/* SPDX-License-Identifier: GPL-2.0 */
/*
* Implementation of the extensible bitmap type.
*
* Author : Stephen Smalley, <[email protected]>
*/
/*
* Updated: Hewlett-Packard <[email protected]>
* Added support to import/export the NetLabel category bitmap
* (c) Copyright Hewlett-Packard Development Company, L.P., 2006
*
* Updated: KaiGai Kohei <[email protected]>
* Applied standard bit operations to improve bitmap scanning.
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/jhash.h>
#include <net/netlabel.h>
#include "ebitmap.h"
#include "policydb.h"
#define BITS_PER_U64 ((u32)(sizeof(u64) * 8))
static struct kmem_cache *ebitmap_node_cachep __ro_after_init;
int ebitmap_cmp(const struct ebitmap *e1, const struct ebitmap *e2)
{
const 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, const struct ebitmap *src)
{
struct ebitmap_node *new, *prev;
const struct ebitmap_node *n;
ebitmap_init(dst);
n = src->node;
prev = NULL;
while (n) {
new = kmem_cache_zalloc(ebitmap_node_cachep, 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;
}
int ebitmap_and(struct ebitmap *dst, const struct ebitmap *e1,
const struct ebitmap *e2)
{
struct ebitmap_node *n;
u32 bit;
int rc;
ebitmap_init(dst);
ebitmap_for_each_positive_bit(e1, n, bit)
{
if (ebitmap_get_bit(e2, bit)) {
rc = ebitmap_set_bit(dst, bit, 1);
if (rc < 0)
return rc;
}
}
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_catmap **catmap)
{
struct ebitmap_node *e_iter = ebmap->node;
unsigned long e_map;
u32 offset;
unsigned int iter;
int rc;
if (e_iter == NULL) {
*catmap = NULL;
return 0;
}
if (*catmap != NULL)
netlbl_catmap_free(*catmap);
*catmap = NULL;
while (e_iter) {
offset = e_iter->startbit;
for (iter = 0; iter < EBITMAP_UNIT_NUMS; iter++) {
e_map = e_iter->maps[iter];
if (e_map != 0) {
rc = netlbl_catmap_setlong(catmap, offset,
e_map, GFP_ATOMIC);
if (rc != 0)
goto netlbl_export_failure;
}
offset += EBITMAP_UNIT_SIZE;
}
e_iter = e_iter->next;
}
return 0;
netlbl_export_failure:
netlbl_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_catmap *catmap)
{
int rc;
struct ebitmap_node *e_iter = NULL;
struct ebitmap_node *e_prev = NULL;
u32 offset = 0, idx;
unsigned long bitmap;
for (;;) {
rc = netlbl_catmap_getlong(catmap, &offset, &bitmap);
if (rc < 0)
goto netlbl_import_failure;
if (offset == (u32)-1)
return 0;
/* don't waste ebitmap space if the netlabel bitmap is empty */
if (bitmap == 0) {
offset += EBITMAP_UNIT_SIZE;
continue;
}
if (e_iter == NULL ||
offset >= e_iter->startbit + EBITMAP_SIZE) {
e_prev = e_iter;
e_iter = kmem_cache_zalloc(ebitmap_node_cachep,
GFP_ATOMIC);
if (e_iter == NULL)
goto netlbl_import_failure;
e_iter->startbit = offset - (offset % EBITMAP_SIZE);
if (e_prev == NULL)
ebmap->node = e_iter;
else
e_prev->next = e_iter;
ebmap->highbit = e_iter->startbit + EBITMAP_SIZE;
}
/* offset will always be aligned to an unsigned long */
idx = EBITMAP_NODE_INDEX(e_iter, offset);
e_iter->maps[idx] = bitmap;
/* next */
offset += EBITMAP_UNIT_SIZE;
}
/* NOTE: we should never reach this return */
return 0;
netlbl_import_failure:
ebitmap_destroy(ebmap);
return -ENOMEM;
}
#endif /* CONFIG_NETLABEL */
/*
* Check to see if all the bits set in e2 are also set in e1. Optionally,
* if last_e2bit is non-zero, the highest set bit in e2 cannot exceed
* last_e2bit.
