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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.
* Support for context based audit filters.
*
* Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
*
* Added conditional policy language extensions
*
* Updated: Hewlett-Packard <paul.moore@hp.com>
*
* Added support for NetLabel
* Added support for the policy capability bitmap
*
* Updated: Chad Sellers <csellers@tresys.com>
*
* Added validation of kernel classes and permissions
*
* Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P.
* Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
* Copyright (C) 2003 - 2004, 2006 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/rcupdate.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/sched.h>
#include <linux/audit.h>
#include <linux/mutex.h>
#include <linux/selinux.h>
#include <net/netlabel.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"
#include "objsec.h"
#include "netlabel.h"
#include "xfrm.h"
#include "ebitmap.h"
extern void selnl_notify_policyload(u32 seqno);
unsigned int policydb_loaded_version;
int selinux_policycap_netpeer;
int selinux_policycap_openperm;
/*
* This is declared in avc.c
*/
extern const struct selinux_class_perm selinux_class_perm;
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 DEFINE_MUTEX(load_mutex);
#define LOAD_LOCK mutex_lock(&load_mutex)
#define LOAD_UNLOCK mutex_unlock(&load_mutex)
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;
const struct selinux_class_perm *kdefs = &selinux_class_perm;
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;
/*
* Initialize the access vectors to the default values.
*/
avd->allowed = 0;
avd->decided = 0xffffffff;
avd->auditallow = 0;
avd->auditdeny = 0xffffffff;
avd->seqno = latest_granting;
/*
* Check for all the invalid cases.
* - tclass 0
* - tclass > policy and > kernel
* - tclass > policy but is a userspace class
* - tclass > policy but we do not allow unknowns
*/
if (unlikely(!tclass))
goto inval_class;
if (unlikely(tclass > policydb.p_classes.nprim))
if (tclass > kdefs->cts_len ||
!kdefs->class_to_string[tclass - 1] ||
!policydb.allow_unknown)
goto inval_class;
/*
* Kernel class and we allow unknown so pad the allow decision
* the pad will be all 1 for unknown classes.
*/
if (tclass <= kdefs->cts_len && policydb.allow_unknown)
avd->allowed = policydb.undefined_perms[tclass - 1];
/*
* Not in policy. Since decision is completed (all 1 or all 0) return.
*/
if (unlikely(tclass > policydb.p_classes.nprim))
return 0;
tclass_datum = policydb.class_val_to_struct[tclass - 1];
/*
* 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);
}
}
/*
* 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;
inval_class:
printk(KERN_ERR "%s: unrecognized class %d\n", __func__, tclass);
return -EINVAL;
}
/*
* Given a sid find if the type has the permissive flag set
*/
int security_permissive_sid(u32 sid)
{
struct context *context;
u32 type;
int rc;
POLICY_RDLOCK;
context = sidtab_search(&sidtab, sid);
BUG_ON(!context);
type = context->type;
/*
* we are intentionally using type here, not type-1, the 0th bit may
* someday indicate that we are globally setting permissive in policy.
