[mirror_ubuntu-focal-kernel.git] / security / selinux / ss / ebitmap.c

/*
 * 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 <net/netlabel.h>
#include "ebitmap.h"
#include "policydb.h"

#define BITS_PER_U64	(sizeof(u64) * 8)

static struct kmem_cache *ebitmap_node_cachep;

int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2)
{
	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, struct ebitmap *src)
{
	struct ebitmap_node *n, *new, *prev;

	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;
}

#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(struct ebitmap *e1, struct ebitmap *e2, u32 last_e2bit)
{
	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(struct ebitmap *e, unsigned long bit)
{
	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;
	return;
}

int ebitmap_read(struct ebitmap *e, void *fp)
{
	struct ebitmap_node *n = NULL;
	u32 mapunit, count, startbit, index;
	u64 map;
	__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) {
		printk(KERN_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(&startbit, fp, sizeof(u32));
		if (rc < 0) {
			printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
			goto bad;
		}
		startbit = le32_to_cpu(startbit);

		if (startbit & (mapunit - 1)) {
			printk(KERN_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) {
			printk(KERN_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) {
				printk(KERN_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) {
			printk(KERN_ERR "SELinux: ebitmap: start bit %d"
			       " comes after start bit %d\n",
			       startbit, n->startbit);
			goto bad;
		}

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

		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(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;
}

