blob: a5813c7629c17f229f6e016cd3d5e0db86f975f7 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Implementation of the security services.
*
* Authors : Stephen Smalley, <sds@tycho.nsa.gov>
* 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@paul-moore.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
*
* Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
*
* Added support for bounds domain and audit messaged on masked permissions
*
* Updated: Guido Trentalancia <guido@trentalancia.com>
*
* Added support for runtime switching of the policy type
*
* Copyright (C) 2008, 2009 NEC Corporation
* 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>
*/
#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/vmalloc.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"
#include "audit.h"
/* Policy capability names */
const char *selinux_policycap_names[__POLICYDB_CAPABILITY_MAX] = {
"network_peer_controls",
"open_perms",
"extended_socket_class",
"always_check_network",
"cgroup_seclabel",
"nnp_nosuid_transition"
};
static struct selinux_ss selinux_ss;
void selinux_ss_init(struct selinux_ss **ss)
{
rwlock_init(&selinux_ss.policy_rwlock);
mutex_init(&selinux_ss.status_lock);
*ss = &selinux_ss;
}
/* Forward declaration. */
static int context_struct_to_string(struct policydb *policydb,
struct context *context,
char **scontext,
u32 *scontext_len);
static void context_struct_compute_av(struct policydb *policydb,
struct context *scontext,
struct context *tcontext,
u16 tclass,
struct av_decision *avd,
struct extended_perms *xperms);
static int selinux_set_mapping(struct policydb *pol,
struct security_class_mapping *map,
struct selinux_map *out_map)
{
u16 i, j;
unsigned k;
bool print_unknown_handle = false;
/* Find number of classes in the input mapping */
if (!map)
return -EINVAL;
i = 0;
while (map[i].name)
i++;
/* Allocate space for the class records, plus one for class zero */
out_map->mapping = kcalloc(++i, sizeof(*out_map->mapping), GFP_ATOMIC);
if (!out_map->mapping)
return -ENOMEM;
/* Store the raw class and permission values */
j = 0;
while (map[j].name) {
struct security_class_mapping *p_in = map + (j++);
struct selinux_mapping *p_out = out_map->mapping + j;
/* An empty class string skips ahead */
if (!strcmp(p_in->name, "")) {
p_out->num_perms = 0;
continue;
}
p_out->value = string_to_security_class(pol, p_in->name);
if (!p_out->value) {
pr_info("SELinux: Class %s not defined in policy.\n",
p_in->name);
if (pol->reject_unknown)
goto err;
p_out->num_perms = 0;
print_unknown_handle = true;
continue;
}
k = 0;
while (p_in->perms[k]) {
/* An empty permission string skips ahead */
if (!*p_in->perms[k]) {
k++;
continue;
}
p_out->perms[k] = string_to_av_perm(pol, p_out->value,
p_in->perms[k]);
if (!p_out->perms[k]) {
pr_info("SELinux: Permission %s in class %s not defined in policy.\n",
p_in->perms[k], p_in->name);
if (pol->reject_unknown)
goto err;
print_unknown_handle = true;
}
k++;
}
p_out->num_perms = k;
}
if (print_unknown_handle)
pr_info("SELinux: the above unknown classes and permissions will be %s\n",
pol->allow_unknown ? "allowed" : "denied");
out_map->size = i;
return 0;
err:
kfree(out_map->mapping);
out_map->mapping = NULL;
return -EINVAL;
}
/*
* Get real, policy values from mapped values
*/
static u16 unmap_class(struct selinux_map *map, u16 tclass)
{
if (tclass < map->size)
return map->mapping[tclass].value;
return tclass;
}
/*
* Get kernel value for class from its policy value
*/
static u16 map_class(struct selinux_map *map, u16 pol_value)
{
u16 i;
for (i = 1; i < map->size; i++) {
if (map->mapping[i].value == pol_value)
return i;
}
return SECCLASS_NULL;
}
static void map_decision(struct selinux_map *map,
u16 tclass, struct av_decision *avd,
int allow_unknown)
{
if (tclass < map->size) {
struct selinux_mapping *mapping = &map->mapping[tclass];
unsigned int i, n = mapping->num_perms;
u32 result;
for (i = 0, result = 0; i < n; i++) {
if (avd->allowed & mapping->perms[i])
result |= 1<<i;
if (allow_unknown && !mapping->perms[i])
result |= 1<<i;
}
avd->allowed = result;
for (i = 0, result = 0; i < n; i++)
if (avd->auditallow & mapping->perms[i])
result |= 1<<i;
avd->auditallow = result;
for (i = 0, result = 0; i < n; i++) {
if (avd->auditdeny & mapping->perms[i])
result |= 1<<i;
if (!allow_unknown && !mapping->perms[i])
result |= 1<<i;
}
/*
* In case the kernel has a bug and requests a permission
* between num_perms and the maximum permission number, we
* should audit that denial
*/
for (; i < (sizeof(u32)*8); i++)
result |= 1<<i;
avd->auditdeny = result;
}
}
int security_mls_enabled(struct selinux_state *state)
{
struct policydb *p = &state->ss->policydb;
return p->mls_enabled;
}
/*
* 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 policydb *policydb,
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];
}
/*
* security_dump_masked_av - dumps masked permissions during
* security_compute_av due to RBAC, MLS/Constraint and Type bounds.
*/
static int dump_masked_av_helper(void *k, void *d, void *args)
{
struct perm_datum *pdatum = d;
char **permission_names = args;
BUG_ON(pdatum->value < 1 || pdatum->value > 32);
permission_names[pdatum->value - 1] = (char *)k;
return 0;
}
static void security_dump_masked_av(struct policydb *policydb,
struct context *scontext,
struct context *tcontext,
u16 tclass,
u32 permissions,
const char *reason)
{
struct common_datum *common_dat;
struct class_datum *tclass_dat;
struct audit_buffer *ab;
char *tclass_name;
char *scontext_name = NULL;
char *tcontext_name = NULL;
char *permission_names[32];
int index;
u32 length;
bool need_comma = false;
if (!permissions)
return;
tclass_name = sym_name(policydb, SYM_CLASSES, tclass - 1);
tclass_dat = policydb->class_val_to_struct[tclass - 1];
common_dat = tclass_dat->comdatum;
/* init permission_names */
if (common_dat &&
hashtab_map(common_dat->permissions.table,
dump_masked_av_helper, permission_names) < 0)
goto out;
if (hashtab_map(tclass_dat->permissions.table,
dump_masked_av_helper, permission_names) < 0)
goto out;
/* get scontext/tcontext in text form */
if (context_struct_to_string(policydb, scontext,
&scontext_name, &length) < 0)
goto out;
if (context_struct_to_string(policydb, tcontext,
&tcontext_name, &length) < 0)
goto out;
/* audit a message */
ab = audit_log_start(audit_context(),
GFP_ATOMIC, AUDIT_SELINUX_ERR);
if (!ab)
goto out;
audit_log_format(ab, "op=security_compute_av reason=%s "
"scontext=%s tcontext=%s tclass=%s perms=",
reason, scontext_name, tcontext_name, tclass_name);
for (index = 0; index < 32; index++) {
u32 mask = (1 << index);
if ((mask & permissions) == 0)
continue;
audit_log_format(ab, "%s%s",
need_comma ? "," : "",
permission_names[index]
? permission_names[index] : "????");
need_comma = true;
}
audit_log_end(ab);
out:
/* release scontext/tcontext */
kfree(tcontext_name);
kfree(scontext_name);
return;
}
/*
* security_boundary_permission - drops violated permissions
* on boundary constraint.
