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1/*
2 * AppArmor security module
3 *
4 * This file contains AppArmor dfa based regular expression matching engine
5 *
6 * Copyright (C) 1998-2008 Novell/SUSE
7 * Copyright 2009-2012 Canonical Ltd.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation, version 2 of the
12 * License.
13 */
14
15#include <linux/errno.h>
16#include <linux/kernel.h>
17#include <linux/mm.h>
18#include <linux/slab.h>
19#include <linux/vmalloc.h>
20#include <linux/err.h>
21#include <linux/kref.h>
22
23#include "include/apparmor.h"
24#include "include/match.h"
25
26#define base_idx(X) ((X) & 0xffffff)
27
28/**
29 * unpack_table - unpack a dfa table (one of accept, default, base, next check)
30 * @blob: data to unpack (NOT NULL)
31 * @bsize: size of blob
32 *
33 * Returns: pointer to table else NULL on failure
34 *
35 * NOTE: must be freed by kvfree (not kfree)
36 */
37static struct table_header *unpack_table(char *blob, size_t bsize)
38{
39 struct table_header *table = NULL;
40 struct table_header th;
41 size_t tsize;
42
43 if (bsize < sizeof(struct table_header))
44 goto out;
45
46 /* loaded td_id's start at 1, subtract 1 now to avoid doing
47 * it every time we use td_id as an index
48 */
49 th.td_id = be16_to_cpu(*(u16 *) (blob)) - 1;
50 th.td_flags = be16_to_cpu(*(u16 *) (blob + 2));
51 th.td_lolen = be32_to_cpu(*(u32 *) (blob + 8));
52 blob += sizeof(struct table_header);
53
54 if (!(th.td_flags == YYTD_DATA16 || th.td_flags == YYTD_DATA32 ||
55 th.td_flags == YYTD_DATA8))
56 goto out;
57
58 tsize = table_size(th.td_lolen, th.td_flags);
59 if (bsize < tsize)
60 goto out;
61
62 table = kvzalloc(tsize);
63 if (table) {
64 *table = th;
65 if (th.td_flags == YYTD_DATA8)
66 UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
67 u8, byte_to_byte);
68 else if (th.td_flags == YYTD_DATA16)
69 UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
70 u16, be16_to_cpu);
71 else if (th.td_flags == YYTD_DATA32)
72 UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
73 u32, be32_to_cpu);
74 else
75 goto fail;
76 }
77
78out:
79 /* if table was vmalloced make sure the page tables are synced
80 * before it is used, as it goes live to all cpus.
81 */
82 if (is_vmalloc_addr(table))
83 vm_unmap_aliases();
84 return table;
85fail:
86 kvfree(table);
87 return NULL;
88}
89
90/**
91 * verify_dfa - verify that transitions and states in the tables are in bounds.
92 * @dfa: dfa to test (NOT NULL)
93 * @flags: flags controlling what type of accept table are acceptable
94 *
95 * Assumes dfa has gone through the first pass verification done by unpacking
96 * NOTE: this does not valid accept table values
97 *
98 * Returns: %0 else error code on failure to verify
99 */
100static int verify_dfa(struct aa_dfa *dfa, int flags)
101{
102 size_t i, state_count, trans_count;
103 int error = -EPROTO;
104
105 /* check that required tables exist */
106 if (!(dfa->tables[YYTD_ID_DEF] &&
107 dfa->tables[YYTD_ID_BASE] &&
108 dfa->tables[YYTD_ID_NXT] && dfa->tables[YYTD_ID_CHK]))
109 goto out;
110
111 /* accept.size == default.size == base.size */
112 state_count = dfa->tables[YYTD_ID_BASE]->td_lolen;
113 if (ACCEPT1_FLAGS(flags)) {