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

void ebitmap_cache_destroy(void)
{
	kmem_cache_destroy(ebitmap_node_cachep);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Implementation of the extensible bitmap type.
	3	*
7efbb60b	4	* Author : Stephen Smalley, <sds@tycho.nsa.gov>
1da177e4	5	*/
7420ed23	6	/*
82c21bfa	7	* Updated: Hewlett-Packard <paul@paul-moore.com>
7420ed23	8	*
02752760	9	* Added support to import/export the NetLabel category bitmap
7420ed23 VY	10	*
	11	* (c) Copyright Hewlett-Packard Development Company, L.P., 2006
	12	*/
9fe79ad1 KK	13	/*
	14	* Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
	15	* Applied standard bit operations to improve bitmap scanning.
	16	*/
7420ed23	17
1da177e4 LT	18	#include <linux/kernel.h>
	19	#include <linux/slab.h>
	20	#include <linux/errno.h>
02752760	21	#include <net/netlabel.h>
1da177e4 LT	22	#include "ebitmap.h"
	23	#include "policydb.h"
	24
cee74f47 EP	25	#define BITS_PER_U64 (sizeof(u64) * 8)
cee74f47 EP	26
b4958c89 JL	27	static struct kmem_cache *ebitmap_node_cachep;
b4958c89 JL	28
1da177e4 LT	29	int ebitmap_cmp(struct ebitmap e1, struct ebitmap e2)
	30	{
	31	struct ebitmap_node n1, n2;
	32
	33	if (e1->highbit != e2->highbit)
	34	return 0;
	35
	36	n1 = e1->node;
	37	n2 = e2->node;
	38	while (n1 && n2 &&
	39	(n1->startbit == n2->startbit) &&
9fe79ad1	40	!memcmp(n1->maps, n2->maps, EBITMAP_SIZE / 8)) {
1da177e4 LT	41	n1 = n1->next;
	42	n2 = n2->next;
	43	}
	44
	45	if (n1 \|\| n2)
	46	return 0;
	47
	48	return 1;
	49	}
	50
	51	int ebitmap_cpy(struct ebitmap dst, struct ebitmap src)
	52	{
	53	struct ebitmap_node n, new, *prev;
	54
	55	ebitmap_init(dst);
	56	n = src->node;
	57	prev = NULL;
	58	while (n) {
b4958c89	59	new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
1da177e4 LT	60	if (!new) {
	61	ebitmap_destroy(dst);
	62	return -ENOMEM;
	63	}
1da177e4	64	new->startbit = n->startbit;
9fe79ad1	65	memcpy(new->maps, n->maps, EBITMAP_SIZE / 8);
1da177e4 LT	66	new->next = NULL;
	67	if (prev)
	68	prev->next = new;
	69	else
	70	dst->node = new;
	71	prev = new;
	72	n = n->next;
	73	}
	74
	75	dst->highbit = src->highbit;
	76	return 0;
	77	}
	78
02752760	79	#ifdef CONFIG_NETLABEL
7420ed23	80	/**
02752760 PM	81	* ebitmap_netlbl_export - Export an ebitmap into a NetLabel category bitmap
	82	* @ebmap: the ebitmap to export
	83	* @catmap: the NetLabel category bitmap
7420ed23 VY	84	*
7420ed23 VY	85	* Description:
02752760 PM	86	* Export a SELinux extensibile bitmap into a NetLabel category bitmap.
02752760 PM	87	* Returns zero on success, negative values on error.
7420ed23 VY	88	*
7420ed23 VY	89	*/
02752760	90	int ebitmap_netlbl_export(struct ebitmap *ebmap,
4fbe63d1	91	struct netlbl_lsm_catmap **catmap)
7420ed23	92	{
02752760	93	struct ebitmap_node *e_iter = ebmap->node;
4b8feff2 PM	94	unsigned long e_map;
	95	u32 offset;
	96	unsigned int iter;
	97	int rc;
02752760 PM	98
	99	if (e_iter == NULL) {
	100	*catmap = NULL;
bf0edf39 PM	101	return 0;
	102	}
	103
4b8feff2	104	if (*catmap != NULL)
4fbe63d1	105	netlbl_catmap_free(*catmap);
4b8feff2	106	*catmap = NULL;
02752760	107
dbc74c65	108	while (e_iter) {
4b8feff2 PM	109	offset = e_iter->startbit;
	110	for (iter = 0; iter < EBITMAP_UNIT_NUMS; iter++) {
	111	e_map = e_iter->maps[iter];
	112	if (e_map != 0) {
4fbe63d1 PM	113	rc = netlbl_catmap_setlong(catmap,
	114	offset,
	115	e_map,
	116	GFP_ATOMIC);
4b8feff2	117	if (rc != 0)
9fe79ad1	118	goto netlbl_export_failure;
9fe79ad1	119	}
4b8feff2	120	offset += EBITMAP_UNIT_SIZE;
02752760	121	}
6d2b6855	122	e_iter = e_iter->next;
02752760	123	}
7420ed23	124
7420ed23	125	return 0;
02752760 PM	126
02752760 PM	127	netlbl_export_failure:
