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11#include <linux/errno.h>
12#include <linux/kernel.h>
13#include <linux/mm.h>
14#include <linux/slab.h>
15#include <linux/vmalloc.h>
16#include <linux/err.h>
17#include <linux/kref.h>
18
19#include "include/lib.h"
20#include "include/match.h"
21
22#define base_idx(X) ((X) & 0xffffff)
23
24static char nulldfa_src[] = {
25 #include "nulldfa.in"
26};
27struct aa_dfa *nulldfa;
28
29static char stacksplitdfa_src[] = {
30 #include "stacksplitdfa.in"
31};
32struct aa_dfa *stacksplitdfa;
33
34int aa_setup_dfa_engine(void)
35{
36 int error;
37
38 nulldfa = aa_dfa_unpack(nulldfa_src, sizeof(nulldfa_src),
39 TO_ACCEPT1_FLAG(YYTD_DATA32) |
40 TO_ACCEPT2_FLAG(YYTD_DATA32));
41 if (IS_ERR(nulldfa)) {
42 error = PTR_ERR(nulldfa);
43 nulldfa = NULL;
44 return error;
45 }
46
47 stacksplitdfa = aa_dfa_unpack(stacksplitdfa_src,
48 sizeof(stacksplitdfa_src),
49 TO_ACCEPT1_FLAG(YYTD_DATA32) |
50 TO_ACCEPT2_FLAG(YYTD_DATA32));
51 if (IS_ERR(stacksplitdfa)) {
52 aa_put_dfa(nulldfa);
53 nulldfa = NULL;
54 error = PTR_ERR(stacksplitdfa);
55 stacksplitdfa = NULL;
56 return error;
57 }
58
59 return 0;
60}
61
62void aa_teardown_dfa_engine(void)
63{
64 aa_put_dfa(stacksplitdfa);
65 aa_put_dfa(nulldfa);
66}
67
68
69
70
71
72
73
74
75
76
77static struct table_header *unpack_table(char *blob, size_t bsize)
78{
79 struct table_header *table = NULL;
80 struct table_header th;
81 size_t tsize;
82
83 if (bsize < sizeof(struct table_header))
84 goto out;
85
86
87
88
89 th.td_id = be16_to_cpu(*(__be16 *) (blob)) - 1;
90 if (th.td_id > YYTD_ID_MAX)
91 goto out;
92 th.td_flags = be16_to_cpu(*(__be16 *) (blob + 2));
93 th.td_lolen = be32_to_cpu(*(__be32 *) (blob + 8));
94 blob += sizeof(struct table_header);
95
96 if (!(th.td_flags == YYTD_DATA16 || th.td_flags == YYTD_DATA32 ||
97 th.td_flags == YYTD_DATA8))
98 goto out;
99
100
101 if (th.td_lolen == 0)
102 goto out;
103 tsize = table_size(th.td_lolen, th.td_flags);
104 if (bsize < tsize)
105 goto out;
106
107 table = kvzalloc(tsize, GFP_KERNEL);
108 if (table) {
109 table->td_id = th.td_id;
110 table->td_flags = th.td_flags;
111 table->td_lolen = th.td_lolen;
112 if (th.td_flags == YYTD_DATA8)
113 UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
114 u8, u8, byte_to_byte);
115 else if (th.td_flags == YYTD_DATA16)
116 UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
117 u16, __be16, be16_to_cpu);
118 else if (th.td_flags == YYTD_DATA32)
119 UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
120 u32, __be32, be32_to_cpu);
121 else
122 goto fail;
123
124
125
126 if (is_vmalloc_addr(table))
127 vm_unmap_aliases();
128 }
129
130out:
131 return table;
132fail:
133 kvfree(table);
134 return NULL;
135}
136
137
138
139
140
141
142
143
144
145
146
147static int verify_table_headers(struct table_header **tables, int flags)
148{
149 size_t state_count, trans_count;
150 int error = -EPROTO;
151
152
153 if (!(tables[YYTD_ID_DEF] && tables[YYTD_ID_BASE] &&
154 tables[YYTD_ID_NXT] && tables[YYTD_ID_CHK]))