*/
rc = ebitmap_get_bit(&policydb.permissive_map, type);
POLICY_RDUNLOCK;
return rc;
}
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, GFP_ATOMIC, 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"
const char *security_get_initial_sid_context(u32 sid)
{
if (unlikely(sid > SECINITSID_NUM))
return NULL;
return initial_sid_to_string[sid];
}
/**
* 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;
*scontext = NULL;
*scontext_len = 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);
if (!scontextp) {
rc = -ENOMEM;
goto out;
}
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, gfp_t gfp_flags)
{
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_flags);
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, GFP_KERNEL);
}
/**
* 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 error
*
* 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, gfp_t gfp_flags)
{
return security_context_to_sid_core(scontext, scontext_len,
sid, def_sid, gfp_flags);
}
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, GFP_ATOMIC, 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;
}
context_init(&newcontext);
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;
}
/* 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 kernel class that is defined in the
* policy is correct
*/
static int validate_classes(struct policydb *p)
{
int i, j;
struct class_datum *cladatum;
struct perm_datum *perdatum;
u32 nprim, tmp, common_pts_len, perm_val, pol_val;
u16 class_val;
const struct selinux_class_perm *kdefs = &selinux_class_perm;
const char *def_class, *def_perm, *pol_class;
struct symtab *perms;
if (p->allow_unknown) {
u32 num_classes = kdefs->cts_len;
p->undefined_perms = kcalloc(num_classes, sizeof(u32), GFP_KERNEL);
if (!p->undefined_perms)
return -ENOMEM;
}
for (i = 1; i < kdefs->cts_len; i++) {
def_class = kdefs->class_to_string[i];
if (!def_class)
continue;
if (i > p->p_classes.nprim) {
printk(KERN_INFO
"SELinux: class %s not defined in policy\n",
def_class);
if (p->reject_unknown)
return -EINVAL;
if (p->allow_unknown)
p->undefined_perms[i-1] = ~0U;
continue;
}
pol_class = p->p_class_val_to_name[i-1];
if (strcmp(pol_class, def_class)) {
printk(KERN_ERR
"SELinux: class %d is incorrect, found %s but should be %s\n",
i, pol_class, def_class);
return -EINVAL;
}
}
for (i = 0; i < kdefs->av_pts_len; i++) {
class_val = kdefs->av_perm_to_string[i].tclass;
perm_val = kdefs->av_perm_to_string[i].value;
def_perm = kdefs->av_perm_to_string[i].name;
if (class_val > p->p_classes.nprim)
continue;
pol_class = p->p_class_val_to_name[class_val-1];
cladatum = hashtab_search(p->p_classes.table, pol_class);
BUG_ON(!cladatum);
perms = &cladatum->permissions;
nprim = 1 << (perms->nprim - 1);
if (perm_val > nprim) {
printk(KERN_INFO
"SELinux: permission %s in class %s not defined in policy\n",
def_perm, pol_class);
if (p->reject_unknown)
return -EINVAL;
if (p->allow_unknown)
p->undefined_perms[class_val-1] |= perm_val;
continue;
}
perdatum = hashtab_search(perms->table, def_perm);
if (perdatum == NULL) {
printk(KERN_ERR
"SELinux: permission %s in class %s not found in policy, bad policy\n",
def_perm, pol_class);
return -EINVAL;
}
pol_val = 1 << (perdatum->value - 1);
if (pol_val != perm_val) {
printk(KERN_ERR
"SELinux: permission %s in class %s has incorrect value\n",
def_perm, pol_class);
return -EINVAL;
}
}
for (i = 0; i < kdefs->av_inherit_len; i++) {
class_val = kdefs->av_inherit[i].tclass;
if (class_val > p->p_classes.nprim)
continue;
pol_class = p->p_class_val_to_name[class_val-1];
cladatum = hashtab_search(p->p_classes.table, pol_class);
BUG_ON(!cladatum);
if (!cladatum->comdatum) {
printk(KERN_ERR
"SELinux: class %s should have an inherits clause but does not\n",
pol_class);
return -EINVAL;
}
tmp = kdefs->av_inherit[i].common_base;
common_pts_len = 0;
while (!(tmp & 0x01)) {
common_pts_len++;
tmp >>= 1;
}
perms = &cladatum->comdatum->permissions;
for (j = 0; j < common_pts_len; j++) {
