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

/*
 * Implementation of the extensible bitmap type.
 *
 * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
 */
/*
 * 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)

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 = kzalloc(sizeof(*new), 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 = kzalloc(sizeof(*e_iter), 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;
				kfree(n);
			}
			return 0;
		}
		prev = n;
		n = n->next;
	}

	if (!value)
		return 0;

	new = kzalloc(sizeof(*new), 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;
		kfree(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 = kzalloc(sizeof(*tmp), 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;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Implementation of the extensible bitmap type.
	3	*
	4	* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
	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
1da177e4 LT	27	int 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) &&
9fe79ad1	38	!memcmp(n1->maps, n2->maps, EBITMAP_SIZE / 8)) {
1da177e4 LT	39	n1 = n1->next;
	40	n2 = n2->next;
	41	}
	42
	43	if (n1 \|\| n2)
	44	return 0;
	45
	46	return 1;
	47	}
	48
	49	int 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) {
89d155ef	57	new = kzalloc(sizeof(*new), GFP_ATOMIC);
1da177e4 LT	58	if (!new) {
	59	ebitmap_destroy(dst);
	60	return -ENOMEM;
	61	}
1da177e4	62	new->startbit = n->startbit;
9fe79ad1	63	memcpy(new->maps, n->maps, EBITMAP_SIZE / 8);
1da177e4 LT	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
02752760	77	#ifdef CONFIG_NETLABEL
7420ed23	78	/**
02752760 PM	79	* ebitmap_netlbl_export - Export an ebitmap into a NetLabel category bitmap
	80	* @ebmap: the ebitmap to export
	81	* @catmap: the NetLabel category bitmap
7420ed23 VY	82	*
7420ed23 VY	83	* Description:
02752760 PM	84	* Export a SELinux extensibile bitmap into a NetLabel category bitmap.
02752760 PM	85	* Returns zero on success, negative values on error.
7420ed23 VY	86	*
7420ed23 VY	87	*/
02752760	88	int ebitmap_netlbl_export(struct ebitmap *ebmap,
4fbe63d1	89	struct netlbl_lsm_catmap **catmap)
7420ed23	90	{
02752760	91	struct ebitmap_node *e_iter = ebmap->node;
4b8feff2 PM	92	unsigned long e_map;
	93	u32 offset;
	94	unsigned int iter;
	95	int rc;
02752760 PM	96
	97	if (e_iter == NULL) {
	98	*catmap = NULL;
bf0edf39 PM	99	return 0;
	100	}
	101
4b8feff2	102	if (*catmap != NULL)
4fbe63d1	103	netlbl_catmap_free(*catmap);
4b8feff2	104	*catmap = NULL;
02752760	105
dbc74c65	106	while (e_iter) {
4b8feff2 PM	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) {
4fbe63d1 PM	111	rc = netlbl_catmap_setlong(catmap,
	112	offset,
	113	e_map,
	114	GFP_ATOMIC);
4b8feff2	115	if (rc != 0)
9fe79ad1	116	goto netlbl_export_failure;
9fe79ad1	117	}
4b8feff2	118	offset += EBITMAP_UNIT_SIZE;
02752760	119	}
6d2b6855	120	e_iter = e_iter->next;
02752760	121	}
7420ed23	122
7420ed23	123	return 0;
02752760 PM	124
02752760 PM	125	netlbl_export_failure:
4fbe63d1	126	netlbl_catmap_free(*catmap);
02752760	127	return -ENOMEM;
7420ed23 VY	128	}
	129
	130	/**
02752760	131	* ebitmap_netlbl_import - Import a NetLabel category bitmap into an ebitmap
9fe79ad1	132	* @ebmap: the ebitmap to import
02752760	133	* @catmap: the NetLabel category bitmap
7420ed23 VY	134	*
7420ed23 VY	135	* Description:
