android_kernel_xiaomi_sm8350/security/selinux/ss/ebitmap.c
Eric Paris cee74f47a6 SELinux: allow userspace to read policy back out of the kernel
There is interest in being able to see what the actual policy is that was
loaded into the kernel.  The patch creates a new selinuxfs file
/selinux/policy which can be read by userspace.  The actual policy that is
loaded into the kernel will be written back out to userspace.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-10-21 10:12:58 +11:00

526 lines
11 KiB
C

/*
* Implementation of the extensible bitmap type.
*
* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
*/
/*
* Updated: Hewlett-Packard <paul.moore@hp.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;
}