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linux/security/selinux/ss/services.c

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/*
* Implementation of the security services.
*
* Authors : Stephen Smalley, <sds@epoch.ncsc.mil>
* James Morris <jmorris@redhat.com>
*
* 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
*
* Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
* Copyright (C) 2003 - 2004 Tresys Technology, LLC
* Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2.
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/sched.h>
#include <linux/audit.h>
#include <asm/semaphore.h>
#include "flask.h"
#include "avc.h"
#include "avc_ss.h"
#include "security.h"
#include "context.h"
#include "policydb.h"
#include "sidtab.h"
#include "services.h"
#include "conditional.h"
#include "mls.h"
extern void selnl_notify_policyload(u32 seqno);
unsigned int policydb_loaded_version;
static DEFINE_RWLOCK(policy_rwlock);
#define POLICY_RDLOCK read_lock(&policy_rwlock)
#define POLICY_WRLOCK write_lock_irq(&policy_rwlock)
#define POLICY_RDUNLOCK read_unlock(&policy_rwlock)
#define POLICY_WRUNLOCK write_unlock_irq(&policy_rwlock)
static DECLARE_MUTEX(load_sem);
#define LOAD_LOCK down(&load_sem)
#define LOAD_UNLOCK up(&load_sem)
static struct sidtab sidtab;
struct policydb policydb;
int ss_initialized = 0;
/*
* 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 u32 latest_granting = 0;
/* Forward declaration. */
static int context_struct_to_string(struct context *context, char **scontext,
u32 *scontext_len);
/*
* 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(struct context *scontext,
struct context *tcontext,
struct context *xcontext,
struct constraint_expr *cexpr)
{
u32 val1, val2;
struct context *c;
struct role_datum *r1, *r2;
struct mls_level *l1, *l2;
struct constraint_expr *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(struct context *scontext,
struct context *tcontext,
u16 tclass,
u32 requested,
struct av_decision *avd)
{
struct constraint_node *constraint;
struct role_allow *ra;
struct avtab_key avkey;
struct avtab_node *node;
struct class_datum *tclass_datum;
struct ebitmap *sattr, *tattr;
struct ebitmap_node *snode, *tnode;
unsigned int i, j;
/*
* Remap extended Netlink classes for old policy versions.
* Do this here rather than socket_type_to_security_class()
* in case a newer policy version is loaded, allowing sockets
* to remain in the correct class.
*/
if (policydb_loaded_version < POLICYDB_VERSION_NLCLASS)
if (tclass >= SECCLASS_NETLINK_ROUTE_SOCKET &&
tclass <= SECCLASS_NETLINK_DNRT_SOCKET)
tclass = SECCLASS_NETLINK_SOCKET;
if (!tclass || tclass > policydb.p_classes.nprim) {
printk(KERN_ERR "security_compute_av: unrecognized class %d\n",
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 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);
}
}
/*
* 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 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);
}
return 0;
}
static int security_validtrans_handle_fail(struct context *ocontext,
struct context *ncontext,
struct context *tcontext,
u16 tclass)
{
char *o = NULL, *n = NULL, *t = NULL;
u32 olen, nlen, tlen;
if (context_struct_to_string(ocontext, &o, &olen) < 0)
goto out;
if (context_struct_to_string(ncontext, &n, &nlen) < 0)
goto out;
if (context_struct_to_string(tcontext, &t, &tlen) < 0)
goto out;
audit_log(current->audit_context, AUDIT_SELINUX_ERR,
"security_validate_transition: denied for"
" oldcontext=%s newcontext=%s taskcontext=%s tclass=%s",
o, n, t, policydb.p_class_val_to_name[tclass-1]);
out:
kfree(o);
kfree(n);
kfree(t);
if (!selinux_enforcing)
return 0;
return -EPERM;
}
int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid,
u16 tclass)
{
struct context *ocontext;
struct context *ncontext;
struct context *tcontext;
struct class_datum *tclass_datum;
struct constraint_node *constraint;
int rc = 0;
if (!ss_initialized)
return 0;
POLICY_RDLOCK;
/*
* Remap extended Netlink classes for old policy versions.
* Do this here rather than socket_type_to_security_class()
* in case a newer policy version is loaded, allowing sockets
* to remain in the correct class.