def_perm = kdefs->av_inherit[i].common_pts[j];
if (j >= perms->nprim) {
printk(KERN_INFO
"SELinux: permission %s in class %s not defined in policy\n",
def_perm, pol_class);
if (p->reject_unknown)
return -EINVAL;
if (p->allow_unknown)
p->undefined_perms[class_val-1] |= (1 << j);
continue;
}
perdatum = hashtab_search(perms->table, def_perm);
if (perdatum == NULL) {
printk(KERN_ERR
"SELinux: permission %s in class %s not found in policy, bad policy\n",
def_perm, pol_class);
return -EINVAL;
}
if (perdatum->value != j + 1) {
printk(KERN_ERR
"SELinux: permission %s in class %s has incorrect value\n",
def_perm, pol_class);
return -EINVAL;
}
}
}
return 0;
}
/* 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 "SELinux: 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 "SELinux: invalidating context %s\n", s);
kfree(s);
goto out;
}
static void security_load_policycaps(void)
{
selinux_policycap_netpeer = ebitmap_get_bit(&policydb.policycaps,
POLICYDB_CAPABILITY_NETPEER);
selinux_policycap_openperm = ebitmap_get_bit(&policydb.policycaps,
POLICYDB_CAPABILITY_OPENPERM);
}
extern void selinux_complete_init(void);
static int security_preserve_bools(struct policydb *p);
/**
* 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;
}
/* Verify that the kernel defined classes are correct. */
if (validate_classes(&policydb)) {
printk(KERN_ERR
"SELinux: the definition of a class is incorrect\n");
LOAD_UNLOCK;
sidtab_destroy(&sidtab);
policydb_destroy(&policydb);
avtab_cache_destroy();
return -EINVAL;
}
security_load_policycaps();
policydb_loaded_version = policydb.policyvers;
ss_initialized = 1;
seqno = ++latest_granting;
LOAD_UNLOCK;
selinux_complete_init();
avc_ss_reset(seqno);
selnl_notify_policyload(seqno);
selinux_netlbl_cache_invalidate();
selinux_xfrm_notify_policyload();
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 kernel defined classes are correct. */
if (validate_classes(&newpolicydb)) {
printk(KERN_ERR
"SELinux: the definition of a class is incorrect\n");
rc = -EINVAL;
goto err;
}
rc = security_preserve_bools(&newpolicydb);
if (rc) {
printk(KERN_ERR "SELinux: unable to preserve booleans\n");
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);
security_load_policycaps();
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);
selinux_netlbl_cache_invalidate();
selinux_xfrm_notify_policyload();
return 0;
err:
LOAD_UNLOCK;
sidtab_destroy(&newsidtab);
policydb_destroy(&newpolicydb);
return rc;
}
/**
* security_port_sid - Obtain the SID for a port.
* @protocol: protocol number
* @port: port number
* @out_sid: security identifier
*/
int security_port_sid(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
*/
int security_netif_sid(char *name, u32 *if_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];
} else
*if_sid = SECINITSID_NETIF;
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 = NULL, *mysids2, sid;
u32 mynel = 0, maxnel = SIDS_NEL;
struct user_datum *user;
struct role_datum *role;
struct ebitmap_node *rnode, *tnode;
int rc = 0, i, j;
*sids = NULL;
*nel = 0;
if (!ss_initialized)
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 = kcalloc(maxnel, sizeof(*mysids), GFP_ATOMIC);
if (!mysids) {
rc = -ENOMEM;
goto out_unlock;
}
ebitmap_for_each_positive_bit(&user->roles, rnode, i) {
role = policydb.role_val_to_struct[i];
usercon.role = i+1;
ebitmap_for_each_positive_bit(&role->types, tnode, j) {
usercon.type = j+1;
if (mls_setup_user_range(fromcon, user, &usercon))
continue;
rc = sidtab_context_to_sid(&sidtab, &usercon, &sid);
if (rc)
goto out_unlock;
if (mynel < maxnel) {
mysids[mynel++] = sid;
} else {
maxnel += SIDS_NEL;
mysids2 = kcalloc(maxnel, sizeof(*mysids2), GFP_ATOMIC);
if (!mysids2) {
rc = -ENOMEM;
goto out_unlock;
}
memcpy(mysids2, mysids, mynel * sizeof(*mysids2));
kfree(mysids);
mysids = mysids2;
mysids[mynel++] = sid;
}
}
}
out_unlock:
POLICY_RDUNLOCK;
if (rc || !mynel) {
kfree(mysids);
goto out;
}
mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL);