*/
static void type_attribute_bounds_av(struct policydb *policydb,
struct context *scontext,
struct context *tcontext,
u16 tclass,
struct av_decision *avd)
{
struct context lo_scontext;
struct context lo_tcontext, *tcontextp = tcontext;
struct av_decision lo_avd;
struct type_datum *source;
struct type_datum *target;
u32 masked = 0;
source = policydb->type_val_to_struct[scontext->type - 1];
BUG_ON(!source);
if (!source->bounds)
return;
target = policydb->type_val_to_struct[tcontext->type - 1];
BUG_ON(!target);
memset(&lo_avd, 0, sizeof(lo_avd));
memcpy(&lo_scontext, scontext, sizeof(lo_scontext));
lo_scontext.type = source->bounds;
if (target->bounds) {
memcpy(&lo_tcontext, tcontext, sizeof(lo_tcontext));
lo_tcontext.type = target->bounds;
tcontextp = &lo_tcontext;
}
context_struct_compute_av(policydb, &lo_scontext,
tcontextp,
tclass,
&lo_avd,
NULL);
masked = ~lo_avd.allowed & avd->allowed;
if (likely(!masked))
return; /* no masked permission */
/* mask violated permissions */
avd->allowed &= ~masked;
/* audit masked permissions */
security_dump_masked_av(policydb, scontext, tcontext,
tclass, masked, "bounds");
}
/*
* flag which drivers have permissions
* only looking for ioctl based extended permssions
*/
void services_compute_xperms_drivers(
struct extended_perms *xperms,
struct avtab_node *node)
{
unsigned int i;
if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
/* if one or more driver has all permissions allowed */
for (i = 0; i < ARRAY_SIZE(xperms->drivers.p); i++)
xperms->drivers.p[i] |= node->datum.u.xperms->perms.p[i];
} else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
/* if allowing permissions within a driver */
security_xperm_set(xperms->drivers.p,
node->datum.u.xperms->driver);
}
/* If no ioctl commands are allowed, ignore auditallow and auditdeny */
if (node->key.specified & AVTAB_XPERMS_ALLOWED)
xperms->len = 1;
}
/*
* Compute access vectors and extended permissions based on a context
* structure pair for the permissions in a particular class.
*/
static void context_struct_compute_av(struct policydb *policydb,
struct context *scontext,
struct context *tcontext,
u16 tclass,
struct av_decision *avd,
struct extended_perms *xperms)
{
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;
avd->allowed = 0;
avd->auditallow = 0;
avd->auditdeny = 0xffffffff;
if (xperms) {
memset(&xperms->drivers, 0, sizeof(xperms->drivers));
xperms->len = 0;
}
if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
if (printk_ratelimit())
pr_warn("SELinux: Invalid class %hu\n", tclass);
return;
}
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 | AVTAB_XPERMS;
sattr = &policydb->type_attr_map_array[scontext->type - 1];
tattr = &policydb->type_attr_map_array[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;
node = avtab_search_node_next(node, avkey.specified)) {
if (node->key.specified == AVTAB_ALLOWED)
avd->allowed |= node->datum.u.data;
else if (node->key.specified == AVTAB_AUDITALLOW)
avd->auditallow |= node->datum.u.data;
else if (node->key.specified == AVTAB_AUDITDENY)
avd->auditdeny &= node->datum.u.data;
else if (xperms && (node->key.specified & AVTAB_XPERMS))
services_compute_xperms_drivers(xperms, node);
}
/* Check conditional av table for additional permissions */
cond_compute_av(&policydb->te_cond_avtab, &avkey,
avd, xperms);
}
}
/*
* 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(policydb, scontext, tcontext, NULL,
constraint->expr)) {
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 == policydb->process_class &&
(avd->allowed & policydb->process_trans_perms) &&
scontext->role != tcontext->role) {
for (ra = policydb->role_allow; ra; ra = ra->next) {
if (scontext->role == ra->role &&
tcontext->role == ra->new_role)
break;
}
if (!ra)
avd->allowed &= ~policydb->process_trans_perms;
}
/*
* If the given source and target types have boundary
* constraint, lazy checks have to mask any violated
* permission and notice it to userspace via audit.
*/
type_attribute_bounds_av(policydb, scontext, tcontext,
tclass, avd);
}
static int security_validtrans_handle_fail(struct selinux_state *state,
struct context *ocontext,
struct context *ncontext,
struct context *tcontext,
u16 tclass)
{
struct policydb *p = &state->ss->policydb;
char *o = NULL, *n = NULL, *t = NULL;
u32 olen, nlen, tlen;
if (context_struct_to_string(p, ocontext, &o, &olen))
goto out;
if (context_struct_to_string(p, ncontext, &n, &nlen))
goto out;
if (context_struct_to_string(p, tcontext, &t, &tlen))
goto out;
audit_log(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR,
"op=security_validate_transition seresult=denied"
" oldcontext=%s newcontext=%s taskcontext=%s tclass=%s",
o, n, t, sym_name(p, SYM_CLASSES, tclass-1));
out:
kfree(o);
kfree(n);
kfree(t);
if (!enforcing_enabled(state))
return 0;
return -EPERM;
}
static int security_compute_validatetrans(struct selinux_state *state,
u32 oldsid, u32 newsid, u32 tasksid,
u16 orig_tclass, bool user)
{
struct policydb *policydb;
struct sidtab *sidtab;
struct context *ocontext;
struct context *ncontext;
struct context *tcontext;
struct class_datum *tclass_datum;
struct constraint_node *constraint;
u16 tclass;
int rc = 0;
if (!state->initialized)
return 0;
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
if (!user)
tclass = unmap_class(&state->ss->map, orig_tclass);
else
tclass = orig_tclass;
if (!tclass || tclass > policydb->p_classes.nprim) {
rc = -EINVAL;
goto out;
}
tclass_datum = policydb->class_val_to_struct[tclass - 1];
ocontext = sidtab_search(sidtab, oldsid);
if (!ocontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, oldsid);
rc = -EINVAL;
goto out;
}
ncontext = sidtab_search(sidtab, newsid);
if (!ncontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, newsid);
rc = -EINVAL;
goto out;
}
tcontext = sidtab_search(sidtab, tasksid);
if (!tcontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, tasksid);
rc = -EINVAL;
goto out;
}
constraint = tclass_datum->validatetrans;
while (constraint) {
if (!constraint_expr_eval(policydb, ocontext, ncontext,
tcontext, constraint->expr)) {
if (user)
rc = -EPERM;
else
rc = security_validtrans_handle_fail(state,
ocontext,
ncontext,
tcontext,
tclass);
goto out;
}
constraint = constraint->next;
}
out:
read_unlock(&state->ss->policy_rwlock);
return rc;
}
int security_validate_transition_user(struct selinux_state *state,
u32 oldsid, u32 newsid, u32 tasksid,
u16 tclass)
{
return security_compute_validatetrans(state, oldsid, newsid, tasksid,
tclass, true);
}
int security_validate_transition(struct selinux_state *state,
u32 oldsid, u32 newsid, u32 tasksid,
u16 orig_tclass)
{
return security_compute_validatetrans(state, oldsid, newsid, tasksid,
orig_tclass, false);
}
/*
* security_bounded_transition - check whether the given
* transition is directed to bounded, or not.