*/
if (policydb_loaded_version < POLICYDB_VERSION_NLCLASS)
if (tclass >= SECCLASS_NETLINK_ROUTE_SOCKET &&
tclass <= SECCLASS_NETLINK_DNRT_SOCKET)
tclass = SECCLASS_NETLINK_SOCKET;
if (!tclass || tclass > policydb.p_classes.nprim) {
printk(KERN_ERR "security_validate_transition: "
"unrecognized class %d\n", tclass);
rc = -EINVAL;
goto out;
}
tclass_datum = policydb.class_val_to_struct[tclass - 1];
ocontext = sidtab_search(&sidtab, oldsid);
if (!ocontext) {
printk(KERN_ERR "security_validate_transition: "
" unrecognized SID %d\n", oldsid);
rc = -EINVAL;
goto out;
}
ncontext = sidtab_search(&sidtab, newsid);
if (!ncontext) {
printk(KERN_ERR "security_validate_transition: "
" unrecognized SID %d\n", newsid);
rc = -EINVAL;
goto out;
}
tcontext = sidtab_search(&sidtab, tasksid);
if (!tcontext) {
printk(KERN_ERR "security_validate_transition: "
" unrecognized SID %d\n", tasksid);
rc = -EINVAL;
goto out;
}
constraint = tclass_datum->validatetrans;
while (constraint) {
if (!constraint_expr_eval(ocontext, ncontext, tcontext,
constraint->expr)) {
rc = security_validtrans_handle_fail(ocontext, ncontext,
tcontext, tclass);
goto out;
}
constraint = constraint->next;
}
out:
POLICY_RDUNLOCK;
return rc;
}
/**
* security_compute_av - Compute access vector decisions.
* @ssid: source security identifier
* @tsid: target security identifier
* @tclass: target security class
* @requested: requested permissions
* @avd: access vector decisions
*
* Compute a set of access vector decisions based on the
* SID pair (@ssid, @tsid) for the permissions in @tclass.
* Return -%EINVAL if any of the parameters are invalid or %0
* if the access vector decisions were computed successfully.
*/
int security_compute_av(u32 ssid,
u32 tsid,
u16 tclass,
u32 requested,
struct av_decision *avd)
{
struct context *scontext = NULL, *tcontext = NULL;
int rc = 0;
if (!ss_initialized) {
avd->allowed = 0xffffffff;
avd->decided = 0xffffffff;
avd->auditallow = 0;
avd->auditdeny = 0xffffffff;
avd->seqno = latest_granting;
return 0;
}
POLICY_RDLOCK;
scontext = sidtab_search(&sidtab, ssid);
if (!scontext) {
printk(KERN_ERR "security_compute_av: unrecognized SID %d\n",
ssid);
rc = -EINVAL;
goto out;
}
tcontext = sidtab_search(&sidtab, tsid);
if (!tcontext) {
printk(KERN_ERR "security_compute_av: unrecognized SID %d\n",
tsid);
rc = -EINVAL;
goto out;
}
rc = context_struct_compute_av(scontext, tcontext, tclass,
requested, avd);
out:
POLICY_RDUNLOCK;
return rc;
}
/*
* Write the security context string representation of
* the context structure `context' 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.
*/
static int context_struct_to_string(struct context *context, char **scontext, u32 *scontext_len)
{
char *scontextp;
*scontext = NULL;
*scontext_len = 0;
/* Compute the size of the context. */
*scontext_len += strlen(policydb.p_user_val_to_name[context->user - 1]) + 1;
*scontext_len += strlen(policydb.p_role_val_to_name[context->role - 1]) + 1;
*scontext_len += strlen(policydb.p_type_val_to_name[context->type - 1]) + 1;
*scontext_len += mls_compute_context_len(context);
/* Allocate space for the context; caller must free this space. */
scontextp = kmalloc(*scontext_len, GFP_ATOMIC);
if (!scontextp) {
return -ENOMEM;
}
*scontext = scontextp;
/*
* Copy the user name, role name and type name into the context.
