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android / platform / external / selinux / 0db1ceb25e2795a469de4d73881a572520e1947f / . / libsepol / src / services.c
blob: 062510ab0ea1c375386e19d53bafd0e73a9f4199 [file] [log] [blame]
/*
* Author : Stephen Smalley, <[email protected]>
*/
/*
* Updated: Trusted Computer Solutions, Inc. <[email protected]>
*
* Support for enhanced MLS infrastructure.
*
* Updated: Frank Mayer <[email protected]>
* and Karl MacMillan <[email protected]>
*
* Added conditional policy language extensions
*
* Updated: Red Hat, Inc. James Morris <[email protected]>
*
* Fine-grained netlink support
* IPv6 support
* Code cleanup
*
* Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
* Copyright (C) 2003 - 2004 Tresys Technology, LLC
* Copyright (C) 2003 - 2004 Red Hat, Inc.
* Copyright (C) 2017 Mellanox Technologies Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* FLASK */
/*
* Implementation of the security services.
*/
/* Initial sizes malloc'd for sepol_compute_av_reason_buffer() support */
#define REASON_BUF_SIZE 2048
#define EXPR_BUF_SIZE 1024
#define STACK_LEN 32
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sepol/policydb/policydb.h>
#include <sepol/policydb/sidtab.h>
#include <sepol/policydb/services.h>
#include <sepol/policydb/conditional.h>
#include <sepol/policydb/util.h>
#include <sepol/sepol.h>
#include "debug.h"
#include "private.h"
#include "context.h"
#include "mls.h"
#include "flask.h"
#define BUG() do { ERR(NULL, "Badness at %s:%d", __FILE__, __LINE__); } while (0)
static int selinux_enforcing = 1;
static sidtab_t mysidtab, *sidtab = &mysidtab;
static policydb_t mypolicydb, *policydb = &mypolicydb;
/* Used by sepol_compute_av_reason_buffer() to keep track of entries */
static int reason_buf_used;
static int reason_buf_len;
/* Stack services for RPN to infix conversion. */
static char **stack;
static int stack_len;
static int next_stack_entry;
static void push(char *expr_ptr)
{
if (next_stack_entry >= stack_len) {
char **new_stack;
int new_stack_len;
if (stack_len == 0)
new_stack_len = STACK_LEN;
else
new_stack_len = stack_len * 2;
new_stack = reallocarray(stack, new_stack_len, sizeof(*stack));
if (!new_stack) {
ERR(NULL, "unable to allocate stack space");
return;
}
stack_len = new_stack_len;
stack = new_stack;
}
stack[next_stack_entry] = expr_ptr;
next_stack_entry++;
}
static char *pop(void)
{
next_stack_entry--;
if (next_stack_entry < 0) {
next_stack_entry = 0;
ERR(NULL, "pop called with no stack entries");
return NULL;
}
return stack[next_stack_entry];
}
/* End Stack services */
int sepol_set_sidtab(sidtab_t * s)
{
sidtab = s;
return 0;
}
int sepol_set_policydb(policydb_t * p)
{
policydb = p;
return 0;
}
int sepol_set_policydb_from_file(FILE * fp)
{
struct policy_file pf;
policy_file_init(&pf);
pf.fp = fp;
pf.type = PF_USE_STDIO;
if (mypolicydb.policy_type)
policydb_destroy(&mypolicydb);
if (policydb_init(&mypolicydb)) {
ERR(NULL, "Out of memory!");
return -1;
}
if (policydb_read(&mypolicydb, &pf, 0)) {
policydb_destroy(&mypolicydb);
ERR(NULL, "can't read binary policy: %m");
return -1;
}
policydb = &mypolicydb;
return sepol_sidtab_init(sidtab);
}
/*
* The largest sequence number that has been used when
* providing an access decision to the access vector cache.
* The sequence number only changes when a policy change
* occurs.
*/
static uint32_t latest_granting = 0;
/*
* cat_expr_buf adds a string to an expression buffer and handles
* realloc's if buffer is too small. The array of expression text
* buffer pointers and its counter are globally defined here as
* constraint_expr_eval_reason() sets them up and cat_expr_buf
* updates the e_buf pointer.
*/
static int expr_counter;
static char **expr_list;
static int expr_buf_used;
static int expr_buf_len;
static void cat_expr_buf(char *e_buf, const char *string)
{
int len, new_buf_len;
char *p, *new_buf;
while (1) {
p = e_buf + expr_buf_used;
len = snprintf(p, expr_buf_len - expr_buf_used, "%s", string);
if (len < 0 || len >= expr_buf_len - expr_buf_used) {
new_buf_len = expr_buf_len + EXPR_BUF_SIZE;
new_buf = realloc(e_buf, new_buf_len);
if (!new_buf) {
ERR(NULL, "failed to realloc expr buffer");
return;
}
/* Update new ptr in expr list and locally + new len */
expr_list[expr_counter] = new_buf;
e_buf = new_buf;
expr_buf_len = new_buf_len;
} else {
expr_buf_used += len;
return;
}
}
}
/*
* If the POLICY_KERN version is >= POLICYDB_VERSION_CONSTRAINT_NAMES,
* then for 'types' only, read the types_names->types list as it will
* contain a list of types and attributes that were defined in the
* policy source.
* For user and role plus types (for policy vers <
* POLICYDB_VERSION_CONSTRAINT_NAMES) just read the e->names list.
*/
static void get_name_list(constraint_expr_t *e, int type,
const char *src, const char *op, int failed)
{
ebitmap_t *types;
int rc = 0;
unsigned int i;
char tmp_buf[128];
int counter = 0;
if (policydb->policy_type == POLICY_KERN &&
policydb->policyvers >= POLICYDB_VERSION_CONSTRAINT_NAMES &&
type == CEXPR_TYPE)
types = &e->type_names->types;
else
types = &e->names;
/* Find out how many entries */
for (i = ebitmap_startbit(types); i < ebitmap_length(types); i++) {
rc = ebitmap_get_bit(types, i);
if (rc == 0)
continue;
else
counter++;
}
snprintf(tmp_buf, sizeof(tmp_buf), "(%s%s", src, op);
cat_expr_buf(expr_list[expr_counter], tmp_buf);
if (counter == 0)
cat_expr_buf(expr_list[expr_counter], "<empty_set> ");
if (counter > 1)
cat_expr_buf(expr_list[expr_counter], " {");
if (counter >= 1) {
for (i = ebitmap_startbit(types); i < ebitmap_length(types); i++) {
rc = ebitmap_get_bit(types, i);
if (rc == 0)
continue;
/* Collect entries */
switch (type) {
case CEXPR_USER:
snprintf(tmp_buf, sizeof(tmp_buf), " %s",
policydb->p_user_val_to_name[i]);
break;
case CEXPR_ROLE:
snprintf(tmp_buf, sizeof(tmp_buf), " %s",
policydb->p_role_val_to_name[i]);
break;
case CEXPR_TYPE:
snprintf(tmp_buf, sizeof(tmp_buf), " %s",
policydb->p_type_val_to_name[i]);
break;
}
cat_expr_buf(expr_list[expr_counter], tmp_buf);
}
}
if (counter > 1)
cat_expr_buf(expr_list[expr_counter], " }");
if (failed)
cat_expr_buf(expr_list[expr_counter], " -Fail-) ");
else
cat_expr_buf(expr_list[expr_counter], ") ");
return;
}
static void msgcat(const char *src, const char *tgt, const char *op, int failed)
{
char tmp_buf[128];
if (failed)
snprintf(tmp_buf, sizeof(tmp_buf), "(%s %s %s -Fail-) ",
src, op, tgt);
else
snprintf(tmp_buf, sizeof(tmp_buf), "(%s %s %s) ",
src, op, tgt);
cat_expr_buf(expr_list[expr_counter], tmp_buf);
}
/* Returns a buffer with class, statement type and permissions */
static char *get_class_info(sepol_security_class_t tclass,
constraint_node_t *constraint,
context_struct_t *xcontext)
{
constraint_expr_t *e;
int mls, state_num;
/* Determine statement type */
const char *statements[] = {
"constrain ", /* 0 */
"mlsconstrain ", /* 1 */
"validatetrans ", /* 2 */
"mlsvalidatetrans ", /* 3 */
0 };
size_t class_buf_len = 0;
size_t new_class_buf_len;
size_t buf_used;
int len;
char *class_buf = NULL, *p;
char *new_class_buf = NULL;
/* Find if MLS statement or not */
mls = 0;
for (e = constraint->expr; e; e = e->next) {
if (e->attr >= CEXPR_L1L2) {
mls = 1;
break;
}
}
if (xcontext == NULL)
state_num = mls + 0;
else
state_num = mls + 2;
while (1) {
new_class_buf_len = class_buf_len + EXPR_BUF_SIZE;
new_class_buf = realloc(class_buf, new_class_buf_len);
if (!new_class_buf) {
free(class_buf);
return NULL;
}
class_buf_len = new_class_buf_len;
class_buf = new_class_buf;
buf_used = 0;
p = class_buf;
/* Add statement type */
len = snprintf(p, class_buf_len - buf_used, "%s", statements[state_num]);
if (len < 0 || (size_t)len >= class_buf_len - buf_used)
continue;
/* Add class entry */
p += len;
buf_used += len;
len = snprintf(p, class_buf_len - buf_used, "%s ",
policydb->p_class_val_to_name[tclass - 1]);
if (len < 0 || (size_t)len >= class_buf_len - buf_used)
continue;
/* Add permission entries (validatetrans does not have perms) */
p += len;
buf_used += len;
if (state_num < 2) {
len = snprintf(p, class_buf_len - buf_used, "{%s } (",
sepol_av_to_string(policydb, tclass,
constraint->permissions));
} else {
len = snprintf(p, class_buf_len - buf_used, "(");
}
if (len < 0 || (size_t)len >= class_buf_len - buf_used)
continue;
break;
}
return class_buf;
}
/*
* Modified version of constraint_expr_eval that will process each
* constraint as before but adds the information to text buffers that
* will hold various components. The expression will be in RPN format,
* therefore there is a stack based RPN to infix converter to produce
* the final readable constraint.