4fbe63d1	128	netlbl_catmap_free(*catmap);
02752760	129	return -ENOMEM;
7420ed23 VY	130	}
	131
	132	/**
02752760	133	* ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
9fe79ad1	134	* @ebmap: the ebitmap to import
02752760	135	* @catmap: the NetLabel category bitmap
7420ed23 VY	136	*
7420ed23 VY	137	* Description:
02752760 PM	138	* Import a NetLabel category bitmap into a SELinux extensibile bitmap.
02752760 PM	139	* Returns zero on success, negative values on error.
7420ed23 VY	140	*
7420ed23 VY	141	*/
02752760	142	int ebitmap_netlbl_import(struct ebitmap *ebmap,
4fbe63d1	143	struct netlbl_lsm_catmap *catmap)
7420ed23	144	{
4b8feff2	145	int rc;
02752760	146	struct ebitmap_node *e_iter = NULL;
4b8feff2 PM	147	struct ebitmap_node *e_prev = NULL;
	148	u32 offset = 0, idx;
	149	unsigned long bitmap;
	150
	151	for (;;) {
4fbe63d1	152	rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
4b8feff2 PM	153	if (rc < 0)
	154	goto netlbl_import_failure;
	155	if (offset == (u32)-1)
	156	return 0;
	157
33246035 PM	158	/* don't waste ebitmap space if the netlabel bitmap is empty */
	159	if (bitmap == 0) {
	160	offset += EBITMAP_UNIT_SIZE;
	161	continue;
	162	}
	163
4b8feff2 PM	164	if (e_iter == NULL \|\|
	165	offset >= e_iter->startbit + EBITMAP_SIZE) {
	166	e_prev = e_iter;
b4958c89	167	e_iter = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
4b8feff2 PM	168	if (e_iter == NULL)
4b8feff2 PM	169	goto netlbl_import_failure;
8bebe88c	170	e_iter->startbit = offset - (offset % EBITMAP_SIZE);
4b8feff2 PM	171	if (e_prev == NULL)
	172	ebmap->node = e_iter;
	173	else
	174	e_prev->next = e_iter;
	175	ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
02752760	176	}
7420ed23	177
4b8feff2 PM	178	/* offset will always be aligned to an unsigned long */
	179	idx = EBITMAP_NODE_INDEX(e_iter, offset);
	180	e_iter->maps[idx] = bitmap;
	181
	182	/* next */
	183	offset += EBITMAP_UNIT_SIZE;
	184	}
	185
	186	/* NOTE: we should never reach this return */
7420ed23	187	return 0;
02752760 PM	188
	189	netlbl_import_failure:
	190	ebitmap_destroy(ebmap);
	191	return -ENOMEM;
7420ed23	192	}
02752760	193	#endif /* CONFIG_NETLABEL */
7420ed23	194
fee71142 WL	195	/*
	196	* Check to see if all the bits set in e2 are also set in e1. Optionally,
	197	* if last_e2bit is non-zero, the highest set bit in e2 cannot exceed
	198	* last_e2bit.
	199	*/
	200	int ebitmap_contains(struct ebitmap e1, struct ebitmap e2, u32 last_e2bit)
1da177e4 LT	201	{
1da177e4 LT	202	struct ebitmap_node n1, n2;
9fe79ad1	203	int i;
1da177e4 LT	204
	205	if (e1->highbit < e2->highbit)
	206	return 0;
	207
	208	n1 = e1->node;
	209	n2 = e2->node;
fee71142	210
1da177e4 LT	211	while (n1 && n2 && (n1->startbit <= n2->startbit)) {
	212	if (n1->startbit < n2->startbit) {
	213	n1 = n1->next;
	214	continue;
	215	}
fee71142 WL	216	for (i = EBITMAP_UNIT_NUMS - 1; (i >= 0) && !n2->maps[i]; )
	217	i--; /* Skip trailing NULL map entries */
	218	if (last_e2bit && (i >= 0)) {
	219	u32 lastsetbit = n2->startbit + i * EBITMAP_UNIT_SIZE +
	220	__fls(n2->maps[i]);
	221	if (lastsetbit > last_e2bit)
	222	return 0;
	223	}
	224
	225	while (i >= 0) {
9fe79ad1 KK	226	if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
9fe79ad1 KK	227	return 0;
fee71142	228	i--;
9fe79ad1	229	}
1da177e4 LT	230
	231	n1 = n1->next;
	232	n2 = n2->next;
	233	}
	234
	235	if (n2)
	236	return 0;
	237
	238	return 1;
	239	}
	240
	241	int ebitmap_get_bit(struct ebitmap *e, unsigned long bit)
	242	{
	243	struct ebitmap_node *n;
	244
	245	if (e->highbit < bit)
	246	return 0;
	247
	248	n = e->node;
	249	while (n && (n->startbit <= bit)) {
9fe79ad1 KK	250	if ((n->startbit + EBITMAP_SIZE) > bit)