* It returns 0, if @newsid is bounded by @oldsid.
* Otherwise, it returns error code.
*
* @oldsid : current security identifier
* @newsid : destinated security identifier
*/
int security_bounded_transition(struct selinux_state *state,
u32 old_sid, u32 new_sid)
{
struct policydb *policydb;
struct sidtab *sidtab;
struct context *old_context, *new_context;
struct type_datum *type;
int index;
int rc;
if (!state->initialized)
return 0;
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
rc = -EINVAL;
old_context = sidtab_search(sidtab, old_sid);
if (!old_context) {
pr_err("SELinux: %s: unrecognized SID %u\n",
__func__, old_sid);
goto out;
}
rc = -EINVAL;
new_context = sidtab_search(sidtab, new_sid);
if (!new_context) {
pr_err("SELinux: %s: unrecognized SID %u\n",
__func__, new_sid);
goto out;
}
rc = 0;
/* type/domain unchanged */
if (old_context->type == new_context->type)
goto out;
index = new_context->type;
while (true) {
type = policydb->type_val_to_struct[index - 1];
BUG_ON(!type);
/* not bounded anymore */
rc = -EPERM;
if (!type->bounds)
break;
/* @newsid is bounded by @oldsid */
rc = 0;
if (type->bounds == old_context->type)
break;
index = type->bounds;
}
if (rc) {
char *old_name = NULL;
char *new_name = NULL;
u32 length;
if (!context_struct_to_string(policydb, old_context,
&old_name, &length) &&
!context_struct_to_string(policydb, new_context,
&new_name, &length)) {
audit_log(audit_context(),
GFP_ATOMIC, AUDIT_SELINUX_ERR,
"op=security_bounded_transition "
"seresult=denied "
"oldcontext=%s newcontext=%s",
old_name, new_name);
}
kfree(new_name);
kfree(old_name);
}
out:
read_unlock(&state->ss->policy_rwlock);
return rc;
}
static void avd_init(struct selinux_state *state, struct av_decision *avd)
{
avd->allowed = 0;
avd->auditallow = 0;
avd->auditdeny = 0xffffffff;
avd->seqno = state->ss->latest_granting;
avd->flags = 0;
}
void services_compute_xperms_decision(struct extended_perms_decision *xpermd,
struct avtab_node *node)
{
unsigned int i;
if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
if (xpermd->driver != node->datum.u.xperms->driver)
return;
} else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
if (!security_xperm_test(node->datum.u.xperms->perms.p,
xpermd->driver))
return;
} else {
BUG();
}
if (node->key.specified == AVTAB_XPERMS_ALLOWED) {
xpermd->used |= XPERMS_ALLOWED;
if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
memset(xpermd->allowed->p, 0xff,
sizeof(xpermd->allowed->p));
}
if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
for (i = 0; i < ARRAY_SIZE(xpermd->allowed->p); i++)
xpermd->allowed->p[i] |=
node->datum.u.xperms->perms.p[i];
}
} else if (node->key.specified == AVTAB_XPERMS_AUDITALLOW) {
xpermd->used |= XPERMS_AUDITALLOW;
if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
memset(xpermd->auditallow->p, 0xff,
sizeof(xpermd->auditallow->p));
}
if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
for (i = 0; i < ARRAY_SIZE(xpermd->auditallow->p); i++)
xpermd->auditallow->p[i] |=
node->datum.u.xperms->perms.p[i];
}
} else if (node->key.specified == AVTAB_XPERMS_DONTAUDIT) {
xpermd->used |= XPERMS_DONTAUDIT;
if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
memset(xpermd->dontaudit->p, 0xff,
sizeof(xpermd->dontaudit->p));
}
if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
for (i = 0; i < ARRAY_SIZE(xpermd->dontaudit->p); i++)
xpermd->dontaudit->p[i] |=
node->datum.u.xperms->perms.p[i];
}
} else {
BUG();
}
}
void security_compute_xperms_decision(struct selinux_state *state,
u32 ssid,
u32 tsid,
u16 orig_tclass,
u8 driver,
struct extended_perms_decision *xpermd)
{
struct policydb *policydb;
struct sidtab *sidtab;
u16 tclass;
struct context *scontext, *tcontext;
struct avtab_key avkey;
struct avtab_node *node;
struct ebitmap *sattr, *tattr;
struct ebitmap_node *snode, *tnode;
unsigned int i, j;
xpermd->driver = driver;
xpermd->used = 0;
memset(xpermd->allowed->p, 0, sizeof(xpermd->allowed->p));
memset(xpermd->auditallow->p, 0, sizeof(xpermd->auditallow->p));
memset(xpermd->dontaudit->p, 0, sizeof(xpermd->dontaudit->p));
read_lock(&state->ss->policy_rwlock);
if (!state->initialized)
goto allow;
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
scontext = sidtab_search(sidtab, ssid);
if (!scontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, ssid);
goto out;
}
tcontext = sidtab_search(sidtab, tsid);
if (!tcontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, tsid);
goto out;
}
tclass = unmap_class(&state->ss->map, orig_tclass);
if (unlikely(orig_tclass && !tclass)) {
if (policydb->allow_unknown)
goto allow;
goto out;
}
if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
pr_warn_ratelimited("SELinux: Invalid class %hu\n", tclass);
goto out;
}
avkey.target_class = tclass;
avkey.specified = AVTAB_XPERMS;
sattr = &policydb->type_attr_map_array[scontext->type - 1];
tattr = &policydb->type_attr_map_array[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;
node = avtab_search_node_next(node, avkey.specified))
services_compute_xperms_decision(xpermd, node);
cond_compute_xperms(&policydb->te_cond_avtab,
&avkey, xpermd);
}
}
out:
read_unlock(&state->ss->policy_rwlock);
return;
allow:
memset(xpermd->allowed->p, 0xff, sizeof(xpermd->allowed->p));
goto out;
}
/**
* security_compute_av - Compute access vector decisions.
