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selinux: allow MLS->non-MLS and vice versa upon policy reload 

Allow runtime switching between different policy types (e.g. from a MLS/MCS
policy to a non-MLS/non-MCS policy or viceversa).

Signed-off-by: Guido Trentalancia <guido@trentalancia.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Guido Trentalancia 2010-02-03 16:40:20 +01:00 committed by James Morris
parent 42596eafdd
commit 0719aaf5ea
9 changed files with 84 additions and 59 deletions
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3
security/selinux/include/security.h
View File

@ -57,7 +57,6 @@
struct netlbl_lsm_secattr;
extern int selinux_enabled;
extern int selinux_mls_enabled;
/* Policy capabilities */
enum {
@ -80,6 +79,8 @@ extern int selinux_policycap_openperm;
/* limitation of boundary depth */
#define POLICYDB_BOUNDS_MAXDEPTH 4
int security_mls_enabled(void);
int security_load_policy(void *data, size_t len);
int security_policycap_supported(unsigned int req_cap);

3
security/selinux/selinuxfs.c
View File

@ -282,7 +282,8 @@ static ssize_t sel_read_mls(struct file *filp, char __user *buf,
char tmpbuf[TMPBUFLEN];
ssize_t length;
length = scnprintf(tmpbuf, TMPBUFLEN, "%d", selinux_mls_enabled);
length = scnprintf(tmpbuf, TMPBUFLEN, "%d",
security_mls_enabled());
return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}

12
security/selinux/ss/context.h
View File

@ -41,9 +41,6 @@ static inline int mls_context_cpy(struct context *dst, struct context *src)
{
int rc;
if (!selinux_mls_enabled)
return 0;
dst->range.level[0].sens = src->range.level[0].sens;
rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat);
if (rc)
@ -64,9 +61,6 @@ static inline int mls_context_cpy_low(struct context *dst, struct context *src)
{
int rc;
if (!selinux_mls_enabled)
return 0;
dst->range.level[0].sens = src->range.level[0].sens;
rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat);
if (rc)
@ -82,9 +76,6 @@ out:
static inline int mls_context_cmp(struct context *c1, struct context *c2)
{
if (!selinux_mls_enabled)
return 1;
return ((c1->range.level[0].sens == c2->range.level[0].sens) &&
ebitmap_cmp(&c1->range.level[0].cat, &c2->range.level[0].cat) &&
(c1->range.level[1].sens == c2->range.level[1].sens) &&
@ -93,9 +84,6 @@ static inline int mls_context_cmp(struct context *c1, struct context *c2)
static inline void mls_context_destroy(struct context *c)
{
if (!selinux_mls_enabled)
return;
ebitmap_destroy(&c->range.level[0].cat);
ebitmap_destroy(&c->range.level[1].cat);
mls_context_init(c);

26
security/selinux/ss/mls.c
View File

@ -39,7 +39,7 @@ int mls_compute_context_len(struct context *context)
struct ebitmap *e;
struct ebitmap_node *node;
if (!selinux_mls_enabled)
if (!policydb.mls_enabled)
return 0;
len = 1; /* for the beginning ":" */
@ -93,7 +93,7 @@ void mls_sid_to_context(struct context *context,
struct ebitmap *e;
struct ebitmap_node *node;
if (!selinux_mls_enabled)
if (!policydb.mls_enabled)
return;
scontextp = *scontext;
@ -200,7 +200,7 @@ int mls_context_isvalid(struct policydb *p, struct context *c)
{
struct user_datum *usrdatum;
if (!selinux_mls_enabled)
if (!p->mls_enabled)
return 1;
if (!mls_range_isvalid(p, &c->range))
@ -253,7 +253,7 @@ int mls_context_to_sid(struct policydb *pol,
struct cat_datum *catdatum, *rngdatum;
int l, rc = -EINVAL;
if (!selinux_mls_enabled) {
if (!pol->mls_enabled) {
if (def_sid != SECSID_NULL && oldc)
*scontext += strlen(*scontext)+1;
return 0;
@ -387,7 +387,7 @@ int mls_from_string(char *str, struct context *context, gfp_t gfp_mask)
char *tmpstr, *freestr;
int rc;
if (!selinux_mls_enabled)
if (!policydb.mls_enabled)
return -EINVAL;
/* we need freestr because mls_context_to_sid will change
@ -407,7 +407,7 @@ int mls_from_string(char *str, struct context *context, gfp_t gfp_mask)
/*
* Copies the MLS range `range' into `context'.
*/
static inline int mls_range_set(struct context *context,
int mls_range_set(struct context *context,
struct mls_range *range)
{
int l, rc = 0;
@ -427,7 +427,7 @@ static inline int mls_range_set(struct context *context,
int mls_setup_user_range(struct context *fromcon, struct user_datum *user,
struct context *usercon)
{
if (selinux_mls_enabled) {
if (policydb.mls_enabled) {
struct mls_level *fromcon_sen = &(fromcon->range.level[0]);
struct mls_level *fromcon_clr = &(fromcon->range.level[1]);
struct mls_level *user_low = &(user->range.level[0]);
@ -477,7 +477,7 @@ int mls_convert_context(struct policydb *oldp,
struct ebitmap_node *node;
int l, i;
if (!selinux_mls_enabled)
if (!policydb.mls_enabled)
return 0;
for (l = 0; l < 2; l++) {
@ -516,7 +516,7 @@ int mls_compute_sid(struct context *scontext,
struct range_trans rtr;
struct mls_range *r;
if (!selinux_mls_enabled)
if (!policydb.mls_enabled)
return 0;
switch (specified) {
@ -559,7 +559,7 @@ int mls_compute_sid(struct context *scontext,
void mls_export_netlbl_lvl(struct context *context,
struct netlbl_lsm_secattr *secattr)
{
if (!selinux_mls_enabled)
if (!policydb.mls_enabled)
return;
secattr->attr.mls.lvl = context->range.level[0].sens - 1;
@ -579,7 +579,7 @@ void mls_export_netlbl_lvl(struct context *context,
void mls_import_netlbl_lvl(struct context *context,
struct netlbl_lsm_secattr *secattr)
{
if (!selinux_mls_enabled)
if (!policydb.mls_enabled)
return;
context->range.level[0].sens = secattr->attr.mls.lvl + 1;
@ -601,7 +601,7 @@ int mls_export_netlbl_cat(struct context *context,
{
int rc;
if (!selinux_mls_enabled)
if (!policydb.mls_enabled)
return 0;
rc = ebitmap_netlbl_export(&context->range.level[0].cat,
@ -629,7 +629,7 @@ int mls_import_netlbl_cat(struct context *context,
{
int rc;
if (!selinux_mls_enabled)
if (!policydb.mls_enabled)
return 0;
rc = ebitmap_netlbl_import(&context->range.level[0].cat,

