/*
* Implementation of the multi-level security (MLS) policy.
*
* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
*/
/*
* Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
*
* Support for enhanced MLS infrastructure.
*
* Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
*/
/*
* Updated: Hewlett-Packard <paul@paul-moore.com>
*
* Added support to import/export the MLS label from NetLabel
*
* (c) Copyright Hewlett-Packard Development Company, L.P., 2006
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <net/netlabel.h>
#include "sidtab.h"
#include "mls.h"
#include "policydb.h"
#include "services.h"
/*
* Return the length in bytes for the MLS fields of the
* security context string representation of `context'.
*/
int mls_compute_context_len(struct context *context)
{
int i, l, len, head, prev;
char *nm;
struct ebitmap *e;
struct ebitmap_node *node;
if (!policydb.mls_enabled)
return 0;
len = 1; /* for the beginning ":" */
for (l = 0; l < 2; l++) {
int index_sens = context->range.level[l].sens;
len += strlen(sym_name(&policydb, SYM_LEVELS, index_sens - 1));
/* categories */
head = -2;
prev = -2;
e = &context->range.level[l].cat;
ebitmap_for_each_positive_bit(e, node, i) {
if (i - prev > 1) {
/* one or more negative bits are skipped */
if (head != prev) {
nm = sym_name(&policydb, SYM_CATS, prev);
len += strlen(nm) + 1;
}
nm = sym_name(&policydb, SYM_CATS, i);
len += strlen(nm) + 1;
head = i;
}
prev = i;
}
if (prev != head) {
nm = sym_name(&policydb, SYM_CATS, prev);
len += strlen(nm) + 1;
}
if (l == 0) {
if (mls_level_eq(&context->range.level[0],
&context->range.level[1]))
break;
else
len++;
}
}
return len;
}
/*
* Write the security context string representation of
* the MLS fields of `context' into the string `*scontext'.
* Update `*scontext' to point to the end of the MLS fields.
*/
void mls_sid_to_context(struct context *context,
char **scontext)
{
char *scontextp, *nm;
int i, l, head, prev;
struct ebitmap *e;
struct ebitmap_node *node;
if (!policydb.mls_enabled)
return;
scontextp = *scontext;
*scontextp = ':';
scontextp++;
for (l = 0; l < 2; l++) {
strcpy(scontextp, sym_name(&policydb, SYM_LEVELS,
context->range.level[l].sens - 1));
scontextp += strlen(scontextp);
/* categories */
head = -2;
prev = -2;
e = &context->range.level[l].cat;
ebitmap_for_each_positive_bit(e, node, i) {
if (i - prev > 1) {
/* one or more negative bits are skipped */
if (prev != head) {
if (prev - head > 1)
*scontextp++ = '.';
else
*scontextp++ = ',';
nm = sym_name(&policydb, SYM_CATS, prev);
strcpy(scontextp, nm);
scontextp += strlen(nm);
}
if (prev < 0)
*scontextp++ = ':';
else
*scontextp++ = ',';
nm = sym_name(&policydb, SYM_CATS, i);
strcpy(scontextp, nm);
scontextp += strlen(nm);
head = i;
}
prev = i;
}
if (prev != head) {
if (prev - head > 1)
*scontextp++ = '.';
else
*scontextp++ = ',';
nm = sym_name(&policydb, SYM_CATS, prev);
strcpy(scontextp, nm);
scontextp += strlen(nm);
}
if (l == 0) {
if (mls_level_eq(&context->range.level[0],
&context->range.level[1]))
break;
else
*scontextp++ = '-';
}
}
*scontext = scontextp;
return;
}
int mls_level_isvalid(struct policydb *p, struct mls_level *l)
{
struct level_datum *levdatum;
if (!l->sens || l->sens > p->p_levels.nprim)
return 0;
levdatum = hashtab_search(p->p_levels.table,
sym_name(p, SYM_LEVELS, l->sens - 1));
if (!levdatum)
return 0;
/*
* Return 1 iff all the bits set in l->cat are also be set in
* levdatum->level->cat and no bit in l->cat is larger than
* p->p_cats.nprim.
*/
return ebitmap_contains(&levdatum->level->cat, &l->cat,
p->p_cats.nprim);
}
int mls_range_isvalid(struct policydb *p, struct mls_range *r)
{
return (mls_level_isvalid(p, &r->level[0]) &&
mls_level_isvalid(p, &r->level[1]) &&
mls_level_dom(&r->level[1], &r->level[0]));
}
/*
* Return 1 if the MLS fields in the security context
* structure `c' are valid. Return 0 otherwise.
*/
int mls_context_isvalid(struct policydb *p, struct context *c)
{
struct user_datum *usrdatum;
if (!p->mls_enabled)
return 1;
if (!mls_range_isvalid(p, &c->range))
return 0;
if (c->role == OBJECT_R_VAL)
return 1