1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Implementation of the extensible bitmap type.
4 *
5 * Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
6 */
7 /*
8 * Updated: Hewlett-Packard <paul@paul-moore.com>
9 * Added support to import/export the NetLabel category bitmap
10 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
11 *
12 * Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
13 * Applied standard bit operations to improve bitmap scanning.
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/slab.h>
18 #include <linux/errno.h>
19 #include <linux/jhash.h>
20 #include <net/netlabel.h>
21 #include "ebitmap.h"
22 #include "policydb.h"
23
24 #define BITS_PER_U64 ((u32)(sizeof(u64) * 8))
25
26 static struct kmem_cache *ebitmap_node_cachep __ro_after_init;
27
28 int ebitmap_cmp(const struct ebitmap *e1, const struct ebitmap *e2)
29 {
30 const struct ebitmap_node *n1, *n2;
31
32 if (e1->highbit != e2->highbit)
33 return 0;
34
35 n1 = e1->node;
36 n2 = e2->node;
37 while (n1 && n2 && (n1->startbit == n2->startbit) &&
38 !memcmp(n1->maps, n2->maps, EBITMAP_SIZE / 8)) {
39 n1 = n1->next;
40 n2 = n2->next;
41 }
42
43 if (n1 || n2)
44 return 0;
45
46 return 1;
47 }
48
49 int ebitmap_cpy(struct ebitmap *dst, const struct ebitmap *src)
50 {
51 struct ebitmap_node *new, *prev;
52 const struct ebitmap_node *n;
53
54 ebitmap_init(dst);
55 n = src->node;
56 prev = NULL;
57 while (n) {
58 new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
59 if (!new) {
60 ebitmap_destroy(dst);
61 return -ENOMEM;
62 }
63 new->startbit = n->startbit;
64 memcpy(new->maps, n->maps, EBITMAP_SIZE / 8);
65 new->next = NULL;
66 if (prev)
67 prev->next = new;
68 else
69 dst->node = new;
70 prev = new;
71 n = n->next;
72 }
73
74 dst->highbit = src->highbit;
75 return 0;
76 }
77
78 int ebitmap_and(struct ebitmap *dst, const struct ebitmap *e1,
79 const struct ebitmap *e2)
80 {
81 struct ebitmap_node *n;
82 u32 bit;
83 int rc;
84
85 ebitmap_init(dst);
86
87 ebitmap_for_each_positive_bit(e1, n, bit)
88 {
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 #ifdef CONFIG_NETLABEL
99 /**
100 * ebitmap_netlbl_export - Export an ebitmap into a NetLabel category bitmap
101 * @ebmap: the ebitmap to export
102 * @catmap: the NetLabel category bitmap
103 *
104 * Description:
105 * Export a SELinux extensibile bitmap into a NetLabel category bitmap.
106 * Returns zero on success, negative values on error.
107 *
108 */
109 int ebitmap_netlbl_export(struct ebitmap *ebmap,
110 struct netlbl_lsm_catmap **catmap)
111 {
112 struct ebitmap_node *e_iter = ebmap->node;
113 unsigned long e_map;
114 u32 offset;
115 unsigned int iter;
116 int rc;
117
118 if (e_iter == NULL) {
119 *catmap = NULL;
120 return 0;
121 }
122
123 if (*catmap != NULL)
124 netlbl_catmap_free(*catmap);
125 *catmap = NULL;
126
127 while (e_iter) {
128 offset = e_iter->startbit;
129 for (iter = 0; iter < EBITMAP_UNIT_NUMS; iter++) {
130 e_map = e_iter->maps[iter];
131 if (e_map != 0) {
132 rc = netlbl_catmap_setlong(catmap, offset,
133 e_map, GFP_ATOMIC);
134 if (rc != 0)
135 goto netlbl_export_failure;
136 }
137 offset += EBITMAP_UNIT_SIZE;
138 }
139 e_iter = e_iter->next;
140 }
141
142 return 0;
143
144 netlbl_export_failure:
145 netlbl_catmap_free(*catmap);
146 return -ENOMEM;
147 }
148
149 /**
150 * ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
151 * @ebmap: the ebitmap to import
152 * @catmap: the NetLabel category bitmap
153 *
154 * Description:
155 * Import a NetLabel category bitmap into a SELinux extensibile bitmap.
156 * Returns zero on success, negative values on error.
