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