155 goto out;
156
157
158 state_count = tables[YYTD_ID_BASE]->td_lolen;
159 if (ACCEPT1_FLAGS(flags)) {
160 if (!tables[YYTD_ID_ACCEPT])
161 goto out;
162 if (state_count != tables[YYTD_ID_ACCEPT]->td_lolen)
163 goto out;
164 }
165 if (ACCEPT2_FLAGS(flags)) {
166 if (!tables[YYTD_ID_ACCEPT2])
167 goto out;
168 if (state_count != tables[YYTD_ID_ACCEPT2]->td_lolen)
169 goto out;
170 }
171 if (state_count != tables[YYTD_ID_DEF]->td_lolen)
172 goto out;
173
174
175 trans_count = tables[YYTD_ID_NXT]->td_lolen;
176 if (trans_count != tables[YYTD_ID_CHK]->td_lolen)
177 goto out;
178
179
180 if (tables[YYTD_ID_EC] && tables[YYTD_ID_EC]->td_lolen != 256)
181 goto out;
182
183 error = 0;
184out:
185 return error;
186}
187
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195
196
197static int verify_dfa(struct aa_dfa *dfa)
198{
199 size_t i, state_count, trans_count;
200 int error = -EPROTO;
201
202 state_count = dfa->tables[YYTD_ID_BASE]->td_lolen;
203 trans_count = dfa->tables[YYTD_ID_NXT]->td_lolen;
204 if (state_count == 0)
205 goto out;
206 for (i = 0; i < state_count; i++) {
207 if (!(BASE_TABLE(dfa)[i] & MATCH_FLAG_DIFF_ENCODE) &&
208 (DEFAULT_TABLE(dfa)[i] >= state_count))
209 goto out;
210 if (BASE_TABLE(dfa)[i] & MATCH_FLAGS_INVALID) {
211 pr_err("AppArmor DFA state with invalid match flags");
212 goto out;
213 }
214 if ((BASE_TABLE(dfa)[i] & MATCH_FLAG_DIFF_ENCODE)) {
215 if (!(dfa->flags & YYTH_FLAG_DIFF_ENCODE)) {
216 pr_err("AppArmor DFA diff encoded transition state without header flag");
217 goto out;
218 }
219 }
220 if ((BASE_TABLE(dfa)[i] & MATCH_FLAG_OOB_TRANSITION)) {
221 if (base_idx(BASE_TABLE(dfa)[i]) < dfa->max_oob) {
222 pr_err("AppArmor DFA out of bad transition out of range");
223 goto out;
224 }
225 if (!(dfa->flags & YYTH_FLAG_OOB_TRANS)) {
226 pr_err("AppArmor DFA out of bad transition state without header flag");
227 goto out;
228 }
229 }
230 if (base_idx(BASE_TABLE(dfa)[i]) + 255 >= trans_count) {
231 pr_err("AppArmor DFA next/check upper bounds error\n");
232 goto out;
233 }
234 }
235
236 for (i = 0; i < trans_count; i++) {
237 if (NEXT_TABLE(dfa)[i] >= state_count)
238 goto out;
239 if (CHECK_TABLE(dfa)[i] >= state_count)
240 goto out;
241 }
242
243
244 for (i = 0; i < state_count; i++) {
245 size_t j, k;
246
247 for (j = i;
248 (BASE_TABLE(dfa)[j] & MATCH_FLAG_DIFF_ENCODE) &&
249 !(BASE_TABLE(dfa)[j] & MARK_DIFF_ENCODE);
250 j = k) {
251 k = DEFAULT_TABLE(dfa)[j];
252 if (j == k)
253 goto out;
254 if (k < j)
255 break;
256 BASE_TABLE(dfa)[j] |= MARK_DIFF_ENCODE;
257 }
258 }
259 error = 0;
260
261out:
262 return error;
263}
264
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269
270
271static void dfa_free(struct aa_dfa *dfa)
272{
273 if (dfa) {
274 int i;
275
276 for (i = 0; i < ARRAY_SIZE(dfa->tables); i++) {
277 kvfree(dfa->tables[i]);
278 dfa->tables[i] = NULL;
279 }
280 kfree(dfa);
281 }
282}
283
284
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286
287
288void aa_dfa_free_kref(struct kref *kref)
