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