare.
916  *
917  * Returns true if matches, false otherwise.
918  *
919  * The following patterns are available.
920  *   \\     \ itself.
921  *   \ooo   Octal representation of a byte.
922  *   \*     Zero or more repetitions of characters other than '/'.
923  *   \@     Zero or more repetitions of characters other than '/' or '.'.
924  *   \?     1 byte character other than '/'.
925  *   \$     One or more repetitions of decimal digits.
926  *   \+     1 decimal digit.
927  *   \X     One or more repetitions of hexadecimal digits.
928  *   \x     1 hexadecimal digit.
929  *   \A     One or more repetitions of alphabet characters.
930  *   \a     1 alphabet character.
931  *
932  *   \-     Subtraction operator.
933  *
934  *   /\{dir\}/   '/' + 'One or more repetitions of dir/' (e.g. /dir/ /dir/dir/
935  *               /dir/dir/dir/ ).
936  */
937 bool tomoyo_path_matches_pattern(const struct tomoyo_path_info *filename,
938 				 const struct tomoyo_path_info *pattern)
939 {
940 	const char *f = filename->name;
941 	const char *p = pattern->name;
942 	const int len = pattern->const_len;
943 
944 	/* If @pattern doesn't contain pattern, I can use strcmp(). */
945 	if (!pattern->is_patterned)
946 		return !tomoyo_pathcmp(filename, pattern);
947 	/* Don't compare directory and non-directory. */
948 	if (filename->is_dir != pattern->is_dir)
949 		return false;
950 	/* Compare the initial length without patterns. */
951 	if (strncmp(f, p, len))
952 		return false;
953 	f += len;
954 	p += len;
955 	return tomoyo_path_matches_pattern2(f, p);
956 }
957 
958 /**
959  * tomoyo_get_exe - Get tomoyo_realpath() of current process.
960  *
961  * Returns the tomoyo_realpath() of current process on success, NULL otherwise.
962  *
963  * This function uses kzalloc(), so the caller must call kfree()
964  * if this function didn't return NULL.
965  */
966 const char *tomoyo_get_exe(void)
967 {
968 	struct file *exe_file;
969 	const char *cp;
970 	struct mm_struct *mm = current->mm;
971 
972 	if (!mm)
973 		return NULL;
974 	exe_file = get_mm_exe_file(mm);
975 	if (!exe_file)
976 		return NULL;
977 
978 	cp = tomoyo_realpath_from_path(&exe_file->f_path);
979 	fput(exe_file);
980 	return cp;
981 }
982 
983 /**
984  * tomoyo_get_mode - Get MAC mode.
985  *
986  * @ns:      Pointer to "struct tomoyo_policy_namespace".
987  * @profile: Profile number.
988  * @index:   Index number of functionality.
989  *
990  * Returns mode.
991  */
992 int tomoyo_get_mode(const struct tomoyo_policy_namespace *ns, const u8 profile,
993 		    const u8 index)
994 {
995 	u8 mode;
996 	struct tomoyo_profile *p;
997 
998 	if (!tomoyo_policy_loaded)
999 		return TOMOYO_CONFIG_DISABLED;
1000 	p = tomoyo_profile(ns, profile);
1001 	mode = p->config[index];
1002 	if (mode == TOMOYO_CONFIG_USE_DEFAULT)
1003 		mode = p->config[tomoyo_index2category[index]
1004 				 + TOMOYO_MAX_MAC_INDEX];
1005 	if (mode == TOMOYO_CONFIG_USE_DEFAULT)
1006 		mode = p->default_config;
1007 	return mode & 3;
1008 }
1009 
1010 /**
1011  * tomoyo_init_request_info - Initialize "struct tomoyo_request_info" members.
1012  *
1013  * @r:      Pointer to "struct tomoyo_request_info" to initialize.
1014  * @domain: Pointer to "struct tomoyo_domain_info". NULL for tomoyo_domain().
1015  * @index:  Index number of functionality.
1016  *
1017  * Returns mode.
