- 根目录:
- 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_secattr_catmap **catmap)
{
struct ebitmap_node *e_iter = ebmap->node;
struct netlbl_lsm_secattr_catmap *c_iter;
u32 cmap_idx, cmap_sft;
int i;
/* NetLabel's NETLBL_CATMAP_MAPTYPE is defined as an array of u64,
* however, it is not always compatible with an array of unsigned long
* in ebitmap_node.
* In addition, you should pay attention the following implementation
* assumes unsigned long has a width equal with or less than 64-bit.
*/
if (e_iter == NULL) {
*catmap = NULL;
return 0;
}
c_iter = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
if (c_iter == NULL)
return -ENOMEM;
*catmap = c_iter;
c_iter->startbit = e_iter->startbit & ~(NETLBL_CATMAP_SIZE - 1);
while (e_iter) {
for (i = 0; i < EBITMAP_UNIT_NUMS; i++) {
unsigned int delta, e_startbit, c_endbit;
e_startbit = e_iter->startbit + i * EBITMAP_UNIT_SIZE;
c_endbit = c_iter->startbit + NETLBL_CATMAP_SIZE;
if (e_startbit >= c_endbit) {
c_iter->next
= netlbl_secattr_catmap_alloc(GFP_ATOMIC);
if (c_iter->next == NULL)
goto netlbl_export_failure;
c_iter = c_iter->next;
c_iter->startbit
= e_startbit & ~(NETLBL_CATMAP_SIZE - 1);
}
delta = e_startbit - c_iter->startbit;
cmap_idx = delta / NETLBL_CATMAP_MAPSIZE;
cmap_sft = delta % NETLBL_CATMAP_MAPSIZE;
c_iter->bitmap[cmap_idx]
|= e_iter->maps[i] << cmap_sft;
}
e_iter = e_iter->next;
}
return 0;
netlbl_export_failure:
netlbl_secattr_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_secattr_catmap *catmap)
{
struct ebitmap_node *e_iter = NULL;
struct ebitmap_node *emap_prev = NULL;
struct netlbl_lsm_secattr_catmap *c_iter = catmap;
u32 c_idx, c_pos, e_idx, e_sft;
/* NetLabel's NETLBL_CATMAP_MAPTYPE is defined as an array of u64,
* however, it is not always compatible with an array of unsigned long
* in ebitmap_node.
* In addition, you should pay attention the following implementation
* assumes unsigned long has a width equal with or less than 64-bit.
*/
do {
for (c_idx = 0; c_idx < NETLBL_CATMAP_MAPCNT; c_idx++) {
unsigned int delta;
u64 map = c_iter->bitmap[c_idx];
if (!map)
continue;
c_pos = c_iter->startbit
+ c_idx * NETLBL_CATMAP_MAPSIZE;
if (!e_iter
|| c_pos >= e_iter->startbit + EBITMAP_SIZE) {
e_iter = kzalloc(sizeof(*e_iter), GFP_ATOMIC);
if (!e_iter)
goto netlbl_import_failure;
e_iter->startbit
= c_pos - (c_pos % EBITMAP_SIZE);
if (emap_prev == NULL)
ebmap->node = e_iter;
else
emap_prev->next = e_iter;
emap_prev = e_iter;
}
delta = c_pos - e_iter->startbit;
e_idx = delta / EBITMAP_UNIT_SIZE;
e_sft = delta % EBITMAP_UNIT_SIZE;
while (map) {
e_iter->maps[e_idx++] |= map & (-1UL);
map = EBITMAP_SHIFT_UNIT_SIZE(map);
}
}
c_iter = c_iter->next;
} while (c_iter);
if (e_iter != NULL)
ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
else
ebitmap_destroy(ebmap);
return 0;
netlbl_import_failure:
ebitmap_destroy(ebmap);
return -ENOMEM;
}
#endif /* CONFIG_NETLABEL */
int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2)
{
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 = 0; i < EBITMAP_UNIT_NUMS; i++) {
if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
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 + 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;
}
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;
}