* @ssid: source security identifier
* @tsid: target security identifier
* @tclass: target security class
* @avd: access vector decisions
* @xperms: extended permissions
*
* Compute a set of access vector decisions based on the
* SID pair (@ssid, @tsid) for the permissions in @tclass.
*/
void security_compute_av(struct selinux_state *state,
u32 ssid,
u32 tsid,
u16 orig_tclass,
struct av_decision *avd,
struct extended_perms *xperms)
{
struct policydb *policydb;
struct sidtab *sidtab;
u16 tclass;
struct context *scontext = NULL, *tcontext = NULL;
read_lock(&state->ss->policy_rwlock);
avd_init(state, avd);
xperms->len = 0;
if (!state->initialized)
goto allow;
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
scontext = sidtab_search(sidtab, ssid);
if (!scontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, ssid);
goto out;
}
/* permissive domain? */
if (ebitmap_get_bit(&policydb->permissive_map, scontext->type))
avd->flags |= AVD_FLAGS_PERMISSIVE;
tcontext = sidtab_search(sidtab, tsid);
if (!tcontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, tsid);
goto out;
}
tclass = unmap_class(&state->ss->map, orig_tclass);
if (unlikely(orig_tclass && !tclass)) {
if (policydb->allow_unknown)
goto allow;
goto out;
}
context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
xperms);
map_decision(&state->ss->map, orig_tclass, avd,
policydb->allow_unknown);
out:
read_unlock(&state->ss->policy_rwlock);
return;
allow:
avd->allowed = 0xffffffff;
goto out;
}
void security_compute_av_user(struct selinux_state *state,
u32 ssid,
u32 tsid,
u16 tclass,
struct av_decision *avd)
{
struct policydb *policydb;
struct sidtab *sidtab;
struct context *scontext = NULL, *tcontext = NULL;
read_lock(&state->ss->policy_rwlock);
avd_init(state, avd);
if (!state->initialized)
goto allow;
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
scontext = sidtab_search(sidtab, ssid);
if (!scontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, ssid);
goto out;
}
/* permissive domain? */
if (ebitmap_get_bit(&policydb->permissive_map, scontext->type))
avd->flags |= AVD_FLAGS_PERMISSIVE;
tcontext = sidtab_search(sidtab, tsid);
if (!tcontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, tsid);
goto out;
}
if (unlikely(!tclass)) {
if (policydb->allow_unknown)
goto allow;
goto out;
}
context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
NULL);
out:
read_unlock(&state->ss->policy_rwlock);
return;
allow:
avd->allowed = 0xffffffff;
goto out;
}
/*
* 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 policydb *p,
struct context *context,
char **scontext, u32 *scontext_len)
{
char *scontextp;
if (scontext)
*scontext = NULL;
*scontext_len = 0;
if (context->len) {
*scontext_len = context->len;
if (scontext) {
*scontext = kstrdup(context->str, GFP_ATOMIC);
if (!(*scontext))
return -ENOMEM;
}
return 0;
}
/* Compute the size of the context. */
*scontext_len += strlen(sym_name(p, SYM_USERS, context->user - 1)) + 1;
*scontext_len += strlen(sym_name(p, SYM_ROLES, context->role - 1)) + 1;
*scontext_len += strlen(sym_name(p, SYM_TYPES, context->type - 1)) + 1;
*scontext_len += mls_compute_context_len(p, context);
if (!scontext)
return 0;
/* 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.
*/
scontextp += sprintf(scontextp, "%s:%s:%s",
sym_name(p, SYM_USERS, context->user - 1),
sym_name(p, SYM_ROLES, context->role - 1),
sym_name(p, SYM_TYPES, context->type - 1));
mls_sid_to_context(p, 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];
}
static int security_sid_to_context_core(struct selinux_state *state,
u32 sid, char **scontext,
u32 *scontext_len, int force,
int only_invalid)
{
struct policydb *policydb;
struct sidtab *sidtab;
struct context *context;
int rc = 0;
if (scontext)
*scontext = NULL;
*scontext_len = 0;
if (!state->initialized) {
if (sid <= SECINITSID_NUM) {
char *scontextp;
*scontext_len = strlen(initial_sid_to_string[sid]) + 1;
if (!scontext)
goto out;
scontextp = kmemdup(initial_sid_to_string[sid],
*scontext_len, GFP_ATOMIC);
if (!scontextp) {
rc = -ENOMEM;
goto out;
}
*scontext = scontextp;
goto out;
}
pr_err("SELinux: %s: called before initial "
"load_policy on unknown SID %d\n", __func__, sid);
rc = -EINVAL;
goto out;
}
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
if (force)
context = sidtab_search_force(sidtab, sid);
else
context = sidtab_search(sidtab, sid);
if (!context) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, sid);
rc = -EINVAL;
goto out_unlock;
}
if (only_invalid && !context->len)
rc = 0;
else
rc = context_struct_to_string(policydb, context, scontext,
scontext_len);
out_unlock:
read_unlock(&state->ss->policy_rwlock);
out:
return rc;
}
/**
* 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(struct selinux_state *state,
u32 sid, char **scontext, u32 *scontext_len)
{
return security_sid_to_context_core(state, sid, scontext,
scontext_len, 0, 0);
}
int security_sid_to_context_force(struct selinux_state *state, u32 sid,
char **scontext, u32 *scontext_len)
{
return security_sid_to_context_core(state, sid, scontext,
scontext_len, 1, 0);
}
/**
* security_sid_to_context_inval - Obtain a context for a given SID if it
* is invalid.
* @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, but only if the
* context is invalid in the current policy. Set @scontext to point to
* this string (or NULL if the context is valid) and set @scontext_len to
* the length of the string (or 0 if the context is valid).
*/
int security_sid_to_context_inval(struct selinux_state *state, u32 sid,
char **scontext, u32 *scontext_len)
{
return security_sid_to_context_core(state, sid, scontext,
scontext_len, 1, 1);
}
/*
* Caveat: Mutates scontext.