1018  */
1019 int tomoyo_init_request_info(struct tomoyo_request_info *r,
1020 			     struct tomoyo_domain_info *domain, const u8 index)
1021 {
1022 	u8 profile;
1023 
1024 	memset(r, 0, sizeof(*r));
1025 	if (!domain)
1026 		domain = tomoyo_domain();
1027 	r->domain = domain;
1028 	profile = domain->profile;
1029 	r->profile = profile;
1030 	r->type = index;
1031 	r->mode = tomoyo_get_mode(domain->ns, profile, index);
1032 	return r->mode;
1033 }
1034 
1035 /**
1036  * tomoyo_domain_quota_is_ok - Check for domain's quota.
1037  *
1038  * @r: Pointer to "struct tomoyo_request_info".
1039  *
1040  * Returns true if the domain is not exceeded quota, false otherwise.
1041  *
1042  * Caller holds tomoyo_read_lock().
1043  */
1044 bool tomoyo_domain_quota_is_ok(struct tomoyo_request_info *r)
1045 {
1046 	unsigned int count = 0;
1047 	struct tomoyo_domain_info *domain = r->domain;
1048 	struct tomoyo_acl_info *ptr;
1049 
1050 	if (r->mode != TOMOYO_CONFIG_LEARNING)
1051 		return false;
1052 	if (!domain)
1053 		return true;
1054 	if (READ_ONCE(domain->flags[TOMOYO_DIF_QUOTA_WARNED]))
1055 		return false;
1056 	list_for_each_entry_rcu(ptr, &domain->acl_info_list, list,
1057 				srcu_read_lock_held(&tomoyo_ss)) {
1058 		u16 perm;
1059 
1060 		if (ptr->is_deleted)
1061 			continue;
1062 		/*
1063 		 * Reading perm bitmap might race with tomoyo_merge_*() because
1064 		 * caller does not hold tomoyo_policy_lock mutex. But exceeding
1065 		 * max_learning_entry parameter by a few entries does not harm.
1066 		 */
1067 		switch (ptr->type) {
1068 		case TOMOYO_TYPE_PATH_ACL:
1069 			perm = data_race(container_of(ptr, struct tomoyo_path_acl, head)->perm);
1070 			break;
1071 		case TOMOYO_TYPE_PATH2_ACL:
1072 			perm = data_race(container_of(ptr, struct tomoyo_path2_acl, head)->perm);
1073 			break;
1074 		case TOMOYO_TYPE_PATH_NUMBER_ACL:
1075 			perm = data_race(container_of(ptr, struct tomoyo_path_number_acl, head)
1076 				  ->perm);
1077 			break;
1078 		case TOMOYO_TYPE_MKDEV_ACL:
1079 			perm = data_race(container_of(ptr, struct tomoyo_mkdev_acl, head)->perm);
1080 			break;
1081 		case TOMOYO_TYPE_INET_ACL:
1082 			perm = data_race(container_of(ptr, struct tomoyo_inet_acl, head)->perm);
1083 			break;
1084 		case TOMOYO_TYPE_UNIX_ACL:
1085 			perm = data_race(container_of(ptr, struct tomoyo_unix_acl, head)->perm);
1086 			break;
1087 		case TOMOYO_TYPE_MANUAL_TASK_ACL:
1088 			perm = 0;
1089 			break;
1090 		default:
1091 			perm = 1;
1092 		}
1093 		count += hweight16(perm);
1094 	}
1095 	if (count < tomoyo_profile(domain->ns, domain->profile)->
1096 	    pref[TOMOYO_PREF_MAX_LEARNING_ENTRY])
1097 		return true;
1098 	WRITE_ONCE(domain->flags[TOMOYO_DIF_QUOTA_WARNED], true);
1099 	/* r->granted = false; */
1100 	tomoyo_write_log(r, "%s", tomoyo_dif[TOMOYO_DIF_QUOTA_WARNED]);
1101 #ifndef CONFIG_SECURITY_TOMOYO_INSECURE_BUILTIN_SETTING
1102 	pr_warn("WARNING: Domain '%s' has too many ACLs to hold. Stopped learning mode.\n",
1103 		domain->domainname->name);
1104 #endif
1105 	return false;
1106 }
1107