security/selinux/ss/ebitmap.c - maze/linux - Git at Google

 /*
  * Implementation of the extensible bitmap type.
  *
  * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
  */
 /*
  * Updated: Hewlett-Packard <paul.moore@hp.com>
  *
  *      Added ebitmap_export() and ebitmap_import()
  *
  * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
  */

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

 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) &&
 	       (n1->map == n2->map)) {
 		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;
 		new->map = n->map;
 		new->next = NULL;
 		if (prev)
 			prev->next = new;
 		else
 			dst->node = new;
 		prev = new;
 		n = n->next;
 	}

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

 /**
  * ebitmap_export - Export an ebitmap to a unsigned char bitmap string
  * @src: the ebitmap to export
  * @dst: the resulting bitmap string
  * @dst_len: length of dst in bytes
  *
  * Description:
  * Allocate a buffer at least src->highbit bits long and export the extensible
  * bitmap into the buffer.  The bitmap string will be in little endian format,
  * i.e. LSB first.  The value returned in dst_len may not the true size of the
  * buffer as the length of the buffer is rounded up to a multiple of MAPTYPE.
  * The caller must free the buffer when finished. Returns zero on success,
  * negative values on failure.
  *
  */
 int ebitmap_export(const struct ebitmap *src,
 		   unsigned char **dst,
 		   size_t *dst_len)
 {
 	size_t bitmap_len;
 	unsigned char *bitmap;
 	struct ebitmap_node *iter_node;
 	MAPTYPE node_val;
 	size_t bitmap_byte;
 	unsigned char bitmask;

 	if (src->highbit == 0) {
 		*dst = NULL;
 		*dst_len = 0;
 		return 0;
 	}

 	bitmap_len = src->highbit / 8;
 	if (src->highbit % 7)
 		bitmap_len += 1;

 	bitmap = kzalloc((bitmap_len & ~(sizeof(MAPTYPE) - 1)) +
 			 sizeof(MAPTYPE),
 			 GFP_ATOMIC);
 	if (bitmap == NULL)
 		return -ENOMEM;

 	iter_node = src->node;
 	do {
 		bitmap_byte = iter_node->startbit / 8;
 		bitmask = 0x80;
 		node_val = iter_node->map;
 		do {
 			if (bitmask == 0) {
 				bitmap_byte++;
 				bitmask = 0x80;
 			}
 			if (node_val & (MAPTYPE)0x01)
 				bitmap[bitmap_byte] |= bitmask;
 			node_val >>= 1;
 			bitmask >>= 1;
 		} while (node_val > 0);
 		iter_node = iter_node->next;
 	} while (iter_node);

 	*dst = bitmap;
 	*dst_len = bitmap_len;
 	return 0;
 }

 /**
  * ebitmap_import - Import an unsigned char bitmap string into an ebitmap
  * @src: the bitmap string
  * @src_len: the bitmap length in bytes
  * @dst: the empty ebitmap
  *
  * Description:
  * This function takes a little endian bitmap string in src and imports it into
  * the ebitmap pointed to by dst.  Returns zero on success, negative values on
  * failure.
  *
  */
 int ebitmap_import(const unsigned char *src,
 		   size_t src_len,
 		   struct ebitmap *dst)
 {
 	size_t src_off = 0;
 	size_t node_limit;
 	struct ebitmap_node *node_new;
 	struct ebitmap_node *node_last = NULL;
 	u32 i_byte;
 	u32 i_bit;
 	unsigned char src_byte;

 	while (src_off < src_len) {
 		if (src_len - src_off >= sizeof(MAPTYPE)) {
 			if (*(MAPTYPE *)&src[src_off] == 0) {
 				src_off += sizeof(MAPTYPE);
 				continue;
 			}
 			node_limit = sizeof(MAPTYPE);
 		} else {
 			for (src_byte = 0, i_byte = src_off;
 			     i_byte < src_len && src_byte == 0;
 			     i_byte++)
 				src_byte |= src[i_byte];
 			if (src_byte == 0)
 				break;
 			node_limit = src_len - src_off;
 		}

