[linux-block.git] / security / selinux / ss / ebitmap.c

// 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 <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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* Implementation of the extensible bitmap type.
	4	*
7efbb60b	5	* Author : Stephen Smalley, <sds@tycho.nsa.gov>
1da177e4	6	*/
7420ed23	7	/*
82c21bfa	8	* Updated: Hewlett-Packard <paul@paul-moore.com>
7420ed23	9	*
02752760	10	* Added support to import/export the NetLabel category bitmap
7420ed23 VY	11	*
	12	* (c) Copyright Hewlett-Packard Development Company, L.P., 2006
	13	*/
9fe79ad1 KK	14	/*
	15	* Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
	16	* Applied standard bit operations to improve bitmap scanning.
	17	*/
7420ed23	18
1da177e4 LT	19	#include <linux/kernel.h>
	20	#include <linux/slab.h>
	21	#include <linux/errno.h>
02752760	22	#include <net/netlabel.h>
1da177e4 LT	23	#include "ebitmap.h"
	24	#include "policydb.h"
	25
cee74f47 EP	26	#define BITS_PER_U64 (sizeof(u64) * 8)
cee74f47 EP	27
b4958c89 JL	28	static struct kmem_cache *ebitmap_node_cachep;
b4958c89 JL	29
1da177e4 LT	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) &&
9fe79ad1	41	!memcmp(n1->maps, n2->maps, EBITMAP_SIZE / 8)) {
1da177e4 LT	42	n1 = n1->next;
	43	n2 = n2->next;
	44	}
	45
	46	if (n1 \|\| n2)
	47	return 0;
	48
	49	return 1;
	50	}
	51
	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) {
b4958c89	60	new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
1da177e4 LT	61	if (!new) {
	62	ebitmap_destroy(dst);
	63	return -ENOMEM;
	64	}
1da177e4	65	new->startbit = n->startbit;
9fe79ad1	66	memcpy(new->maps, n->maps, EBITMAP_SIZE / 8);
1da177e4 LT	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
02752760	80	#ifdef CONFIG_NETLABEL
7420ed23	81	/**
02752760 PM	82	* ebitmap_netlbl_export - Export an ebitmap into a NetLabel category bitmap
	83	* @ebmap: the ebitmap to export
	84	* @catmap: the NetLabel category bitmap
7420ed23 VY	85	*
7420ed23 VY	86	* Description:
02752760 PM	87	* Export a SELinux extensibile bitmap into a NetLabel category bitmap.
02752760 PM	88	* Returns zero on success, negative values on error.
7420ed23 VY	89	*
7420ed23 VY	90	*/
02752760	91	int ebitmap_netlbl_export(struct ebitmap *ebmap,
4fbe63d1	92	struct netlbl_lsm_catmap **catmap)
7420ed23	93	{
02752760	94	struct ebitmap_node *e_iter = ebmap->node;
4b8feff2 PM	95	unsigned long e_map;
	96	u32 offset;
	97	unsigned int iter;
	98	int rc;
02752760 PM	99
	100	if (e_iter == NULL) {
	101	*catmap = NULL;
bf0edf39 PM	102	return 0;
	103	}
	104
4b8feff2	105	if (*catmap != NULL)
4fbe63d1	106	netlbl_catmap_free(*catmap);
4b8feff2	107	*catmap = NULL;
02752760	108
dbc74c65	109	while (e_iter) {
4b8feff2 PM	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) {
4fbe63d1 PM	114	rc = netlbl_catmap_setlong(catmap,
	115	offset,
	116	e_map,
	117	GFP_ATOMIC);
4b8feff2	118	if (rc != 0)
9fe79ad1	119	goto netlbl_export_failure;
9fe79ad1	120	}
4b8feff2	121	offset += EBITMAP_UNIT_SIZE;
02752760	122	}
6d2b6855	123	e_iter = e_iter->next;
02752760	124	}
7420ed23	125
7420ed23	126	return 0;
02752760 PM	127
02752760 PM	128	netlbl_export_failure:
4fbe63d1	129	netlbl_catmap_free(*catmap);
02752760	130	return -ENOMEM;
7420ed23 VY	131	}
	132
	133	/**
02752760	134	* ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
9fe79ad1	135	* @ebmap: the ebitmap to import
02752760	136	* @catmap: the NetLabel category bitmap
7420ed23 VY	137	*
7420ed23 VY	138	* Description:
