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platform_external_selinux/libsepol/src/services.c
Joshua Brindle 13cd4c8960 initial import from svn trunk revision 2950
2008-08-19 15:30:36 -04:00

1471 lines
34 KiB
C
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/*
* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
*/
/*
* Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
*
* Support for enhanced MLS infrastructure.
*
* Updated: Frank Mayer <mayerf@tresys.com>
* and Karl MacMillan <kmacmillan@tresys.com>
*
* Added conditional policy language extensions
*
* Updated: Red Hat, Inc. James Morris <jmorris@redhat.com>
*
* 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.
*
* 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.
*/
#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/flask.h>
#include "debug.h"
#include "private.h"
#include "context.h"
#include "av_permissions.h"
#include "dso.h"
#include "mls.h"
#define BUG() do { ERR(NULL, "Badness at %s:%d", __FILE__, __LINE__); } while (0)
#define BUG_ON(x) do { if (x) 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;
int hidden sepol_set_sidtab(sidtab_t * s)
{
sidtab = s;
return 0;
}
int hidden 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)) {
ERR(NULL, "can't read binary policy: %s", strerror(errno));
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;
/*
* 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 should pass in NULL for xcontext.
*/
static int constraint_expr_eval(context_struct_t * scontext,
context_struct_t * tcontext,
context_struct_t * xcontext,
constraint_expr_t * cexpr)
{
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;
for (e = cexpr; e; e = e->next) {
switch (e->expr_type) {
case CEXPR_NOT:
BUG_ON(sp < 0);
s[sp] = !s[sp];
break;
case CEXPR_AND:
BUG_ON(sp < 1);
sp--;
s[sp] &= s[sp + 1];
break;
case CEXPR_OR:
BUG_ON(sp < 1);
sp--;
s[sp] |= s[sp + 1];
break;
case CEXPR_ATTR:
if (sp == (CEXPR_MAXDEPTH - 1))
return 0;
switch (e->attr) {
case CEXPR_USER:
val1 = scontext->user;
val2 = tcontext->user;
break;
case CEXPR_TYPE:
val1 = scontext->type;
val2 = tcontext->type;
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];
switch (e->op) {
case CEXPR_DOM:
s[++sp] =
ebitmap_get_bit(&r1->dominates,
val2 - 1);
continue;
case CEXPR_DOMBY:
s[++sp] =
ebitmap_get_bit(&r2->dominates,
val1 - 1);
continue;
case CEXPR_INCOMP:
s[++sp] =
(!ebitmap_get_bit
(&r1->dominates, val2 - 1)
&& !ebitmap_get_bit(&r2->dominates,
val1 - 1));
continue;
default:
break;
}
break;
case CEXPR_L1L2:
l1 = &(scontext->range.level[0]);
l2 = &(tcontext->range.level[0]);
goto mls_ops;
case CEXPR_L1H2:
l1 = &(scontext->range.level[0]);
l2 = &(tcontext->range.level[1]);
goto mls_ops;
case CEXPR_H1L2:
l1 = &(scontext->range.level[1]);
l2 = &(tcontext->range.level[0]);
goto mls_ops;
case CEXPR_H1H2:
l1 = &(scontext->range.level[1]);
l2 = &(tcontext->range.level[1]);
goto mls_ops;
case CEXPR_L1H1:
l1 = &(scontext->range.level[0]);
l2 = &(scontext->range.level[1]);
goto mls_ops;
case CEXPR_L2H2:
l1 = &(tcontext->range.level[0]);
l2 = &(tcontext->range.level[1]);
goto mls_ops;
mls_ops:
switch (e->op) {
case CEXPR_EQ:
s[++sp] = mls_level_eq(l1, l2);
continue;
case CEXPR_NEQ:
s[++sp] = !mls_level_eq(l1, l2);
continue;
case CEXPR_DOM:
s[++sp] = mls_level_dom(l1, l2);
continue;
case CEXPR_DOMBY:
s[++sp] = mls_level_dom(l2, l1);
continue;
case CEXPR_INCOMP:
s[++sp] = mls_level_incomp(l2, l1);
continue;
default:
BUG();
return 0;
}
break;
default:
BUG();
return 0;
}
switch (e->op) {
case CEXPR_EQ:
s[++sp] = (val1 == val2);
break;
case CEXPR_NEQ:
s[++sp] = (val1 != val2);
break;
default:
BUG();
return 0;
}
break;
case CEXPR_NAMES:
if (sp == (CEXPR_MAXDEPTH - 1))
return 0;
c = scontext;
if (e->attr & CEXPR_TARGET)
c = tcontext;
else if (e->attr & CEXPR_XTARGET) {
c = xcontext;
if (!c) {
BUG();
return 0;
}
}
if (e->attr & CEXPR_USER)
val1 = c->user;
else if (e->attr & CEXPR_ROLE)
val1 = c->role;
else if (e->attr & CEXPR_TYPE)
val1 = c->type;
else {
BUG();
return 0;
}
switch (e->op) {
case CEXPR_EQ:
s[++sp] = ebitmap_get_bit(&e->names, val1 - 1);
break;
case CEXPR_NEQ:
s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1);
break;
default:
BUG();
return 0;
}
break;
default:
BUG();
return 0;
}
}
BUG_ON(sp != 0);
return s[0];
}
/*
* 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)
{
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;
*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_bit(sattr, snode, i) {
if (!ebitmap_node_get_bit(snode, i))
continue;
ebitmap_for_each_bit(tattr, tnode, j) {
if (!ebitmap_node_get_bit(tnode, j))
continue;
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) {
*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(scontext, tcontext, NULL,
constraint->expr)) {
