linux/security/selinux/ss/ebitmap.c

294 lines
5.4 KiB
C

/*
* Implementation of the extensible bitmap type.
*
* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
*/
#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 = kmalloc(sizeof(*new), GFP_ATOMIC);
if (!new) {
ebitmap_destroy(dst);
return -ENOMEM;
}
memset(new, 0, sizeof(*new));
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;
}
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 = kmalloc(sizeof(*new), GFP_ATOMIC);
if (!new)
return -ENOMEM;
memset(new, 0, sizeof(*new));
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;
u32 buf[3], mapsize, count, i;
u64 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 = kmalloc(sizeof(*n), GFP_KERNEL);
if (!n) {
printk(KERN_ERR "security: ebitmap: out of memory\n");
rc = -ENOMEM;
goto bad;
}
memset(n, 0, sizeof(*n));
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;
}