157 *
158 */
159 int ebitmap_netlbl_import(struct ebitmap *ebmap,
160 struct netlbl_lsm_catmap *catmap)
161 {
162 int rc;
163 struct ebitmap_node *e_iter = NULL;
164 struct ebitmap_node *e_prev = NULL;
165 u32 offset = 0, idx;
166 unsigned long bitmap;
167
168 for (;;) {
169 rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
170 if (rc < 0)
171 goto netlbl_import_failure;
172 if (offset == (u32)-1)
173 return 0;
174
175 /* don't waste ebitmap space if the netlabel bitmap is empty */
176 if (bitmap == 0) {
177 offset += EBITMAP_UNIT_SIZE;
178 continue;
179 }
180
181 if (e_iter == NULL ||
182 offset >= e_iter->startbit + EBITMAP_SIZE) {
183 e_prev = e_iter;
184 e_iter = kmem_cache_zalloc(ebitmap_node_cachep,
185 GFP_ATOMIC);
186 if (e_iter == NULL)
187 goto netlbl_import_failure;
188 e_iter->startbit = offset - (offset % EBITMAP_SIZE);
189 if (e_prev == NULL)
190 ebmap->node = e_iter;
191 else
192 e_prev->next = e_iter;
193 ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
194 }
195
196 /* offset will always be aligned to an unsigned long */
197 idx = EBITMAP_NODE_INDEX(e_iter, offset);
198 e_iter->maps[idx] = bitmap;
199
200 /* next */
201 offset += EBITMAP_UNIT_SIZE;
202 }
203
204 /* NOTE: we should never reach this return */
205 return 0;
206
207 netlbl_import_failure:
208 ebitmap_destroy(ebmap);
209 return -ENOMEM;
210 }
211 #endif /* CONFIG_NETLABEL */
212
213 /*
214 * Check to see if all the bits set in e2 are also set in e1. Optionally,
215 * if last_e2bit is non-zero, the highest set bit in e2 cannot exceed
216 * last_e2bit.
217 */
218 int ebitmap_contains(const struct ebitmap *e1, const struct ebitmap *e2,
219 u32 last_e2bit)
220 {
221 const struct ebitmap_node *n1, *n2;
222 int i;
223
224 if (e1->highbit < e2->highbit)
225 return 0;
226
227 n1 = e1->node;
228 n2 = e2->node;
229
230 while (n1 && n2 && (n1->startbit <= n2->startbit)) {
231 if (n1->startbit < n2->startbit) {
232 n1 = n1->next;
233 continue;
234 }
235 for (i = EBITMAP_UNIT_NUMS - 1; (i >= 0) && !n2->maps[i];)
236 i--; /* Skip trailing NULL map entries */
237 if (last_e2bit && (i >= 0)) {
238 u32 lastsetbit = n2->startbit + i * EBITMAP_UNIT_SIZE +
239 __fls(n2->maps[i]);
240 if (lastsetbit > last_e2bit)
241 return 0;
242 }
243
244 while (i >= 0) {
245 if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
246 return 0;
247 i--;
248 }
249
250 n1 = n1->next;
251 n2 = n2->next;
252 }
253
254 if (n2)
255 return 0;
256
257 return 1;
258 }
259
260 int ebitmap_get_bit(const struct ebitmap *e, u32 bit)
261 {
262 const struct ebitmap_node *n;
263
264 if (e->highbit < bit)
265 return 0;
266
267 n = e->node;
268 while (n && (n->startbit <= bit)) {
269 if ((n->startbit + EBITMAP_SIZE) > bit)
270 return ebitmap_node_get_bit(n, bit);
271 n = n->next;
272 }
273
274 return 0;
275 }
276
277 int ebitmap_set_bit(struct ebitmap *e, u32 bit, int value)
278 {
279 struct ebitmap_node *n, *prev, *new;
280
281 prev = NULL;
282 n = e->node;
283 while (n && n->startbit <= bit) {
284 if ((n->startbit + EBITMAP_SIZE) > bit) {
285 if (value) {
286 ebitmap_node_set_bit(n, bit);
287 } else {
288 u32 s;
289
290 ebitmap_node_clr_bit(n, bit);
291
292 s = find_first_bit(n->maps, EBITMAP_SIZE);
293 if (s < EBITMAP_SIZE)
294 return 0;