02752760 PM	136	* Import a NetLabel category bitmap into a SELinux extensibile bitmap.
02752760 PM	137	* Returns zero on success, negative values on error.
7420ed23 VY	138	*
7420ed23 VY	139	*/
02752760	140	int ebitmap_netlbl_import(struct ebitmap *ebmap,
4fbe63d1	141	struct netlbl_lsm_catmap *catmap)
7420ed23	142	{
4b8feff2	143	int rc;
02752760	144	struct ebitmap_node *e_iter = NULL;
4b8feff2 PM	145	struct ebitmap_node *e_prev = NULL;
	146	u32 offset = 0, idx;
	147	unsigned long bitmap;
	148
	149	for (;;) {
4fbe63d1	150	rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
4b8feff2 PM	151	if (rc < 0)
	152	goto netlbl_import_failure;
	153	if (offset == (u32)-1)
	154	return 0;
	155
33246035 PM	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
4b8feff2 PM	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;
8bebe88c	168	e_iter->startbit = offset - (offset % EBITMAP_SIZE);
4b8feff2 PM	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;
02752760	174	}
7420ed23	175
4b8feff2 PM	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 */
7420ed23	185	return 0;
02752760 PM	186
	187	netlbl_import_failure:
	188	ebitmap_destroy(ebmap);
	189	return -ENOMEM;
7420ed23	190	}
02752760	191	#endif /* CONFIG_NETLABEL */
7420ed23	192
fee71142 WL	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	*/
	198	int ebitmap_contains(struct ebitmap e1, struct ebitmap e2, u32 last_e2bit)
1da177e4 LT	199	{
1da177e4 LT	200	struct ebitmap_node n1, n2;
9fe79ad1	201	int i;
1da177e4 LT	202
	203	if (e1->highbit < e2->highbit)
	204	return 0;
	205
	206	n1 = e1->node;
	207	n2 = e2->node;
fee71142	208
1da177e4 LT	209	while (n1 && n2 && (n1->startbit <= n2->startbit)) {
	210	if (n1->startbit < n2->startbit) {
	211	n1 = n1->next;
	212	continue;
	213	}
fee71142 WL	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) {
9fe79ad1 KK	224	if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
9fe79ad1 KK	225	return 0;
fee71142	226	i--;
9fe79ad1	227	}
1da177e4 LT	228
	229	n1 = n1->next;
	230	n2 = n2->next;
	231	}
	232
	233	if (n2)
	234	return 0;
	235
	236	return 1;
	237	}
	238
	239	int 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)) {
9fe79ad1 KK	248	if ((n->startbit + EBITMAP_SIZE) > bit)
9fe79ad1 KK	249	return ebitmap_node_get_bit(n, bit);
1da177e4 LT	250	n = n->next;
	251	}
	252
	253	return 0;
	254	}
	255
	256	int 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) {
9fe79ad1	263	if ((n->startbit + EBITMAP_SIZE) > bit) {
1da177e4	264	if (value) {
9fe79ad1	265	ebitmap_node_set_bit(n, bit);
1da177e4	266	} else {
9fe79ad1 KK	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	*/
1da177e4	281	if (prev)
9fe79ad1 KK	282	e->highbit = prev->startbit
9fe79ad1 KK	283	+ EBITMAP_SIZE;
1da177e4	284	else
9fe79ad1	285	e->highbit = 0;
1da177e4	286	}
9fe79ad1 KK	287	if (prev)
	288	prev->next = n->next;
	289	else
	290	e->node = n->next;
	291	kfree(n);
1da177e4 LT	292	}
	293	return 0;
	294	}
	295	prev = n;
	296	n = n->next;
	297	}
	298
	299	if (!value)
	300	return 0;
	301
89d155ef	302	new = kzalloc(sizeof(*new), GFP_ATOMIC);
1da177e4 LT	303	if (!new)
1da177e4 LT	304	return -ENOMEM;
1da177e4	305
9fe79ad1 KK	306	new->startbit = bit - (bit % EBITMAP_SIZE);
9fe79ad1 KK	307	ebitmap_node_set_bit(new, bit);
1da177e4 LT	308
	309	if (!n)
	310	/* this node will be the highest map within the bitmap */
9fe79ad1	311	e->highbit = new->startbit + EBITMAP_SIZE;
1da177e4 LT	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
	324	void 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
	343	int ebitmap_read(struct ebitmap e, void fp)
	344	{
9fe79ad1 KK	345	struct ebitmap_node *n = NULL;
	346	u32 mapunit, count, startbit, index;
	347	u64 map;
b5bf6c55	348	__le32 buf[3];
9fe79ad1	349	int rc, i;
1da177e4 LT	350
	351	ebitmap_init(e);
	352
	353	rc = next_entry(buf, fp, sizeof buf);
	354	if (rc < 0)
	355	goto out;
	356
9fe79ad1	357	mapunit = le32_to_cpu(buf[0]);
1da177e4 LT	358	e->highbit = le32_to_cpu(buf[1]);
	359	count = le32_to_cpu(buf[2]);
	360
cee74f47	361	if (mapunit != BITS_PER_U64) {
454d972c	362	printk(KERN_ERR "SELinux: ebitmap: map size %u does not "
9fe79ad1	363	"match my size %Zd (high bit was %d)\n",
cee74f47	364	mapunit, BITS_PER_U64, e->highbit);
1da177e4 LT	365	goto bad;
1da177e4 LT	366	}
9fe79ad1 KK	367
	368	/* round up e->highbit */