114 if (!dfa->tables[YYTD_ID_ACCEPT])
115 goto out;
116 if (state_count != dfa->tables[YYTD_ID_ACCEPT]->td_lolen)
117 goto out;
118 }
119 if (ACCEPT2_FLAGS(flags)) {
120 if (!dfa->tables[YYTD_ID_ACCEPT2])
121 goto out;
122 if (state_count != dfa->tables[YYTD_ID_ACCEPT2]->td_lolen)
123 goto out;
124 }
125 if (state_count != dfa->tables[YYTD_ID_DEF]->td_lolen)
126 goto out;
127
128 /* next.size == chk.size */
129 trans_count = dfa->tables[YYTD_ID_NXT]->td_lolen;
130 if (trans_count != dfa->tables[YYTD_ID_CHK]->td_lolen)
131 goto out;
132
133 /* if equivalence classes then its table size must be 256 */
134 if (dfa->tables[YYTD_ID_EC] &&
135 dfa->tables[YYTD_ID_EC]->td_lolen != 256)
136 goto out;
137
138 if (flags & DFA_FLAG_VERIFY_STATES) {
139 for (i = 0; i < state_count; i++) {
140 if (DEFAULT_TABLE(dfa)[i] >= state_count)
141 goto out;
142 if (base_idx(BASE_TABLE(dfa)[i]) + 255 >= trans_count) {
143 printk(KERN_ERR "AppArmor DFA next/check upper "
144 "bounds error\n");
145 goto out;
146 }
147 }
148
149 for (i = 0; i < trans_count; i++) {
150 if (NEXT_TABLE(dfa)[i] >= state_count)
151 goto out;
152 if (CHECK_TABLE(dfa)[i] >= state_count)
153 goto out;
154 }
155 }
156
157 error = 0;
158out:
159 return error;
160}
161
162/**
163 * dfa_free - free a dfa allocated by aa_dfa_unpack
164 * @dfa: the dfa to free (MAYBE NULL)
165 *
166 * Requires: reference count to dfa == 0
167 */
168static void dfa_free(struct aa_dfa *dfa)
169{
170 if (dfa) {
171 int i;
172
173 for (i = 0; i < ARRAY_SIZE(dfa->tables); i++) {
174 kvfree(dfa->tables[i]);
175 dfa->tables[i] = NULL;
176 }
177 kfree(dfa);
178 }
179}
180
181/**
182 * aa_dfa_free_kref - free aa_dfa by kref (called by aa_put_dfa)
183 * @kr: kref callback for freeing of a dfa (NOT NULL)
184 */
185void aa_dfa_free_kref(struct kref *kref)
186{
187 struct aa_dfa *dfa = container_of(kref, struct aa_dfa, count);
188 dfa_free(dfa);
189}
190
191/**
192 * aa_dfa_unpack - unpack the binary tables of a serialized dfa
193 * @blob: aligned serialized stream of data to unpack (NOT NULL)
194 * @size: size of data to unpack
195 * @flags: flags controlling what type of accept tables are acceptable
196 *
197 * Unpack a dfa that has been serialized. To find information on the dfa
198 * format look in Documentation/security/apparmor.txt
199 * Assumes the dfa @blob stream has been aligned on a 8 byte boundary
200 *
201 * Returns: an unpacked dfa ready for matching or ERR_PTR on failure
202 */
203struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags)
204{
205 int hsize;
206 int error = -ENOMEM;
207 char *data = blob;
208 struct table_header *table = NULL;
209 struct aa_dfa *dfa = kzalloc(sizeof(struct aa_dfa), GFP_KERNEL);
210 if (!dfa)
211 goto fail;
212
213 kref_init(&dfa->count);
214
215 error = -EPROTO;
216
217 /* get dfa table set header */
218 if (size < sizeof(struct table_set_header))
219 goto fail;
220
221 if (ntohl(*(u32 *) data) != YYTH_MAGIC)
222 goto fail;
223
224 hsize = ntohl(*(u32 *) (data + 4));
225 if (size < hsize)
226 goto fail;
227
228 dfa->flags = ntohs(*(u16 *) (data + 12));
229 data += hsize;
230 size -= hsize;
231
232 while (size > 0) {
233 table = unpack_table(data, size);
234 if (!table)