02752760 PM	139	* Import a NetLabel category bitmap into a SELinux extensibile bitmap.
02752760 PM	140	* Returns zero on success, negative values on error.
7420ed23 VY	141	*
7420ed23 VY	142	*/
02752760	143	int ebitmap_netlbl_import(struct ebitmap *ebmap,
4fbe63d1	144	struct netlbl_lsm_catmap *catmap)
7420ed23	145	{
4b8feff2	146	int rc;
02752760	147	struct ebitmap_node *e_iter = NULL;
4b8feff2 PM	148	struct ebitmap_node *e_prev = NULL;
	149	u32 offset = 0, idx;
	150	unsigned long bitmap;
	151
	152	for (;;) {
4fbe63d1	153	rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
4b8feff2 PM	154	if (rc < 0)
	155	goto netlbl_import_failure;
	156	if (offset == (u32)-1)
	157	return 0;
	158
33246035 PM	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
4b8feff2 PM	165	if (e_iter == NULL \|\|
	166	offset >= e_iter->startbit + EBITMAP_SIZE) {
	167	e_prev = e_iter;
b4958c89	168	e_iter = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
4b8feff2 PM	169	if (e_iter == NULL)
4b8feff2 PM	170	goto netlbl_import_failure;
8bebe88c	171	e_iter->startbit = offset - (offset % EBITMAP_SIZE);
4b8feff2 PM	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;
02752760	177	}
7420ed23	178
4b8feff2 PM	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 */
7420ed23	188	return 0;
02752760 PM	189
	190	netlbl_import_failure:
	191	ebitmap_destroy(ebmap);
	192	return -ENOMEM;
7420ed23	193	}
02752760	194	#endif /* CONFIG_NETLABEL */
7420ed23	195
fee71142 WL	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	*/
	201	int ebitmap_contains(struct ebitmap e1, struct ebitmap e2, u32 last_e2bit)
1da177e4 LT	202	{
1da177e4 LT	203	struct ebitmap_node n1, n2;
9fe79ad1	204	int i;
1da177e4 LT	205
	206	if (e1->highbit < e2->highbit)
	207	return 0;
	208
	209	n1 = e1->node;
	210	n2 = e2->node;
fee71142	211
1da177e4 LT	212	while (n1 && n2 && (n1->startbit <= n2->startbit)) {
	213	if (n1->startbit < n2->startbit) {
	214	n1 = n1->next;
	215	continue;
	216	}
fee71142 WL	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) {
9fe79ad1 KK	227	if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
9fe79ad1 KK	228	return 0;
fee71142	229	i--;
9fe79ad1	230	}
1da177e4 LT	231
	232	n1 = n1->next;
	233	n2 = n2->next;
	234	}
	235
	236	if (n2)
	237	return 0;
	238
	239	return 1;
	240	}
	241
	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)) {
9fe79ad1 KK	251	if ((n->startbit + EBITMAP_SIZE) > bit)
9fe79ad1 KK	252	return ebitmap_node_get_bit(n, bit);
1da177e4 LT	253	n = n->next;
	254	}
	255
	256	return 0;
	257	}
	258
	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) {
9fe79ad1	266	if ((n->startbit + EBITMAP_SIZE) > bit) {
1da177e4	267	if (value) {
9fe79ad1	268	ebitmap_node_set_bit(n, bit);
1da177e4	269	} else {
9fe79ad1 KK	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	*/
1da177e4	284	if (prev)
9fe79ad1 KK	285	e->highbit = prev->startbit
9fe79ad1 KK	286	+ EBITMAP_SIZE;
1da177e4	287	else
9fe79ad1	288	e->highbit = 0;
1da177e4	289	}
9fe79ad1 KK	290	if (prev)
	291	prev->next = n->next;
	292	else
	293	e->node = n->next;
b4958c89	294	kmem_cache_free(ebitmap_node_cachep, n);