 		node_new = kzalloc(sizeof(*node_new), GFP_ATOMIC);
 		if (unlikely(node_new == NULL)) {
 			ebitmap_destroy(dst);
 			return -ENOMEM;
 		}
 		node_new->startbit = src_off * 8;
 		for (i_byte = 0; i_byte < node_limit; i_byte++) {
 			src_byte = src[src_off++];
 			for (i_bit = i_byte * 8; src_byte != 0; i_bit++) {
 				if (src_byte & 0x80)
 					node_new->map |= MAPBIT << i_bit;
 				src_byte <<= 1;
 			}
 		}

 		if (node_last != NULL)
 			node_last->next = node_new;
 		else
 			dst->node = node_new;
 		node_last = node_new;
 	}

 	if (likely(node_last != NULL))
 		dst->highbit = node_last->startbit + MAPSIZE;
 	else
 		ebitmap_init(dst);

 	return 0;
 }

 int ebitmap_contains(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)) {
 		if (n1->startbit < n2->startbit) {
 			n1 = n1->next;
 			continue;
 		}
 		if ((n1->map & n2->map) != n2->map)
 			return 0;

 		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 + MAPSIZE) > bit) {
 			if (n->map & (MAPBIT << (bit - n->startbit)))
 				return 1;
 			else
 				return 0;
 		}
 		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 + MAPSIZE) > bit) {
 			if (value) {
 				n->map |= (MAPBIT << (bit - n->startbit));
 			} else {
 				n->map &= ~(MAPBIT << (bit - n->startbit));
 				if (!n->map) {
 					/* drop this node from the bitmap */

 					if (!n->next) {
 						/*
 						 * this was the highest map
 						 * within the bitmap
 						 */
 						if (prev)
 							e->highbit = prev->startbit + MAPSIZE;
 						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 & ~(MAPSIZE - 1);
 	new->map = (MAPBIT << (bit - new->startbit));

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

 	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)
 {
 	int rc;
 	struct ebitmap_node *n, *l;
 	__le32 buf[3];
 	u32 mapsize, count, i;
 	__le64 map;

 	ebitmap_init(e);

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

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

 	if (mapsize != MAPSIZE) {
 		printk(KERN_ERR "security: ebitmap: map size %u does not "
 		       "match my size %Zd (high bit was %d)\n", mapsize,
 		       MAPSIZE, e->highbit);
 		goto bad;
 	}
 	if (!e->highbit) {
 		e->node = NULL;
 		goto ok;
 	}
 	if (e->highbit & (MAPSIZE - 1)) {
 		printk(KERN_ERR "security: ebitmap: high bit (%d) is not a "
 		       "multiple of the map size (%Zd)\n", e->highbit, MAPSIZE);
 		goto bad;
 	}
 	l = NULL;
 	for (i = 0; i < count; i++) {
 		rc = next_entry(buf, fp, sizeof(u32));
 		if (rc < 0) {
 			printk(KERN_ERR "security: ebitmap: truncated map\n");
 			goto bad;
 		}
 		n = kzalloc(sizeof(*n), GFP_KERNEL);
 		if (!n) {
 			printk(KERN_ERR "security: ebitmap: out of memory\n");
 			rc = -ENOMEM;
 			goto bad;
 		}

 		n->startbit = le32_to_cpu(buf[0]);

 		if (n->startbit & (MAPSIZE - 1)) {
 			printk(KERN_ERR "security: ebitmap start bit (%d) is "
 			       "not a multiple of the map size (%Zd)\n",
 			       n->startbit, MAPSIZE);
 			goto bad_free;
 		}
 		if (n->startbit > (e->highbit - MAPSIZE)) {
 			printk(KERN_ERR "security: ebitmap start bit (%d) is "
 			       "beyond the end of the bitmap (%Zd)\n",
 			       n->startbit, (e->highbit - MAPSIZE));
 			goto bad_free;
 		}
 		rc = next_entry(&map, fp, sizeof(u64));
 		if (rc < 0) {
 			printk(KERN_ERR "security: ebitmap: truncated map\n");
 			goto bad_free;
 		}
 		n->map = le64_to_cpu(map);

 		if (!n->map) {
 			printk(KERN_ERR "security: ebitmap: null map in "
 			       "ebitmap (startbit %d)\n", n->startbit);
 			goto bad_free;
 		}
 		if (l) {
 			if (n->startbit <= l->startbit) {
 				printk(KERN_ERR "security: ebitmap: start "
 				       "bit %d comes after start bit %d\n",
 				       n->startbit, l->startbit);
 				goto bad_free;
 			}
 			l->next = n;
 		} else
 			e->node = n;

 		l = n;
 	}

 ok:
 	rc = 0;
 out:
 	return rc;
 bad_free:
 	kfree(n);
 bad:
 	if (!rc)
 		rc = -EINVAL;
 	ebitmap_destroy(e);
 	goto out;
 }
	/*
	* Implementation of the extensible bitmap type.
	*
	* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
	*/
	/*
	* Updated: Hewlett-Packard <paul.moore@hp.com>
	*
	* Added ebitmap_export() and ebitmap_import()
	*
	* (c) Copyright Hewlett-Packard Development Company, L.P., 2006
	*/

