summaryrefslogtreecommitdiff
path: root/security/selinux/ss/ebitmap.c
blob: d31b87be9a1ed2ec48c7922689f8962e5f05ecd4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
// SPDX-License-Identifier: GPL-2.0
/*
 * Implementation of the extensible bitmap type.
 *
 * Author : Stephen Smalley, <sds@tycho.nsa.gov>
 */
/*
 * Updated: Hewlett-Packard <paul@paul-moore.com>
 *
 *      Added support to import/export the NetLabel category bitmap
 *
 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
 */
/*
 * Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
 *      Applied standard bit operations to improve bitmap scanning.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/jhash.h>
#include <net/netlabel.h>
#include "ebitmap.h"
#include "policydb.h"

#define BITS_PER_U64	(sizeof(u64) * 8)

static struct kmem_cache *ebitmap_node_cachep __ro_after_init;

int ebitmap_cmp(const struct ebitmap *e1, const struct ebitmap *e2)
{
	const struct ebitmap_node *n1, *n2;

	if (e1->highbit != e2->highbit)
		return 0;

	n1 = e1->node;
	n2 = e2->node;
	while (n1 && n2 &&
	       (n1->startbit == n2->startbit) &&
	       !memcmp(n1->maps, n2->maps, EBITMAP_SIZE / 8)) {
		n1 = n1->next;
		n2 = n2->next;
	}

	if (n1 || n2)
		return 0;

	return 1;
}

int ebitmap_cpy(struct ebitmap *dst, const struct ebitmap *src)
{
	struct ebitmap_node *new, *prev;
	const struct ebitmap_node *n;

	ebitmap_init(dst);
	n = src->node;
	prev = NULL;
	while (n) {
		new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
		if (!new) {
			ebitmap_destroy(dst);
			return -ENOMEM;
		}
		new->startbit = n->startbit;
		memcpy(new->maps, n->maps, EBITMAP_SIZE / 8);
		new->next = NULL;
		if (prev)
			prev->next = new;
		else
			dst->node = new;
		prev = new;
		n = n->next;
	}

	dst->highbit = src->highbit;
	return 0;
}

int ebitmap_and(struct ebitmap *dst, const struct ebitmap *e1, const struct ebitmap *e2)
{
	struct ebitmap_node *n;
	int bit, rc;

	ebitmap_init(dst);

	ebitmap_for_each_positive_bit(e1, n, bit) {
		if (ebitmap_get_bit(e2, bit)) {
			rc = ebitmap_set_bit(dst, bit, 1);
			if (rc < 0)
				return rc;
		}
	}
	return 0;
}


#ifdef CONFIG_NETLABEL
/**
 * ebitmap_netlbl_export - Export an ebitmap into a NetLabel category bitmap
 * @ebmap: the ebitmap to export
 * @catmap: the NetLabel category bitmap
 *
 * Description:
 * Export a SELinux extensibile bitmap into a NetLabel category bitmap.
 * Returns zero on success, negative values on error.
 *
 */
int ebitmap_netlbl_export(struct ebitmap *ebmap,
			  struct netlbl_lsm_catmap **catmap)
{
	struct ebitmap_node *e_iter = ebmap->node;
	unsigned long e_map;
	u32 offset;
	unsigned int iter;
	int rc;

	if (e_iter == NULL) {
		*catmap = NULL;
		return 0;
	}

	if (*catmap != NULL)
		netlbl_catmap_free(*catmap);
	*catmap = NULL;

	while (e_iter) {
		offset = e_iter->startbit;
		for (iter = 0; iter < EBITMAP_UNIT_NUMS; iter++) {
			e_map = e_iter->maps[iter];
			if (e_map != 0) {
				rc = netlbl_catmap_setlong(catmap,
							   offset,
							   e_map,
							   GFP_ATOMIC);
				if (rc != 0)
					goto netlbl_export_failure;
			}
			offset += EBITMAP_UNIT_SIZE;
		}
		e_iter = e_iter->next;
	}

	return 0;

netlbl_export_failure:
	netlbl_catmap_free(*catmap);
	return -ENOMEM;
}

/**
 * ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
 * @ebmap: the ebitmap to import
 * @catmap: the NetLabel category bitmap
 *
 * Description:
 * Import a NetLabel category bitmap into a SELinux extensibile bitmap.
 * Returns zero on success, negative values on error.
 *
 */
int ebitmap_netlbl_import(struct ebitmap *ebmap,
			  struct netlbl_lsm_catmap *catmap)
{
	int rc;
	struct ebitmap_node *e_iter = NULL;
	struct ebitmap_node *e_prev = NULL;
	u32 offset = 0, idx;
	unsigned long bitmap;

	for (;;) {
		rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
		if (rc < 0)
			goto netlbl_import_failure;
		if (offset == (u32)-1)
			return 0;