*
* Return the boolean value of a constraint expression
* when it is applied to the specified source and target
* security contexts.
*
* xcontext is a special beast... It is used by the validatetrans rules
* only. For these rules, scontext is the context before the transition,
* tcontext is the context after the transition, and xcontext is the
* context of the process performing the transition. All other callers
* of constraint_expr_eval_reason should pass in NULL for xcontext.
*
* This function will also build a buffer as the constraint is processed
* for analysis. If this option is not required, then:
* 'tclass' should be '0' and r_buf MUST be NULL.
*/
static int constraint_expr_eval_reason(context_struct_t *scontext,
context_struct_t *tcontext,
context_struct_t *xcontext,
sepol_security_class_t tclass,
constraint_node_t *constraint,
char **r_buf,
unsigned int flags)
{
uint32_t val1, val2;
context_struct_t *c;
role_datum_t *r1, *r2;
mls_level_t *l1, *l2;
constraint_expr_t *e;
int s[CEXPR_MAXDEPTH] = {};
int sp = -1;
char tmp_buf[128];
/*
* Define the s_t_x_num values that make up r1, t2 etc. in text strings
* Set 1 = source, 2 = target, 3 = xcontext for validatetrans
*/
#define SOURCE 1
#define TARGET 2
#define XTARGET 3
int s_t_x_num;
/* Set 0 = fail, u = CEXPR_USER, r = CEXPR_ROLE, t = CEXPR_TYPE */
int u_r_t = 0;
char *src = NULL;
char *tgt = NULL;
int rc = 0, x;
char *class_buf = NULL;
int expr_list_len = 0;
int expr_count;
/*
* The array of expression answer buffer pointers and counter.
*/
char **answer_list = NULL;
int answer_counter = 0;
/* The pop operands */
char *a;
char *b;
int a_len, b_len;
class_buf = get_class_info(tclass, constraint, xcontext);
if (!class_buf) {
ERR(NULL, "failed to allocate class buffer");
return -ENOMEM;
}
/* Original function but with buffer support */
expr_counter = 0;
expr_list = NULL;
for (e = constraint->expr; e; e = e->next) {
/* Allocate a stack to hold expression buffer entries */
if (expr_counter >= expr_list_len) {
char **new_expr_list;
int new_expr_list_len;
if (expr_list_len == 0)
new_expr_list_len = STACK_LEN;
else
new_expr_list_len = expr_list_len * 2;
new_expr_list = reallocarray(expr_list,
new_expr_list_len, sizeof(*expr_list));
if (!new_expr_list) {
ERR(NULL, "failed to allocate expr buffer stack");
rc = -ENOMEM;
goto out;
}
expr_list_len = new_expr_list_len;
expr_list = new_expr_list;
}
/*
* malloc a buffer to store each expression text component. If
* buffer is too small cat_expr_buf() will realloc extra space.
*/
expr_buf_len = EXPR_BUF_SIZE;
expr_list[expr_counter] = malloc(expr_buf_len);
if (!expr_list[expr_counter]) {
ERR(NULL, "failed to allocate expr buffer");
rc = -ENOMEM;
goto out;
}
expr_buf_used = 0;
/* Now process each expression of the constraint */
switch (e->expr_type) {
case CEXPR_NOT:
if (sp < 0) {
BUG();
rc = -EINVAL;
goto out;
}
s[sp] = !s[sp];
cat_expr_buf(expr_list[expr_counter], "not");
break;
case CEXPR_AND:
if (sp < 1) {
BUG();
rc = -EINVAL;
goto out;
}
sp--;
s[sp] &= s[sp + 1];
cat_expr_buf(expr_list[expr_counter], "and");
break;
case CEXPR_OR:
if (sp < 1) {
BUG();
rc = -EINVAL;
goto out;
}
sp--;
s[sp] |= s[sp + 1];
cat_expr_buf(expr_list[expr_counter], "or");
break;
case CEXPR_ATTR:
if (sp == (CEXPR_MAXDEPTH - 1))
goto out;
switch (e->attr) {
case CEXPR_USER:
val1 = scontext->user;
val2 = tcontext->user;
free(src); src = strdup("u1");
free(tgt); tgt = strdup("u2");
break;
case CEXPR_TYPE:
val1 = scontext->type;
val2 = tcontext->type;
free(src); src = strdup("t1");
free(tgt); tgt = strdup("t2");
break;
case CEXPR_ROLE:
val1 = scontext->role;
val2 = tcontext->role;
r1 = policydb->role_val_to_struct[val1 - 1];
r2 = policydb->role_val_to_struct[val2 - 1];
free(src); src = strdup("r1");
free(tgt); tgt = strdup("r2");
switch (e->op) {
case CEXPR_DOM:
s[++sp] = ebitmap_get_bit(&r1->dominates, val2 - 1);
msgcat(src, tgt, "dom", s[sp] == 0);
expr_counter++;
continue;
case CEXPR_DOMBY:
s[++sp] = ebitmap_get_bit(&r2->dominates, val1 - 1);
msgcat(src, tgt, "domby", s[sp] == 0);
expr_counter++;
continue;
case CEXPR_INCOMP:
s[++sp] = (!ebitmap_get_bit(&r1->dominates, val2 - 1)
&& !ebitmap_get_bit(&r2->dominates, val1 - 1));
msgcat(src, tgt, "incomp", s[sp] == 0);
expr_counter++;
continue;
default:
break;
}
break;
case CEXPR_L1L2:
l1 = &(scontext->range.level[0]);
l2 = &(tcontext->range.level[0]);
free(src); src = strdup("l1");
free(tgt); tgt = strdup("l2");
goto mls_ops;
case CEXPR_L1H2:
l1 = &(scontext->range.level[0]);
l2 = &(tcontext->range.level[1]);
free(src); src = strdup("l1");
free(tgt); tgt = strdup("h2");
goto mls_ops;
case CEXPR_H1L2:
l1 = &(scontext->range.level[1]);
l2 = &(tcontext->range.level[0]);
free(src); src = strdup("h1");
free(tgt); tgt = strdup("l2");
goto mls_ops;
case CEXPR_H1H2:
l1 = &(scontext->range.level[1]);
l2 = &(tcontext->range.level[1]);
free(src); src = strdup("h1");
free(tgt); tgt = strdup("h2");
goto mls_ops;