*/
static int string_to_context_struct(struct policydb *pol,
struct sidtab *sidtabp,
char *scontext,
struct context *ctx,
u32 def_sid)
{
struct role_datum *role;
struct type_datum *typdatum;
struct user_datum *usrdatum;
char *scontextp, *p, oldc;
int rc = 0;
context_init(ctx);
/* Parse the security context. */
rc = -EINVAL;
scontextp = (char *) scontext;
/* Extract the user. */
p = scontextp;
while (*p && *p != ':')
p++;
if (*p == 0)
goto out;
*p++ = 0;
usrdatum = hashtab_search(pol->p_users.table, scontextp);
if (!usrdatum)
goto out;
ctx->user = usrdatum->value;
/* Extract role. */
scontextp = p;
while (*p && *p != ':')
p++;
if (*p == 0)
goto out;
*p++ = 0;
role = hashtab_search(pol->p_roles.table, scontextp);
if (!role)
goto out;
ctx->role = role->value;
/* Extract type. */
scontextp = p;
while (*p && *p != ':')
p++;
oldc = *p;
*p++ = 0;
typdatum = hashtab_search(pol->p_types.table, scontextp);
if (!typdatum || typdatum->attribute)
goto out;
ctx->type = typdatum->value;
rc = mls_context_to_sid(pol, oldc, p, ctx, sidtabp, def_sid);
if (rc)
goto out;
/* Check the validity of the new context. */
rc = -EINVAL;
if (!policydb_context_isvalid(pol, ctx))
goto out;
rc = 0;
out:
if (rc)
context_destroy(ctx);
return rc;
}
static int security_context_to_sid_core(struct selinux_state *state,
const char *scontext, u32 scontext_len,
u32 *sid, u32 def_sid, gfp_t gfp_flags,
int force)
{
struct policydb *policydb;
struct sidtab *sidtab;
char *scontext2, *str = NULL;
struct context context;
int rc = 0;
/* An empty security context is never valid. */
if (!scontext_len)
return -EINVAL;
/* Copy the string to allow changes and ensure a NUL terminator */
scontext2 = kmemdup_nul(scontext, scontext_len, gfp_flags);
if (!scontext2)
return -ENOMEM;
if (!state->initialized) {
int i;
for (i = 1; i < SECINITSID_NUM; i++) {
if (!strcmp(initial_sid_to_string[i], scontext2)) {
*sid = i;
goto out;
}
}
*sid = SECINITSID_KERNEL;
goto out;
}
*sid = SECSID_NULL;
if (force) {
/* Save another copy for storing in uninterpreted form */
rc = -ENOMEM;
str = kstrdup(scontext2, gfp_flags);
if (!str)
goto out;
}
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
rc = string_to_context_struct(policydb, sidtab, scontext2,
&context, def_sid);
if (rc == -EINVAL && force) {
context.str = str;
context.len = strlen(str) + 1;
str = NULL;
} else if (rc)
goto out_unlock;
rc = sidtab_context_to_sid(sidtab, &context, sid);
context_destroy(&context);
out_unlock:
read_unlock(&state->ss->policy_rwlock);
out:
kfree(scontext2);
kfree(str);
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
* @gfp: context for the allocation
*
* 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(struct selinux_state *state,
const char *scontext, u32 scontext_len, u32 *sid,
gfp_t gfp)
{
return security_context_to_sid_core(state, scontext, scontext_len,
sid, SECSID_NULL, gfp, 0);
}
int security_context_str_to_sid(struct selinux_state *state,
const char *scontext, u32 *sid, gfp_t gfp)
{
return security_context_to_sid(state, scontext, strlen(scontext),
sid, gfp);
}
/**
* 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).
* Implicitly forces adding of the context even if it cannot be mapped yet.
* Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
* memory is available, or 0 on success.
*/
int security_context_to_sid_default(struct selinux_state *state,
const char *scontext, u32 scontext_len,
u32 *sid, u32 def_sid, gfp_t gfp_flags)
{
return security_context_to_sid_core(state, scontext, scontext_len,
sid, def_sid, gfp_flags, 1);
}
int security_context_to_sid_force(struct selinux_state *state,
const char *scontext, u32 scontext_len,
u32 *sid)
{
return security_context_to_sid_core(state, scontext, scontext_len,
sid, SECSID_NULL, GFP_KERNEL, 1);
}
static int compute_sid_handle_invalid_context(
struct selinux_state *state,
struct context *scontext,
struct context *tcontext,
u16 tclass,
struct context *newcontext)
{
struct policydb *policydb = &state->ss->policydb;
char *s = NULL, *t = NULL, *n = NULL;
u32 slen, tlen, nlen;
struct audit_buffer *ab;
if (context_struct_to_string(policydb, scontext, &s, &slen))
goto out;
if (context_struct_to_string(policydb, tcontext, &t, &tlen))
goto out;
if (context_struct_to_string(policydb, newcontext, &n, &nlen))
goto out;
ab = audit_log_start(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR);
audit_log_format(ab,
"op=security_compute_sid invalid_context=");
/* no need to record the NUL with untrusted strings */
audit_log_n_untrustedstring(ab, n, nlen - 1);
audit_log_format(ab, " scontext=%s tcontext=%s tclass=%s",
s, t, sym_name(policydb, SYM_CLASSES, tclass-1));
audit_log_end(ab);
out:
kfree(s);
kfree(t);
kfree(n);
if (!enforcing_enabled(state))
return 0;
return -EACCES;
}
static void filename_compute_type(struct policydb *policydb,
struct context *newcontext,
u32 stype, u32 ttype, u16 tclass,
const char *objname)
{
struct filename_trans ft;
struct filename_trans_datum *otype;
/*
* Most filename trans rules are going to live in specific directories
* like /dev or /var/run. This bitmap will quickly skip rule searches
* if the ttype does not contain any rules.