*/
sprintf(scontextp, "%s:%s:%s",
policydb.p_user_val_to_name[context->user - 1],
policydb.p_role_val_to_name[context->role - 1],
policydb.p_type_val_to_name[context->type - 1]);
scontextp += strlen(policydb.p_user_val_to_name[context->user - 1]) +
1 + strlen(policydb.p_role_val_to_name[context->role - 1]) +
1 + strlen(policydb.p_type_val_to_name[context->type - 1]);
mls_sid_to_context(context, &scontextp);
*scontextp = 0;
return 0;
}
#include "initial_sid_to_string.h"
/**
* security_sid_to_context - Obtain a context for a given SID.
* @sid: security identifier, SID
* @scontext: security context
* @scontext_len: length in bytes
*
* Write the 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 security_sid_to_context(u32 sid, char **scontext, u32 *scontext_len)
{
struct context *context;
int rc = 0;
if (!ss_initialized) {
if (sid <= SECINITSID_NUM) {
char *scontextp;
*scontext_len = strlen(initial_sid_to_string[sid]) + 1;
scontextp = kmalloc(*scontext_len,GFP_ATOMIC);
strcpy(scontextp, initial_sid_to_string[sid]);
*scontext = scontextp;
goto out;
}
printk(KERN_ERR "security_sid_to_context: called before initial "
"load_policy on unknown SID %d\n", sid);
rc = -EINVAL;
goto out;
}
POLICY_RDLOCK;
context = sidtab_search(&sidtab, sid);
if (!context) {
printk(KERN_ERR "security_sid_to_context: unrecognized SID "
"%d\n", sid);
rc = -EINVAL;
goto out_unlock;
}
rc = context_struct_to_string(context, scontext, scontext_len);
out_unlock:
POLICY_RDUNLOCK;
out:
return rc;
}
static int security_context_to_sid_core(char *scontext, u32 scontext_len, u32 *sid, u32 def_sid)
{
char *scontext2;
struct context context;
struct role_datum *role;
struct type_datum *typdatum;
struct user_datum *usrdatum;
char *scontextp, *p, oldc;
int rc = 0;
if (!ss_initialized) {
int i;
for (i = 1; i < SECINITSID_NUM; i++) {
if (!strcmp(initial_sid_to_string[i], scontext)) {
*sid = i;
goto out;
}
}
*sid = SECINITSID_KERNEL;
goto out;
}
*sid = SECSID_NULL;
/* Copy the string so that we can modify the copy as we parse it.
The string should already by null terminated, but we append a
null suffix to the copy to avoid problems with the existing
attr package, which doesn't view the null terminator as part
of the attribute value. */
scontext2 = kmalloc(scontext_len+1,GFP_KERNEL);
if (!scontext2) {
rc = -ENOMEM;
goto out;
}
memcpy(scontext2, scontext, scontext_len);
scontext2[scontext_len] = 0;
context_init(&context);
*sid = SECSID_NULL;
POLICY_RDLOCK;
/* Parse the security context. */
rc = -EINVAL;
scontextp = (char *) scontext2;
/* Extract the user. */
p = scontextp;
while (*p && *p != ':')
p++;
if (*p == 0)
goto out_unlock;
*p++ = 0;
usrdatum = hashtab_search(policydb.p_users.table, scontextp);
if (!usrdatum)
goto out_unlock;
context.user = usrdatum->value;
/* Extract role. */
scontextp = p;
while (*p && *p != ':')
p++;
if (*p == 0)
goto out_unlock;
*p++ = 0;
role = hashtab_search(policydb.p_roles.table, scontextp);
if (!role)
goto out_unlock;
context.role = role->value;
/* Extract type. */
scontextp = p;
while (*p && *p != ':')
p++;
oldc = *p;
*p++ = 0;
typdatum = hashtab_search(policydb.p_types.table, scontextp);
if (!typdatum)
goto out_unlock;
context.type = typdatum->value;
rc = mls_context_to_sid(oldc, &p, &context, &sidtab, def_sid);
if (rc)
goto out_unlock;
if ((p - scontext2) < scontext_len) {
rc = -EINVAL;
goto out_unlock;
}
/* Check the validity of the new context. */
if (!policydb_context_isvalid(&policydb, &context)) {
rc = -EINVAL;
goto out_unlock;
}
/* Obtain the new sid. */
rc = sidtab_context_to_sid(&sidtab, &context, sid);
out_unlock:
POLICY_RDUNLOCK;
context_destroy(&context);
kfree(scontext2);
out:
return rc;
}
/**
* security_context_to_sid - Obtain a SID for a given security context.