case CEXPR_L1H1:
l1 = &(scontext->range.level[0]);
l2 = &(scontext->range.level[1]);
free(src); src = strdup("l1");
free(tgt); tgt = strdup("h1");
goto mls_ops;
case CEXPR_L2H2:
l1 = &(tcontext->range.level[0]);
l2 = &(tcontext->range.level[1]);
free(src); src = strdup("l2");
free(tgt); tgt = strdup("h2");
mls_ops:
switch (e->op) {
case CEXPR_EQ:
s[++sp] = mls_level_eq(l1, l2);
msgcat(src, tgt, "eq", s[sp] == 0);
expr_counter++;
continue;
case CEXPR_NEQ:
s[++sp] = !mls_level_eq(l1, l2);
msgcat(src, tgt, "!=", s[sp] == 0);
expr_counter++;
continue;
case CEXPR_DOM:
s[++sp] = mls_level_dom(l1, l2);
msgcat(src, tgt, "dom", s[sp] == 0);
expr_counter++;
continue;
case CEXPR_DOMBY:
s[++sp] = mls_level_dom(l2, l1);
msgcat(src, tgt, "domby", s[sp] == 0);
expr_counter++;
continue;
case CEXPR_INCOMP:
s[++sp] = mls_level_incomp(l2, l1);
msgcat(src, tgt, "incomp", s[sp] == 0);
expr_counter++;
continue;
default:
BUG();
goto out;
}
break;
default:
BUG();
goto out;
}
switch (e->op) {
case CEXPR_EQ:
s[++sp] = (val1 == val2);
msgcat(src, tgt, "==", s[sp] == 0);
break;
case CEXPR_NEQ:
s[++sp] = (val1 != val2);
msgcat(src, tgt, "!=", s[sp] == 0);
break;
default:
BUG();
goto out;
}
break;
case CEXPR_NAMES:
if (sp == (CEXPR_MAXDEPTH - 1))
goto out;
s_t_x_num = SOURCE;
c = scontext;
if (e->attr & CEXPR_TARGET) {
s_t_x_num = TARGET;
c = tcontext;
} else if (e->attr & CEXPR_XTARGET) {
s_t_x_num = XTARGET;
c = xcontext;
}
if (!c) {
BUG();
goto out;
}
if (e->attr & CEXPR_USER) {
u_r_t = CEXPR_USER;
val1 = c->user;
snprintf(tmp_buf, sizeof(tmp_buf), "u%d ", s_t_x_num);
free(src); src = strdup(tmp_buf);
} else if (e->attr & CEXPR_ROLE) {
u_r_t = CEXPR_ROLE;
val1 = c->role;
snprintf(tmp_buf, sizeof(tmp_buf), "r%d ", s_t_x_num);
free(src); src = strdup(tmp_buf);
} else if (e->attr & CEXPR_TYPE) {
u_r_t = CEXPR_TYPE;
val1 = c->type;
snprintf(tmp_buf, sizeof(tmp_buf), "t%d ", s_t_x_num);
free(src); src = strdup(tmp_buf);
} else {
BUG();
goto out;
}
switch (e->op) {
case CEXPR_EQ:
s[++sp] = ebitmap_get_bit(&e->names, val1 - 1);
get_name_list(e, u_r_t, src, "==", s[sp] == 0);
break;
case CEXPR_NEQ:
s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1);
get_name_list(e, u_r_t, src, "!=", s[sp] == 0);
break;
default:
BUG();
goto out;
}
break;
default:
BUG();
goto out;
}
expr_counter++;
}
/*
* At this point each expression of the constraint is in
* expr_list[n+1] and in RPN format. Now convert to 'infix'
*/
/*
* Save expr count but zero expr_counter to detect if
* 'BUG(); goto out;' was called as we need to release any used
* expr_list malloc's. Normally they are released by the RPN to
* infix code.
*/
expr_count = expr_counter;
expr_counter = 0;
/*
* Generate the same number of answer buffer entries as expression
* buffers (as there will never be more).
*/
answer_list = calloc(expr_count, sizeof(*answer_list));
if (!answer_list) {
ERR(NULL, "failed to allocate answer stack");
rc = -ENOMEM;
goto out;
}
/* Convert constraint from RPN to infix notation. */
for (x = 0; x != expr_count; x++) {
if (strncmp(expr_list[x], "and", 3) == 0 || strncmp(expr_list[x],
"or", 2) == 0) {
b = pop();
b_len = strlen(b);
a = pop();
a_len = strlen(a);
/* get a buffer to hold the answer */
answer_list[answer_counter] = malloc(a_len + b_len + 8);
if (!answer_list[answer_counter]) {
ERR(NULL, "failed to allocate answer buffer");
rc = -ENOMEM;
goto out;
}
memset(answer_list[answer_counter], '\0', a_len + b_len + 8);
sprintf(answer_list[answer_counter], "%s %s %s", a,
expr_list[x], b);
push(answer_list[answer_counter++]);
free(a);
free(b);
free(expr_list[x]);
} else if (strncmp(expr_list[x], "not", 3) == 0) {
b = pop();
b_len = strlen(b);
answer_list[answer_counter] = malloc(b_len + 8);
if (!answer_list[answer_counter]) {
ERR(NULL, "failed to allocate answer buffer");
rc = -ENOMEM;
goto out;
}
memset(answer_list[answer_counter], '\0', b_len + 8);
if (strncmp(b, "not", 3) == 0)
sprintf(answer_list[answer_counter], "%s (%s)",
expr_list[x], b);
else
sprintf(answer_list[answer_counter], "%s%s",
expr_list[x], b);
push(answer_list[answer_counter++]);
free(b);
free(expr_list[x]);
} else {
push(expr_list[x]);
}
}
/* Get the final answer from tos and build constraint text */
a = pop();
/* validatetrans / constraint calculation:
rc = 0 is denied, rc = 1 is granted */
sprintf(tmp_buf, "%s %s\n",
xcontext ? "Validatetrans" : "Constraint",
s[0] ? "GRANTED" : "DENIED");
/*
* This will add the constraints to the callers reason buffer (who is
* responsible for freeing the memory). It will handle any realloc's
* should the buffer be too short.
* The reason_buf_used and reason_buf_len counters are defined
* globally as multiple constraints can be in the buffer.
*/
if (r_buf && ((s[0] == 0) || ((s[0] == 1 &&
(flags & SHOW_GRANTED) == SHOW_GRANTED)))) {
int len, new_buf_len;
char *p, **new_buf = r_buf;
/*
* These contain the constraint components that are added to the
* callers reason buffer.
