1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Implementation of the extensible bitmap type.
4 *
5 * Author : Stephen Smalley, <sds@tycho.nsa.gov>
6 */
7 /*
8 * Updated: Hewlett-Packard <paul@paul-moore.com>
9 *
10 * Added support to import/export the NetLabel category bitmap
11 *
12 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
13 */
14 /*
15 * Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
16 * Applied standard bit operations to improve bitmap scanning.
17 */
18
19 #include <linux/kernel.h>
20 #include <linux/slab.h>
21 #include <linux/errno.h>
22 #include <linux/jhash.h>
23 #include <net/netlabel.h>
24 #include "ebitmap.h"
25 #include "policydb.h"
26
27 #define BITS_PER_U64 (sizeof(u64) * 8)
28
29 static struct kmem_cache *ebitmap_node_cachep __ro_after_init;
30
ebitmap_cmp(struct ebitmap * e1,struct ebitmap * e2)31 int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2)
32 {
33 struct ebitmap_node *n1, *n2;
34
35 if (e1->highbit != e2->highbit)
36 return 0;
37
38 n1 = e1->node;
39 n2 = e2->node;
40 while (n1 && n2 &&
41 (n1->startbit == n2->startbit) &&
42 !memcmp(n1->maps, n2->maps, EBITMAP_SIZE / 8)) {
43 n1 = n1->next;
44 n2 = n2->next;
45 }
46
47 if (n1 || n2)
48 return 0;
49
50 return 1;
51 }
52
ebitmap_cpy(struct ebitmap * dst,struct ebitmap * src)53 int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src)
54 {
55 struct ebitmap_node *n, *new, *prev;
56
57 ebitmap_init(dst);
58 n = src->node;
59 prev = NULL;
60 while (n) {
61 new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
62 if (!new) {
63 ebitmap_destroy(dst);
64 return -ENOMEM;
65 }
66 new->startbit = n->startbit;
67 memcpy(new->maps, n->maps, EBITMAP_SIZE / 8);
68 new->next = NULL;
69 if (prev)
70 prev->next = new;
71 else
72 dst->node = new;
73 prev = new;
74 n = n->next;
75 }
76
77 dst->highbit = src->highbit;
78 return 0;
79 }
80
ebitmap_and(struct ebitmap * dst,struct ebitmap * e1,struct ebitmap * e2)81 int ebitmap_and(struct ebitmap *dst, struct ebitmap *e1, struct ebitmap *e2)
82 {
83 struct ebitmap_node *n;
84 int bit, rc;
85
86 ebitmap_init(dst);
87
88 ebitmap_for_each_positive_bit(e1, n, bit) {
89 if (ebitmap_get_bit(e2, bit)) {
90 rc = ebitmap_set_bit(dst, bit, 1);
91 if (rc < 0)
92 return rc;
93 }
94 }
95 return 0;
96 }
97
98
99 #ifdef CONFIG_NETLABEL
100 /**
101 * ebitmap_netlbl_export - Export an ebitmap into a NetLabel category bitmap
102 * @ebmap: the ebitmap to export
103 * @catmap: the NetLabel category bitmap
104 *
105 * Description:
106 * Export a SELinux extensibile bitmap into a NetLabel category bitmap.
107 * Returns zero on success, negative values on error.
108 *
109 */
ebitmap_netlbl_export(struct ebitmap * ebmap,struct netlbl_lsm_catmap ** catmap)110 int ebitmap_netlbl_export(struct ebitmap *ebmap,
111 struct netlbl_lsm_catmap **catmap)
112 {
113 struct ebitmap_node *e_iter = ebmap->node;
114 unsigned long e_map;
115 u32 offset;
116 unsigned int iter;
117 int rc;
118
119 if (e_iter == NULL) {
120 *catmap = NULL;
121 return 0;
122 }
123
124 if (*catmap != NULL)
125 netlbl_catmap_free(*catmap);
126 *catmap = NULL;
127
128 while (e_iter) {
129 offset = e_iter->startbit;
130 for (iter = 0; iter < EBITMAP_UNIT_NUMS; iter++) {
131 e_map = e_iter->maps[iter];
132 if (e_map != 0) {
133 rc = netlbl_catmap_setlong(catmap,
134 offset,
135 e_map,
136 GFP_ATOMIC);
137 if (rc != 0)
138 goto netlbl_export_failure;
139 }
140 offset += EBITMAP_UNIT_SIZE;
141 }
142 e_iter = e_iter->next;
143 }
144
145 return 0;
146
147 netlbl_export_failure:
148 netlbl_catmap_free(*catmap);
149 return -ENOMEM;
150 }
151
152 /**
153 * ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
154 * @ebmap: the ebitmap to import
155 * @catmap: the NetLabel category bitmap
156 *
157 * Description:
158 * Import a NetLabel category bitmap into a SELinux extensibile bitmap.