289{
290 struct aa_dfa *dfa = container_of(kref, struct aa_dfa, count);
291 dfa_free(dfa);
292}
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305
306struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags)
307{
308 int hsize;
309 int error = -ENOMEM;
310 char *data = blob;
311 struct table_header *table = NULL;
312 struct aa_dfa *dfa = kzalloc(sizeof(struct aa_dfa), GFP_KERNEL);
313 if (!dfa)
314 goto fail;
315
316 kref_init(&dfa->count);
317
318 error = -EPROTO;
319
320
321 if (size < sizeof(struct table_set_header))
322 goto fail;
323
324 if (ntohl(*(__be32 *) data) != YYTH_MAGIC)
325 goto fail;
326
327 hsize = ntohl(*(__be32 *) (data + 4));
328 if (size < hsize)
329 goto fail;
330
331 dfa->flags = ntohs(*(__be16 *) (data + 12));
332 if (dfa->flags & ~(YYTH_FLAGS))
333 goto fail;
334
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345
346
347 dfa->max_oob = 1;
348
349 data += hsize;
350 size -= hsize;
351
352 while (size > 0) {
353 table = unpack_table(data, size);
354 if (!table)
355 goto fail;
356
357 switch (table->td_id) {
358 case YYTD_ID_ACCEPT:
359 if (!(table->td_flags & ACCEPT1_FLAGS(flags)))
360 goto fail;
361 break;
362 case YYTD_ID_ACCEPT2:
363 if (!(table->td_flags & ACCEPT2_FLAGS(flags)))
364 goto fail;
365 break;
366 case YYTD_ID_BASE:
367 if (table->td_flags != YYTD_DATA32)
368 goto fail;
369 break;
370 case YYTD_ID_DEF:
371 case YYTD_ID_NXT:
372 case YYTD_ID_CHK:
373 if (table->td_flags != YYTD_DATA16)
374 goto fail;
375 break;
376 case YYTD_ID_EC:
377 if (table->td_flags != YYTD_DATA8)
378 goto fail;
379 break;
380 default:
381 goto fail;
382 }
383
384 if (dfa->tables[table->td_id])
385 goto fail;
386 dfa->tables[table->td_id] = table;
387 data += table_size(table->td_lolen, table->td_flags);
388 size -= table_size(table->td_lolen, table->td_flags);
389 table = NULL;
390 }
391 error = verify_table_headers(dfa->tables, flags);
392 if (error)
393 goto fail;
394
395 if (flags & DFA_FLAG_VERIFY_STATES) {
396 error = verify_dfa(dfa);
397 if (error)
398 goto fail;
399 }
400
401 return dfa;
402
403fail:
404 kvfree(table);
405 dfa_free(dfa);
406 return ERR_PTR(error);
407}
408
409#define match_char(state, def, base, next, check, C) \
410do { \
411 u32 b = (base)[(state)]; \
412 unsigned int pos = base_idx(b) + (C); \
413 if ((check)[pos] != (state)) { \
414 (state) = (def)[(state)]; \
415 if (b & MATCH_FLAG_DIFF_ENCODE) \
416 continue; \
417 break; \
418 } \
419 (state) = (next)[pos]; \
420 break; \
421} while (1)
422
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439unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
440 const char *str, int len)
441{
442 u16 *def = DEFAULT_TABLE(dfa);
443 u32 *base = BASE_TABLE(dfa);
444 u16 *next = NEXT_TABLE(dfa);
445 u16 *check = CHECK_TABLE(dfa);
446 unsigned int state = start;
447
448 if (state == 0)
449 return 0;
450
451
452 if (dfa->tables[YYTD_ID_EC]) {
453
454 u8 *equiv = EQUIV_TABLE(dfa);
455 for (; len; len--)
456 match_char(state, def, base, next, check,