*/
const char *buffers[] = { class_buf, a, "); ", tmp_buf, 0 };
for (x = 0; buffers[x] != NULL; x++) {
while (1) {
p = *r_buf ? (*r_buf + reason_buf_used) : NULL;
len = snprintf(p, reason_buf_len - reason_buf_used,
"%s", buffers[x]);
if (len < 0 || len >= reason_buf_len - reason_buf_used) {
new_buf_len = reason_buf_len + REASON_BUF_SIZE;
*new_buf = realloc(*r_buf, new_buf_len);
if (!*new_buf) {
ERR(NULL, "failed to realloc reason buffer");
goto out1;
}
**r_buf = **new_buf;
reason_buf_len = new_buf_len;
continue;
} else {
reason_buf_used += len;
break;
}
}
}
}
out1:
rc = s[0];
free(a);
out:
free(class_buf);
free(src);
free(tgt);
if (expr_counter) {
for (x = 0; expr_list[x] != NULL; x++)
free(expr_list[x]);
}
free(answer_list);
free(expr_list);
return rc;
}
/* Forward declaration */
static int context_struct_compute_av(context_struct_t * scontext,
context_struct_t * tcontext,
sepol_security_class_t tclass,
sepol_access_vector_t requested,
struct sepol_av_decision *avd,
unsigned int *reason,
char **r_buf,
unsigned int flags);
static void type_attribute_bounds_av(context_struct_t *scontext,
context_struct_t *tcontext,
sepol_security_class_t tclass,
sepol_access_vector_t requested,
struct sepol_av_decision *avd,
unsigned int *reason)
{
context_struct_t lo_scontext;
context_struct_t lo_tcontext, *tcontextp = tcontext;
struct sepol_av_decision lo_avd;
type_datum_t *source;
type_datum_t *target;
sepol_access_vector_t masked = 0;
source = policydb->type_val_to_struct[scontext->type - 1];
if (!source->bounds)
return;
target = policydb->type_val_to_struct[tcontext->type - 1];
memset(&lo_avd, 0, sizeof(lo_avd));
memcpy(&lo_scontext, scontext, sizeof(lo_scontext));
lo_scontext.type = source->bounds;
if (target->bounds) {
memcpy(&lo_tcontext, tcontext, sizeof(lo_tcontext));
lo_tcontext.type = target->bounds;
tcontextp = &lo_tcontext;
}
context_struct_compute_av(&lo_scontext,
tcontextp,
tclass,
requested,
&lo_avd,
NULL, /* reason intentionally omitted */
NULL,
0);
masked = ~lo_avd.allowed & avd->allowed;
if (!masked)
return; /* no masked permission */
/* mask violated permissions */
avd->allowed &= ~masked;
if (reason)
*reason |= SEPOL_COMPUTEAV_BOUNDS;
}
/*
* Compute access vectors based on a context structure pair for
* the permissions in a particular class.
*/
static int context_struct_compute_av(context_struct_t * scontext,
context_struct_t * tcontext,
sepol_security_class_t tclass,
sepol_access_vector_t requested,
struct sepol_av_decision *avd,
unsigned int *reason,
char **r_buf,
unsigned int flags)
{
constraint_node_t *constraint;
struct role_allow *ra;
avtab_key_t avkey;
class_datum_t *tclass_datum;
avtab_ptr_t node;
ebitmap_t *sattr, *tattr;
ebitmap_node_t *snode, *tnode;
unsigned int i, j;
if (!tclass || tclass > policydb->p_classes.nprim) {
ERR(NULL, "unrecognized class %d", tclass);
return -EINVAL;
}
tclass_datum = policydb->class_val_to_struct[tclass - 1];
/*
* Initialize the access vectors to the default values.
*/
avd->allowed = 0;
avd->decided = 0xffffffff;
avd->auditallow = 0;
avd->auditdeny = 0xffffffff;
avd->seqno = latest_granting;
if (reason)
*reason = 0;
/*
* If a specific type enforcement rule was defined for
* this permission check, then use it.
*/
avkey.target_class = tclass;
avkey.specified = AVTAB_AV;
sattr = &policydb->type_attr_map[scontext->type - 1];
tattr = &policydb->type_attr_map[tcontext->type - 1];
ebitmap_for_each_positive_bit(sattr, snode, i) {
ebitmap_for_each_positive_bit(tattr, tnode, j) {
avkey.source_type = i + 1;
avkey.target_type = j + 1;
for (node =
avtab_search_node(&policydb->te_avtab, &avkey);
node != NULL;
node =
avtab_search_node_next(node, avkey.specified)) {
if (node->key.specified == AVTAB_ALLOWED)
avd->allowed |= node->datum.data;
else if (node->key.specified ==
AVTAB_AUDITALLOW)
avd->auditallow |= node->datum.data;
else if (node->key.specified == AVTAB_AUDITDENY)
avd->auditdeny &= node->datum.data;
}
/* Check conditional av table for additional permissions */
cond_compute_av(&policydb->te_cond_avtab, &avkey, avd);
}
}
if (requested & ~avd->allowed) {
if (reason)
*reason |= SEPOL_COMPUTEAV_TE;
requested &= avd->allowed;
}
/*
* Remove any permissions prohibited by a constraint (this includes
* the MLS policy).
*/
constraint = tclass_datum->constraints;
while (constraint) {
if ((constraint->permissions & (avd->allowed)) &&
!constraint_expr_eval_reason(scontext, tcontext, NULL,
tclass, constraint, r_buf, flags)) {
avd->allowed =
(avd->allowed) & ~(constraint->permissions);
}
constraint = constraint->next;
}
if (requested & ~avd->allowed) {
if (reason)
*reason |= SEPOL_COMPUTEAV_CONS;
requested &= avd->allowed;
}
/*
* If checking process transition permission and the
* role is changing, then check the (current_role, new_role)
* pair.
*/
if (tclass == policydb->process_class &&
(avd->allowed & policydb->process_trans_dyntrans) &&
scontext->role != tcontext->role) {
for (ra = policydb->role_allow; ra; ra = ra->next) {
if (scontext->role == ra->role &&
tcontext->role == ra->new_role)
break;
}
if (!ra)
avd->allowed &= ~policydb->process_trans_dyntrans;
}
if (requested & ~avd->allowed) {
if (reason)
*reason |= SEPOL_COMPUTEAV_RBAC;
requested &= avd->allowed;
}
type_attribute_bounds_av(scontext, tcontext, tclass, requested, avd,
reason);
return 0;
}
/*
* sepol_validate_transition_reason_buffer - the reason buffer is realloc'd
* in the constraint_expr_eval_reason() function.
*/
int sepol_validate_transition_reason_buffer(sepol_security_id_t oldsid,
sepol_security_id_t newsid,
sepol_security_id_t tasksid,
sepol_security_class_t tclass,
char **reason_buf,
unsigned int flags)
{
context_struct_t *ocontext;
context_struct_t *ncontext;
context_struct_t *tcontext;
class_datum_t *tclass_datum;
constraint_node_t *constraint;
if (!tclass || tclass > policydb->p_classes.nprim) {
ERR(NULL, "unrecognized class %d", tclass);
return -EINVAL;
}
tclass_datum = policydb->class_val_to_struct[tclass - 1];
ocontext = sepol_sidtab_search(sidtab, oldsid);
if (!ocontext) {
ERR(NULL, "unrecognized SID %d", oldsid);
return -EINVAL;
}
ncontext = sepol_sidtab_search(sidtab, newsid);
if (!ncontext) {
ERR(NULL, "unrecognized SID %d", newsid);
return -EINVAL;
}
tcontext = sepol_sidtab_search(sidtab, tasksid);
if (!tcontext) {
ERR(NULL, "unrecognized SID %d", tasksid);
return -EINVAL;
}
/*
* Set the buffer to NULL as mls/validatetrans may not be processed.
* If a buffer is required, then the routines in
* constraint_expr_eval_reason will realloc in REASON_BUF_SIZE
* chunks (as it gets called for each mls/validatetrans processed).
* We just make sure these start from zero.