159 * Returns zero on success, negative values on error.
160 *
161 */
ebitmap_netlbl_import(struct ebitmap * ebmap,struct netlbl_lsm_catmap * catmap)162 int ebitmap_netlbl_import(struct ebitmap *ebmap,
163 struct netlbl_lsm_catmap *catmap)
164 {
165 int rc;
166 struct ebitmap_node *e_iter = NULL;
167 struct ebitmap_node *e_prev = NULL;
168 u32 offset = 0, idx;
169 unsigned long bitmap;
170
171 for (;;) {
172 rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
173 if (rc < 0)
174 goto netlbl_import_failure;
175 if (offset == (u32)-1)
176 return 0;
177
178 /* don't waste ebitmap space if the netlabel bitmap is empty */
179 if (bitmap == 0) {
180 offset += EBITMAP_UNIT_SIZE;
181 continue;
182 }
183
184 if (e_iter == NULL ||
185 offset >= e_iter->startbit + EBITMAP_SIZE) {
186 e_prev = e_iter;
187 e_iter = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
188 if (e_iter == NULL)
189 goto netlbl_import_failure;
190 e_iter->startbit = offset - (offset % EBITMAP_SIZE);
191 if (e_prev == NULL)
192 ebmap->node = e_iter;
193 else
194 e_prev->next = e_iter;
195 ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
196 }
197
198 /* offset will always be aligned to an unsigned long */
199 idx = EBITMAP_NODE_INDEX(e_iter, offset);
200 e_iter->maps[idx] = bitmap;
201
202 /* next */
203 offset += EBITMAP_UNIT_SIZE;
204 }
205
206 /* NOTE: we should never reach this return */
207 return 0;
208
209 netlbl_import_failure:
210 ebitmap_destroy(ebmap);
211 return -ENOMEM;
212 }
213 #endif /* CONFIG_NETLABEL */
214
215 /*
216 * Check to see if all the bits set in e2 are also set in e1. Optionally,
217 * if last_e2bit is non-zero, the highest set bit in e2 cannot exceed
218 * last_e2bit.
219 */
ebitmap_contains(struct ebitmap * e1,struct ebitmap * e2,u32 last_e2bit)220 int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2, u32 last_e2bit)
221 {
222 struct ebitmap_node *n1, *n2;
223 int i;
224
225 if (e1->highbit < e2->highbit)
226 return 0;
227
228 n1 = e1->node;
229 n2 = e2->node;
230
231 while (n1 && n2 && (n1->startbit <= n2->startbit)) {
232 if (n1->startbit < n2->startbit) {
233 n1 = n1->next;
234 continue;
235 }
236 for (i = EBITMAP_UNIT_NUMS - 1; (i >= 0) && !n2->maps[i]; )
237 i--; /* Skip trailing NULL map entries */
238 if (last_e2bit && (i >= 0)) {
239 u32 lastsetbit = n2->startbit + i * EBITMAP_UNIT_SIZE +
240 __fls(n2->maps[i]);
241 if (lastsetbit > last_e2bit)
242 return 0;
243 }
244
245 while (i >= 0) {
246 if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
247 return 0;
248 i--;
249 }
250
251 n1 = n1->next;
252 n2 = n2->next;
253 }
254
255 if (n2)
256 return 0;
257
258 return 1;
259 }
260
ebitmap_get_bit(struct ebitmap * e,unsigned long bit)261 int ebitmap_get_bit(struct ebitmap *e, unsigned long bit)
262 {
263 struct ebitmap_node *n;
264
265 if (e->highbit < bit)
266 return 0;
267
268 n = e->node;
269 while (n && (n->startbit <= bit)) {
270 if ((n->startbit + EBITMAP_SIZE) > bit)
271 return ebitmap_node_get_bit(n, bit);
272 n = n->next;
273 }
274
275 return 0;
276 }
277
ebitmap_set_bit(struct ebitmap * e,unsigned long bit,int value)278 int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
279 {
280 struct ebitmap_node *n, *prev, *new;
281
282 prev = NULL;
283 n = e->node;
284 while (n && n->startbit <= bit) {