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

	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) &&
	(n1->map == n2->map)) {
	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;
	new->map = n->map;
	new->next = NULL;
	if (prev)
	prev->next = new;
	else
	dst->node = new;
	prev = new;
	n = n->next;
	}

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

	/**
	* ebitmap_export - Export an ebitmap to a unsigned char bitmap string
	* @src: the ebitmap to export
	* @dst: the resulting bitmap string
	* @dst_len: length of dst in bytes
	*
	* Description:
	* Allocate a buffer at least src->highbit bits long and export the extensible
	* bitmap into the buffer. The bitmap string will be in little endian format,
	* i.e. LSB first. The value returned in dst_len may not the true size of the
	* buffer as the length of the buffer is rounded up to a multiple of MAPTYPE.
	* The caller must free the buffer when finished. Returns zero on success,
	* negative values on failure.
	*
	*/
	int ebitmap_export(const struct ebitmap *src,
	unsigned char **dst,
	size_t *dst_len)
	{
	size_t bitmap_len;
	unsigned char *bitmap;
	struct ebitmap_node *iter_node;
	MAPTYPE node_val;
	size_t bitmap_byte;
	unsigned char bitmask;

	if (src->highbit == 0) {
	*dst = NULL;
	*dst_len = 0;
	return 0;
	}

	bitmap_len = src->highbit / 8;
	if (src->highbit % 7)
	bitmap_len += 1;

	bitmap = kzalloc((bitmap_len & ~(sizeof(MAPTYPE) - 1)) +
	sizeof(MAPTYPE),
	GFP_ATOMIC);
	if (bitmap == NULL)
	return -ENOMEM;

	iter_node = src->node;
	do {
	bitmap_byte = iter_node->startbit / 8;
	bitmask = 0x80;
	node_val = iter_node->map;
	do {
	if (bitmask == 0) {
	bitmap_byte++;
	bitmask = 0x80;
	}
	if (node_val & (MAPTYPE)0x01)
	bitmap[bitmap_byte] \|= bitmask;
	node_val >>= 1;
	bitmask >>= 1;
	} while (node_val > 0);
	iter_node = iter_node->next;
	} while (iter_node);

	*dst = bitmap;
	*dst_len = bitmap_len;
	return 0;
	}

	/**
	* ebitmap_import - Import an unsigned char bitmap string into an ebitmap
	* @src: the bitmap string
	* @src_len: the bitmap length in bytes
	* @dst: the empty ebitmap
	*
	* Description:
	* This function takes a little endian bitmap string in src and imports it into
	* the ebitmap pointed to by dst. Returns zero on success, negative values on
	* failure.
	*
	*/
	int ebitmap_import(const unsigned char *src,
	size_t src_len,
	struct ebitmap *dst)
	{
	size_t src_off = 0;
	size_t node_limit;
	struct ebitmap_node *node_new;
	struct ebitmap_node *node_last = NULL;
	u32 i_byte;
	u32 i_bit;
	unsigned char src_byte;

	while (src_off < src_len) {
	if (src_len - src_off >= sizeof(MAPTYPE)) {
	if ((MAPTYPE )&src[src_off] == 0) {
	src_off += sizeof(MAPTYPE);
	continue;
	}
	node_limit = sizeof(MAPTYPE);
	} else {
	for (src_byte = 0, i_byte = src_off;
	i_byte < src_len && src_byte == 0;
	i_byte++)
	src_byte \|= src[i_byte];
	if (src_byte == 0)
	break;
	node_limit = src_len - src_off;
	}