		/* don't waste ebitmap space if the netlabel bitmap is empty */
		if (bitmap == 0) {
			offset += EBITMAP_UNIT_SIZE;
			continue;
		}

		if (e_iter == NULL ||
		    offset >= e_iter->startbit + EBITMAP_SIZE) {
			e_prev = e_iter;
			e_iter = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
			if (e_iter == NULL)
				goto netlbl_import_failure;
			e_iter->startbit = offset - (offset % EBITMAP_SIZE);
			if (e_prev == NULL)
				ebmap->node = e_iter;
			else
				e_prev->next = e_iter;
			ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
		}

		/* offset will always be aligned to an unsigned long */
		idx = EBITMAP_NODE_INDEX(e_iter, offset);
		e_iter->maps[idx] = bitmap;

		/* next */
		offset += EBITMAP_UNIT_SIZE;
	}

	/* NOTE: we should never reach this return */
	return 0;

netlbl_import_failure:
	ebitmap_destroy(ebmap);
	return -ENOMEM;
}
#endif /* CONFIG_NETLABEL */

/*
 * Check to see if all the bits set in e2 are also set in e1. Optionally,
 * if last_e2bit is non-zero, the highest set bit in e2 cannot exceed
 * last_e2bit.
 */
int ebitmap_contains(const struct ebitmap *e1, const struct ebitmap *e2, u32 last_e2bit)
{
	const struct ebitmap_node *n1, *n2;
	int i;

	if (e1->highbit < e2->highbit)
		return 0;

	n1 = e1->node;
	n2 = e2->node;

	while (n1 && n2 && (n1->startbit <= n2->startbit)) {
		if (n1->startbit < n2->startbit) {
			n1 = n1->next;
			continue;
		}
		for (i = EBITMAP_UNIT_NUMS - 1; (i >= 0) && !n2->maps[i]; )
			i--;	/* Skip trailing NULL map entries */
		if (last_e2bit && (i >= 0)) {
			u32 lastsetbit = n2->startbit + i * EBITMAP_UNIT_SIZE +
					 __fls(n2->maps[i]);
			if (lastsetbit > last_e2bit)
				return 0;
		}

		while (i >= 0) {
			if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
				return 0;
			i--;
		}

		n1 = n1->next;
		n2 = n2->next;
	}

	if (n2)
		return 0;

	return 1;
}

int ebitmap_get_bit(const struct ebitmap *e, unsigned long bit)
{
	const struct ebitmap_node *n;

	if (e->highbit < bit)
		return 0;

	n = e->node;
	while (n && (n->startbit <= bit)) {
		if ((n->startbit + EBITMAP_SIZE) > bit)
			return ebitmap_node_get_bit(n, bit);
		n = n->next;
	}

	return 0;
}

int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
{
	struct ebitmap_node *n, *prev, *new;

	prev = NULL;
	n = e->node;
	while (n && n->startbit <= bit) {
		if ((n->startbit + EBITMAP_SIZE) > bit) {
			if (value) {
				ebitmap_node_set_bit(n, bit);
			} else {
				unsigned int s;

				ebitmap_node_clr_bit(n, bit);

				s = find_first_bit(n->maps, EBITMAP_SIZE);
				if (s < EBITMAP_SIZE)
					return 0;

				/* drop this node from the bitmap */
				if (!n->next) {
					/*
					 * this was the highest map
					 * within the bitmap
					 */
					if (prev)
						e->highbit = prev->startbit
							     + EBITMAP_SIZE;
					else
						e->highbit = 0;
				}
				if (prev)
					prev->next = n->next;
				else
					e->node = n->next;
				kmem_cache_free(ebitmap_node_cachep, n);
			}
			return 0;
		}
		prev = n;
		n = n->next;
	}

	if (!value)
		return 0;

	new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
	if (!new)
		return -ENOMEM;

	new->startbit = bit - (bit % EBITMAP_SIZE);
	ebitmap_node_set_bit(new, bit);

	if (!n)
		/* this node will be the highest map within the bitmap */
		e->highbit = new->startbit + EBITMAP_SIZE;

	if (prev) {
		new->next = prev->next;
		prev->next = new;
	} else {
		new->next = e->node;
		e->node = new;
	}

	return 0;
}

void ebitmap_destroy(struct ebitmap *e)
{
	struct ebitmap_node *n, *temp;

	if (!e)
		return;

	n = e->node;
	while (n) {
		temp = n;
		n = n->next;
		kmem_cache_free(ebitmap_node_cachep, temp);
	}

	e->highbit = 0;
	e->node = NULL;
}

int ebitmap_read(struct ebitmap *e, void *fp)
{
	struct ebitmap_node *n = NULL;
	u32 mapunit, count, startbit, index;
	__le32 ebitmap_start;
	u64 map;
	__le64 mapbits;
	__le32 buf[3];
	int rc, i;

	ebitmap_init(e);

	rc = next_entry(buf, fp, sizeof buf);
	if (rc < 0)
		goto out;

	mapunit = le32_to_cpu(buf[0]);
	e->highbit = le32_to_cpu(buf[1]);
	count = le32_to_cpu(buf[2]);

	if (mapunit != BITS_PER_U64) {
		pr_err("SELinux: ebitmap: map size %u does not "
		       "match my size %zd (high bit was %d)\n",
		       mapunit, BITS_PER_U64, e->highbit);
		goto bad;
	}