*/
*reason_buf = NULL;
reason_buf_used = 0;
reason_buf_len = 0;
constraint = tclass_datum->validatetrans;
while (constraint) {
if (!constraint_expr_eval_reason(ocontext, ncontext, tcontext,
tclass, constraint, reason_buf, flags)) {
return -EPERM;
}
constraint = constraint->next;
}
return 0;
}
int sepol_compute_av_reason(sepol_security_id_t ssid,
sepol_security_id_t tsid,
sepol_security_class_t tclass,
sepol_access_vector_t requested,
struct sepol_av_decision *avd,
unsigned int *reason)
{
context_struct_t *scontext = 0, *tcontext = 0;
int rc = 0;
scontext = sepol_sidtab_search(sidtab, ssid);
if (!scontext) {
ERR(NULL, "unrecognized source SID %d", ssid);
rc = -EINVAL;
goto out;
}
tcontext = sepol_sidtab_search(sidtab, tsid);
if (!tcontext) {
ERR(NULL, "unrecognized target SID %d", tsid);
rc = -EINVAL;
goto out;
}
rc = context_struct_compute_av(scontext, tcontext, tclass,
requested, avd, reason, NULL, 0);
out:
return rc;
}
/*
* sepol_compute_av_reason_buffer - the reason buffer is malloc'd to
* REASON_BUF_SIZE. If the buffer size is exceeded, then it is realloc'd
* in the constraint_expr_eval_reason() function.
*/
int sepol_compute_av_reason_buffer(sepol_security_id_t ssid,
sepol_security_id_t tsid,
sepol_security_class_t tclass,
sepol_access_vector_t requested,
struct sepol_av_decision *avd,
unsigned int *reason,
char **reason_buf,
unsigned int flags)
{
context_struct_t *scontext = 0, *tcontext = 0;
int rc = 0;
scontext = sepol_sidtab_search(sidtab, ssid);
if (!scontext) {
ERR(NULL, "unrecognized source SID %d", ssid);
rc = -EINVAL;
goto out;
}
tcontext = sepol_sidtab_search(sidtab, tsid);
if (!tcontext) {
ERR(NULL, "unrecognized target SID %d", tsid);
rc = -EINVAL;
goto out;
}
/*
* Set the buffer to NULL as constraints may not be processed.
* If a buffer is required, then the routines in
* constraint_expr_eval_reason will realloc in REASON_BUF_SIZE
* chunks (as it gets called for each constraint processed).
* We just make sure these start from zero.
*/
*reason_buf = NULL;
reason_buf_used = 0;
reason_buf_len = 0;
rc = context_struct_compute_av(scontext, tcontext, tclass,
requested, avd, reason, reason_buf, flags);
out:
return rc;
}
int sepol_compute_av(sepol_security_id_t ssid,
sepol_security_id_t tsid,
sepol_security_class_t tclass,
sepol_access_vector_t requested,
struct sepol_av_decision *avd)
{
unsigned int reason = 0;
return sepol_compute_av_reason(ssid, tsid, tclass, requested, avd,
&reason);
}
/*
* Return a class ID associated with the class string specified by
* class_name.
*/
int sepol_string_to_security_class(const char *class_name,
sepol_security_class_t *tclass)
{
class_datum_t *tclass_datum;
tclass_datum = hashtab_search(policydb->p_classes.table,
class_name);
if (!tclass_datum) {
ERR(NULL, "unrecognized class %s", class_name);
return STATUS_ERR;
}
*tclass = tclass_datum->s.value;
return STATUS_SUCCESS;
}
/*
* Return access vector bit associated with the class ID and permission
* string.
*/
int sepol_string_to_av_perm(sepol_security_class_t tclass,
const char *perm_name,
sepol_access_vector_t *av)
{
class_datum_t *tclass_datum;
perm_datum_t *perm_datum;
if (!tclass || tclass > policydb->p_classes.nprim) {
ERR(NULL, "unrecognized class %d", tclass);
return -EINVAL;
}
tclass_datum = policydb->class_val_to_struct[tclass - 1];
/* Check for unique perms then the common ones (if any) */
perm_datum = (perm_datum_t *)
hashtab_search(tclass_datum->permissions.table,
perm_name);
if (perm_datum != NULL) {
*av = UINT32_C(1) << (perm_datum->s.value - 1);
return STATUS_SUCCESS;
}
if (tclass_datum->comdatum == NULL)
goto out;
perm_datum = (perm_datum_t *)
hashtab_search(tclass_datum->comdatum->permissions.table,
perm_name);
if (perm_datum != NULL) {
*av = UINT32_C(1) << (perm_datum->s.value - 1);
return STATUS_SUCCESS;
}
out:
ERR(NULL, "could not convert %s to av bit", perm_name);
return STATUS_ERR;
}
const char *sepol_av_perm_to_string(sepol_security_class_t tclass,
sepol_access_vector_t av)
{
return sepol_av_to_string(policydb, tclass, av);
}
/*
* Write the security context string representation of
* the context associated with `sid' into a dynamically
* allocated string of the correct size. Set `*scontext'
* to point to this string and set `*scontext_len' to
* the length of the string.
*/
int sepol_sid_to_context(sepol_security_id_t sid,
sepol_security_context_t * scontext,
size_t * scontext_len)
{
context_struct_t *context;
int rc = 0;
context = sepol_sidtab_search(sidtab, sid);
if (!context) {
ERR(NULL, "unrecognized SID %d", sid);
rc = -EINVAL;
goto out;
}
rc = context_to_string(NULL, policydb, context, scontext, scontext_len);
out:
return rc;
}
/*
* Return a SID associated with the security context that
* has the string representation specified by `scontext'.
*/
int sepol_context_to_sid(sepol_const_security_context_t scontext,
size_t scontext_len, sepol_security_id_t * sid)
{
context_struct_t *context = NULL;
/* First, create the context */
if (context_from_string(NULL, policydb, &context,
scontext, scontext_len) < 0)
goto err;
/* Obtain the new sid */
if (sid && (sepol_sidtab_context_to_sid(sidtab, context, sid) < 0))
goto err;
context_destroy(context);
free(context);
return STATUS_SUCCESS;
err:
if (context) {
context_destroy(context);
free(context);
}
ERR(NULL, "could not convert %s to sid", scontext);
return STATUS_ERR;
}
static inline int compute_sid_handle_invalid_context(context_struct_t *
scontext,
context_struct_t *
tcontext,
sepol_security_class_t
tclass,
context_struct_t *
newcontext)
{
if (selinux_enforcing) {
return -EACCES;
} else {
sepol_security_context_t s, t, n;
size_t slen, tlen, nlen;
context_to_string(NULL, policydb, scontext, &s, &slen);
context_to_string(NULL, policydb, tcontext, &t, &tlen);
context_to_string(NULL, policydb, newcontext, &n, &nlen);
ERR(NULL, "invalid context %s for "
"scontext=%s tcontext=%s tclass=%s",
n, s, t, policydb->p_class_val_to_name[tclass - 1]);
free(s);
free(t);
free(n);
return 0;
}
}
static int sepol_compute_sid(sepol_security_id_t ssid,
sepol_security_id_t tsid,
sepol_security_class_t tclass,
uint32_t specified, sepol_security_id_t * out_sid)
{
struct class_datum *cladatum = NULL;
context_struct_t *scontext = 0, *tcontext = 0, newcontext;
struct role_trans *roletr = 0;
avtab_key_t avkey;
avtab_datum_t *avdatum;
avtab_ptr_t node;
int rc = 0;
scontext = sepol_sidtab_search(sidtab, ssid);
if (!scontext) {
ERR(NULL, "unrecognized SID %d", ssid);
rc = -EINVAL;
goto out;
}
tcontext = sepol_sidtab_search(sidtab, tsid);
if (!tcontext) {
ERR(NULL, "unrecognized SID %d", tsid);
rc = -EINVAL;
goto out;
}
if (tclass && tclass <= policydb->p_classes.nprim)
cladatum = policydb->class_val_to_struct[tclass - 1];
context_init(&newcontext);
/* Set the user identity. */
switch (specified) {
case AVTAB_TRANSITION:
case AVTAB_CHANGE:
if (cladatum && cladatum->default_user == DEFAULT_TARGET) {
newcontext.user = tcontext->user;
} else {
/* notice this gets both DEFAULT_SOURCE and unset */
/* Use the process user identity. */
newcontext.user = scontext->user;
}
break;
case AVTAB_MEMBER:
/* Use the related object owner. */
newcontext.user = tcontext->user;
break;
}
/* Set the role to default values. */
if (cladatum && cladatum->default_role == DEFAULT_SOURCE) {
newcontext.role = scontext->role;
} else if (cladatum && cladatum->default_role == DEFAULT_TARGET) {
newcontext.role = tcontext->role;
} else {
if (tclass == policydb->process_class)
newcontext.role = scontext->role;
else
newcontext.role = OBJECT_R_VAL;
}
/* Set the type to default values. */
if (cladatum && cladatum->default_type == DEFAULT_SOURCE) {
newcontext.type = scontext->type;
} else if (cladatum && cladatum->default_type == DEFAULT_TARGET) {
newcontext.type = tcontext->type;
} else {
if (tclass == policydb->process_class) {
/* Use the type of process. */
newcontext.type = scontext->type;
} else {
/* Use the type of the related object. */
newcontext.type = tcontext->type;
}
}
/* Look for a type transition/member/change rule. */
avkey.source_type = scontext->type;
avkey.target_type = tcontext->type;
avkey.target_class = tclass;
avkey.specified = specified;
avdatum = avtab_search(&policydb->te_avtab, &avkey);
/* If no permanent rule, also check for enabled conditional rules */
if (!avdatum) {
node = avtab_search_node(&policydb->te_cond_avtab, &avkey);
for (; node != NULL;
node = avtab_search_node_next(node, specified)) {
if (node->key.specified & AVTAB_ENABLED) {
avdatum = &node->datum;
break;
}
}
}
if (avdatum) {
/* Use the type from the type transition/member/change rule. */
newcontext.type = avdatum->data;
}
/* Check for class-specific changes. */
if (specified & AVTAB_TRANSITION) {
/* Look for a role transition rule. */
for (roletr = policydb->role_tr; roletr;
roletr = roletr->next) {
if (roletr->role == scontext->role &&
roletr->type == tcontext->type &&
roletr->tclass == tclass) {
/* Use the role transition rule. */
newcontext.role = roletr->new_role;
break;
}
}
}
/* Set the MLS attributes.