avd->allowed =
(avd->allowed) & ~(constraint->permissions);
}
constraint = constraint->next;
}
if (requested & ~avd->allowed) {
*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 == SECCLASS_PROCESS &&
(avd->allowed & (PROCESS__TRANSITION | PROCESS__DYNTRANSITION)) &&
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 = (avd->allowed) & ~(PROCESS__TRANSITION |
PROCESS__DYNTRANSITION);
}
if (requested & ~avd->allowed) {
*reason |= SEPOL_COMPUTEAV_RBAC;
requested &= avd->allowed;
}
return 0;
}
int hidden sepol_validate_transition(sepol_security_id_t oldsid,
sepol_security_id_t newsid,
sepol_security_id_t tasksid,
sepol_security_class_t tclass)
{
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;
}
constraint = tclass_datum->validatetrans;
while (constraint) {
if (!constraint_expr_eval(ocontext, ncontext, tcontext,
constraint->expr)) {
return -EPERM;
}
constraint = constraint->next;
}
return 0;
}
int hidden 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 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;
}
rc = context_struct_compute_av(scontext, tcontext, tclass,
requested, avd, reason);
out:
return rc;
}
int hidden 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);
}
/*
* 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 hidden 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 hidden sepol_context_to_sid(const sepol_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)
{
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;
}
context_init(&newcontext);
/* Set the user identity. */
switch (specified) {
case AVTAB_TRANSITION:
case AVTAB_CHANGE:
/* 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 and type to default values. */
switch (tclass) {
case SECCLASS_PROCESS:
/* Use the current role and type of process. */
newcontext.role = scontext->role;
newcontext.type = scontext->type;
break;
default:
/* Use the well-defined object role. */
newcontext.role = OBJECT_R_VAL;
/* 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. */
switch (tclass) {
case SECCLASS_PROCESS:
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) {
/* Use the role transition rule. */
newcontext.role = roletr->new_role;
break;
}
}
}
break;
default:
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 hidden 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 hidden 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 hidden 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\n", 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 hidden 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)
return -1;
memcpy(buf, fp->data, bytes);
fp->data += bytes;
fp->len -= bytes;
break;
default:
return -1;
}
return 0;
}
size_t hidden 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;
}
/*
* 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 hidden sepol_load_policy(void *data, size_t len)
{
policydb_t oldpolicydb, newpolicydb;
sidtab_t oldsidtab, newsidtab;
convert_context_args_t args;
uint32_t seqno;
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)) {
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);
seqno = ++latest_granting;
/* 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 hidden 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 port specified by
* `domain', `type', `protocol', and `port'.
*/
int hidden 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 hidden 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 hidden 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 hidden 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 = malloc(maxnel * sizeof(sepol_security_id_t));
if (!mysids) {
rc = -ENOMEM;
goto out;
}
memset(mysids, 0, maxnel * sizeof(sepol_security_id_t));
ebitmap_for_each_bit(&user->roles.roles, rnode, i) {
if (!ebitmap_node_get_bit(rnode, i))
continue;
role = policydb->role_val_to_struct[i];
usercon.role = i + 1;
ebitmap_for_each_bit(&role->types.types, tnode, j) {
if (!ebitmap_node_get_bit(tnode, j))
continue;
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,
SECCLASS_PROCESS,
PROCESS__TRANSITION,
&avd, &reason);
if (rc || !(avd.allowed & PROCESS__TRANSITION))
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 =
malloc(maxnel *
sizeof(sepol_security_id_t));
if (!mysids2) {
rc = -ENOMEM;
free(mysids);
goto out;
}
memset(mysids2, 0,
maxnel * sizeof(sepol_security_id_t));
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 hidden sepol_genfs_sid(const char *fstype,
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 hidden 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, "/", SECCLASS_DIR, sid);
if (rc) {
*behavior = SECURITY_FS_USE_NONE;
rc = 0;
} else {
*behavior = SECURITY_FS_USE_GENFS;
}
}
out:
return rc;
}
/* FLASK */
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