1da177e4 LT	295	}
	296	return 0;
	297	}
	298	prev = n;
	299	n = n->next;
	300	}
	301
	302	if (!value)
	303	return 0;
	304
b4958c89	305	new = kmem_cache_zalloc(ebitmap_node_cachep, GFP_ATOMIC);
1da177e4 LT	306	if (!new)
1da177e4 LT	307	return -ENOMEM;
1da177e4	308
9fe79ad1 KK	309	new->startbit = bit - (bit % EBITMAP_SIZE);
9fe79ad1 KK	310	ebitmap_node_set_bit(new, bit);
1da177e4 LT	311
	312	if (!n)
	313	/* this node will be the highest map within the bitmap */
9fe79ad1	314	e->highbit = new->startbit + EBITMAP_SIZE;
1da177e4 LT	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
	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;
b4958c89	338	kmem_cache_free(ebitmap_node_cachep, temp);
1da177e4 LT	339	}
	340
	341	e->highbit = 0;
	342	e->node = NULL;
	343	return;
	344	}
	345
	346	int ebitmap_read(struct ebitmap e, void fp)
	347	{
9fe79ad1 KK	348	struct ebitmap_node *n = NULL;
	349	u32 mapunit, count, startbit, index;
	350	u64 map;
b5bf6c55	351	__le32 buf[3];
9fe79ad1	352	int rc, i;
1da177e4 LT	353
	354	ebitmap_init(e);
	355
	356	rc = next_entry(buf, fp, sizeof buf);
	357	if (rc < 0)
	358	goto out;
	359
9fe79ad1	360	mapunit = le32_to_cpu(buf[0]);
1da177e4 LT	361	e->highbit = le32_to_cpu(buf[1]);
	362	count = le32_to_cpu(buf[2]);
	363
cee74f47	364	if (mapunit != BITS_PER_U64) {
454d972c	365	printk(KERN_ERR "SELinux: ebitmap: map size %u does not "
5b5e0928	366	"match my size %zd (high bit was %d)\n",
cee74f47	367	mapunit, BITS_PER_U64, e->highbit);
1da177e4 LT	368	goto bad;
1da177e4 LT	369	}
9fe79ad1 KK	370
	371	/* round up e->highbit */
	372	e->highbit += EBITMAP_SIZE - 1;
	373	e->highbit -= (e->highbit % EBITMAP_SIZE);
	374
1da177e4 LT	375	if (!e->highbit) {
	376	e->node = NULL;
	377	goto ok;
	378	}
9fe79ad1	379
74d977b6 WR	380	if (e->highbit && !count)
	381	goto bad;
	382
1da177e4	383	for (i = 0; i < count; i++) {
9fe79ad1	384	rc = next_entry(&startbit, fp, sizeof(u32));
1da177e4	385	if (rc < 0) {
454d972c	386	printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
1da177e4 LT	387	goto bad;
1da177e4 LT	388	}
9fe79ad1	389	startbit = le32_to_cpu(startbit);
1da177e4	390
9fe79ad1	391	if (startbit & (mapunit - 1)) {
454d972c	392	printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
087feb98	393	"not a multiple of the map unit size (%u)\n",
9fe79ad1 KK	394	startbit, mapunit);
9fe79ad1 KK	395	goto bad;
1da177e4	396	}
9fe79ad1	397	if (startbit > e->highbit - mapunit) {
454d972c	398	printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
087feb98	399	"beyond the end of the bitmap (%u)\n",
9fe79ad1 KK	400	startbit, (e->highbit - mapunit));
	401	goto bad;
	402	}
	403
	404	if (!n \|\| startbit >= n->startbit + EBITMAP_SIZE) {
	405	struct ebitmap_node *tmp;
b4958c89	406	tmp = kmem_cache_zalloc(ebitmap_node_cachep, GFP_KERNEL);
9fe79ad1 KK	407	if (!tmp) {
9fe79ad1 KK	408	printk(KERN_ERR
454d972c	409	"SELinux: ebitmap: out of memory\n");
9fe79ad1 KK	410	rc = -ENOMEM;
	411	goto bad;
	412	}
	413	/* round down */
	414	tmp->startbit = startbit - (startbit % EBITMAP_SIZE);
7696ee80	415	if (n)
9fe79ad1	416	n->next = tmp;