if (!mysids2) {
rc = -ENOMEM;
kfree(mysids);
goto out;
}
for (i = 0, j = 0; i < mynel; i++) {
rc = avc_has_perm_noaudit(fromsid, mysids[i],
SECCLASS_PROCESS,
PROCESS__TRANSITION, AVC_STRICT,
NULL);
if (!rc)
mysids2[j++] = mysids[i];
cond_resched();
}
rc = 0;
kfree(mysids);
*sids = mysids2;
*nel = j;
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;
while (path[0] == '/' && path[1] == '/')
path++;
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 = kcalloc(*len, sizeof(char*), GFP_ATOMIC);
if (!*names)
goto err;
*values = kcalloc(*len, sizeof(int), 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] = 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;
}
for (i = 0; i < len; i++) {
if (!!values[i] != policydb.bool_val_to_struct[i]->state) {
audit_log(current->audit_context, GFP_ATOMIC,
AUDIT_MAC_CONFIG_CHANGE,
"bool=%s val=%d old_val=%d auid=%u ses=%u",
policydb.p_bool_val_to_name[i],
!!values[i],
policydb.bool_val_to_struct[i]->state,
audit_get_loginuid(current),
audit_get_sessionid(current));
}
if (values[i]) {
policydb.bool_val_to_struct[i]->state = 1;
} else {
policydb.bool_val_to_struct[i]->state = 0;
}
}
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);
selinux_xfrm_notify_policyload();
}
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;
}
static int security_preserve_bools(struct policydb *p)
{
int rc, nbools = 0, *bvalues = NULL, i;
char **bnames = NULL;
struct cond_bool_datum *booldatum;
struct cond_node *cur;
rc = security_get_bools(&nbools, &bnames, &bvalues);
if (rc)
goto out;
for (i = 0; i < nbools; i++) {
booldatum = hashtab_search(p->p_bools.table, bnames[i]);
if (booldatum)
booldatum->state = bvalues[i];
}
for (cur = p->cond_list; cur != NULL; cur = cur->next) {
rc = evaluate_cond_node(p, cur);
if (rc)
goto out;
}
out:
if (bnames) {
for (i = 0; i < nbools; i++)
kfree(bnames[i]);
}
kfree(bnames);
kfree(bvalues);
return rc;
}
/*
* security_sid_mls_copy() - computes a new sid based on the given
* sid and the mls portion of mls_sid.
*/
int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid)
{
struct context *context1;
struct context *context2;
struct context newcon;
char *s;
u32 len;
int rc = 0;
if (!ss_initialized || !selinux_mls_enabled) {
*new_sid = sid;
goto out;
}
context_init(&newcon);
POLICY_RDLOCK;
context1 = sidtab_search(&sidtab, sid);
if (!context1) {
printk(KERN_ERR "security_sid_mls_copy: unrecognized SID "
"%d\n", sid);
rc = -EINVAL;
goto out_unlock;
}
context2 = sidtab_search(&sidtab, mls_sid);
if (!context2) {
printk(KERN_ERR "security_sid_mls_copy: unrecognized SID "
"%d\n", mls_sid);
rc = -EINVAL;
goto out_unlock;
}
newcon.user = context1->user;
newcon.role = context1->role;
newcon.type = context1->type;
rc = mls_context_cpy(&newcon, context2);
if (rc)
goto out_unlock;
/* Check the validity of the new context. */
if (!policydb_context_isvalid(&policydb, &newcon)) {
rc = convert_context_handle_invalid_context(&newcon);
if (rc)
goto bad;
}
rc = sidtab_context_to_sid(&sidtab, &newcon, new_sid);
goto out_unlock;
bad:
if (!context_struct_to_string(&newcon, &s, &len)) {
audit_log(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR,
"security_sid_mls_copy: invalid context %s", s);
kfree(s);
}
out_unlock:
POLICY_RDUNLOCK;
context_destroy(&newcon);
out:
return rc;
}
/**
* security_net_peersid_resolve - Compare and resolve two network peer SIDs
* @nlbl_sid: NetLabel SID
* @nlbl_type: NetLabel labeling protocol type
* @xfrm_sid: XFRM SID
*
* Description:
* Compare the @nlbl_sid and @xfrm_sid values and if the two SIDs can be
* resolved into a single SID it is returned via @peer_sid and the function
* returns zero. Otherwise @peer_sid is set to SECSID_NULL and the function
* returns a negative value. A table summarizing the behavior is below:
*
* | function return | @sid
* ------------------------------+-----------------+-----------------
* no peer labels | 0 | SECSID_NULL
* single peer label | 0 | <peer_label>
