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 *
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(const struct ebitmap * e1,const struct ebitmap * e2)31 int ebitmap_cmp(const struct ebitmap *e1, const struct ebitmap *e2)
32 {
33 const 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,const struct ebitmap * src)53 int ebitmap_cpy(struct ebitmap *dst, const struct ebitmap *src)
54 {
55 struct ebitmap_node *new, *prev;
56 const struct ebitmap_node *n;
57
58 ebitmap_init(dst);
59 n = src->node;
60 prev = NULL;
61 while (n) {
62 new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
63 if (!new) {
64 ebitmap_destroy(dst);
65 return -ENOMEM;
66 }
67 new->startbit = n->startbit;
68 memcpy(new->maps, n->maps, EBITMAP_SIZE / 8);
69 new->next = NULL;
70 if (prev)
71 prev->next = new;
72 else
73 dst->node = new;
74 prev = new;
75 n = n->next;
76 }
77
78 dst->highbit = src->highbit;
79 return 0;
80 }
81
ebitmap_and(struct ebitmap * dst,const struct ebitmap * e1,const struct ebitmap * e2)82 int ebitmap_and(struct ebitmap *dst, const struct ebitmap *e1, const struct ebitmap *e2)
83 {
84 struct ebitmap_node *n;
85 int bit, rc;
86
87 ebitmap_init(dst);
88
89 ebitmap_for_each_positive_bit(e1, n, bit) {
90 if (ebitmap_get_bit(e2, bit)) {
91 rc = ebitmap_set_bit(dst, bit, 1);
92 if (rc < 0)
93 return rc;
94 }
95 }
96 return 0;
97 }
98
99
100 #ifdef CONFIG_NETLABEL
101 /**
102 * ebitmap_netlbl_export - Export an ebitmap into a NetLabel category bitmap
103 * @ebmap: the ebitmap to export
104 * @catmap: the NetLabel category bitmap
105 *
106 * Description:
107 * Export a SELinux extensibile bitmap into a NetLabel category bitmap.
108 * Returns zero on success, negative values on error.
109 *
110 */
ebitmap_netlbl_export(struct ebitmap * ebmap,struct netlbl_lsm_catmap ** catmap)111 int ebitmap_netlbl_export(struct ebitmap *ebmap,
112 struct netlbl_lsm_catmap **catmap)
113 {
114 struct ebitmap_node *e_iter = ebmap->node;
115 unsigned long e_map;
116 u32 offset;
117 unsigned int iter;
118 int rc;
119
120 if (e_iter == NULL) {
121 *catmap = NULL;
122 return 0;
123 }
124
125 if (*catmap != NULL)
126 netlbl_catmap_free(*catmap);
127 *catmap = NULL;
128
129 while (e_iter) {
130 offset = e_iter->startbit;
131 for (iter = 0; iter < EBITMAP_UNIT_NUMS; iter++) {
132 e_map = e_iter->maps[iter];
133 if (e_map != 0) {
134 rc = netlbl_catmap_setlong(catmap,
135 offset,
136 e_map,
137 GFP_ATOMIC);
138 if (rc != 0)
139 goto netlbl_export_failure;
140 }
141 offset += EBITMAP_UNIT_SIZE;
142 }
143 e_iter = e_iter->next;
144 }
145
146 return 0;
147
148 netlbl_export_failure:
149 netlbl_catmap_free(*catmap);
150 return -ENOMEM;
151 }
152
153 /**
154 * ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
155 * @ebmap: the ebitmap to import
156 * @catmap: the NetLabel category bitmap
157 *
158 * Description:
159 * Import a NetLabel category bitmap into a SELinux extensibile bitmap.
160 * Returns zero on success, negative values on error.
161 *
162 */
ebitmap_netlbl_import(struct ebitmap * ebmap,struct netlbl_lsm_catmap * catmap)163 int ebitmap_netlbl_import(struct ebitmap *ebmap,
164 struct netlbl_lsm_catmap *catmap)
165 {
166 int rc;
167 struct ebitmap_node *e_iter = NULL;
168 struct ebitmap_node *e_prev = NULL;
169 u32 offset = 0, idx;
170 unsigned long bitmap;
171
172 for (;;) {
173 rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
174 if (rc < 0)
175 goto netlbl_import_failure;
176 if (offset == (u32)-1)
177 return 0;
178
179 /* don't waste ebitmap space if the netlabel bitmap is empty */
180 if (bitmap == 0) {
181 offset += EBITMAP_UNIT_SIZE;
182 continue;
183 }
184
185 if (e_iter == NULL ||
186 offset >= e_iter->startbit + EBITMAP_SIZE) {
187 e_prev = e_iter;
188 e_iter = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
189 if (e_iter == NULL)
190 goto netlbl_import_failure;
191 e_iter->startbit = offset - (offset % EBITMAP_SIZE);
192 if (e_prev == NULL)
193 ebmap->node = e_iter;
194 else
195 e_prev->next = e_iter;
196 ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
197 }
198
199 /* offset will always be aligned to an unsigned long */
200 idx = EBITMAP_NODE_INDEX(e_iter, offset);
201 e_iter->maps[idx] = bitmap;
202
203 /* next */
204 offset += EBITMAP_UNIT_SIZE;
205 }
206
207 /* NOTE: we should never reach this return */
208 return 0;
209
210 netlbl_import_failure:
211 ebitmap_destroy(ebmap);
212 return -ENOMEM;
213 }
214 #endif /* CONFIG_NETLABEL */
215
216 /*
217 * Check to see if all the bits set in e2 are also set in e1. Optionally,
218 * if last_e2bit is non-zero, the highest set bit in e2 cannot exceed
219 * last_e2bit.