457 equiv[(u8) *str++]);
458 } else {
459
460 for (; len; len--)
461 match_char(state, def, base, next, check, (u8) *str++);
462 }
463
464 return state;
465}
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478
479unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
480 const char *str)
481{
482 u16 *def = DEFAULT_TABLE(dfa);
483 u32 *base = BASE_TABLE(dfa);
484 u16 *next = NEXT_TABLE(dfa);
485 u16 *check = CHECK_TABLE(dfa);
486 unsigned int state = start;
487
488 if (state == 0)
489 return 0;
490
491
492 if (dfa->tables[YYTD_ID_EC]) {
493
494 u8 *equiv = EQUIV_TABLE(dfa);
495
496 while (*str)
497 match_char(state, def, base, next, check,
498 equiv[(u8) *str++]);
499 } else {
500
501 while (*str)
502 match_char(state, def, base, next, check, (u8) *str++);
503 }
504
505 return state;
506}
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517
518unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state,
519 const char c)
520{
521 u16 *def = DEFAULT_TABLE(dfa);
522 u32 *base = BASE_TABLE(dfa);
523 u16 *next = NEXT_TABLE(dfa);
524 u16 *check = CHECK_TABLE(dfa);
525
526
527 if (dfa->tables[YYTD_ID_EC]) {
528
529 u8 *equiv = EQUIV_TABLE(dfa);
530 match_char(state, def, base, next, check, equiv[(u8) c]);
531 } else
532 match_char(state, def, base, next, check, (u8) c);
533
534 return state;
535}
536
537unsigned int aa_dfa_outofband_transition(struct aa_dfa *dfa, unsigned int state)
538{
539 u16 *def = DEFAULT_TABLE(dfa);
540 u32 *base = BASE_TABLE(dfa);
541 u16 *next = NEXT_TABLE(dfa);
542 u16 *check = CHECK_TABLE(dfa);
543 u32 b = (base)[(state)];
544
545 if (!(b & MATCH_FLAG_OOB_TRANSITION))
546 return DFA_NOMATCH;
547
548
549 match_char(state, def, base, next, check, -1);
550
551 return state;
552}
553
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566
567unsigned int aa_dfa_match_until(struct aa_dfa *dfa, unsigned int start,
568 const char *str, const char **retpos)
569{
570 u16 *def = DEFAULT_TABLE(dfa);
571 u32 *base = BASE_TABLE(dfa);
572 u16 *next = NEXT_TABLE(dfa);
573 u16 *check = CHECK_TABLE(dfa);
574 u32 *accept = ACCEPT_TABLE(dfa);
575 unsigned int state = start, pos;
576
577 if (state == 0)
578 return 0;
579
580
581 if (dfa->tables[YYTD_ID_EC]) {
582
583 u8 *equiv = EQUIV_TABLE(dfa);
584
585 while (*str) {
586 pos = base_idx(base[state]) + equiv[(u8) *str++];
587 if (check[pos] == state)
588 state = next[pos];
589 else
590 state = def[state];
591 if (accept[state])
592 break;
593 }
594 } else {
595
596 while (*str) {
597 pos = base_idx(base[state]) + (u8) *str++;
598 if (check[pos] == state)
599 state = next[pos];
600 else
601 state = def[state];
602 if (accept[state])
603 break;
604 }
605 }
606
607 *retpos = str;
608 return state;
609}
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627
628unsigned int aa_dfa_matchn_until(struct aa_dfa *dfa, unsigned int start,
629 const char *str, int n, const char **retpos)
630{
631 u16 *def = DEFAULT_TABLE(dfa);
632 u32 *base = BASE_TABLE(dfa);
633 u16 *next = NEXT_TABLE(dfa);