* multiple, consistent labels | 0 | <peer_label>
* multiple, inconsistent labels | -<errno> | SECSID_NULL
*
*/
int security_net_peersid_resolve(u32 nlbl_sid, u32 nlbl_type,
u32 xfrm_sid,
u32 *peer_sid)
{
int rc;
struct context *nlbl_ctx;
struct context *xfrm_ctx;
/* handle the common (which also happens to be the set of easy) cases
* right away, these two if statements catch everything involving a
* single or absent peer SID/label */
if (xfrm_sid == SECSID_NULL) {
*peer_sid = nlbl_sid;
return 0;
}
/* NOTE: an nlbl_type == NETLBL_NLTYPE_UNLABELED is a "fallback" label
* and is treated as if nlbl_sid == SECSID_NULL when a XFRM SID/label
* is present */
if (nlbl_sid == SECSID_NULL || nlbl_type == NETLBL_NLTYPE_UNLABELED) {
*peer_sid = xfrm_sid;
return 0;
}
/* we don't need to check ss_initialized here since the only way both
* nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the
* security server was initialized and ss_initialized was true */
if (!selinux_mls_enabled) {
*peer_sid = SECSID_NULL;
return 0;
}
POLICY_RDLOCK;
nlbl_ctx = sidtab_search(&sidtab, nlbl_sid);
if (!nlbl_ctx) {
printk(KERN_ERR
"security_sid_mls_cmp: unrecognized SID %d\n",
nlbl_sid);
rc = -EINVAL;
goto out_slowpath;
}
xfrm_ctx = sidtab_search(&sidtab, xfrm_sid);
if (!xfrm_ctx) {
printk(KERN_ERR
"security_sid_mls_cmp: unrecognized SID %d\n",
xfrm_sid);
rc = -EINVAL;
goto out_slowpath;
}
rc = (mls_context_cmp(nlbl_ctx, xfrm_ctx) ? 0 : -EACCES);
out_slowpath:
POLICY_RDUNLOCK;
if (rc == 0)
/* at present NetLabel SIDs/labels really only carry MLS
* information so if the MLS portion of the NetLabel SID
* matches the MLS portion of the labeled XFRM SID/label
* then pass along the XFRM SID as it is the most
* expressive */
*peer_sid = xfrm_sid;
else
*peer_sid = SECSID_NULL;
return rc;
}
static int get_classes_callback(void *k, void *d, void *args)
{
struct class_datum *datum = d;
char *name = k, **classes = args;
int value = datum->value - 1;
classes[value] = kstrdup(name, GFP_ATOMIC);
if (!classes[value])
return -ENOMEM;
return 0;
}
int security_get_classes(char ***classes, int *nclasses)
{
int rc = -ENOMEM;
POLICY_RDLOCK;
*nclasses = policydb.p_classes.nprim;
*classes = kcalloc(*nclasses, sizeof(*classes), GFP_ATOMIC);
if (!*classes)
goto out;
rc = hashtab_map(policydb.p_classes.table, get_classes_callback,
*classes);
if (rc < 0) {
int i;
for (i = 0; i < *nclasses; i++)
kfree((*classes)[i]);
kfree(*classes);
}
out:
POLICY_RDUNLOCK;
return rc;
}
static int get_permissions_callback(void *k, void *d, void *args)
{
struct perm_datum *datum = d;
char *name = k, **perms = args;
int value = datum->value - 1;
perms[value] = kstrdup(name, GFP_ATOMIC);
if (!perms[value])
return -ENOMEM;
return 0;
}
int security_get_permissions(char *class, char ***perms, int *nperms)
{
int rc = -ENOMEM, i;
struct class_datum *match;
POLICY_RDLOCK;
match = hashtab_search(policydb.p_classes.table, class);
if (!match) {
printk(KERN_ERR "%s: unrecognized class %s\n",
__func__, class);
rc = -EINVAL;
goto out;
}
*nperms = match->permissions.nprim;
*perms = kcalloc(*nperms, sizeof(*perms), GFP_ATOMIC);
if (!*perms)
goto out;
if (match->comdatum) {
rc = hashtab_map(match->comdatum->permissions.table,
get_permissions_callback, *perms);
if (rc < 0)
goto err;
}
rc = hashtab_map(match->permissions.table, get_permissions_callback,
*perms);
if (rc < 0)
goto err;
out:
POLICY_RDUNLOCK;
return rc;
err:
POLICY_RDUNLOCK;
for (i = 0; i < *nperms; i++)
kfree((*perms)[i]);
kfree(*perms);
return rc;
}
int security_get_reject_unknown(void)
{
return policydb.reject_unknown;
}
int security_get_allow_unknown(void)
{
return policydb.allow_unknown;
}
/**
* security_policycap_supported - Check for a specific policy capability
* @req_cap: capability
*
* Description:
* This function queries the currently loaded policy to see if it supports the
* capability specified by @req_cap. Returns true (1) if the capability is
* supported, false (0) if it isn't supported.