This is done last because it may allocate memory. */
rc = mls_compute_sid(policydb, scontext, tcontext, tclass, specified,
&newcontext);
if (rc)
goto out;
/* Check the validity of the context. */
if (!policydb_context_isvalid(policydb, &newcontext)) {
rc = compute_sid_handle_invalid_context(scontext,
tcontext,
tclass, &newcontext);
if (rc)
goto out;
}
/* Obtain the sid for the context. */
rc = sepol_sidtab_context_to_sid(sidtab, &newcontext, out_sid);
out:
context_destroy(&newcontext);
return rc;
}
/*
* Compute a SID to use for labeling a new object in the
* class `tclass' based on a SID pair.
*/
int sepol_transition_sid(sepol_security_id_t ssid,
sepol_security_id_t tsid,
sepol_security_class_t tclass,
sepol_security_id_t * out_sid)
{
return sepol_compute_sid(ssid, tsid, tclass, AVTAB_TRANSITION, out_sid);
}
/*
* Compute a SID to use when selecting a member of a
* polyinstantiated object of class `tclass' based on
* a SID pair.
*/
int sepol_member_sid(sepol_security_id_t ssid,
sepol_security_id_t tsid,
sepol_security_class_t tclass,
sepol_security_id_t * out_sid)
{
return sepol_compute_sid(ssid, tsid, tclass, AVTAB_MEMBER, out_sid);
}
/*
* Compute a SID to use for relabeling an object in the
* class `tclass' based on a SID pair.
*/
int sepol_change_sid(sepol_security_id_t ssid,
sepol_security_id_t tsid,
sepol_security_class_t tclass,
sepol_security_id_t * out_sid)
{
return sepol_compute_sid(ssid, tsid, tclass, AVTAB_CHANGE, out_sid);
}
/*
* Verify that each permission that is defined under the
* existing policy is still defined with the same value
* in the new policy.
*/
static int validate_perm(hashtab_key_t key, hashtab_datum_t datum, void *p)
{
hashtab_t h;
perm_datum_t *perdatum, *perdatum2;
h = (hashtab_t) p;
perdatum = (perm_datum_t *) datum;
perdatum2 = (perm_datum_t *) hashtab_search(h, key);
if (!perdatum2) {
ERR(NULL, "permission %s disappeared", key);
return -1;
}
if (perdatum->s.value != perdatum2->s.value) {
ERR(NULL, "the value of permissions %s changed", key);
return -1;
}
return 0;
}
/*
* Verify that each class that is defined under the
* existing policy is still defined with the same
* attributes in the new policy.
*/
static int validate_class(hashtab_key_t key, hashtab_datum_t datum, void *p)
{
policydb_t *newp;
class_datum_t *cladatum, *cladatum2;
newp = (policydb_t *) p;
cladatum = (class_datum_t *) datum;
cladatum2 =
(class_datum_t *) hashtab_search(newp->p_classes.table, key);
if (!cladatum2) {
ERR(NULL, "class %s disappeared", key);
return -1;
}
if (cladatum->s.value != cladatum2->s.value) {
ERR(NULL, "the value of class %s changed", key);
return -1;
}
if ((cladatum->comdatum && !cladatum2->comdatum) ||
(!cladatum->comdatum && cladatum2->comdatum)) {
ERR(NULL, "the inherits clause for the access "
"vector definition for class %s changed", key);
return -1;
}
if (cladatum->comdatum) {
if (hashtab_map
(cladatum->comdatum->permissions.table, validate_perm,
cladatum2->comdatum->permissions.table)) {
ERR(NULL,
" in the access vector definition "
"for class %s", key);
return -1;
}
}
if (hashtab_map(cladatum->permissions.table, validate_perm,
cladatum2->permissions.table)) {
ERR(NULL, " in access vector definition for class %s", key);
return -1;
}
return 0;
}
/* Clone the SID into the new SID table. */
static int clone_sid(sepol_security_id_t sid,
context_struct_t * context, void *arg)
{
sidtab_t *s = arg;
return sepol_sidtab_insert(s, sid, context);
}
static inline int convert_context_handle_invalid_context(context_struct_t *
context)
{
if (selinux_enforcing) {
return -EINVAL;
} else {
sepol_security_context_t s;
size_t len;
context_to_string(NULL, policydb, context, &s, &len);
ERR(NULL, "context %s is invalid", s);
free(s);
return 0;
}
}
typedef struct {
policydb_t *oldp;
policydb_t *newp;
} convert_context_args_t;
/*
* Convert the values in the security context
* structure `c' from the values specified
* in the policy `p->oldp' to the values specified
* in the policy `p->newp'. Verify that the
* context is valid under the new policy.