9fe79ad1 KK	251	return ebitmap_node_get_bit(n, bit);
1da177e4 LT	252	n = n->next;
	253	}
	254
	255	return 0;
	256	}
	257
	258	int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value)
	259	{
	260	struct ebitmap_node n, prev, *new;
	261
	262	prev = NULL;
	263	n = e->node;
	264	while (n && n->startbit <= bit) {
9fe79ad1	265	if ((n->startbit + EBITMAP_SIZE) > bit) {
1da177e4	266	if (value) {
9fe79ad1	267	ebitmap_node_set_bit(n, bit);
1da177e4	268	} else {
9fe79ad1 KK	269	unsigned int s;
	270
	271	ebitmap_node_clr_bit(n, bit);
	272
	273	s = find_first_bit(n->maps, EBITMAP_SIZE);
	274	if (s < EBITMAP_SIZE)
	275	return 0;
	276
	277	/* drop this node from the bitmap */
	278	if (!n->next) {
	279	/*
	280	* this was the highest map
	281	* within the bitmap
	282	*/
1da177e4	283	if (prev)
9fe79ad1 KK	284	e->highbit = prev->startbit
9fe79ad1 KK	285	+ EBITMAP_SIZE;
1da177e4	286	else
9fe79ad1	287	e->highbit = 0;
1da177e4	288	}
9fe79ad1 KK	289	if (prev)
	290	prev->next = n->next;
	291	else
	292	e->node = n->next;
b4958c89	293	kmem_cache_free(ebitmap_node_cachep, n);
1da177e4 LT	294	}
	295	return 0;
	296	}
	297	prev = n;
	298	n = n->next;
	299	}
	300
	301	if (!value)
	302	return 0;
	303
b4958c89	304	new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
1da177e4 LT	305	if (!new)
1da177e4 LT	306	return -ENOMEM;
1da177e4	307
9fe79ad1 KK	308	new->startbit = bit - (bit % EBITMAP_SIZE);
9fe79ad1 KK	309	ebitmap_node_set_bit(new, bit);
1da177e4 LT	310
	311	if (!n)
	312	/* this node will be the highest map within the bitmap */
9fe79ad1	313	e->highbit = new->startbit + EBITMAP_SIZE;
1da177e4 LT	314
	315	if (prev) {
	316	new->next = prev->next;
	317	prev->next = new;
	318	} else {
	319	new->next = e->node;
	320	e->node = new;
	321	}
	322
	323	return 0;
	324	}
	325
	326	void ebitmap_destroy(struct ebitmap *e)
	327	{
	328	struct ebitmap_node n, temp;
	329
	330	if (!e)
	331	return;
	332
	333	n = e->node;
	334	while (n) {
	335	temp = n;
	336	n = n->next;
b4958c89	337	kmem_cache_free(ebitmap_node_cachep, temp);
1da177e4 LT	338	}
	339
	340	e->highbit = 0;
	341	e->node = NULL;
	342	return;
	343	}
	344
	345	int ebitmap_read(struct ebitmap e, void fp)
	346	{
9fe79ad1 KK	347	struct ebitmap_node *n = NULL;
	348	u32 mapunit, count, startbit, index;
	349	u64 map;
b5bf6c55	350	__le32 buf[3];
9fe79ad1	351	int rc, i;
1da177e4 LT	352
	353	ebitmap_init(e);
	354
	355	rc = next_entry(buf, fp, sizeof buf);
	356	if (rc < 0)
	357	goto out;
	358
9fe79ad1	359	mapunit = le32_to_cpu(buf[0]);
1da177e4 LT	360	e->highbit = le32_to_cpu(buf[1]);
	361	count = le32_to_cpu(buf[2]);
	362
cee74f47	363	if (mapunit != BITS_PER_U64) {
454d972c	364	printk(KERN_ERR "SELinux: ebitmap: map size %u does not "
5b5e0928	365	"match my size %zd (high bit was %d)\n",
cee74f47	366	mapunit, BITS_PER_U64, e->highbit);
1da177e4 LT	367	goto bad;
1da177e4 LT	368	}
9fe79ad1 KK	369
	370	/* round up e->highbit */
	371	e->highbit += EBITMAP_SIZE - 1;
	372	e->highbit -= (e->highbit % EBITMAP_SIZE);
	373
1da177e4 LT	374	if (!e->highbit) {
	375	e->node = NULL;
	376	goto ok;
	377	}
9fe79ad1	378
74d977b6 WR	379	if (e->highbit && !count)
	380	goto bad;
	381
1da177e4	382	for (i = 0; i < count; i++) {
9fe79ad1	383	rc = next_entry(&startbit, fp, sizeof(u32));
1da177e4	384	if (rc < 0) {
454d972c	385	printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
1da177e4 LT	386	goto bad;
1da177e4 LT	387	}
9fe79ad1	388	startbit = le32_to_cpu(startbit);
1da177e4	389
9fe79ad1	390	if (startbit & (mapunit - 1)) {
454d972c	391	printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
087feb98	392	"not a multiple of the map unit size (%u)\n",