235 goto fail;
236
237 switch (table->td_id) {
238 case YYTD_ID_ACCEPT:
239 if (!(table->td_flags & ACCEPT1_FLAGS(flags)))
240 goto fail;
241 break;
242 case YYTD_ID_ACCEPT2:
243 if (!(table->td_flags & ACCEPT2_FLAGS(flags)))
244 goto fail;
245 break;
246 case YYTD_ID_BASE:
247 if (table->td_flags != YYTD_DATA32)
248 goto fail;
249 break;
250 case YYTD_ID_DEF:
251 case YYTD_ID_NXT:
252 case YYTD_ID_CHK:
253 if (table->td_flags != YYTD_DATA16)
254 goto fail;
255 break;
256 case YYTD_ID_EC:
257 if (table->td_flags != YYTD_DATA8)
258 goto fail;
259 break;
260 default:
261 goto fail;
262 }
263 /* check for duplicate table entry */
264 if (dfa->tables[table->td_id])
265 goto fail;
266 dfa->tables[table->td_id] = table;
267 data += table_size(table->td_lolen, table->td_flags);
268 size -= table_size(table->td_lolen, table->td_flags);
269 table = NULL;
270 }
271
272 error = verify_dfa(dfa, flags);
273 if (error)
274 goto fail;
275
276 return dfa;
277
278fail:
279 kvfree(table);
280 dfa_free(dfa);
281 return ERR_PTR(error);
282}
283
284/**
285 * aa_dfa_match_len - traverse @dfa to find state @str stops at
286 * @dfa: the dfa to match @str against (NOT NULL)
287 * @start: the state of the dfa to start matching in
288 * @str: the string of bytes to match against the dfa (NOT NULL)
289 * @len: length of the string of bytes to match
290 *
291 * aa_dfa_match_len will match @str against the dfa and return the state it
292 * finished matching in. The final state can be used to look up the accepting
293 * label, or as the start state of a continuing match.
294 *
295 * This function will happily match again the 0 byte and only finishes
296 * when @len input is consumed.
297 *
298 * Returns: final state reached after input is consumed
299 */
300unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
301 const char *str, int len)
302{
303 u16 *def = DEFAULT_TABLE(dfa);
304 u32 *base = BASE_TABLE(dfa);
305 u16 *next = NEXT_TABLE(dfa);
306 u16 *check = CHECK_TABLE(dfa);
307 unsigned int state = start, pos;
308
309 if (state == 0)
310 return 0;
311
312 /* current state is <state>, matching character *str */
313 if (dfa->tables[YYTD_ID_EC]) {
314 /* Equivalence class table defined */
315 u8 *equiv = EQUIV_TABLE(dfa);
316 /* default is direct to next state */
317 for (; len; len--) {
318 pos = base_idx(base[state]) + equiv[(u8) *str++];
319 if (check[pos] == state)
320 state = next[pos];
321 else
322 state = def[state];
323 }
324 } else {
325 /* default is direct to next state */
326 for (; len; len--) {
327 pos = base_idx(base[state]) + (u8) *str++;
328 if (check[pos] == state)
329 state = next[pos];
330 else
331 state = def[state];
332 }
333 }
334
335 return state;
336}
337
338/**
339 * aa_dfa_match - traverse @dfa to find state @str stops at
340 * @dfa: the dfa to match @str against (NOT NULL)
341 * @start: the state of the dfa to start matching in
342 * @str: the null terminated string of bytes to match against the dfa (NOT NULL)
343 *
344 * aa_dfa_match will match @str against the dfa and return the state it
345 * finished matching in. The final state can be used to look up the accepting
346 * label, or as the start state of a continuing match.