295
296 /* drop this node from the bitmap */
297 if (!n->next) {
298 /*
299 * this was the highest map
300 * within the bitmap
301 */
302 if (prev)
303 e->highbit = prev->startbit +
304 EBITMAP_SIZE;
305 else
306 e->highbit = 0;
307 }
308 if (prev)
309 prev->next = n->next;
310 else
311 e->node = n->next;
312 kmem_cache_free(ebitmap_node_cachep, n);
313 }
314 return 0;
315 }
316 prev = n;
317 n = n->next;
318 }
319
320 if (!value)
321 return 0;
322
323 new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
324 if (!new)
325 return -ENOMEM;
326
327 new->startbit = bit - (bit % EBITMAP_SIZE);
328 ebitmap_node_set_bit(new, bit);
329
330 if (!n)
331 /* this node will be the highest map within the bitmap */
332 e->highbit = new->startbit + EBITMAP_SIZE;
333
334 if (prev) {
335 new->next = prev->next;
336 prev->next = new;
337 } else {
338 new->next = e->node;
339 e->node = new;
340 }
341
342 return 0;
343 }
344
345 void ebitmap_destroy(struct ebitmap *e)
346 {
347 struct ebitmap_node *n, *temp;
348
349 if (!e)
350 return;
351
352 n = e->node;
353 while (n) {
354 temp = n;
355 n = n->next;
356 kmem_cache_free(ebitmap_node_cachep, temp);
357 }
358
359 e->highbit = 0;
360 e->node = NULL;
361 }
362
363 int ebitmap_read(struct ebitmap *e, void *fp)
364 {
365 struct ebitmap_node *n = NULL;
366 u32 mapunit, count, startbit, index, i;
367 __le32 ebitmap_start;
368 u64 map;
369 __le64 mapbits;
370 __le32 buf[3];
371 int rc;
372
373 ebitmap_init(e);
374
375 rc = next_entry(buf, fp, sizeof buf);
376 if (rc < 0)
377 goto out;
378
379 mapunit = le32_to_cpu(buf[0]);
380 e->highbit = le32_to_cpu(buf[1]);
381 count = le32_to_cpu(buf[2]);
382
383 if (mapunit != BITS_PER_U64) {
384 pr_err("SELinux: ebitmap: map size %u does not "
385 "match my size %u (high bit was %u)\n",
386 mapunit, BITS_PER_U64, e->highbit);
387 goto bad;
388 }
389
390 /* round up e->highbit */
391 e->highbit += EBITMAP_SIZE - 1;
392 e->highbit -= (e->highbit % EBITMAP_SIZE);
393
394 if (!e->highbit) {
395 e->node = NULL;
396 goto ok;
397 }
398
399 if (e->highbit && !count)
400 goto bad;
401
402 for (i = 0; i < count; i++) {
403 rc = next_entry(&ebitmap_start, fp, sizeof(u32));
404 if (rc < 0) {
405 pr_err("SELinux: ebitmap: truncated map\n");
406 goto bad;
407 }
408 startbit = le32_to_cpu(ebitmap_start);
409
410 if (startbit & (mapunit - 1)) {
411 pr_err("SELinux: ebitmap start bit (%u) is "
412 "not a multiple of the map unit size (%u)\n",
413 startbit, mapunit);
414 goto bad;
415 }
416 if (startbit > e->highbit - mapunit) {
417 pr_err("SELinux: ebitmap start bit (%u) is "
418 "beyond the end of the bitmap (%u)\n",
419 startbit, (e->highbit - mapunit));
420 goto bad;
421 }
422
423 if (!n || startbit >= n->startbit + EBITMAP_SIZE) {
424 struct ebitmap_node *tmp;
425 tmp = kmem_cache_zalloc(ebitmap_node_cachep,
426 GFP_KERNEL);
427 if (!tmp) {
428 pr_err("SELinux: ebitmap: out of memory\n");
429 rc = -ENOMEM;
430 goto bad;
431 }
432 /* round down */
433 tmp->startbit = startbit - (startbit % EBITMAP_SIZE);
434 if (n)
435 n->next = tmp;
436 else
437 e->node = tmp;
438 n = tmp;
439 } else if (startbit <= n->startbit) {
440 pr_err("SELinux: ebitmap: start bit %u"
441 " comes after start bit %u\n",
442 startbit, n->startbit);
443 goto bad;