*/
static int convert_context(sepol_security_id_t key __attribute__ ((unused)),
context_struct_t * c, void *p)
{
convert_context_args_t *args;
context_struct_t oldc;
role_datum_t *role;
type_datum_t *typdatum;
user_datum_t *usrdatum;
sepol_security_context_t s;
size_t len;
int rc = -EINVAL;
args = (convert_context_args_t *) p;
if (context_cpy(&oldc, c))
return -ENOMEM;
/* Convert the user. */
usrdatum = (user_datum_t *) hashtab_search(args->newp->p_users.table,
args->oldp->
p_user_val_to_name[c->user -
1]);
if (!usrdatum) {
goto bad;
}
c->user = usrdatum->s.value;
/* Convert the role. */
role = (role_datum_t *) hashtab_search(args->newp->p_roles.table,
args->oldp->
p_role_val_to_name[c->role - 1]);
if (!role) {
goto bad;
}
c->role = role->s.value;
/* Convert the type. */
typdatum = (type_datum_t *)
hashtab_search(args->newp->p_types.table,
args->oldp->p_type_val_to_name[c->type - 1]);
if (!typdatum) {
goto bad;
}
c->type = typdatum->s.value;
rc = mls_convert_context(args->oldp, args->newp, c);
if (rc)
goto bad;
/* Check the validity of the new context. */
if (!policydb_context_isvalid(args->newp, c)) {
rc = convert_context_handle_invalid_context(&oldc);
if (rc)
goto bad;
}
context_destroy(&oldc);
return 0;
bad:
context_to_string(NULL, policydb, &oldc, &s, &len);
context_destroy(&oldc);
ERR(NULL, "invalidating context %s", s);
free(s);
return rc;
}
/* Reading from a policy "file". */
int next_entry(void *buf, struct policy_file *fp, size_t bytes)
{
size_t nread;
switch (fp->type) {
case PF_USE_STDIO:
nread = fread(buf, bytes, 1, fp->fp);
if (nread != 1)
return -1;
break;
case PF_USE_MEMORY:
if (bytes > fp->len) {
errno = EOVERFLOW;
return -1;
}
memcpy(buf, fp->data, bytes);
fp->data += bytes;
fp->len -= bytes;
break;
default:
errno = EINVAL;
return -1;
}
return 0;
}
size_t put_entry(const void *ptr, size_t size, size_t n,
struct policy_file *fp)
{
size_t bytes = size * n;
switch (fp->type) {
case PF_USE_STDIO:
return fwrite(ptr, size, n, fp->fp);
case PF_USE_MEMORY:
if (bytes > fp->len) {
errno = ENOSPC;
return 0;
}
memcpy(fp->data, ptr, bytes);
fp->data += bytes;
fp->len -= bytes;
return n;
case PF_LEN:
fp->len += bytes;
return n;
default:
return 0;
}
return 0;
}
/*
* Reads a string and null terminates it from the policy file.
* This is a port of str_read from the SE Linux kernel code.
*
* It returns:
* 0 - Success
* -1 - Failure with errno set
*/
int str_read(char **strp, struct policy_file *fp, size_t len)
{
int rc;
char *str;
if (zero_or_saturated(len)) {
errno = EINVAL;
return -1;
}
str = malloc(len + 1);
if (!str)
return -1;
/* it's expected the caller should free the str */
*strp = str;
/* next_entry sets errno */
rc = next_entry(str, fp, len);
if (rc)
return rc;
str[len] = '\0';
return 0;
}
/*
* Read a new set of configuration data from
* a policy database binary representation file.
*
* Verify that each class that is defined under the
* existing policy is still defined with the same
* attributes in the new policy.
*
* Convert the context structures in the SID table to the
* new representation and verify that all entries
* in the SID table are valid under the new policy.
*
* Change the active policy database to use the new
* configuration data.
*
* Reset the access vector cache.
*/
int sepol_load_policy(void *data, size_t len)
{
policydb_t oldpolicydb, newpolicydb;
sidtab_t oldsidtab, newsidtab;
convert_context_args_t args;
int rc = 0;
struct policy_file file, *fp;
policy_file_init(&file);
file.type = PF_USE_MEMORY;
file.data = data;
file.len = len;
fp = &file;
if (policydb_init(&newpolicydb))
return -ENOMEM;
if (policydb_read(&newpolicydb, fp, 1)) {
policydb_destroy(&mypolicydb);
return -EINVAL;
}
sepol_sidtab_init(&newsidtab);
/* Verify that the existing classes did not change. */
if (hashtab_map
(policydb->p_classes.table, validate_class, &newpolicydb)) {
ERR(NULL, "the definition of an existing class changed");
rc = -EINVAL;
goto err;
}
/* Clone the SID table. */
sepol_sidtab_shutdown(sidtab);
if (sepol_sidtab_map(sidtab, clone_sid, &newsidtab)) {
rc = -ENOMEM;
goto err;
}
/* Convert the internal representations of contexts
in the new SID table and remove invalid SIDs. */
args.oldp = policydb;
args.newp = &newpolicydb;
sepol_sidtab_map_remove_on_error(&newsidtab, convert_context, &args);
/* Save the old policydb and SID table to free later. */
memcpy(&oldpolicydb, policydb, sizeof *policydb);
sepol_sidtab_set(&oldsidtab, sidtab);
/* Install the new policydb and SID table. */
memcpy(policydb, &newpolicydb, sizeof *policydb);
sepol_sidtab_set(sidtab, &newsidtab);
/* Free the old policydb and SID table. */
policydb_destroy(&oldpolicydb);
sepol_sidtab_destroy(&oldsidtab);
return 0;
err:
sepol_sidtab_destroy(&newsidtab);
policydb_destroy(&newpolicydb);
return rc;
}
/*
* Return the SIDs to use for an unlabeled file system
* that is being mounted from the device with the
* the kdevname `name'. The `fs_sid' SID is returned for
* the file system and the `file_sid' SID is returned
* for all files within that file system.
*/
int sepol_fs_sid(char *name,
sepol_security_id_t * fs_sid,
sepol_security_id_t * file_sid)
{
int rc = 0;
ocontext_t *c;
c = policydb->ocontexts[OCON_FS];
while (c) {
if (strcmp(c->u.name, name) == 0)
break;
c = c->next;
}
if (c) {
if (!c->sid[0] || !c->sid[1]) {
rc = sepol_sidtab_context_to_sid(sidtab,
&c->context[0],
&c->sid[0]);
if (rc)
goto out;
rc = sepol_sidtab_context_to_sid(sidtab,
&c->context[1],
&c->sid[1]);
if (rc)
goto out;
}
*fs_sid = c->sid[0];
*file_sid = c->sid[1];
} else {
*fs_sid = SECINITSID_FS;
*file_sid = SECINITSID_FILE;
}
out:
return rc;
}
/*
* Return the SID of the ibpkey specified by
* `subnet prefix', and `pkey number'.
*/
int sepol_ibpkey_sid(uint64_t subnet_prefix,
uint16_t pkey, sepol_security_id_t *out_sid)
{
ocontext_t *c;
int rc = 0;
c = policydb->ocontexts[OCON_IBPKEY];
while (c) {
if (c->u.ibpkey.low_pkey <= pkey &&
c->u.ibpkey.high_pkey >= pkey &&
subnet_prefix == c->u.ibpkey.subnet_prefix)
break;
c = c->next;
}
if (c) {
if (!c->sid[0]) {
rc = sepol_sidtab_context_to_sid(sidtab,
&c->context[0],
&c->sid[0]);
if (rc)
goto out;
}
*out_sid = c->sid[0];
} else {
*out_sid = SECINITSID_UNLABELED;
}
out:
return rc;
}
/*
* Return the SID of the subnet management interface specified by
* `device name', and `port'.
*/
int sepol_ibendport_sid(char *dev_name,
uint8_t port,
sepol_security_id_t *out_sid)
{
ocontext_t *c;
int rc = 0;
c = policydb->ocontexts[OCON_IBENDPORT];
while (c) {
if (c->u.ibendport.port == port &&
!strcmp(dev_name, c->u.ibendport.dev_name))
break;
c = c->next;
}
if (c) {
if (!c->sid[0]) {
rc = sepol_sidtab_context_to_sid(sidtab,
&c->context[0],
&c->sid[0]);
if (rc)
goto out;
}
*out_sid = c->sid[0];
} else {
*out_sid = SECINITSID_UNLABELED;
}
out:
return rc;
}
/*
* Return the SID of the port specified by
* `domain', `type', `protocol', and `port'.