220 */
ebitmap_contains(const struct ebitmap * e1,const struct ebitmap * e2,u32 last_e2bit)221 int ebitmap_contains(const struct ebitmap *e1, const struct ebitmap *e2, u32 last_e2bit)
222 {
223 const struct ebitmap_node *n1, *n2;
224 int i;
225
226 if (e1->highbit < e2->highbit)
227 return 0;
228
229 n1 = e1->node;
230 n2 = e2->node;
231
232 while (n1 && n2 && (n1->startbit <= n2->startbit)) {
233 if (n1->startbit < n2->startbit) {
234 n1 = n1->next;
235 continue;
236 }
237 for (i = EBITMAP_UNIT_NUMS - 1; (i >= 0) && !n2->maps[i]; )
238 i--; /* Skip trailing NULL map entries */
239 if (last_e2bit && (i >= 0)) {
240 u32 lastsetbit = n2->startbit + i * EBITMAP_UNIT_SIZE +
241 __fls(n2->maps[i]);
242 if (lastsetbit > last_e2bit)
243 return 0;
244 }
245
246 while (i >= 0) {
247 if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
248 return 0;
249 i--;
250 }
251
252 n1 = n1->next;
253 n2 = n2->next;
254 }
255
256 if (n2)
257 return 0;
258
259 return 1;
260 }
261
ebitmap_get_bit(const struct ebitmap * e,unsigned long bit)262 int ebitmap_get_bit(const struct ebitmap *e, unsigned long bit)
263 {
264 const struct ebitmap_node *n;
265
266 if (e->highbit < bit)
267 return 0;
268
269 n = e->node;
270 while (n && (n->startbit <= bit)) {
271 if ((n->startbit + EBITMAP_SIZE) > bit)
272 return ebitmap_node_get_bit(n, bit);
273 n = n->next;
274 }
275
276 return 0;
277 }
278
ebitmap_set_bit(struct ebitmap * e,unsigned long bit,int value)279 int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
280 {
281 struct ebitmap_node *n, *prev, *new;
282
283 prev = NULL;
284 n = e->node;
285 while (n && n->startbit <= bit) {
286 if ((n->startbit + EBITMAP_SIZE) > bit) {
287 if (value) {
288 ebitmap_node_set_bit(n, bit);
289 } else {
290 unsigned int s;
291
292 ebitmap_node_clr_bit(n, bit);
293
294 s = find_first_bit(n->maps, EBITMAP_SIZE);
295 if (s < EBITMAP_SIZE)
296 return 0;
297
298 /* drop this node from the bitmap */
299 if (!n->next) {
300 /*
301 * this was the highest map
302 * within the bitmap
303 */
304 if (prev)
305 e->highbit = prev->startbit
306 + EBITMAP_SIZE;
307 else
308 e->highbit = 0;
309 }
310 if (prev)
311 prev->next = n->next;
312 else
313 e->node = n->next;
314 kmem_cache_free(ebitmap_node_cachep, n);
315 }
316 return 0;
317 }
318 prev = n;
319 n = n->next;
320 }
321
322 if (!value)
323 return 0;
324
325 new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
326 if (!new)
327 return -ENOMEM;
328
329 new->startbit = bit - (bit % EBITMAP_SIZE);
330 ebitmap_node_set_bit(new, bit);
331
332 if (!n)
333 /* this node will be the highest map within the bitmap */
334 e->highbit = new->startbit + EBITMAP_SIZE;
335
336 if (prev) {
337 new->next = prev->next;
338 prev->next = new;
339 } else {
340 new->next = e->node;
341 e->node = new;
342 }
343
344 return 0;
345 }
346
ebitmap_destroy(struct ebitmap * e)347 void ebitmap_destroy(struct ebitmap *e)
348 {
349 struct ebitmap_node *n, *temp;
350
351 if (!e)
352 return;
353
354 n = e->node;
355 while (n) {
356 temp = n;
357 n = n->next;
358 kmem_cache_free(ebitmap_node_cachep, temp);
359 }
360
361 e->highbit = 0;
362 e->node = NULL;
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(const struct ebitmap * e,void * fp)471 int ebitmap_write(const 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