7696ee80	417	else
9fe79ad1	418	e->node = tmp;
9fe79ad1 KK	419	n = tmp;
9fe79ad1 KK	420	} else if (startbit <= n->startbit) {
454d972c	421	printk(KERN_ERR "SELinux: ebitmap: start bit %d"
9fe79ad1 KK	422	" comes after start bit %d\n",
	423	startbit, n->startbit);
	424	goto bad;
1da177e4	425	}
9fe79ad1	426
1da177e4 LT	427	rc = next_entry(&map, fp, sizeof(u64));
1da177e4 LT	428	if (rc < 0) {
454d972c	429	printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
9fe79ad1	430	goto bad;
1da177e4	431	}
9fe79ad1	432	map = le64_to_cpu(map);
1da177e4	433
9fe79ad1 KK	434	index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
9fe79ad1 KK	435	while (map) {
087feb98 KK	436	n->maps[index++] = map & (-1UL);
087feb98 KK	437	map = EBITMAP_SHIFT_UNIT_SIZE(map);
1da177e4	438	}
1da177e4	439	}
1da177e4 LT	440	ok:
	441	rc = 0;
	442	out:
	443	return rc;
1da177e4 LT	444	bad:
	445	if (!rc)
	446	rc = -EINVAL;
	447	ebitmap_destroy(e);
	448	goto out;
	449	}
cee74f47 EP	450
	451	int ebitmap_write(struct ebitmap e, void fp)
	452	{
	453	struct ebitmap_node *n;
	454	u32 count;
	455	__le32 buf[3];
	456	u64 map;
	457	int bit, last_bit, last_startbit, rc;
	458
	459	buf[0] = cpu_to_le32(BITS_PER_U64);
	460
	461	count = 0;
	462	last_bit = 0;
	463	last_startbit = -1;
	464	ebitmap_for_each_positive_bit(e, n, bit) {
	465	if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
	466	count++;
	467	last_startbit = rounddown(bit, BITS_PER_U64);
	468	}
	469	last_bit = roundup(bit + 1, BITS_PER_U64);
	470	}
	471	buf[1] = cpu_to_le32(last_bit);
	472	buf[2] = cpu_to_le32(count);
	473
	474	rc = put_entry(buf, sizeof(u32), 3, fp);
	475	if (rc)
	476	return rc;
	477
	478	map = 0;
	479	last_startbit = INT_MIN;
	480	ebitmap_for_each_positive_bit(e, n, bit) {
	481	if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
	482	__le64 buf64[1];
	483
	484	/* this is the very first bit */
	485	if (!map) {
	486	last_startbit = rounddown(bit, BITS_PER_U64);
	487	map = (u64)1 << (bit - last_startbit);
	488	continue;
	489	}
	490
	491	/* write the last node */
	492	buf[0] = cpu_to_le32(last_startbit);
	493	rc = put_entry(buf, sizeof(u32), 1, fp);
	494	if (rc)
	495	return rc;
	496
	497	buf64[0] = cpu_to_le64(map);
	498	rc = put_entry(buf64, sizeof(u64), 1, fp);
	499	if (rc)
	500	return rc;
	501
	502	/* set up for the next node */
	503	map = 0;
	504	last_startbit = rounddown(bit, BITS_PER_U64);
	505	}
	506	map \|= (u64)1 << (bit - last_startbit);
	507	}
	508	/* write the last node */
	509	if (map) {
	510	__le64 buf64[1];
	511
	512	/* write the last node */
	513	buf[0] = cpu_to_le32(last_startbit);
514	rc = put_entry(buf, sizeof(u32), 1, fp);
515	if (rc)
516	return rc;
517
518	buf64[0] = cpu_to_le64(map);
519	rc = put_entry(buf64, sizeof(u64), 1, fp);
520	if (rc)
521	return rc;
522	}
523	return 0;
524	}
b4958c89 JL	525
	526	void ebitmap_cache_init(void)
	527	{
	528	ebitmap_node_cachep = kmem_cache_create("ebitmap_node",
	529	sizeof(struct ebitmap_node),
	530	0, SLAB_PANIC, NULL);
	531	}
	532
	533	void ebitmap_cache_destroy(void)
	534	{
	535	kmem_cache_destroy(ebitmap_node_cachep);
	536	}