* @scontext: security context
* @scontext_len: length in bytes
* @sid: security identifier, SID
*
* Obtains a SID associated with the security context that
* has the string representation specified by @scontext.
* Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
* memory is available, or 0 on success.
*/
int security_context_to_sid(char *scontext, u32 scontext_len, u32 *sid)
{
return security_context_to_sid_core(scontext, scontext_len,
sid, SECSID_NULL);
}
/**
* security_context_to_sid_default - Obtain a SID for a given security context,
* falling back to specified default if needed.
*
* @scontext: security context
* @scontext_len: length in bytes
* @sid: security identifier, SID
* @def_sid: default SID to assign on errror
*
* Obtains a SID associated with the security context that
* has the string representation specified by @scontext.
* The default SID is passed to the MLS layer to be used to allow
* kernel labeling of the MLS field if the MLS field is not present
* (for upgrading to MLS without full relabel).
* Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
* memory is available, or 0 on success.
*/
int security_context_to_sid_default(char *scontext, u32 scontext_len, u32 *sid, u32 def_sid)
{
return security_context_to_sid_core(scontext, scontext_len,
sid, def_sid);
}
static int compute_sid_handle_invalid_context(
struct context *scontext,
struct context *tcontext,
u16 tclass,
struct context *newcontext)
{
char *s = NULL, *t = NULL, *n = NULL;
u32 slen, tlen, nlen;
if (context_struct_to_string(scontext, &s, &slen) < 0)
goto out;
if (context_struct_to_string(tcontext, &t, &tlen) < 0)
goto out;
if (context_struct_to_string(newcontext, &n, &nlen) < 0)
goto out;
audit_log(current->audit_context, AUDIT_SELINUX_ERR,
"security_compute_sid: invalid context %s"
" for scontext=%s"
" tcontext=%s"
" tclass=%s",
n, s, t, policydb.p_class_val_to_name[tclass-1]);
out:
kfree(s);
kfree(t);
kfree(n);
if (!selinux_enforcing)
return 0;
return -EACCES;
}
static int security_compute_sid(u32 ssid,
u32 tsid,
u16 tclass,
u32 specified,
u32 *out_sid)
{
struct context *scontext = NULL, *tcontext = NULL, newcontext;
struct role_trans *roletr = NULL;
struct avtab_key avkey;
struct avtab_datum *avdatum;
struct avtab_node *node;
int rc = 0;
if (!ss_initialized) {
switch (tclass) {
case SECCLASS_PROCESS:
*out_sid = ssid;
break;
default:
*out_sid = tsid;
break;
}
goto out;
}
POLICY_RDLOCK;
scontext = sidtab_search(&sidtab, ssid);
if (!scontext) {
printk(KERN_ERR "security_compute_sid: unrecognized SID %d\n",
ssid);
rc = -EINVAL;
goto out_unlock;
}
tcontext = sidtab_search(&sidtab, tsid);
if (!tcontext) {
printk(KERN_ERR "security_compute_sid: unrecognized SID %d\n",
tsid);
rc = -EINVAL;
goto out_unlock;
}
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(scontext, tcontext, tclass, specified, &newcontext);
if (rc)
goto out_unlock;
/* 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_unlock;
}
/* Obtain the sid for the context. */
rc = sidtab_context_to_sid(&sidtab, &newcontext, out_sid);
out_unlock:
POLICY_RDUNLOCK;
context_destroy(&newcontext);
out:
return rc;
}
/**
* security_transition_sid - Compute the SID for a new subject/object.
* @ssid: source security identifier
* @tsid: target security identifier
* @tclass: target security class
* @out_sid: security identifier for new subject/object
*
* Compute a SID to use for labeling a new subject or object in the
* class @tclass based on a SID pair (@ssid, @tsid).
* Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
* if insufficient memory is available, or %0 if the new SID was
* computed successfully.