	node_new = kzalloc(sizeof(*node_new), GFP_ATOMIC);
	if (unlikely(node_new == NULL)) {
	ebitmap_destroy(dst);
	return -ENOMEM;
	}
	node_new->startbit = src_off * 8;
	for (i_byte = 0; i_byte < node_limit; i_byte++) {
	src_byte = src[src_off++];
	for (i_bit = i_byte * 8; src_byte != 0; i_bit++) {
	if (src_byte & 0x80)
	node_new->map \|= MAPBIT << i_bit;
	src_byte <<= 1;
	}
	}

	if (node_last != NULL)
	node_last->next = node_new;
	else
	dst->node = node_new;
	node_last = node_new;
	}

	if (likely(node_last != NULL))
	dst->highbit = node_last->startbit + MAPSIZE;
	else
	ebitmap_init(dst);

	return 0;
	}

	int ebitmap_contains(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)) {
	if (n1->startbit < n2->startbit) {
	n1 = n1->next;
	continue;
	}
	if ((n1->map & n2->map) != n2->map)
	return 0;

	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 + MAPSIZE) > bit) {
	if (n->map & (MAPBIT << (bit - n->startbit)))
	return 1;
	else
	return 0;
	}
	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 + MAPSIZE) > bit) {
	if (value) {
	n->map \|= (MAPBIT << (bit - n->startbit));
	} else {
	n->map &= ~(MAPBIT << (bit - n->startbit));
	if (!n->map) {
	/* drop this node from the bitmap */

	if (!n->next) {
	/*
	* this was the highest map
	* within the bitmap
	*/
	if (prev)
	e->highbit = prev->startbit + MAPSIZE;
	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 & ~(MAPSIZE - 1);
	new->map = (MAPBIT << (bit - new->startbit));

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

	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)
	{
	int rc;
	struct ebitmap_node n, l;
	__le32 buf[3];
	u32 mapsize, count, i;
	__le64 map;

	ebitmap_init(e);

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

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

	if (mapsize != MAPSIZE) {
	printk(KERN_ERR "security: ebitmap: map size %u does not "
	"match my size %Zd (high bit was %d)\n", mapsize,
	MAPSIZE, e->highbit);
	goto bad;
	}
	if (!e->highbit) {
	e->node = NULL;
	goto ok;
	}
	if (e->highbit & (MAPSIZE - 1)) {
	printk(KERN_ERR "security: ebitmap: high bit (%d) is not a "
	"multiple of the map size (%Zd)\n", e->highbit, MAPSIZE);
	goto bad;
	}
	l = NULL;
	for (i = 0; i < count; i++) {
	rc = next_entry(buf, fp, sizeof(u32));
	if (rc < 0) {
	printk(KERN_ERR "security: ebitmap: truncated map\n");
	goto bad;
	}
	n = kzalloc(sizeof(*n), GFP_KERNEL);
	if (!n) {
	printk(KERN_ERR "security: ebitmap: out of memory\n");
	rc = -ENOMEM;
	goto bad;
	}

	n->startbit = le32_to_cpu(buf[0]);

	if (n->startbit & (MAPSIZE - 1)) {
	printk(KERN_ERR "security: ebitmap start bit (%d) is "
	"not a multiple of the map size (%Zd)\n",
	n->startbit, MAPSIZE);
	goto bad_free;
	}
	if (n->startbit > (e->highbit - MAPSIZE)) {
	printk(KERN_ERR "security: ebitmap start bit (%d) is "
	"beyond the end of the bitmap (%Zd)\n",
	n->startbit, (e->highbit - MAPSIZE));
	goto bad_free;
	}
	rc = next_entry(&map, fp, sizeof(u64));
	if (rc < 0) {
	printk(KERN_ERR "security: ebitmap: truncated map\n");
	goto bad_free;
	}
	n->map = le64_to_cpu(map);

	if (!n->map) {
	printk(KERN_ERR "security: ebitmap: null map in "
	"ebitmap (startbit %d)\n", n->startbit);
	goto bad_free;
	}
	if (l) {
	if (n->startbit <= l->startbit) {
	printk(KERN_ERR "security: ebitmap: start "
	"bit %d comes after start bit %d\n",
	n->startbit, l->startbit);
	goto bad_free;
	}
	l->next = n;
	} else
	e->node = n;

	l = n;
	}

	ok:
	rc = 0;
	out:
	return rc;
	bad_free:
	kfree(n);
	bad:
	if (!rc)
	rc = -EINVAL;
	ebitmap_destroy(e);
	goto out;
	}