*
*/
int security_policycap_supported(unsigned int req_cap)
{
int rc;
POLICY_RDLOCK;
rc = ebitmap_get_bit(&policydb.policycaps, req_cap);
POLICY_RDUNLOCK;
return rc;
}
struct selinux_audit_rule {
u32 au_seqno;
struct context au_ctxt;
};
void selinux_audit_rule_free(struct selinux_audit_rule *rule)
{
if (rule) {
context_destroy(&rule->au_ctxt);
kfree(rule);
}
}
int selinux_audit_rule_init(u32 field, u32 op, char *rulestr,
struct selinux_audit_rule **rule)
{
struct selinux_audit_rule *tmprule;
struct role_datum *roledatum;
struct type_datum *typedatum;
struct user_datum *userdatum;
int rc = 0;
*rule = NULL;
if (!ss_initialized)
return -EOPNOTSUPP;
switch (field) {
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
case AUDIT_OBJ_USER:
case AUDIT_OBJ_ROLE:
case AUDIT_OBJ_TYPE:
/* only 'equals' and 'not equals' fit user, role, and type */
if (op != AUDIT_EQUAL && op != AUDIT_NOT_EQUAL)
return -EINVAL;
break;
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
case AUDIT_OBJ_LEV_LOW:
case AUDIT_OBJ_LEV_HIGH:
/* we do not allow a range, indicated by the presense of '-' */
if (strchr(rulestr, '-'))
return -EINVAL;
break;
default:
/* only the above fields are valid */
return -EINVAL;
}
tmprule = kzalloc(sizeof(struct selinux_audit_rule), GFP_KERNEL);
if (!tmprule)
return -ENOMEM;
context_init(&tmprule->au_ctxt);
POLICY_RDLOCK;
tmprule->au_seqno = latest_granting;
switch (field) {
case AUDIT_SUBJ_USER:
case AUDIT_OBJ_USER:
userdatum = hashtab_search(policydb.p_users.table, rulestr);
if (!userdatum)
rc = -EINVAL;
else
tmprule->au_ctxt.user = userdatum->value;
break;
case AUDIT_SUBJ_ROLE:
case AUDIT_OBJ_ROLE:
roledatum = hashtab_search(policydb.p_roles.table, rulestr);
if (!roledatum)
rc = -EINVAL;
else
tmprule->au_ctxt.role = roledatum->value;
break;
case AUDIT_SUBJ_TYPE:
case AUDIT_OBJ_TYPE:
typedatum = hashtab_search(policydb.p_types.table, rulestr);
if (!typedatum)
rc = -EINVAL;
else
tmprule->au_ctxt.type = typedatum->value;
break;
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
case AUDIT_OBJ_LEV_LOW:
case AUDIT_OBJ_LEV_HIGH:
rc = mls_from_string(rulestr, &tmprule->au_ctxt, GFP_ATOMIC);
break;
}
POLICY_RDUNLOCK;
if (rc) {
selinux_audit_rule_free(tmprule);
tmprule = NULL;
}
*rule = tmprule;
return rc;
}
int selinux_audit_rule_match(u32 sid, u32 field, u32 op,
struct selinux_audit_rule *rule,
struct audit_context *actx)
{
struct context *ctxt;
struct mls_level *level;
int match = 0;
if (!rule) {
audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
"selinux_audit_rule_match: missing rule\n");
return -ENOENT;
}
POLICY_RDLOCK;
if (rule->au_seqno < latest_granting) {
audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
"selinux_audit_rule_match: stale rule\n");
match = -ESTALE;
goto out;
}
ctxt = sidtab_search(&sidtab, sid);
if (!ctxt) {
audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
"selinux_audit_rule_match: unrecognized SID %d\n",
sid);
match = -ENOENT;
goto out;
}
/* a field/op pair that is not caught here will simply fall through
without a match */
switch (field) {
case AUDIT_SUBJ_USER:
case AUDIT_OBJ_USER:
switch (op) {
case AUDIT_EQUAL:
match = (ctxt->user == rule->au_ctxt.user);
break;
case AUDIT_NOT_EQUAL:
match = (ctxt->user != rule->au_ctxt.user);
break;
}
break;
case AUDIT_SUBJ_ROLE:
case AUDIT_OBJ_ROLE:
switch (op) {
case AUDIT_EQUAL:
match = (ctxt->role == rule->au_ctxt.role);
break;
case AUDIT_NOT_EQUAL:
match = (ctxt->role != rule->au_ctxt.role);
break;
}
break;
case AUDIT_SUBJ_TYPE:
case AUDIT_OBJ_TYPE:
switch (op) {
case AUDIT_EQUAL:
match = (ctxt->type == rule->au_ctxt.type);
break;
case AUDIT_NOT_EQUAL:
match = (ctxt->type != rule->au_ctxt.type);
break;
}
break;
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
case AUDIT_OBJ_LEV_LOW:
case AUDIT_OBJ_LEV_HIGH:
level = ((field == AUDIT_SUBJ_SEN ||
field == AUDIT_OBJ_LEV_LOW) ?
&ctxt->range.level[0] : &ctxt->range.level[1]);
switch (op) {
case AUDIT_EQUAL:
match = mls_level_eq(&rule->au_ctxt.range.level[0],
level);
break;
case AUDIT_NOT_EQUAL:
match = !mls_level_eq(&rule->au_ctxt.range.level[0],
level);
break;
case AUDIT_LESS_THAN:
match = (mls_level_dom(&rule->au_ctxt.range.level[0],
level) &&
!mls_level_eq(&rule->au_ctxt.range.level[0],
level));
break;
case AUDIT_LESS_THAN_OR_EQUAL:
match = mls_level_dom(&rule->au_ctxt.range.level[0],
level);
break;
case AUDIT_GREATER_THAN:
match = (mls_level_dom(level,
&rule->au_ctxt.range.level[0]) &&
!mls_level_eq(level,
&rule->au_ctxt.range.level[0]));
break;
case AUDIT_GREATER_THAN_OR_EQUAL:
match = mls_level_dom(level,
&rule->au_ctxt.range.level[0]);
break;
}
}
out:
POLICY_RDUNLOCK;
return match;
}
static int (*aurule_callback)(void) = NULL;
static int aurule_avc_callback(u32 event, u32 ssid, u32 tsid,
u16 class, u32 perms, u32 *retained)
{
int err = 0;
if (event == AVC_CALLBACK_RESET && aurule_callback)
err = aurule_callback();
return err;
}
static int __init aurule_init(void)
{
int err;
err = avc_add_callback(aurule_avc_callback, AVC_CALLBACK_RESET,
SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
if (err)
panic("avc_add_callback() failed, error %d\n", err);
return err;
}
__initcall(aurule_init);
void selinux_audit_set_callback(int (*callback)(void))
{
aurule_callback = callback;
}
#ifdef CONFIG_NETLABEL
/**
* security_netlbl_cache_add - Add an entry to the NetLabel cache
* @secattr: the NetLabel packet security attributes
* @sid: the SELinux SID
*
* Description:
* Attempt to cache the context in @ctx, which was derived from the packet in
* @skb, in the NetLabel subsystem cache. This function assumes @secattr has
* already been initialized.