*/
int security_transition_sid(u32 ssid,
u32 tsid,
u16 tclass,
u32 *out_sid)
{
return security_compute_sid(ssid, tsid, tclass, AVTAB_TRANSITION, out_sid);
}
/**
* security_member_sid - Compute the SID for member selection.
* @ssid: source security identifier
* @tsid: target security identifier
* @tclass: target security class
* @out_sid: security identifier for selected member
*
* Compute a SID to use when selecting a member of a polyinstantiated
* object of class @tclass based on a SID pair (@ssid, @tsid).
* Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
* if insufficient memory is available, or %0 if the SID was
* computed successfully.
*/
int security_member_sid(u32 ssid,
u32 tsid,
u16 tclass,
u32 *out_sid)
{
return security_compute_sid(ssid, tsid, tclass, AVTAB_MEMBER, out_sid);
}
/**
* security_change_sid - Compute the SID for object relabeling.
* @ssid: source security identifier
* @tsid: target security identifier
* @tclass: target security class
* @out_sid: security identifier for selected member
*
* Compute a SID to use for relabeling an object of class @tclass
* based on a SID pair (@ssid, @tsid).
* Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
* if insufficient memory is available, or %0 if the SID was
* computed successfully.
*/
int security_change_sid(u32 ssid,
u32 tsid,
u16 tclass,
u32 *out_sid)
{
return security_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(void *key, void *datum, void *p)
{
struct hashtab *h;
struct perm_datum *perdatum, *perdatum2;
int rc = 0;
h = p;
perdatum = datum;
perdatum2 = hashtab_search(h, key);
if (!perdatum2) {
printk(KERN_ERR "security: permission %s disappeared",
(char *)key);
rc = -ENOENT;
goto out;
}
if (perdatum->value != perdatum2->value) {
printk(KERN_ERR "security: the value of permission %s changed",
(char *)key);
rc = -EINVAL;
}
out:
return rc;
}
/*
* 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(void *key, void *datum, void *p)
{
struct policydb *newp;
struct class_datum *cladatum, *cladatum2;
int rc;
newp = p;
cladatum = datum;
cladatum2 = hashtab_search(newp->p_classes.table, key);
if (!cladatum2) {
printk(KERN_ERR "security: class %s disappeared\n",
(char *)key);
rc = -ENOENT;
goto out;
}
if (cladatum->value != cladatum2->value) {
printk(KERN_ERR "security: the value of class %s changed\n",
(char *)key);
rc = -EINVAL;
goto out;
}
if ((cladatum->comdatum && !cladatum2->comdatum) ||
(!cladatum->comdatum && cladatum2->comdatum)) {
printk(KERN_ERR "security: the inherits clause for the access "
"vector definition for class %s changed\n", (char *)key);
rc = -EINVAL;
goto out;
}
if (cladatum->comdatum) {
rc = hashtab_map(cladatum->comdatum->permissions.table, validate_perm,
cladatum2->comdatum->permissions.table);
if (rc) {
printk(" in the access vector definition for class "
"%s\n", (char *)key);
goto out;
}
}
rc = hashtab_map(cladatum->permissions.table, validate_perm,
cladatum2->permissions.table);
if (rc)
printk(" in access vector definition for class %s\n",
(char *)key);
out:
return rc;
}
/* Clone the SID into the new SID table. */
static int clone_sid(u32 sid,
struct context *context,
void *arg)
{
struct sidtab *s = arg;
return sidtab_insert(s, sid, context);
}
static inline int convert_context_handle_invalid_context(struct context *context)
{
int rc = 0;
if (selinux_enforcing) {
rc = -EINVAL;
} else {
char *s;
u32 len;
context_struct_to_string(context, &s, &len);
printk(KERN_ERR "security: context %s is invalid\n", s);
kfree(s);
}
return rc;
}
struct convert_context_args {
struct policydb *oldp;
struct policydb *newp;
};
/*
* 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(u32 key,
struct context *c,
void *p)
{
struct convert_context_args *args;
struct context oldc;
struct role_datum *role;
struct type_datum *typdatum;
struct user_datum *usrdatum;
char *s;
u32 len;
int rc;
args = p;
rc = context_cpy(&oldc, c);
if (rc)
goto out;
rc = -EINVAL;
/* Convert the user. */
usrdatum = hashtab_search(args->newp->p_users.table,
args->oldp->p_user_val_to_name[c->user - 1]);
if (!usrdatum) {
goto bad;
}
c->user = usrdatum->value;
/* Convert the role. */
role = hashtab_search(args->newp->p_roles.table,
args->oldp->p_role_val_to_name[c->role - 1]);
if (!role) {
goto bad;
}
c->role = role->value;
/* Convert the type. */
typdatum = hashtab_search(args->newp->p_types.table,
args->oldp->p_type_val_to_name[c->type - 1]);
if (!typdatum) {
goto bad;
}
c->type = typdatum->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);
out:
return rc;
bad:
context_struct_to_string(&oldc, &s, &len);
context_destroy(&oldc);
printk(KERN_ERR "security: invalidating context %s\n", s);
kfree(s);
goto out;
}
extern void selinux_complete_init(void);
/**
* security_load_policy - Load a security policy configuration.