*/
if (!ebitmap_get_bit(&policydb->filename_trans_ttypes, ttype))
return;
ft.stype = stype;
ft.ttype = ttype;
ft.tclass = tclass;
ft.name = objname;
otype = hashtab_search(policydb->filename_trans, &ft);
if (otype)
newcontext->type = otype->otype;
}
static int security_compute_sid(struct selinux_state *state,
u32 ssid,
u32 tsid,
u16 orig_tclass,
u32 specified,
const char *objname,
u32 *out_sid,
bool kern)
{
struct policydb *policydb;
struct sidtab *sidtab;
struct class_datum *cladatum = NULL;
struct context *scontext = NULL, *tcontext = NULL, newcontext;
struct role_trans *roletr = NULL;
struct avtab_key avkey;
struct avtab_datum *avdatum;
struct avtab_node *node;
u16 tclass;
int rc = 0;
bool sock;
if (!state->initialized) {
switch (orig_tclass) {
case SECCLASS_PROCESS: /* kernel value */
*out_sid = ssid;
break;
default:
*out_sid = tsid;
break;
}
goto out;
}
context_init(&newcontext);
read_lock(&state->ss->policy_rwlock);
if (kern) {
tclass = unmap_class(&state->ss->map, orig_tclass);
sock = security_is_socket_class(orig_tclass);
} else {
tclass = orig_tclass;
sock = security_is_socket_class(map_class(&state->ss->map,
tclass));
}
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
scontext = sidtab_search(sidtab, ssid);
if (!scontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, ssid);
rc = -EINVAL;
goto out_unlock;
}
tcontext = sidtab_search(sidtab, tsid);
if (!tcontext) {
pr_err("SELinux: %s: unrecognized SID %d\n",
__func__, tsid);
rc = -EINVAL;
goto out_unlock;
}
if (tclass && tclass <= policydb->p_classes.nprim)
cladatum = policydb->class_val_to_struct[tclass - 1];
/* Set the user identity. */
switch (specified) {
case AVTAB_TRANSITION:
case AVTAB_CHANGE:
if (cladatum && cladatum->default_user == DEFAULT_TARGET) {
newcontext.user = tcontext->user;
} else {
/* notice this gets both DEFAULT_SOURCE and unset */
/* Use the process user identity. */
newcontext.user = scontext->user;
}
break;
case AVTAB_MEMBER:
/* Use the related object owner. */
newcontext.user = tcontext->user;
break;
}
/* Set the role to default values. */
if (cladatum && cladatum->default_role == DEFAULT_SOURCE) {
newcontext.role = scontext->role;
} else if (cladatum && cladatum->default_role == DEFAULT_TARGET) {
newcontext.role = tcontext->role;
} else {
if ((tclass == policydb->process_class) || (sock == true))
newcontext.role = scontext->role;
else
newcontext.role = OBJECT_R_VAL;
}
/* Set the type to default values. */
if (cladatum && cladatum->default_type == DEFAULT_SOURCE) {
newcontext.type = scontext->type;
} else if (cladatum && cladatum->default_type == DEFAULT_TARGET) {
newcontext.type = tcontext->type;
} else {
if ((tclass == policydb->process_class) || (sock == true)) {
/* Use the type of process. */
newcontext.type = scontext->type;
} else {
/* Use the type of the related object. */
newcontext.type = tcontext->type;
}
}
/* Look for a type transition/member/change rule. */
avkey.source_type = scontext->type;
avkey.target_type = tcontext->type;
avkey.target_class = tclass;
avkey.specified = specified;
avdatum = avtab_search(&policydb->te_avtab, &avkey);
/* If no permanent rule, also check for enabled conditional rules */
if (!avdatum) {
node = avtab_search_node(&policydb->te_cond_avtab, &avkey);
for (; node; 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->u.data;
}
/* if we have a objname this is a file trans check so check those rules */
if (objname)
filename_compute_type(policydb, &newcontext, scontext->type,
tcontext->type, tclass, objname);
/* Check for class-specific changes. */
if (specified & AVTAB_TRANSITION) {
/* Look for a role transition rule. */
for (roletr = policydb->role_tr; roletr;
roletr = roletr->next) {
if ((roletr->role == scontext->role) &&
(roletr->type == tcontext->type) &&
(roletr->tclass == tclass)) {
/* Use the role transition rule. */
newcontext.role = roletr->new_role;
break;
}
}
}
/* Set the MLS attributes.
This is done last because it may allocate memory. */
rc = mls_compute_sid(policydb, scontext, tcontext, tclass, specified,
&newcontext, sock);
if (rc)
goto out_unlock;
/* Check the validity of the context. */
if (!policydb_context_isvalid(policydb, &newcontext)) {
rc = compute_sid_handle_invalid_context(state, 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:
read_unlock(&state->ss->policy_rwlock);
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(struct selinux_state *state,
u32 ssid, u32 tsid, u16 tclass,
const struct qstr *qstr, u32 *out_sid)
{
return security_compute_sid(state, ssid, tsid, tclass,
AVTAB_TRANSITION,
qstr ? qstr->name : NULL, out_sid, true);
}
int security_transition_sid_user(struct selinux_state *state,
u32 ssid, u32 tsid, u16 tclass,
const char *objname, u32 *out_sid)
{
return security_compute_sid(state, ssid, tsid, tclass,
AVTAB_TRANSITION,
objname, out_sid, false);
}
/**
* 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(struct selinux_state *state,
u32 ssid,
u32 tsid,
u16 tclass,
u32 *out_sid)
{
return security_compute_sid(state, ssid, tsid, tclass,
AVTAB_MEMBER, NULL,
out_sid, false);
}
/**
* 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(struct selinux_state *state,
u32 ssid,
u32 tsid,
u16 tclass,
u32 *out_sid)
{
return security_compute_sid(state,
ssid, tsid, tclass, AVTAB_CHANGE, NULL,
out_sid, false);
}
static inline int convert_context_handle_invalid_context(
struct selinux_state *state,
struct context *context)
{
struct policydb *policydb = &state->ss->policydb;
char *s;
u32 len;
if (enforcing_enabled(state))
return -EINVAL;
if (!context_struct_to_string(policydb, context, &s, &len)) {
pr_warn("SELinux: Context %s would be invalid if enforcing\n",
s);
kfree(s);
}
return 0;
}
struct convert_context_args {
struct selinux_state *state;
struct policydb *oldp;
struct policydb *newp;
};
/*
* Convert the values in the security context
* structure `oldc' from the values specified
* in the policy `p->oldp' to the values specified
* in the policy `p->newp', storing the new context
* in `newc'. Verify that the context is valid
* under the new policy.
*/
static int convert_context(struct context *oldc, struct context *newc, void *p)
{
struct convert_context_args *args;
struct ocontext *oc;
struct role_datum *role;
struct type_datum *typdatum;
struct user_datum *usrdatum;
char *s;
u32 len;
int rc;
args = p;
if (oldc->str) {
s = kstrdup(oldc->str, GFP_KERNEL);
if (!s)
return -ENOMEM;
rc = string_to_context_struct(args->newp, NULL, s,
newc, SECSID_NULL);
if (rc == -EINVAL) {
/*
* Retain string representation for later mapping.
*
* IMPORTANT: We need to copy the contents of oldc->str
* back into s again because string_to_context_struct()
* may have garbled it.
*/
memcpy(s, oldc->str, oldc->len);
context_init(newc);
newc->str = s;
newc->len = oldc->len;
return 0;
}
kfree(s);
if (rc) {
/* Other error condition, e.g. ENOMEM. */
pr_err("SELinux: Unable to map context %s, rc = %d.\n",
oldc->str, -rc);
return rc;
}
pr_info("SELinux: Context %s became valid (mapped).\n",
oldc->str);
return 0;
}
context_init(newc);
/* Convert the user. */
rc = -EINVAL;
usrdatum = hashtab_search(args->newp->p_users.table,
sym_name(args->oldp,
SYM_USERS, oldc->user - 1));
if (!usrdatum)
goto bad;
newc->user = usrdatum->value;
/* Convert the role. */
rc = -EINVAL;
role = hashtab_search(args->newp->p_roles.table,
sym_name(args->oldp, SYM_ROLES, oldc->role - 1));
if (!role)
goto bad;
newc->role = role->value;
/* Convert the type. */
rc = -EINVAL;
typdatum = hashtab_search(args->newp->p_types.table,
sym_name(args->oldp,
SYM_TYPES, oldc->type - 1));
if (!typdatum)
goto bad;
newc->type = typdatum->value;
/* Convert the MLS fields if dealing with MLS policies */
if (args->oldp->mls_enabled && args->newp->mls_enabled) {
rc = mls_convert_context(args->oldp, args->newp, oldc, newc);
if (rc)
goto bad;
} else if (!args->oldp->mls_enabled && args->newp->mls_enabled) {
/*
* Switching between non-MLS and MLS policy:
* ensure that the MLS fields of the context for all
* existing entries in the sidtab are filled in with a
* suitable default value, likely taken from one of the
* initial SIDs.