285 if ((n->startbit + EBITMAP_SIZE) > bit) {
286 if (value) {
287 ebitmap_node_set_bit(n, bit);
288 } else {
289 unsigned int s;
290
291 ebitmap_node_clr_bit(n, bit);
292
293 s = find_first_bit(n->maps, EBITMAP_SIZE);
294 if (s < EBITMAP_SIZE)
295 return 0;
296
297 /* drop this node from the bitmap */
298 if (!n->next) {
299 /*
300 * this was the highest map
301 * within the bitmap
302 */
303 if (prev)
304 e->highbit = prev->startbit
305 + EBITMAP_SIZE;
306 else
307 e->highbit = 0;
308 }
309 if (prev)
310 prev->next = n->next;
311 else
312 e->node = n->next;
313 kmem_cache_free(ebitmap_node_cachep, n);
314 }
315 return 0;
316 }
317 prev = n;
318 n = n->next;
319 }
320
321 if (!value)
322 return 0;
323
324 new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
325 if (!new)
326 return -ENOMEM;
327
328 new->startbit = bit - (bit % EBITMAP_SIZE);
329 ebitmap_node_set_bit(new, bit);
330
331 if (!n)
332 /* this node will be the highest map within the bitmap */
333 e->highbit = new->startbit + EBITMAP_SIZE;
334
335 if (prev) {
336 new->next = prev->next;
337 prev->next = new;
338 } else {
339 new->next = e->node;
340 e->node = new;
341 }
342
343 return 0;
344 }
345
ebitmap_destroy(struct ebitmap * e)346 void ebitmap_destroy(struct ebitmap *e)
347 {
348 struct ebitmap_node *n, *temp;
349
350 if (!e)
351 return;
352
353 n = e->node;
354 while (n) {
355 temp = n;
356 n = n->next;
357 kmem_cache_free(ebitmap_node_cachep, temp);
358 }
359
360 e->highbit = 0;
361 e->node = NULL;
362 return;
363 }
364
ebitmap_read(struct ebitmap * e,void * fp)365 int ebitmap_read(struct ebitmap *e, void *fp)
366 {
367 struct ebitmap_node *n = NULL;
368 u32 mapunit, count, startbit, index;
369 __le32 ebitmap_start;
370 u64 map;
371 __le64 mapbits;
372 __le32 buf[3];
373 int rc, i;
374
375 ebitmap_init(e);
376
377 rc = next_entry(buf, fp, sizeof buf);
378 if (rc < 0)
379 goto out;
380
381 mapunit = le32_to_cpu(buf[0]);
382 e->highbit = le32_to_cpu(buf[1]);
383 count = le32_to_cpu(buf[2]);
384
385 if (mapunit != BITS_PER_U64) {
386 pr_err("SELinux: ebitmap: map size %u does not "
387 "match my size %zd (high bit was %d)\n",
388 mapunit, BITS_PER_U64, e->highbit);
389 goto bad;
390 }
391
392 /* round up e->highbit */
393 e->highbit += EBITMAP_SIZE - 1;
394 e->highbit -= (e->highbit % EBITMAP_SIZE);
395
396 if (!e->highbit) {
397 e->node = NULL;
398 goto ok;
399 }
400
401 if (e->highbit && !count)
402 goto bad;
403
404 for (i = 0; i < count; i++) {
405 rc = next_entry(&ebitmap_start, fp, sizeof(u32));
406 if (rc < 0) {
407 pr_err("SELinux: ebitmap: truncated map\n");
408 goto bad;
409 }
410 startbit = le32_to_cpu(ebitmap_start);
411
412 if (startbit & (mapunit - 1)) {
413 pr_err("SELinux: ebitmap start bit (%d) is "
414 "not a multiple of the map unit size (%u)\n",
415 startbit, mapunit);
416 goto bad;
417 }
418 if (startbit > e->highbit - mapunit) {
419 pr_err("SELinux: ebitmap start bit (%d) is "
420 "beyond the end of the bitmap (%u)\n",
421 startbit, (e->highbit - mapunit));
422 goto bad;
423 }
424
425 if (!n || startbit >= n->startbit + EBITMAP_SIZE) {
426 struct ebitmap_node *tmp;
427 tmp = kmem_cache_zalloc(ebitmap_node_cachep, GFP_KERNEL);
428 if (!tmp) {
429 pr_err("SELinux: ebitmap: out of memory\n");