* @data: binary policy data
* @len: length of data in bytes
*
* Load a new set of security policy configuration data,
* validate it and convert the SID table as necessary.
* This function will flush the access vector cache after
* loading the new policy.
*/
int security_load_policy(void *data, size_t len)
{
struct policydb oldpolicydb, newpolicydb;
struct sidtab oldsidtab, newsidtab;
struct convert_context_args args;
u32 seqno;
int rc = 0;
struct policy_file file = { data, len }, *fp = &file;
LOAD_LOCK;
if (!ss_initialized) {
avtab_cache_init();
if (policydb_read(&policydb, fp)) {
LOAD_UNLOCK;
avtab_cache_destroy();
return -EINVAL;
}
if (policydb_load_isids(&policydb, &sidtab)) {
LOAD_UNLOCK;
policydb_destroy(&policydb);
avtab_cache_destroy();
return -EINVAL;
}
policydb_loaded_version = policydb.policyvers;
ss_initialized = 1;
seqno = ++latest_granting;
LOAD_UNLOCK;
selinux_complete_init();
avc_ss_reset(seqno);
selnl_notify_policyload(seqno);
return 0;
}
#if 0
sidtab_hash_eval(&sidtab, "sids");
#endif
if (policydb_read(&newpolicydb, fp)) {
LOAD_UNLOCK;
return -EINVAL;
}
sidtab_init(&newsidtab);
/* Verify that the existing classes did not change. */
if (hashtab_map(policydb.p_classes.table, validate_class, &newpolicydb)) {
printk(KERN_ERR "security: the definition of an existing "
"class changed\n");
rc = -EINVAL;
goto err;
}
/* Clone the SID table. */
sidtab_shutdown(&sidtab);
if (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;
sidtab_map_remove_on_error(&newsidtab, convert_context, &args);
/* Save the old policydb and SID table to free later. */
memcpy(&oldpolicydb, &policydb, sizeof policydb);
sidtab_set(&oldsidtab, &sidtab);
/* Install the new policydb and SID table. */
POLICY_WRLOCK;
memcpy(&policydb, &newpolicydb, sizeof policydb);
sidtab_set(&sidtab, &newsidtab);
seqno = ++latest_granting;
policydb_loaded_version = policydb.policyvers;
POLICY_WRUNLOCK;
LOAD_UNLOCK;
/* Free the old policydb and SID table. */
policydb_destroy(&oldpolicydb);
sidtab_destroy(&oldsidtab);
avc_ss_reset(seqno);
selnl_notify_policyload(seqno);
return 0;
err:
LOAD_UNLOCK;
sidtab_destroy(&newsidtab);
policydb_destroy(&newpolicydb);
return rc;
}
/**
* security_port_sid - Obtain the SID for a port.
* @domain: communication domain aka address family
* @type: socket type
* @protocol: protocol number
* @port: port number
* @out_sid: security identifier
*/
int security_port_sid(u16 domain,
u16 type,
u8 protocol,
u16 port,
u32 *out_sid)
{
struct ocontext *c;
int rc = 0;
POLICY_RDLOCK;
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 = 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:
POLICY_RDUNLOCK;
return rc;
}
/**
* security_netif_sid - Obtain the SID for a network interface.