634 u16 *check = CHECK_TABLE(dfa);
635 u32 *accept = ACCEPT_TABLE(dfa);
636 unsigned int state = start, pos;
637
638 *retpos = NULL;
639 if (state == 0)
640 return 0;
641
642
643 if (dfa->tables[YYTD_ID_EC]) {
644
645 u8 *equiv = EQUIV_TABLE(dfa);
646
647 for (; n; n--) {
648 pos = base_idx(base[state]) + equiv[(u8) *str++];
649 if (check[pos] == state)
650 state = next[pos];
651 else
652 state = def[state];
653 if (accept[state])
654 break;
655 }
656 } else {
657
658 for (; n; n--) {
659 pos = base_idx(base[state]) + (u8) *str++;
660 if (check[pos] == state)
661 state = next[pos];
662 else
663 state = def[state];
664 if (accept[state])
665 break;
666 }
667 }
668
669 *retpos = str;
670 return state;
671}
672
673#define inc_wb_pos(wb) \
674do { \
675 wb->pos = (wb->pos + 1) & (WB_HISTORY_SIZE - 1); \
676 wb->len = (wb->len + 1) & (WB_HISTORY_SIZE - 1); \
677} while (0)
678
679
680static bool is_loop(struct match_workbuf *wb, unsigned int state,
681 unsigned int *adjust)
682{
683 unsigned int pos = wb->pos;
684 unsigned int i;
685
686 if (wb->history[pos] < state)
687 return false;
688
689 for (i = 0; i <= wb->len; i++) {
690 if (wb->history[pos] == state) {
691 *adjust = i;
692 return true;
693 }
694 if (pos == 0)
695 pos = WB_HISTORY_SIZE;
696 pos--;
697 }
698
699 *adjust = i;
700 return true;
701}
702
703static unsigned int leftmatch_fb(struct aa_dfa *dfa, unsigned int start,
704 const char *str, struct match_workbuf *wb,
705 unsigned int *count)
706{
707 u16 *def = DEFAULT_TABLE(dfa);
708 u32 *base = BASE_TABLE(dfa);
709 u16 *next = NEXT_TABLE(dfa);
710 u16 *check = CHECK_TABLE(dfa);
711 unsigned int state = start, pos;
712
713 AA_BUG(!dfa);
714 AA_BUG(!str);
715 AA_BUG(!wb);
716 AA_BUG(!count);
717
718 *count = 0;
719 if (state == 0)
720 return 0;
721
722
723 if (dfa->tables[YYTD_ID_EC]) {
724
725 u8 *equiv = EQUIV_TABLE(dfa);
726
727 while (*str) {
728 unsigned int adjust;
729
730 wb->history[wb->pos] = state;
731 pos = base_idx(base[state]) + equiv[(u8) *str++];
732 if (check[pos] == state)
733 state = next[pos];
734 else
735 state = def[state];
736 if (is_loop(wb, state, &adjust)) {
737 state = aa_dfa_match(dfa, state, str);
738 *count -= adjust;
739 goto out;
740 }
741 inc_wb_pos(wb);
742 (*count)++;
743 }
744 } else {
745
746 while (*str) {
747 unsigned int adjust;
748
749 wb->history[wb->pos] = state;
750 pos = base_idx(base[state]) + (u8) *str++;
751 if (check[pos] == state)
752 state = next[pos];
753 else
754 state = def[state];
755 if (is_loop(wb, state, &adjust)) {
756 state = aa_dfa_match(dfa, state, str);
757 *count -= adjust;
758 goto out;
759 }
760 inc_wb_pos(wb);
761 (*count)++;
762 }
763 }
764
765out:
766 if (!state)
767 *count = 0;
768 return state;
769}
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783
784unsigned int aa_dfa_leftmatch(struct aa_dfa *dfa, unsigned int start,
785 const char *str, unsigned int *count)
786{
787 DEFINE_MATCH_WB(wb);
788
789
790
791 return leftmatch_fb(dfa, start, str, &wb, count);
792}
793