347 *
348 * Returns: final state reached after input is consumed
349 */
350unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
351 const char *str)
352{
353 u16 *def = DEFAULT_TABLE(dfa);
354 u32 *base = BASE_TABLE(dfa);
355 u16 *next = NEXT_TABLE(dfa);
356 u16 *check = CHECK_TABLE(dfa);
357 unsigned int state = start, pos;
358
359 if (state == 0)
360 return 0;
361
362 /* current state is <state>, matching character *str */
363 if (dfa->tables[YYTD_ID_EC]) {
364 /* Equivalence class table defined */
365 u8 *equiv = EQUIV_TABLE(dfa);
366 /* default is direct to next state */
367 while (*str) {
368 pos = base_idx(base[state]) + equiv[(u8) *str++];
369 if (check[pos] == state)
370 state = next[pos];
371 else
372 state = def[state];
373 }
374 } else {
375 /* default is direct to next state */
376 while (*str) {
377 pos = base_idx(base[state]) + (u8) *str++;
378 if (check[pos] == state)
379 state = next[pos];
380 else
381 state = def[state];
382 }
383 }
384
385 return state;
386}
387
388/**
389 * aa_dfa_next - step one character to the next state in the dfa
390 * @dfa: the dfa to tranverse (NOT NULL)
391 * @state: the state to start in
392 * @c: the input character to transition on
393 *
394 * aa_dfa_match will step through the dfa by one input character @c
395 *
396 * Returns: state reach after input @c
397 */
398unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state,
399 const char c)
400{
401 u16 *def = DEFAULT_TABLE(dfa);
402 u32 *base = BASE_TABLE(dfa);
403 u16 *next = NEXT_TABLE(dfa);
404 u16 *check = CHECK_TABLE(dfa);
405 unsigned int pos;
406
407 /* current state is <state>, matching character *str */
408 if (dfa->tables[YYTD_ID_EC]) {
409 /* Equivalence class table defined */
410 u8 *equiv = EQUIV_TABLE(dfa);
411 /* default is direct to next state */
412
413 pos = base_idx(base[state]) + equiv[(u8) c];
414 if (check[pos] == state)
415 state = next[pos];
416 else
417 state = def[state];
418 } else {
419 /* default is direct to next state */
420 pos = base_idx(base[state]) + (u8) c;
421 if (check[pos] == state)
422 state = next[pos];
423 else
424 state = def[state];
425 }
426
427 return state;
428}
1/*
2 * AppArmor security module
3 *
4 * This file contains AppArmor dfa based regular expression matching engine
5 *
6 * Copyright (C) 1998-2008 Novell/SUSE
7 * Copyright 2009-2010 Canonical Ltd.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation, version 2 of the
12 * License.
13 */
14
15#include <linux/errno.h>
16#include <linux/kernel.h>
17#include <linux/mm.h>
18#include <linux/slab.h>
19#include <linux/vmalloc.h>
20#include <linux/err.h>
21#include <linux/kref.h>
22
23#include "include/apparmor.h"
24#include "include/match.h"
25
26/**
27 * unpack_table - unpack a dfa table (one of accept, default, base, next check)
28 * @blob: data to unpack (NOT NULL)
29 * @bsize: size of blob
30 *
31 * Returns: pointer to table else NULL on failure
32 *
33 * NOTE: must be freed by kvfree (not kmalloc)
34 */
35static struct table_header *unpack_table(char *blob, size_t bsize)
36{
37 struct table_header *table = NULL;
38 struct table_header th;
39 size_t tsize;
40
41 if (bsize < sizeof(struct table_header))
42 goto out;
43
44 /* loaded td_id's start at 1, subtract 1 now to avoid doing
45 * it every time we use td_id as an index
46 */
47 th.td_id = be16_to_cpu(*(u16 *) (blob)) - 1;
48 th.td_flags = be16_to_cpu(*(u16 *) (blob + 2));
49 th.td_lolen = be32_to_cpu(*(u32 *) (blob + 8));
50 blob += sizeof(struct table_header);
51
52 if (!(th.td_flags == YYTD_DATA16 || th.td_flags == YYTD_DATA32 ||
53 th.td_flags == YYTD_DATA8))
54 goto out;
55
56 tsize = table_size(th.td_lolen, th.td_flags);
57 if (bsize < tsize)
58 goto out;
59
60 table = kvmalloc(tsize);
61 if (table) {
62 *table = th;
63 if (th.td_flags == YYTD_DATA8)
64 UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
65 u8, byte_to_byte);
66 else if (th.td_flags == YYTD_DATA16)
67 UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
68 u16, be16_to_cpu);
69 else if (th.td_flags == YYTD_DATA32)
70 UNPACK_ARRAY(table->td_data, blob, th.td_lolen,
71 u32, be32_to_cpu);
72 else
73 goto fail;
74 }
75
76out:
77 /* if table was vmalloced make sure the page tables are synced
78 * before it is used, as it goes live to all cpus.