* @name: interface name
* @if_sid: interface SID
* @msg_sid: default SID for received packets
*/
int security_netif_sid(char *name,
u32 *if_sid,
u32 *msg_sid)
{
int rc = 0;
struct ocontext *c;
POLICY_RDLOCK;
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 = sidtab_context_to_sid(&sidtab,
&c->context[0],
&c->sid[0]);
if (rc)
goto out;
rc = 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:
POLICY_RDUNLOCK;
return rc;
}
static int match_ipv6_addrmask(u32 *input, u32 *addr, u32 *mask)
{
int i, fail = 0;
for(i = 0; i < 4; i++)
if(addr[i] != (input[i] & mask[i])) {
fail = 1;
break;
}
return !fail;
}
/**
* security_node_sid - Obtain the SID for a node (host).
* @domain: communication domain aka address family
* @addrp: address
* @addrlen: address length in bytes
* @out_sid: security identifier
*/
int security_node_sid(u16 domain,
void *addrp,
u32 addrlen,
u32 *out_sid)
{
int rc = 0;
struct ocontext *c;
POLICY_RDLOCK;
switch (domain) {
case AF_INET: {
u32 addr;
if (addrlen != sizeof(u32)) {
rc = -EINVAL;
goto out;
}
addr = *((u32 *)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(u64) * 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 = 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:
POLICY_RDUNLOCK;
return rc;
}
#define SIDS_NEL 25
/**
* security_get_user_sids - Obtain reachable SIDs for a user.
* @fromsid: starting SID
* @username: username
* @sids: array of reachable SIDs for user
* @nel: number of elements in @sids
*
* 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.
*/
int security_get_user_sids(u32 fromsid,
char *username,
u32 **sids,
u32 *nel)
{
struct context *fromcon, usercon;
u32 *mysids, *mysids2, sid;
u32 mynel = 0, maxnel = SIDS_NEL;
struct user_datum *user;
struct role_datum *role;
struct av_decision avd;
struct ebitmap_node *rnode, *tnode;
int rc = 0, i, j;
if (!ss_initialized) {
*sids = NULL;
*nel = 0;
goto out;
}
POLICY_RDLOCK;
fromcon = sidtab_search(&sidtab, fromsid);
if (!fromcon) {
rc = -EINVAL;
goto out_unlock;
}
user = hashtab_search(policydb.p_users.table, username);
if (!user) {
rc = -EINVAL;
goto out_unlock;
}
usercon.user = user->value;
mysids = kmalloc(maxnel*sizeof(*mysids), GFP_ATOMIC);
if (!mysids) {
rc = -ENOMEM;
goto out_unlock;
}
memset(mysids, 0, maxnel*sizeof(*mysids));
ebitmap_for_each_bit(&user->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, tnode, j) {
if (!ebitmap_node_get_bit(tnode, j))
continue;
usercon.type = j+1;
if (mls_setup_user_range(fromcon, user, &usercon))
continue;
rc = context_struct_compute_av(fromcon, &usercon,
SECCLASS_PROCESS,
PROCESS__TRANSITION,
&avd);
if (rc || !(avd.allowed & PROCESS__TRANSITION))
continue;
rc = sidtab_context_to_sid(&sidtab, &usercon, &sid);
if (rc) {
kfree(mysids);
goto out_unlock;
}
if (mynel < maxnel) {
mysids[mynel++] = sid;
} else {
maxnel += SIDS_NEL;
mysids2 = kmalloc(maxnel*sizeof(*mysids2), GFP_ATOMIC);
if (!mysids2) {
rc = -ENOMEM;
kfree(mysids);
goto out_unlock;
}
memset(mysids2, 0, maxnel*sizeof(*mysids2));
memcpy(mysids2, mysids, mynel * sizeof(*mysids2));
kfree(mysids);
mysids = mysids2;
mysids[mynel++] = sid;
}
}
}
*sids = mysids;
*nel = mynel;
out_unlock:
POLICY_RDUNLOCK;
out:
return rc;
}
/**
* security_genfs_sid - Obtain a SID for a file in a filesystem
* @fstype: filesystem type
* @path: path from root of mount
* @sclass: file security class
* @sid: SID for path
*
* Obtain a SID to use for a file in a filesystem that
* cannot support xattr or use a fixed labeling behavior like
* transition SIDs or task SIDs.