*/
oc = args->newp->ocontexts[OCON_ISID];
while (oc && oc->sid[0] != SECINITSID_UNLABELED)
oc = oc->next;
rc = -EINVAL;
if (!oc) {
pr_err("SELinux: unable to look up"
" the initial SIDs list\n");
goto bad;
}
rc = mls_range_set(newc, &oc->context[0].range);
if (rc)
goto bad;
}
/* Check the validity of the new context. */
if (!policydb_context_isvalid(args->newp, newc)) {
rc = convert_context_handle_invalid_context(args->state, oldc);
if (rc)
goto bad;
}
return 0;
bad:
/* Map old representation to string and save it. */
rc = context_struct_to_string(args->oldp, oldc, &s, &len);
if (rc)
return rc;
context_destroy(newc);
newc->str = s;
newc->len = len;
pr_info("SELinux: Context %s became invalid (unmapped).\n",
newc->str);
return 0;
}
static void security_load_policycaps(struct selinux_state *state)
{
struct policydb *p = &state->ss->policydb;
unsigned int i;
struct ebitmap_node *node;
for (i = 0; i < ARRAY_SIZE(state->policycap); i++)
state->policycap[i] = ebitmap_get_bit(&p->policycaps, i);
for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
pr_info("SELinux: policy capability %s=%d\n",
selinux_policycap_names[i],
ebitmap_get_bit(&p->policycaps, i));
ebitmap_for_each_positive_bit(&p->policycaps, node, i) {
if (i >= ARRAY_SIZE(selinux_policycap_names))
pr_info("SELinux: unknown policy capability %u\n",
i);
}
}
static int security_preserve_bools(struct selinux_state *state,
struct policydb *newpolicydb);
/**
* 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(struct selinux_state *state, void *data, size_t len)
{
struct policydb *policydb;
struct sidtab *oldsidtab, *newsidtab;
struct policydb *oldpolicydb, *newpolicydb;
struct selinux_mapping *oldmapping;
struct selinux_map newmap;
struct sidtab_convert_params convert_params;
struct convert_context_args args;
u32 seqno;
int rc = 0;
struct policy_file file = { data, len }, *fp = &file;
oldpolicydb = kcalloc(2, sizeof(*oldpolicydb), GFP_KERNEL);
if (!oldpolicydb) {
rc = -ENOMEM;
goto out;
}
newpolicydb = oldpolicydb + 1;
policydb = &state->ss->policydb;
newsidtab = kmalloc(sizeof(*newsidtab), GFP_KERNEL);
if (!newsidtab) {
rc = -ENOMEM;
goto out;
}
if (!state->initialized) {
rc = policydb_read(policydb, fp);
if (rc) {
kfree(newsidtab);
goto out;
}
policydb->len = len;
rc = selinux_set_mapping(policydb, secclass_map,
&state->ss->map);
if (rc) {
kfree(newsidtab);
policydb_destroy(policydb);
goto out;
}
rc = policydb_load_isids(policydb, newsidtab);
if (rc) {
kfree(newsidtab);
policydb_destroy(policydb);
goto out;
}
state->ss->sidtab = newsidtab;
security_load_policycaps(state);
state->initialized = 1;
seqno = ++state->ss->latest_granting;
selinux_complete_init();
avc_ss_reset(state->avc, seqno);
selnl_notify_policyload(seqno);
selinux_status_update_policyload(state, seqno);
selinux_netlbl_cache_invalidate();
selinux_xfrm_notify_policyload();
goto out;
}
rc = policydb_read(newpolicydb, fp);
if (rc) {
kfree(newsidtab);
goto out;
}
newpolicydb->len = len;
/* If switching between different policy types, log MLS status */
if (policydb->mls_enabled && !newpolicydb->mls_enabled)
pr_info("SELinux: Disabling MLS support...\n");
else if (!policydb->mls_enabled && newpolicydb->mls_enabled)
pr_info("SELinux: Enabling MLS support...\n");
rc = policydb_load_isids(newpolicydb, newsidtab);
if (rc) {
pr_err("SELinux: unable to load the initial SIDs\n");
policydb_destroy(newpolicydb);
kfree(newsidtab);
goto out;
}
rc = selinux_set_mapping(newpolicydb, secclass_map, &newmap);
if (rc)
goto err;
rc = security_preserve_bools(state, newpolicydb);
if (rc) {
pr_err("SELinux: unable to preserve booleans\n");
goto err;
}
oldsidtab = state->ss->sidtab;
/*
* Convert the internal representations of contexts
* in the new SID table.
*/
args.state = state;
args.oldp = policydb;
args.newp = newpolicydb;
convert_params.func = convert_context;
convert_params.args = &args;
convert_params.target = newsidtab;
rc = sidtab_convert(oldsidtab, &convert_params);
if (rc) {
pr_err("SELinux: unable to convert the internal"
" representation of contexts in the new SID"
" table\n");
goto err;
}
/* Save the old policydb and SID table to free later. */
memcpy(oldpolicydb, policydb, sizeof(*policydb));
/* Install the new policydb and SID table. */
write_lock_irq(&state->ss->policy_rwlock);
memcpy(policydb, newpolicydb, sizeof(*policydb));
state->ss->sidtab = newsidtab;
security_load_policycaps(state);
oldmapping = state->ss->map.mapping;
state->ss->map.mapping = newmap.mapping;
state->ss->map.size = newmap.size;
seqno = ++state->ss->latest_granting;
write_unlock_irq(&state->ss->policy_rwlock);
/* Free the old policydb and SID table. */
policydb_destroy(oldpolicydb);
sidtab_destroy(oldsidtab);
kfree(oldsidtab);
kfree(oldmapping);
avc_ss_reset(state->avc, seqno);
selnl_notify_policyload(seqno);
selinux_status_update_policyload(state, seqno);
selinux_netlbl_cache_invalidate();
selinux_xfrm_notify_policyload();
rc = 0;
goto out;
err:
kfree(newmap.mapping);
sidtab_destroy(newsidtab);
kfree(newsidtab);
policydb_destroy(newpolicydb);
out:
kfree(oldpolicydb);
return rc;
}
size_t security_policydb_len(struct selinux_state *state)
{
struct policydb *p = &state->ss->policydb;
size_t len;
read_lock(&state->ss->policy_rwlock);
len = p->len;
read_unlock(&state->ss->policy_rwlock);
return len;
}
/**
* security_port_sid - Obtain the SID for a port.