79 */
80 if (is_vmalloc_addr(table))
81 vm_unmap_aliases();
82 return table;
83fail:
84 kvfree(table);
85 return NULL;
86}
87
88/**
89 * verify_dfa - verify that transitions and states in the tables are in bounds.
90 * @dfa: dfa to test (NOT NULL)
91 * @flags: flags controlling what type of accept table are acceptable
92 *
93 * Assumes dfa has gone through the first pass verification done by unpacking
94 * NOTE: this does not valid accept table values
95 *
96 * Returns: %0 else error code on failure to verify
97 */
98static int verify_dfa(struct aa_dfa *dfa, int flags)
99{
100 size_t i, state_count, trans_count;
101 int error = -EPROTO;
102
103 /* check that required tables exist */
104 if (!(dfa->tables[YYTD_ID_DEF] &&
105 dfa->tables[YYTD_ID_BASE] &&
106 dfa->tables[YYTD_ID_NXT] && dfa->tables[YYTD_ID_CHK]))
107 goto out;
108
109 /* accept.size == default.size == base.size */
110 state_count = dfa->tables[YYTD_ID_BASE]->td_lolen;
111 if (ACCEPT1_FLAGS(flags)) {
112 if (!dfa->tables[YYTD_ID_ACCEPT])
113 goto out;
114 if (state_count != dfa->tables[YYTD_ID_ACCEPT]->td_lolen)
115 goto out;
116 }
117 if (ACCEPT2_FLAGS(flags)) {
118 if (!dfa->tables[YYTD_ID_ACCEPT2])
119 goto out;
120 if (state_count != dfa->tables[YYTD_ID_ACCEPT2]->td_lolen)
121 goto out;
122 }
123 if (state_count != dfa->tables[YYTD_ID_DEF]->td_lolen)
124 goto out;
125
126 /* next.size == chk.size */
127 trans_count = dfa->tables[YYTD_ID_NXT]->td_lolen;
128 if (trans_count != dfa->tables[YYTD_ID_CHK]->td_lolen)
129 goto out;
130
131 /* if equivalence classes then its table size must be 256 */
132 if (dfa->tables[YYTD_ID_EC] &&
133 dfa->tables[YYTD_ID_EC]->td_lolen != 256)
134 goto out;
135
136 if (flags & DFA_FLAG_VERIFY_STATES) {
137 for (i = 0; i < state_count; i++) {
138 if (DEFAULT_TABLE(dfa)[i] >= state_count)
139 goto out;
140 /* TODO: do check that DEF state recursion terminates */
141 if (BASE_TABLE(dfa)[i] + 255 >= trans_count) {
142 printk(KERN_ERR "AppArmor DFA next/check upper "
143 "bounds error\n");
144 goto out;
145 }
146 }
147
148 for (i = 0; i < trans_count; i++) {
149 if (NEXT_TABLE(dfa)[i] >= state_count)
150 goto out;
151 if (CHECK_TABLE(dfa)[i] >= state_count)
152 goto out;
153 }
154 }
155
156 error = 0;
157out:
158 return error;
159}
160
161/**
162 * dfa_free - free a dfa allocated by aa_dfa_unpack
163 * @dfa: the dfa to free (MAYBE NULL)
164 *
165 * Requires: reference count to dfa == 0
166 */
167static void dfa_free(struct aa_dfa *dfa)
168{
169 if (dfa) {
170 int i;
171
172 for (i = 0; i < ARRAY_SIZE(dfa->tables); i++) {
173 kvfree(dfa->tables[i]);
174 dfa->tables[i] = NULL;
175 }
176 kfree(dfa);
177 }
178}
179
180/**
181 * aa_dfa_free_kref - free aa_dfa by kref (called by aa_put_dfa)
182 * @kr: kref callback for freeing of a dfa (NOT NULL)
183 */
184void aa_dfa_free_kref(struct kref *kref)
185{
186 struct aa_dfa *dfa = container_of(kref, struct aa_dfa, count);