	/* round up e->highbit */
	e->highbit += EBITMAP_SIZE - 1;
	e->highbit -= (e->highbit % EBITMAP_SIZE);

	if (!e->highbit) {
		e->node = NULL;
		goto ok;
	}

	if (e->highbit && !count)
		goto bad;

	for (i = 0; i < count; i++) {
		rc = next_entry(&ebitmap_start, fp, sizeof(u32));
		if (rc < 0) {
			pr_err("SELinux: ebitmap: truncated map\n");
			goto bad;
		}
		startbit = le32_to_cpu(ebitmap_start);

		if (startbit & (mapunit - 1)) {
			pr_err("SELinux: ebitmap start bit (%d) is "
			       "not a multiple of the map unit size (%u)\n",
			       startbit, mapunit);
			goto bad;
		}
		if (startbit > e->highbit - mapunit) {
			pr_err("SELinux: ebitmap start bit (%d) is "
			       "beyond the end of the bitmap (%u)\n",
			       startbit, (e->highbit - mapunit));
			goto bad;
		}

		if (!n || startbit >= n->startbit + EBITMAP_SIZE) {
			struct ebitmap_node *tmp;
			tmp = kmem_cache_zalloc(ebitmap_node_cachep, GFP_KERNEL);
			if (!tmp) {
				pr_err("SELinux: ebitmap: out of memory\n");
				rc = -ENOMEM;
				goto bad;
			}
			/* round down */
			tmp->startbit = startbit - (startbit % EBITMAP_SIZE);
			if (n)
				n->next = tmp;
			else
				e->node = tmp;
			n = tmp;
		} else if (startbit <= n->startbit) {
			pr_err("SELinux: ebitmap: start bit %d"
			       " comes after start bit %d\n",
			       startbit, n->startbit);
			goto bad;
		}

		rc = next_entry(&mapbits, fp, sizeof(u64));
		if (rc < 0) {
			pr_err("SELinux: ebitmap: truncated map\n");
			goto bad;
		}
		map = le64_to_cpu(mapbits);

		index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
		while (map) {
			n->maps[index++] = map & (-1UL);
			map = EBITMAP_SHIFT_UNIT_SIZE(map);
		}
	}
ok:
	rc = 0;
out:
	return rc;
bad:
	if (!rc)
		rc = -EINVAL;
	ebitmap_destroy(e);
	goto out;
}

int ebitmap_write(const struct ebitmap *e, void *fp)
{
	struct ebitmap_node *n;
	u32 count;
	__le32 buf[3];
	u64 map;
	int bit, last_bit, last_startbit, rc;

	buf[0] = cpu_to_le32(BITS_PER_U64);

	count = 0;
	last_bit = 0;
	last_startbit = -1;
	ebitmap_for_each_positive_bit(e, n, bit) {
		if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
			count++;
			last_startbit = rounddown(bit, BITS_PER_U64);
		}
		last_bit = roundup(bit + 1, BITS_PER_U64);
	}
	buf[1] = cpu_to_le32(last_bit);
	buf[2] = cpu_to_le32(count);

	rc = put_entry(buf, sizeof(u32), 3, fp);
	if (rc)
		return rc;

	map = 0;
	last_startbit = INT_MIN;
	ebitmap_for_each_positive_bit(e, n, bit) {
		if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
			__le64 buf64[1];

			/* this is the very first bit */
			if (!map) {
				last_startbit = rounddown(bit, BITS_PER_U64);
				map = (u64)1 << (bit - last_startbit);
				continue;
			}

			/* write the last node */
			buf[0] = cpu_to_le32(last_startbit);
			rc = put_entry(buf, sizeof(u32), 1, fp);
			if (rc)
				return rc;

			buf64[0] = cpu_to_le64(map);
			rc = put_entry(buf64, sizeof(u64), 1, fp);
			if (rc)
				return rc;

			/* set up for the next node */
			map = 0;
			last_startbit = rounddown(bit, BITS_PER_U64);
		}
		map |= (u64)1 << (bit - last_startbit);
	}
	/* write the last node */
	if (map) {
		__le64 buf64[1];

		/* write the last node */
		buf[0] = cpu_to_le32(last_startbit);
		rc = put_entry(buf, sizeof(u32), 1, fp);
		if (rc)
			return rc;

		buf64[0] = cpu_to_le64(map);
		rc = put_entry(buf64, sizeof(u64), 1, fp);
		if (rc)
			return rc;
	}
	return 0;
}

u32 ebitmap_hash(const struct ebitmap *e, u32 hash)
{
	struct ebitmap_node *node;

	/* need to change hash even if ebitmap is empty */
	hash = jhash_1word(e->highbit, hash);
	for (node = e->node; node; node = node->next) {
		hash = jhash_1word(node->startbit, hash);
		hash = jhash(node->maps, sizeof(node->maps), hash);
	}
	return hash;
}

void __init ebitmap_cache_init(void)
{
	ebitmap_node_cachep = kmem_cache_create("ebitmap_node",
							sizeof(struct ebitmap_node),
							0, SLAB_PANIC, NULL);
}