	369	e->highbit += EBITMAP_SIZE - 1;
	370	e->highbit -= (e->highbit % EBITMAP_SIZE);
	371
1da177e4 LT	372	if (!e->highbit) {
	373	e->node = NULL;
	374	goto ok;
	375	}
9fe79ad1	376
74d977b6 WR	377	if (e->highbit && !count)
	378	goto bad;
	379
1da177e4	380	for (i = 0; i < count; i++) {
9fe79ad1	381	rc = next_entry(&startbit, fp, sizeof(u32));
1da177e4	382	if (rc < 0) {
454d972c	383	printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
1da177e4 LT	384	goto bad;
1da177e4 LT	385	}
9fe79ad1	386	startbit = le32_to_cpu(startbit);
1da177e4	387
9fe79ad1	388	if (startbit & (mapunit - 1)) {
454d972c	389	printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
087feb98	390	"not a multiple of the map unit size (%u)\n",
9fe79ad1 KK	391	startbit, mapunit);
9fe79ad1 KK	392	goto bad;
1da177e4	393	}
9fe79ad1	394	if (startbit > e->highbit - mapunit) {
454d972c	395	printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
087feb98	396	"beyond the end of the bitmap (%u)\n",
9fe79ad1 KK	397	startbit, (e->highbit - mapunit));
	398	goto bad;
	399	}
	400
	401	if (!n \|\| startbit >= n->startbit + EBITMAP_SIZE) {
	402	struct ebitmap_node *tmp;
	403	tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
	404	if (!tmp) {
	405	printk(KERN_ERR
454d972c	406	"SELinux: ebitmap: out of memory\n");
9fe79ad1 KK	407	rc = -ENOMEM;
	408	goto bad;
	409	}
	410	/* round down */
	411	tmp->startbit = startbit - (startbit % EBITMAP_SIZE);
7696ee80	412	if (n)
9fe79ad1	413	n->next = tmp;
7696ee80	414	else
9fe79ad1	415	e->node = tmp;
9fe79ad1 KK	416	n = tmp;
9fe79ad1 KK	417	} else if (startbit <= n->startbit) {
454d972c	418	printk(KERN_ERR "SELinux: ebitmap: start bit %d"
9fe79ad1 KK	419	" comes after start bit %d\n",
	420	startbit, n->startbit);
	421	goto bad;
1da177e4	422	}
9fe79ad1	423
1da177e4 LT	424	rc = next_entry(&map, fp, sizeof(u64));
1da177e4 LT	425	if (rc < 0) {
454d972c	426	printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
9fe79ad1	427	goto bad;
1da177e4	428	}
9fe79ad1	429	map = le64_to_cpu(map);
1da177e4	430
9fe79ad1 KK	431	index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
9fe79ad1 KK	432	while (map) {
087feb98 KK	433	n->maps[index++] = map & (-1UL);
087feb98 KK	434	map = EBITMAP_SHIFT_UNIT_SIZE(map);
1da177e4	435	}
1da177e4	436	}
1da177e4 LT	437	ok:
	438	rc = 0;
	439	out:
	440	return rc;
1da177e4 LT	441	bad:
	442	if (!rc)
	443	rc = -EINVAL;
	444	ebitmap_destroy(e);
	445	goto out;
	446	}
cee74f47 EP	447
	448	int ebitmap_write(struct ebitmap e, void fp)
	449	{
	450	struct ebitmap_node *n;
	451	u32 count;
	452	__le32 buf[3];
	453	u64 map;
	454	int bit, last_bit, last_startbit, rc;
	455
	456	buf[0] = cpu_to_le32(BITS_PER_U64);
	457
	458	count = 0;
	459	last_bit = 0;
	460	last_startbit = -1;
	461	ebitmap_for_each_positive_bit(e, n, bit) {
	462	if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
	463	count++;
	464	last_startbit = rounddown(bit, BITS_PER_U64);
	465	}
	466	last_bit = roundup(bit + 1, BITS_PER_U64);
	467	}
	468	buf[1] = cpu_to_le32(last_bit);
	469	buf[2] = cpu_to_le32(count);
	470
	471	rc = put_entry(buf, sizeof(u32), 3, fp);
	472	if (rc)
	473	return rc;
	474
	475	map = 0;
	476	last_startbit = INT_MIN;
	477	ebitmap_for_each_positive_bit(e, n, bit) {
	478	if (rounddown(bit, (int)BITS_PER_U64) > last_startbit) {
	479	__le64 buf64[1];
	480
	481	/* this is the very first bit */
	482	if (!map) {
	483	last_startbit = rounddown(bit, BITS_PER_U64);
	484	map = (u64)1 << (bit - last_startbit);
	485	continue;
	486	}
	487
	488	/* write the last node */
	489	buf[0] = cpu_to_le32(last_startbit);
	490	rc = put_entry(buf, sizeof(u32), 1, fp);
	491	if (rc)
	492	return rc;
	493
	494	buf64[0] = cpu_to_le64(map);
	495	rc = put_entry(buf64, sizeof(u64), 1, fp);
	496	if (rc)
	497	return rc;
	498
	499	/* set up for the next node */
	500	map = 0;
	501	last_startbit = rounddown(bit, BITS_PER_U64);
	502	}
	503	map \|= (u64)1 << (bit - last_startbit);
	504	}
	505	/* write the last node */
	506	if (map) {
	507	__le64 buf64[1];
	508
	509	/* write the last node */
	510	buf[0] = cpu_to_le32(last_startbit);
511	rc = put_entry(buf, sizeof(u32), 1, fp);
512	if (rc)
513	return rc;
514
515	buf64[0] = cpu_to_le64(map);
516	rc = put_entry(buf64, sizeof(u64), 1, fp);
517	if (rc)
518	return rc;
519	}
520	return 0;
521	}