*
*/
static void security_netlbl_cache_add(struct netlbl_lsm_secattr *secattr,
u32 sid)
{
u32 *sid_cache;
sid_cache = kmalloc(sizeof(*sid_cache), GFP_ATOMIC);
if (sid_cache == NULL)
return;
secattr->cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
if (secattr->cache == NULL) {
kfree(sid_cache);
return;
}
*sid_cache = sid;
secattr->cache->free = kfree;
secattr->cache->data = sid_cache;
secattr->flags |= NETLBL_SECATTR_CACHE;
}
/**
* security_netlbl_secattr_to_sid - Convert a NetLabel secattr to a SELinux SID
* @secattr: the NetLabel packet security attributes
* @sid: the SELinux SID
*
* Description:
* Convert the given NetLabel security attributes in @secattr into a
* SELinux SID. If the @secattr field does not contain a full SELinux
* SID/context then use SECINITSID_NETMSG as the foundation. If possibile the
* 'cache' field of @secattr is set and the CACHE flag is set; this is to
* allow the @secattr to be used by NetLabel to cache the secattr to SID
* conversion for future lookups. Returns zero on success, negative values on
* failure.
*
*/
int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
u32 *sid)
{
int rc = -EIDRM;
struct context *ctx;
struct context ctx_new;
if (!ss_initialized) {
*sid = SECSID_NULL;
return 0;
}
POLICY_RDLOCK;
if (secattr->flags & NETLBL_SECATTR_CACHE) {
*sid = *(u32 *)secattr->cache->data;
rc = 0;
} else if (secattr->flags & NETLBL_SECATTR_SECID) {
*sid = secattr->attr.secid;
rc = 0;
} else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
ctx = sidtab_search(&sidtab, SECINITSID_NETMSG);
if (ctx == NULL)
goto netlbl_secattr_to_sid_return;
ctx_new.user = ctx->user;
ctx_new.role = ctx->role;
ctx_new.type = ctx->type;
mls_import_netlbl_lvl(&ctx_new, secattr);
if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
if (ebitmap_netlbl_import(&ctx_new.range.level[0].cat,
secattr->attr.mls.cat) != 0)
goto netlbl_secattr_to_sid_return;
ctx_new.range.level[1].cat.highbit =
ctx_new.range.level[0].cat.highbit;
ctx_new.range.level[1].cat.node =
ctx_new.range.level[0].cat.node;
} else {
ebitmap_init(&ctx_new.range.level[0].cat);
ebitmap_init(&ctx_new.range.level[1].cat);
}
if (mls_context_isvalid(&policydb, &ctx_new) != 1)
goto netlbl_secattr_to_sid_return_cleanup;
rc = sidtab_context_to_sid(&sidtab, &ctx_new, sid);
if (rc != 0)
goto netlbl_secattr_to_sid_return_cleanup;
security_netlbl_cache_add(secattr, *sid);
ebitmap_destroy(&ctx_new.range.level[0].cat);
} else {
*sid = SECSID_NULL;
rc = 0;
}
netlbl_secattr_to_sid_return:
POLICY_RDUNLOCK;
return rc;
netlbl_secattr_to_sid_return_cleanup:
ebitmap_destroy(&ctx_new.range.level[0].cat);
goto netlbl_secattr_to_sid_return;
}
/**
* security_netlbl_sid_to_secattr - Convert a SELinux SID to a NetLabel secattr
* @sid: the SELinux SID
* @secattr: the NetLabel packet security attributes
*
* Description:
* Convert the given SELinux SID in @sid into a NetLabel security attribute.
* Returns zero on success, negative values on failure.
*
*/
int security_netlbl_sid_to_secattr(u32 sid, struct netlbl_lsm_secattr *secattr)
{
int rc = -ENOENT;
struct context *ctx;
if (!ss_initialized)
return 0;
POLICY_RDLOCK;
ctx = sidtab_search(&sidtab, sid);
if (ctx == NULL)
goto netlbl_sid_to_secattr_failure;
secattr->domain = kstrdup(policydb.p_type_val_to_name[ctx->type - 1],
GFP_ATOMIC);
secattr->flags |= NETLBL_SECATTR_DOMAIN;
mls_export_netlbl_lvl(ctx, secattr);
rc = mls_export_netlbl_cat(ctx, secattr);
if (rc != 0)
goto netlbl_sid_to_secattr_failure;
POLICY_RDUNLOCK;
return 0;
netlbl_sid_to_secattr_failure:
POLICY_RDUNLOCK;
return rc;
}
#endif /* CONFIG_NETLABEL */
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