9fe79ad1 KK	393	startbit, mapunit);
9fe79ad1 KK	394	goto bad;
1da177e4	395	}
9fe79ad1	396	if (startbit > e->highbit - mapunit) {
454d972c	397	printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
087feb98	398	"beyond the end of the bitmap (%u)\n",
9fe79ad1 KK	399	startbit, (e->highbit - mapunit));
	400	goto bad;
	401	}
	402
	403	if (!n \|\| startbit >= n->startbit + EBITMAP_SIZE) {
	404	struct ebitmap_node *tmp;
b4958c89	405	tmp = kmem_cache_zalloc(ebitmap_node_cachep, GFP_KERNEL);
9fe79ad1 KK	406	if (!tmp) {
9fe79ad1 KK	407	printk(KERN_ERR
454d972c	408	"SELinux: ebitmap: out of memory\n");
9fe79ad1 KK	409	rc = -ENOMEM;
	410	goto bad;
	411	}
	412	/* round down */
	413	tmp->startbit = startbit - (startbit % EBITMAP_SIZE);
7696ee80	414	if (n)
9fe79ad1	415	n->next = tmp;
7696ee80	416	else
9fe79ad1	417	e->node = tmp;
9fe79ad1 KK	418	n = tmp;
9fe79ad1 KK	419	} else if (startbit <= n->startbit) {
454d972c	420	printk(KERN_ERR "SELinux: ebitmap: start bit %d"
9fe79ad1 KK	421	" comes after start bit %d\n",
	422	startbit, n->startbit);
	423	goto bad;
1da177e4	424	}
9fe79ad1	425
1da177e4 LT	426	rc = next_entry(&map, fp, sizeof(u64));
1da177e4 LT	427	if (rc < 0) {
454d972c	428	printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
9fe79ad1	429	goto bad;
1da177e4	430	}
9fe79ad1	431	map = le64_to_cpu(map);
1da177e4	432
9fe79ad1 KK	433	index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
9fe79ad1 KK	434	while (map) {
087feb98 KK	435	n->maps[index++] = map & (-1UL);
087feb98 KK	436	map = EBITMAP_SHIFT_UNIT_SIZE(map);
1da177e4	437	}
1da177e4	438	}
1da177e4 LT	439	ok:
	440	rc = 0;
	441	out:
	442	return rc;
1da177e4 LT	443	bad:
	444	if (!rc)
	445	rc = -EINVAL;
	446	ebitmap_destroy(e);
	447	goto out;
	448	}
cee74f47 EP	449
	450	int ebitmap_write(struct ebitmap e, void fp)
	451	{
	452	struct ebitmap_node *n;
	453	u32 count;
	454	__le32 buf[3];
	455	u64 map;
	456	int bit, last_bit, last_startbit, rc;
	457
	458	buf[0] = cpu_to_le32(BITS_PER_U64);
	459
	460	count = 0;
	461	last_bit = 0;
	462	last_startbit = -1;
	463	ebitmap_for_each_positive_bit(e, n, bit) {
	464	if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
	465	count++;
	466	last_startbit = rounddown(bit, BITS_PER_U64);
	467	}
	468	last_bit = roundup(bit + 1, BITS_PER_U64);
	469	}
	470	buf[1] = cpu_to_le32(last_bit);
	471	buf[2] = cpu_to_le32(count);
	472
	473	rc = put_entry(buf, sizeof(u32), 3, fp);
	474	if (rc)
	475	return rc;
	476
	477	map = 0;
	478	last_startbit = INT_MIN;
	479	ebitmap_for_each_positive_bit(e, n, bit) {
	480	if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
	481	__le64 buf64[1];
	482
	483	/* this is the very first bit */
	484	if (!map) {
	485	last_startbit = rounddown(bit, BITS_PER_U64);
	486	map = (u64)1 << (bit - last_startbit);
	487	continue;
	488	}
	489
	490	/* write the last node */
	491	buf[0] = cpu_to_le32(last_startbit);
	492	rc = put_entry(buf, sizeof(u32), 1, fp);
	493	if (rc)
	494	return rc;
	495
	496	buf64[0] = cpu_to_le64(map);
	497	rc = put_entry(buf64, sizeof(u64), 1, fp);
	498	if (rc)
	499	return rc;
	500
	501	/* set up for the next node */
	502	map = 0;
	503	last_startbit = rounddown(bit, BITS_PER_U64);
	504	}
	505	map \|= (u64)1 << (bit - last_startbit);
	506	}
	507	/* write the last node */
	508	if (map) {
	509	__le64 buf64[1];
	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	return 0;
523	}
b4958c89 JL	524
	525	void ebitmap_cache_init(void)
	526	{
	527	ebitmap_node_cachep = kmem_cache_create("ebitmap_node",
	528	sizeof(struct ebitmap_node),
	529	0, SLAB_PANIC, NULL);
	530	}
	531
	532	void ebitmap_cache_destroy(void)
	533	{
	534	kmem_cache_destroy(ebitmap_node_cachep);
	535	}