*/
int security_genfs_sid(const char *fstype,
char *path,
u16 sclass,
u32 *sid)
{
int len;
struct genfs *genfs;
struct ocontext *c;
int rc = 0, cmp = 0;
POLICY_RDLOCK;
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 = sidtab_context_to_sid(&sidtab,
&c->context[0],
&c->sid[0]);
if (rc)
goto out;
}
*sid = c->sid[0];
out:
POLICY_RDUNLOCK;
return rc;
}
/**
* security_fs_use - Determine how to handle labeling for a filesystem.
* @fstype: filesystem type
* @behavior: labeling behavior
* @sid: SID for filesystem (superblock)
*/
int security_fs_use(
const char *fstype,
unsigned int *behavior,
u32 *sid)
{
int rc = 0;
struct ocontext *c;
POLICY_RDLOCK;
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 = sidtab_context_to_sid(&sidtab,
&c->context[0],
&c->sid[0]);
if (rc)
goto out;
}
*sid = c->sid[0];
} else {
rc = security_genfs_sid(fstype, "/", SECCLASS_DIR, sid);
if (rc) {
*behavior = SECURITY_FS_USE_NONE;
rc = 0;
} else {
*behavior = SECURITY_FS_USE_GENFS;
}
}
out:
POLICY_RDUNLOCK;
return rc;
}
int security_get_bools(int *len, char ***names, int **values)
{
int i, rc = -ENOMEM;
POLICY_RDLOCK;
*names = NULL;
*values = NULL;
*len = policydb.p_bools.nprim;
if (!*len) {
rc = 0;
goto out;
}
*names = (char**)kmalloc(sizeof(char*) * *len, GFP_ATOMIC);
if (!*names)
goto err;
memset(*names, 0, sizeof(char*) * *len);
*values = (int*)kmalloc(sizeof(int) * *len, GFP_ATOMIC);
if (!*values)
goto err;
for (i = 0; i < *len; i++) {
size_t name_len;
(*values)[i] = policydb.bool_val_to_struct[i]->state;
name_len = strlen(policydb.p_bool_val_to_name[i]) + 1;
(*names)[i] = (char*)kmalloc(sizeof(char) * name_len, GFP_ATOMIC);
if (!(*names)[i])
goto err;
strncpy((*names)[i], policydb.p_bool_val_to_name[i], name_len);
(*names)[i][name_len - 1] = 0;
}
rc = 0;
out:
POLICY_RDUNLOCK;
return rc;
err:
if (*names) {
for (i = 0; i < *len; i++)
kfree((*names)[i]);
}
kfree(*values);
goto out;
}
int security_set_bools(int len, int *values)
{
int i, rc = 0;
int lenp, seqno = 0;
struct cond_node *cur;
POLICY_WRLOCK;
lenp = policydb.p_bools.nprim;
if (len != lenp) {
rc = -EFAULT;
goto out;
}
printk(KERN_INFO "security: committed booleans { ");
for (i = 0; i < len; i++) {
if (values[i]) {
policydb.bool_val_to_struct[i]->state = 1;
} else {
policydb.bool_val_to_struct[i]->state = 0;
}
if (i != 0)
printk(", ");
printk("%s:%d", policydb.p_bool_val_to_name[i],
policydb.bool_val_to_struct[i]->state);
}
printk(" }\n");
for (cur = policydb.cond_list; cur != NULL; cur = cur->next) {
rc = evaluate_cond_node(&policydb, cur);
if (rc)
goto out;
}
seqno = ++latest_granting;
out:
POLICY_WRUNLOCK;
if (!rc) {
avc_ss_reset(seqno);
selnl_notify_policyload(seqno);
}
return rc;
}
int security_get_bool_value(int bool)
{
int rc = 0;
int len;
POLICY_RDLOCK;
len = policydb.p_bools.nprim;
if (bool >= len) {
rc = -EFAULT;
goto out;
}
rc = policydb.bool_val_to_struct[bool]->state;
out:
POLICY_RDUNLOCK;
return rc;
}
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