187 dfa_free(dfa);
188}
189
190/**
191 * aa_dfa_unpack - unpack the binary tables of a serialized dfa
192 * @blob: aligned serialized stream of data to unpack (NOT NULL)
193 * @size: size of data to unpack
194 * @flags: flags controlling what type of accept tables are acceptable
195 *
196 * Unpack a dfa that has been serialized. To find information on the dfa
197 * format look in Documentation/security/apparmor.txt
198 * Assumes the dfa @blob stream has been aligned on a 8 byte boundary
199 *
200 * Returns: an unpacked dfa ready for matching or ERR_PTR on failure
201 */
202struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags)
203{
204 int hsize;
205 int error = -ENOMEM;
206 char *data = blob;
207 struct table_header *table = NULL;
208 struct aa_dfa *dfa = kzalloc(sizeof(struct aa_dfa), GFP_KERNEL);
209 if (!dfa)
210 goto fail;
211
212 kref_init(&dfa->count);
213
214 error = -EPROTO;
215
216 /* get dfa table set header */
217 if (size < sizeof(struct table_set_header))
218 goto fail;
219
220 if (ntohl(*(u32 *) data) != YYTH_MAGIC)
221 goto fail;
222
223 hsize = ntohl(*(u32 *) (data + 4));
224 if (size < hsize)
225 goto fail;
226
227 dfa->flags = ntohs(*(u16 *) (data + 12));
228 data += hsize;
229 size -= hsize;
230
231 while (size > 0) {
232 table = unpack_table(data, size);
233 if (!table)
234 goto fail;
235
236 switch (table->td_id) {
237 case YYTD_ID_ACCEPT:
238 if (!(table->td_flags & ACCEPT1_FLAGS(flags)))
239 goto fail;
240 break;
241 case YYTD_ID_ACCEPT2:
242 if (!(table->td_flags & ACCEPT2_FLAGS(flags)))
243 goto fail;
244 break;
245 case YYTD_ID_BASE:
246 if (table->td_flags != YYTD_DATA32)
247 goto fail;
248 break;
249 case YYTD_ID_DEF:
250 case YYTD_ID_NXT:
251 case YYTD_ID_CHK:
252 if (table->td_flags != YYTD_DATA16)
253 goto fail;
254 break;
255 case YYTD_ID_EC:
256 if (table->td_flags != YYTD_DATA8)
257 goto fail;
258 break;
259 default:
260 goto fail;
261 }
262 /* check for duplicate table entry */
263 if (dfa->tables[table->td_id])
264 goto fail;
265 dfa->tables[table->td_id] = table;
266 data += table_size(table->td_lolen, table->td_flags);
267 size -= table_size(table->td_lolen, table->td_flags);
268 table = NULL;
269 }
270
271 error = verify_dfa(dfa, flags);
272 if (error)
273 goto fail;
274
275 return dfa;
276
277fail:
278 kvfree(table);
279 dfa_free(dfa);
280 return ERR_PTR(error);
281}
282
283/**
284 * aa_dfa_match_len - traverse @dfa to find state @str stops at
285 * @dfa: the dfa to match @str against (NOT NULL)
286 * @start: the state of the dfa to start matching in
287 * @str: the string of bytes to match against the dfa (NOT NULL)
288 * @len: length of the string of bytes to match
289 *
290 * aa_dfa_match_len will match @str against the dfa and return the state it
291 * finished matching in. The final state can be used to look up the accepting
292 * label, or as the start state of a continuing match.