*/
int sepol_port_sid(uint16_t domain __attribute__ ((unused)),
uint16_t type __attribute__ ((unused)),
uint8_t protocol,
uint16_t port, sepol_security_id_t * out_sid)
{
ocontext_t *c;
int rc = 0;
c = policydb->ocontexts[OCON_PORT];
while (c) {
if (c->u.port.protocol == protocol &&
c->u.port.low_port <= port && c->u.port.high_port >= port)
break;
c = c->next;
}
if (c) {
if (!c->sid[0]) {
rc = sepol_sidtab_context_to_sid(sidtab,
&c->context[0],
&c->sid[0]);
if (rc)
goto out;
}
*out_sid = c->sid[0];
} else {
*out_sid = SECINITSID_PORT;
}
out:
return rc;
}
/*
* Return the SIDs to use for a network interface
* with the name `name'. The `if_sid' SID is returned for
* the interface and the `msg_sid' SID is returned as
* the default SID for messages received on the
* interface.
*/
int sepol_netif_sid(char *name,
sepol_security_id_t * if_sid,
sepol_security_id_t * msg_sid)
{
int rc = 0;
ocontext_t *c;
c = policydb->ocontexts[OCON_NETIF];
while (c) {
if (strcmp(name, c->u.name) == 0)
break;
c = c->next;
}
if (c) {
if (!c->sid[0] || !c->sid[1]) {
rc = sepol_sidtab_context_to_sid(sidtab,
&c->context[0],
&c->sid[0]);
if (rc)
goto out;
rc = sepol_sidtab_context_to_sid(sidtab,
&c->context[1],
&c->sid[1]);
if (rc)
goto out;
}
*if_sid = c->sid[0];
*msg_sid = c->sid[1];
} else {
*if_sid = SECINITSID_NETIF;
*msg_sid = SECINITSID_NETMSG;
}
out:
return rc;
}
static int match_ipv6_addrmask(uint32_t * input, uint32_t * addr,
uint32_t * mask)
{
int i, fail = 0;
for (i = 0; i < 4; i++)
if (addr[i] != (input[i] & mask[i])) {
fail = 1;
break;
}
return !fail;
}
/*
* Return the SID of the node specified by the address
* `addrp' where `addrlen' is the length of the address
* in bytes and `domain' is the communications domain or
* address family in which the address should be interpreted.
*/
int sepol_node_sid(uint16_t domain,
void *addrp,
size_t addrlen, sepol_security_id_t * out_sid)
{
int rc = 0;
ocontext_t *c;
switch (domain) {
case AF_INET:{
uint32_t addr;
if (addrlen != sizeof(uint32_t)) {
rc = -EINVAL;
goto out;
}
addr = *((uint32_t *) addrp);
c = policydb->ocontexts[OCON_NODE];
while (c) {
if (c->u.node.addr == (addr & c->u.node.mask))
break;
c = c->next;
}
break;
}
case AF_INET6:
if (addrlen != sizeof(uint64_t) * 2) {
rc = -EINVAL;
goto out;
}
c = policydb->ocontexts[OCON_NODE6];
while (c) {
if (match_ipv6_addrmask(addrp, c->u.node6.addr,
c->u.node6.mask))
break;
c = c->next;
}
break;
default:
*out_sid = SECINITSID_NODE;
goto out;
}
if (c) {
if (!c->sid[0]) {
rc = sepol_sidtab_context_to_sid(sidtab,
&c->context[0],
&c->sid[0]);
if (rc)
goto out;
}
*out_sid = c->sid[0];
} else {
*out_sid = SECINITSID_NODE;
}
out:
return rc;
}
/*
* Generate the set of SIDs for legal security contexts
* for a given user that can be reached by `fromsid'.
* Set `*sids' to point to a dynamically allocated
* array containing the set of SIDs. Set `*nel' to the
* number of elements in the array.
*/
#define SIDS_NEL 25
int sepol_get_user_sids(sepol_security_id_t fromsid,
char *username,
sepol_security_id_t ** sids, uint32_t * nel)
{
context_struct_t *fromcon, usercon;
sepol_security_id_t *mysids, *mysids2, sid;
uint32_t mynel = 0, maxnel = SIDS_NEL;
user_datum_t *user;
role_datum_t *role;
struct sepol_av_decision avd;
int rc = 0;
unsigned int i, j, reason;
ebitmap_node_t *rnode, *tnode;
fromcon = sepol_sidtab_search(sidtab, fromsid);
if (!fromcon) {
rc = -EINVAL;
goto out;
}
user = (user_datum_t *) hashtab_search(policydb->p_users.table,
username);
if (!user) {
rc = -EINVAL;
goto out;
}
usercon.user = user->s.value;
mysids = calloc(maxnel, sizeof(sepol_security_id_t));
if (!mysids) {
rc = -ENOMEM;
goto out;
}
ebitmap_for_each_positive_bit(&user->roles.roles, rnode, i) {
role = policydb->role_val_to_struct[i];
usercon.role = i + 1;
ebitmap_for_each_positive_bit(&role->types.types, tnode, j) {
usercon.type = j + 1;
if (usercon.type == fromcon->type)
continue;
if (mls_setup_user_range
(fromcon, user, &usercon, policydb->mls))
continue;
rc = context_struct_compute_av(fromcon, &usercon,
policydb->process_class,
policydb->process_trans,
&avd, &reason, NULL, 0);
if (rc || !(avd.allowed & policydb->process_trans))
continue;
rc = sepol_sidtab_context_to_sid(sidtab, &usercon,
&sid);
if (rc) {
free(mysids);
goto out;
}
if (mynel < maxnel) {
mysids[mynel++] = sid;
} else {
maxnel += SIDS_NEL;
mysids2 = calloc(maxnel, sizeof(sepol_security_id_t));
if (!mysids2) {
rc = -ENOMEM;
free(mysids);
goto out;
}
memcpy(mysids2, mysids,
mynel * sizeof(sepol_security_id_t));
free(mysids);
mysids = mysids2;
mysids[mynel++] = sid;
}
}
}
*sids = mysids;
*nel = mynel;
out:
return rc;
}
/*
* Return the SID to use for a file in a filesystem
* that cannot support a persistent label mapping or use another
* fixed labeling behavior like transition SIDs or task SIDs.
*/
int sepol_genfs_sid(const char *fstype,
const char *path,
sepol_security_class_t sclass,
sepol_security_id_t * sid)
{
size_t len;
genfs_t *genfs;
ocontext_t *c;
int rc = 0, cmp = 0;
for (genfs = policydb->genfs; genfs; genfs = genfs->next) {
cmp = strcmp(fstype, genfs->fstype);
if (cmp <= 0)
break;
}
if (!genfs || cmp) {
*sid = SECINITSID_UNLABELED;
rc = -ENOENT;
goto out;
}
for (c = genfs->head; c; c = c->next) {
len = strlen(c->u.name);
if ((!c->v.sclass || sclass == c->v.sclass) &&
(strncmp(c->u.name, path, len) == 0))
break;
}
if (!c) {
*sid = SECINITSID_UNLABELED;
rc = -ENOENT;
goto out;
}
if (!c->sid[0]) {
rc = sepol_sidtab_context_to_sid(sidtab,
&c->context[0], &c->sid[0]);
if (rc)
goto out;
}
*sid = c->sid[0];
out:
return rc;
}
int sepol_fs_use(const char *fstype,
unsigned int *behavior, sepol_security_id_t * sid)
{
int rc = 0;
ocontext_t *c;
c = policydb->ocontexts[OCON_FSUSE];
while (c) {
if (strcmp(fstype, c->u.name) == 0)
break;
c = c->next;
}
if (c) {
*behavior = c->v.behavior;
if (!c->sid[0]) {
rc = sepol_sidtab_context_to_sid(sidtab,
&c->context[0],
&c->sid[0]);
if (rc)
goto out;
}
*sid = c->sid[0];
} else {
rc = sepol_genfs_sid(fstype, "/", policydb->dir_class, sid);
if (rc) {
*behavior = SECURITY_FS_USE_NONE;
rc = 0;
} else {
*behavior = SECURITY_FS_USE_GENFS;
}
}
out:
return rc;
}
/* FLASK */