444 }
445
446 rc = next_entry(&mapbits, fp, sizeof(u64));
447 if (rc < 0) {
448 pr_err("SELinux: ebitmap: truncated map\n");
449 goto bad;
450 }
451 map = le64_to_cpu(mapbits);
452 if (!map) {
453 pr_err("SELinux: ebitmap: empty map\n");
454 goto bad;
455 }
456
457 index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
458 while (map) {
459 n->maps[index++] = map & (-1UL);
460 map = EBITMAP_SHIFT_UNIT_SIZE(map);
461 }
462 }
463
464 if (n && n->startbit + EBITMAP_SIZE != e->highbit) {
465 pr_err("SELinux: ebitmap: high bit %u is not equal to the expected value %zu\n",
466 e->highbit, n->startbit + EBITMAP_SIZE);
467 goto bad;
468 }
469
470 ok:
471 rc = 0;
472 out:
473 return rc;
474 bad:
475 if (!rc)
476 rc = -EINVAL;
477 ebitmap_destroy(e);
478 goto out;
479 }
480
481 int ebitmap_write(const struct ebitmap *e, void *fp)
482 {
483 struct ebitmap_node *n;
484 u32 bit, count, last_bit, last_startbit;
485 __le32 buf[3];
486 u64 map;
487 int rc;
488
489 buf[0] = cpu_to_le32(BITS_PER_U64);
490
491 count = 0;
492 last_bit = 0;
493 last_startbit = U32_MAX;
494 ebitmap_for_each_positive_bit(e, n, bit)
495 {
496 if (last_startbit == U32_MAX ||
497 rounddown(bit, BITS_PER_U64) > last_startbit) {
498 count++;
499 last_startbit = rounddown(bit, BITS_PER_U64);
500 }
501 last_bit = roundup(bit + 1, BITS_PER_U64);
502 }
503 buf[1] = cpu_to_le32(last_bit);
504 buf[2] = cpu_to_le32(count);
505
506 rc = put_entry(buf, sizeof(u32), 3, fp);
507 if (rc)
508 return rc;
509
510 map = 0;
511 last_startbit = U32_MAX;
512 ebitmap_for_each_positive_bit(e, n, bit)
513 {
514 if (last_startbit == U32_MAX ||
515 rounddown(bit, BITS_PER_U64) > last_startbit) {
516 __le64 buf64[1];
517
518 /* this is the very first bit */
519 if (!map) {
520 last_startbit = rounddown(bit, BITS_PER_U64);
521 map = (u64)1 << (bit - last_startbit);
522 continue;
523 }
524
525 /* write the last node */
526 buf[0] = cpu_to_le32(last_startbit);
527 rc = put_entry(buf, sizeof(u32), 1, fp);
528 if (rc)
529 return rc;
530
531 buf64[0] = cpu_to_le64(map);
532 rc = put_entry(buf64, sizeof(u64), 1, fp);
533 if (rc)
534 return rc;
535
536 /* set up for the next node */
537 map = 0;
538 last_startbit = rounddown(bit, BITS_PER_U64);
539 }
540 map |= (u64)1 << (bit - last_startbit);
541 }
542 /* write the last node */
543 if (map) {
544 __le64 buf64[1];
545
546 /* write the last node */
547 buf[0] = cpu_to_le32(last_startbit);
548 rc = put_entry(buf, sizeof(u32), 1, fp);
549 if (rc)
550 return rc;
551
552 buf64[0] = cpu_to_le64(map);
553 rc = put_entry(buf64, sizeof(u64), 1, fp);
554 if (rc)
555 return rc;
556 }
557 return 0;
558 }
559
560 u32 ebitmap_hash(const struct ebitmap *e, u32 hash)
561 {
562 struct ebitmap_node *node;
563
564 /* need to change hash even if ebitmap is empty */
565 hash = jhash_1word(e->highbit, hash);
566 for (node = e->node; node; node = node->next) {
567 hash = jhash_1word(node->startbit, hash);
568 hash = jhash(node->maps, sizeof(node->maps), hash);
569 }
570 return hash;
571 }
572
573 void __init ebitmap_cache_init(void)
574 {
575 ebitmap_node_cachep = kmem_cache_create("ebitmap_node",
576 sizeof(struct ebitmap_node), 0,
577 SLAB_PANIC, NULL);
578 }
579
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