* @protocol: protocol number
* @port: port number
* @out_sid: security identifier
*/
int security_port_sid(struct selinux_state *state,
u8 protocol, u16 port, u32 *out_sid)
{
struct policydb *policydb;
struct sidtab *sidtab;
struct ocontext *c;
int rc = 0;
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
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:
read_unlock(&state->ss->policy_rwlock);
return rc;
}
/**
* security_pkey_sid - Obtain the SID for a pkey.
* @subnet_prefix: Subnet Prefix
* @pkey_num: pkey number
* @out_sid: security identifier
*/
int security_ib_pkey_sid(struct selinux_state *state,
u64 subnet_prefix, u16 pkey_num, u32 *out_sid)
{
struct policydb *policydb;
struct sidtab *sidtab;
struct ocontext *c;
int rc = 0;
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
c = policydb->ocontexts[OCON_IBPKEY];
while (c) {
if (c->u.ibpkey.low_pkey <= pkey_num &&
c->u.ibpkey.high_pkey >= pkey_num &&
c->u.ibpkey.subnet_prefix == subnet_prefix)
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_UNLABELED;
out:
read_unlock(&state->ss->policy_rwlock);
return rc;
}
/**
* security_ib_endport_sid - Obtain the SID for a subnet management interface.
* @dev_name: device name
* @port: port number
* @out_sid: security identifier
*/
int security_ib_endport_sid(struct selinux_state *state,
const char *dev_name, u8 port_num, u32 *out_sid)
{
struct policydb *policydb;
struct sidtab *sidtab;
struct ocontext *c;
int rc = 0;
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
c = policydb->ocontexts[OCON_IBENDPORT];
while (c) {
if (c->u.ibendport.port == port_num &&
!strncmp(c->u.ibendport.dev_name,
dev_name,
IB_DEVICE_NAME_MAX))
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_UNLABELED;
out:
read_unlock(&state->ss->policy_rwlock);
return rc;
}
/**
* security_netif_sid - Obtain the SID for a network interface.
* @name: interface name
* @if_sid: interface SID
*/
int security_netif_sid(struct selinux_state *state,
char *name, u32 *if_sid)
{
struct policydb *policydb;
struct sidtab *sidtab;
int rc = 0;
struct ocontext *c;
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
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:
read_unlock(&state->ss->policy_rwlock);
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(struct selinux_state *state,
u16 domain,
void *addrp,
u32 addrlen,
u32 *out_sid)
{
struct policydb *policydb;
struct sidtab *sidtab;
int rc;
struct ocontext *c;
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
switch (domain) {
case AF_INET: {
u32 addr;
rc = -EINVAL;
if (addrlen != sizeof(u32))
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:
rc = -EINVAL;
if (addrlen != sizeof(u64) * 2)
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:
rc = 0;
*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;
}
rc = 0;
out:
read_unlock(&state->ss->policy_rwlock);
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(struct selinux_state *state,
u32 fromsid,
char *username,
u32 **sids,
u32 *nel)
{
struct policydb *policydb;
struct sidtab *sidtab;
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 (!state->initialized)
goto out;
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
context_init(&usercon);
rc = -EINVAL;
fromcon = sidtab_search(sidtab, fromsid);
if (!fromcon)
goto out_unlock;
rc = -EINVAL;
user = hashtab_search(policydb->p_users.table, username);
if (!user)
goto out_unlock;
usercon.user = user->value;
rc = -ENOMEM;
mysids = kcalloc(maxnel, sizeof(*mysids), GFP_ATOMIC);
if (!mysids)
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(policydb, fromcon, user,
&usercon))
continue;
rc = sidtab_context_to_sid(sidtab, &usercon, &sid);
if (rc)
goto out_unlock;
if (mynel < maxnel) {
mysids[mynel++] = sid;
} else {
rc = -ENOMEM;
maxnel += SIDS_NEL;
mysids2 = kcalloc(maxnel, sizeof(*mysids2), GFP_ATOMIC);
if (!mysids2)
goto out_unlock;
memcpy(mysids2, mysids, mynel * sizeof(*mysids2));
kfree(mysids);
mysids = mysids2;
mysids[mynel++] = sid;
}
}
}
rc = 0;
out_unlock:
read_unlock(&state->ss->policy_rwlock);
if (rc || !mynel) {
kfree(mysids);
goto out;
}
rc = -ENOMEM;
mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL);
if (!mysids2) {
kfree(mysids);
goto out;
}
for (i = 0, j = 0; i < mynel; i++) {
struct av_decision dummy_avd;
rc = avc_has_perm_noaudit(state,
fromsid, mysids[i],
SECCLASS_PROCESS, /* kernel value */
PROCESS__TRANSITION, AVC_STRICT,
&dummy_avd);
if (!rc)
mysids2[j++] = mysids[i];
cond_resched();
}
rc = 0;
kfree(mysids);
*sids = mysids2;
*nel = j;
out:
return rc;
}
/**
* __security_genfs_sid - Helper to 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.
*
* The caller must acquire the policy_rwlock before calling this function.
*/
static inline int __security_genfs_sid(struct selinux_state *state,
const char *fstype,
char *path,
u16 orig_sclass,
u32 *sid)
{
struct policydb *policydb = &state->ss->policydb;
struct sidtab *sidtab = state->ss->sidtab;
int len;
u16 sclass;
struct genfs *genfs;
struct ocontext *c;
int rc, cmp = 0;
while (path[0] == '/' && path[1] == '/')
path++;
sclass = unmap_class(&state->ss->map, orig_sclass);
*sid = SECINITSID_UNLABELED;
for (genfs = policydb->genfs; genfs; genfs = genfs->next) {
cmp = strcmp(fstype, genfs->fstype);
if (cmp <= 0)
break;
}
rc = -ENOENT;
if (!genfs || cmp)
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;
}
rc = -ENOENT;
if (!c)
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];
rc = 0;
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
*
* Acquire policy_rwlock before calling __security_genfs_sid() and release
* it afterward.
*/
int security_genfs_sid(struct selinux_state *state,
const char *fstype,
char *path,
u16 orig_sclass,
u32 *sid)
{
int retval;
read_lock(&state->ss->policy_rwlock);
retval = __security_genfs_sid(state, fstype, path, orig_sclass, sid);
read_unlock(&state->ss->policy_rwlock);
return retval;
}
/**
* security_fs_use - Determine how to handle labeling for a filesystem.
* @sb: superblock in question
*/
int security_fs_use(struct selinux_state *state, struct super_block *sb)
{
struct policydb *policydb;
struct sidtab *sidtab;
int rc = 0;
struct ocontext *c;
struct superblock_security_struct *sbsec = sb->s_security;
const char *fstype = sb->s_type->name;
read_lock(&state->ss->policy_rwlock);
policydb = &state->ss->policydb;
sidtab = state->ss->sidtab;
c = policydb->ocontexts[OCON_FSUSE];
while (c) {
if (strcmp(fstype, c->u.name) == 0)
break;
c = c->next;
}
if (c) {