*/
int ebitmap_contains(const struct ebitmap *e1, const struct ebitmap *e2,
u32 last_e2bit)
{
const 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 = EBITMAP_UNIT_NUMS - 1; (i >= 0) && !n2->maps[i];)
i--; /* Skip trailing NULL map entries */
if (last_e2bit && (i >= 0)) {
u32 lastsetbit = n2->startbit + i * EBITMAP_UNIT_SIZE +
__fls(n2->maps[i]);
if (lastsetbit > last_e2bit)
return 0;
}
while (i >= 0) {
if ((n1->maps[i] & n2->maps[i]) != n2->maps[i])
return 0;
i--;
}
n1 = n1->next;
n2 = n2->next;
}
if (n2)
return 0;
return 1;
}
int ebitmap_get_bit(const struct ebitmap *e, u32 bit)
{
const 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, u32 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 {
u32 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;
kmem_cache_free(ebitmap_node_cachep, n);
}
return 0;
}
prev = n;
n = n->next;
}
if (!value)
return 0;
new = kmem_cache_zalloc(ebitmap_node_cachep, 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;
kmem_cache_free(ebitmap_node_cachep, temp);
}
e->highbit = 0;
e->node = NULL;
}
int ebitmap_read(struct ebitmap *e, void *fp)
{
struct ebitmap_node *n = NULL;
u32 mapunit, count, startbit, index, i;
__le32 ebitmap_start;
u64 map;
__le64 mapbits;
__le32 buf[3];
int rc;
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) {
pr_err("SELinux: ebitmap: map size %u does not "
"match my size %u (high bit was %u)\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;
}
if (e->highbit && !count)
goto bad;
for (i = 0; i < count; i++) {
rc = next_entry(&ebitmap_start, fp, sizeof(u32));
if (rc < 0) {
pr_err("SELinux: ebitmap: truncated map\n");
goto bad;
}
startbit = le32_to_cpu(ebitmap_start);
if (startbit & (mapunit - 1)) {
pr_err("SELinux: ebitmap start bit (%u) is "
"not a multiple of the map unit size (%u)\n",
startbit, mapunit);
goto bad;
}
if (startbit > e->highbit - mapunit) {
pr_err("SELinux: ebitmap start bit (%u) 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 = kmem_cache_zalloc(ebitmap_node_cachep,
GFP_KERNEL);
if (!tmp) {
pr_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) {
pr_err("SELinux: ebitmap: start bit %u"
" comes after start bit %u\n",
startbit, n->startbit);
goto bad;
}
rc = next_entry(&mapbits, fp, sizeof(u64));
if (rc < 0) {
pr_err("SELinux: ebitmap: truncated map\n");
goto bad;
}
map = le64_to_cpu(mapbits);
if (!map) {
pr_err("SELinux: ebitmap: empty map\n");
goto bad;
}
index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
while (map) {
n->maps[index++] = map & (-1UL);
map = EBITMAP_SHIFT_UNIT_SIZE(map);
}
}
if (n && n->startbit + EBITMAP_SIZE != e->highbit) {
pr_err("SELinux: ebitmap: high bit %u is not equal to the expected value %zu\n",
e->highbit, n->startbit + EBITMAP_SIZE);
goto bad;
}
ok:
rc = 0;
out:
return rc;
bad:
if (!rc)
rc = -EINVAL;
ebitmap_destroy(e);
goto out;
}
int ebitmap_write(const struct ebitmap *e, void *fp)
{
struct ebitmap_node *n;
u32 bit, count, last_bit, last_startbit;
__le32 buf[3];
u64 map;
int rc;
buf[0] = cpu_to_le32(BITS_PER_U64);
count = 0;
last_bit = 0;
last_startbit = U32_MAX;
ebitmap_for_each_positive_bit(e, n, bit)
{
if (last_startbit == U32_MAX ||
rounddown(bit, 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 = U32_MAX;
ebitmap_for_each_positive_bit(e, n, bit)
{
if (last_startbit == U32_MAX ||
rounddown(bit, 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;
}
u32 ebitmap_hash(const struct ebitmap *e, u32 hash)
{
struct ebitmap_node *node;
/* need to change hash even if ebitmap is empty */
hash = jhash_1word(e->highbit, hash);
for (node = e->node; node; node = node->next) {
hash = jhash_1word(node->startbit, hash);
hash = jhash(node->maps, sizeof(node->maps), hash);
}
return hash;
}
void __init ebitmap_cache_init(void)
{
ebitmap_node_cachep = KMEM_CACHE(ebitmap_node, SLAB_PANIC);
}
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