293 *
294 * This function will happily match again the 0 byte and only finishes
295 * when @len input is consumed.
296 *
297 * Returns: final state reached after input is consumed
298 */
299unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
300 const char *str, int len)
301{
302 u16 *def = DEFAULT_TABLE(dfa);
303 u32 *base = BASE_TABLE(dfa);
304 u16 *next = NEXT_TABLE(dfa);
305 u16 *check = CHECK_TABLE(dfa);
306 unsigned int state = start, pos;
307
308 if (state == 0)
309 return 0;
310
311 /* current state is <state>, matching character *str */
312 if (dfa->tables[YYTD_ID_EC]) {
313 /* Equivalence class table defined */
314 u8 *equiv = EQUIV_TABLE(dfa);
315 /* default is direct to next state */
316 for (; len; len--) {
317 pos = base[state] + equiv[(u8) *str++];
318 if (check[pos] == state)
319 state = next[pos];
320 else
321 state = def[state];
322 }
323 } else {
324 /* default is direct to next state */
325 for (; len; len--) {
326 pos = base[state] + (u8) *str++;
327 if (check[pos] == state)
328 state = next[pos];
329 else
330 state = def[state];
331 }
332 }
333
334 return state;
335}
336
337/**
338 * aa_dfa_match - traverse @dfa to find state @str stops at
339 * @dfa: the dfa to match @str against (NOT NULL)
340 * @start: the state of the dfa to start matching in
341 * @str: the null terminated string of bytes to match against the dfa (NOT NULL)
342 *
343 * aa_dfa_match will match @str against the dfa and return the state it
344 * finished matching in. The final state can be used to look up the accepting
345 * label, or as the start state of a continuing match.
346 *
347 * Returns: final state reached after input is consumed
348 */
349unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
350 const char *str)
351{
352 u16 *def = DEFAULT_TABLE(dfa);
353 u32 *base = BASE_TABLE(dfa);
354 u16 *next = NEXT_TABLE(dfa);
355 u16 *check = CHECK_TABLE(dfa);
356 unsigned int state = start, pos;
357
358 if (state == 0)
359 return 0;
360
361 /* current state is <state>, matching character *str */
362 if (dfa->tables[YYTD_ID_EC]) {
363 /* Equivalence class table defined */
364 u8 *equiv = EQUIV_TABLE(dfa);
365 /* default is direct to next state */
366 while (*str) {
367 pos = base[state] + equiv[(u8) *str++];
368 if (check[pos] == state)
369 state = next[pos];
370 else
371 state = def[state];
372 }
373 } else {
374 /* default is direct to next state */
375 while (*str) {
376 pos = base[state] + (u8) *str++;
377 if (check[pos] == state)
378 state = next[pos];
379 else
380 state = def[state];
381 }
382 }
383
384 return state;
385}
386
387/**
388 * aa_dfa_next - step one character to the next state in the dfa
389 * @dfa: the dfa to tranverse (NOT NULL)
390 * @state: the state to start in
391 * @c: the input character to transition on
392 *
393 * aa_dfa_match will step through the dfa by one input character @c
394 *
395 * Returns: state reach after input @c
396 */
397unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state,
398 const char c)
399{
400 u16 *def = DEFAULT_TABLE(dfa);
401 u32 *base = BASE_TABLE(dfa);
402 u16 *next = NEXT_TABLE(dfa);
403 u16 *check = CHECK_TABLE(dfa);
404 unsigned int pos;
405
406 /* current state is <state>, matching character *str */
407 if (dfa->tables[YYTD_ID_EC]) {
408 /* Equivalence class table defined */
409 u8 *equiv = EQUIV_TABLE(dfa);
410 /* default is direct to next state */
411
412 pos = base[state] + equiv[(u8) c];
413 if (check[pos] == state)
414 state = next[pos];
415 else
416 state = def[state];
417 } else {
418 /* default is direct to next state */
419 pos = base[state] + (u8) c;
420 if (check[pos] == state)
421 state = next[pos];
422 else
423 state = def[state];
424 }
425
426 return state;
427}