/*
* 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;
}