430 rc = -ENOMEM;
431 goto bad;
432 }
433 /* round down */
434 tmp->startbit = startbit - (startbit % EBITMAP_SIZE);
435 if (n)
436 n->next = tmp;
437 else
438 e->node = tmp;
439 n = tmp;
440 } else if (startbit <= n->startbit) {
441 pr_err("SELinux: ebitmap: start bit %d"
442 " comes after start bit %d\n",
443 startbit, n->startbit);
444 goto bad;
445 }
446
447 rc = next_entry(&mapbits, fp, sizeof(u64));
448 if (rc < 0) {
449 pr_err("SELinux: ebitmap: truncated map\n");
450 goto bad;
451 }
452 map = le64_to_cpu(mapbits);
453
454 index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
455 while (map) {
456 n->maps[index++] = map & (-1UL);
457 map = EBITMAP_SHIFT_UNIT_SIZE(map);
458 }
459 }
460 ok:
461 rc = 0;
462 out:
463 return rc;
464 bad:
465 if (!rc)
466 rc = -EINVAL;
467 ebitmap_destroy(e);
468 goto out;
469 }
470
ebitmap_write(struct ebitmap * e,void * fp)471 int ebitmap_write(struct ebitmap *e, void *fp)
472 {
473 struct ebitmap_node *n;
474 u32 count;
475 __le32 buf[3];
476 u64 map;
477 int bit, last_bit, last_startbit, rc;
478
479 buf[0] = cpu_to_le32(BITS_PER_U64);
480
481 count = 0;
482 last_bit = 0;
483 last_startbit = -1;
484 ebitmap_for_each_positive_bit(e, n, bit) {
485 if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
486 count++;
487 last_startbit = rounddown(bit, BITS_PER_U64);
488 }
489 last_bit = roundup(bit + 1, BITS_PER_U64);
490 }
491 buf[1] = cpu_to_le32(last_bit);
492 buf[2] = cpu_to_le32(count);
493
494 rc = put_entry(buf, sizeof(u32), 3, fp);
495 if (rc)
496 return rc;
497
498 map = 0;
499 last_startbit = INT_MIN;
500 ebitmap_for_each_positive_bit(e, n, bit) {
501 if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
502 __le64 buf64[1];
503
504 /* this is the very first bit */
505 if (!map) {
506 last_startbit = rounddown(bit, BITS_PER_U64);
507 map = (u64)1 << (bit - last_startbit);
508 continue;
509 }
510
511 /* write the last node */
512 buf[0] = cpu_to_le32(last_startbit);
513 rc = put_entry(buf, sizeof(u32), 1, fp);
514 if (rc)
515 return rc;
516
517 buf64[0] = cpu_to_le64(map);
518 rc = put_entry(buf64, sizeof(u64), 1, fp);
519 if (rc)
520 return rc;
521
522 /* set up for the next node */
523 map = 0;
524 last_startbit = rounddown(bit, BITS_PER_U64);
525 }
526 map |= (u64)1 << (bit - last_startbit);
527 }
528 /* write the last node */
529 if (map) {
530 __le64 buf64[1];
531
532 /* write the last node */
533 buf[0] = cpu_to_le32(last_startbit);
534 rc = put_entry(buf, sizeof(u32), 1, fp);
535 if (rc)
536 return rc;
537
538 buf64[0] = cpu_to_le64(map);
539 rc = put_entry(buf64, sizeof(u64), 1, fp);
540 if (rc)
541 return rc;
542 }
543 return 0;
544 }
545
ebitmap_hash(const struct ebitmap * e,u32 hash)546 u32 ebitmap_hash(const struct ebitmap *e, u32 hash)
547 {
548 struct ebitmap_node *node;
549
550 /* need to change hash even if ebitmap is empty */
551 hash = jhash_1word(e->highbit, hash);
552 for (node = e->node; node; node = node->next) {
553 hash = jhash_1word(node->startbit, hash);
554 hash = jhash(node->maps, sizeof(node->maps), hash);
555 }
556 return hash;
557 }
558
ebitmap_cache_init(void)559 void __init ebitmap_cache_init(void)
560 {
561 ebitmap_node_cachep = kmem_cache_create("ebitmap_node",
562 sizeof(struct ebitmap_node),
563 0, SLAB_PANIC, NULL);
564 }
565