2
security/selinux/ss/mls.h
View File

@ -39,6 +39,8 @@ int mls_context_to_sid(struct policydb *p,
int mls_from_string(char *str, struct context *context, gfp_t gfp_mask);
int mls_range_set(struct context *context, struct mls_range *range);
int mls_convert_context(struct policydb *oldp,
struct policydb *newp,
struct context *context);

7
security/selinux/ss/mls_types.h
View File

@ -15,6 +15,7 @@
#define _SS_MLS_TYPES_H_
#include "security.h"
#include "ebitmap.h"
struct mls_level {
u32 sens; /* sensitivity */
@ -27,18 +28,12 @@ struct mls_range {
static inline int mls_level_eq(struct mls_level *l1, struct mls_level *l2)
{
if (!selinux_mls_enabled)
return 1;
return ((l1->sens == l2->sens) &&
ebitmap_cmp(&l1->cat, &l2->cat));
}
static inline int mls_level_dom(struct mls_level *l1, struct mls_level *l2)
{
if (!selinux_mls_enabled)
return 1;
return ((l1->sens >= l2->sens) &&
ebitmap_contains(&l1->cat, &l2->cat));
}

24
security/selinux/ss/policydb.c
View File

@ -52,8 +52,6 @@ static char *symtab_name[SYM_NUM] = {
};
#endif
int selinux_mls_enabled;
static unsigned int symtab_sizes[SYM_NUM] = {
2,
32,
@ -455,7 +453,7 @@ static int policydb_index_others(struct policydb *p)
printk(KERN_DEBUG "SELinux: %d users, %d roles, %d types, %d bools",
p->p_users.nprim, p->p_roles.nprim, p->p_types.nprim, p->p_bools.nprim);
if (selinux_mls_enabled)
if (p->mls_enabled)
printk(", %d sens, %d cats", p->p_levels.nprim,
p->p_cats.nprim);
printk("\n");
@ -1717,14 +1715,12 @@ int policydb_read(struct policydb *p, void *fp)
int i, j, rc;
__le32 buf[4];
u32 nodebuf[8];
u32 len, len2, config, nprim, nel, nel2;
u32 len, len2, nprim, nel, nel2;
char *policydb_str;
struct policydb_compat_info *info;
struct range_trans *rt;
struct mls_range *r;
config = 0;
rc = policydb_init(p);
if (rc)
goto out;
@ -1772,7 +1768,7 @@ int policydb_read(struct policydb *p, void *fp)
kfree(policydb_str);
policydb_str = NULL;
/* Read the version, config, and table sizes. */
/* Read the version and table sizes. */
rc = next_entry(buf, fp, sizeof(u32)*4);
if (rc < 0)
goto bad;
@ -1787,13 +1783,7 @@ int policydb_read(struct policydb *p, void *fp)
}
if ((le32_to_cpu(buf[1]) & POLICYDB_CONFIG_MLS)) {
if (ss_initialized && !selinux_mls_enabled) {
printk(KERN_ERR "SELinux: Cannot switch between non-MLS"
" and MLS policies\n");
goto bad;
}
selinux_mls_enabled = 1;
config |= POLICYDB_CONFIG_MLS;
p->mls_enabled = 1;
if (p->policyvers < POLICYDB_VERSION_MLS) {
printk(KERN_ERR "SELinux: security policydb version %d "
@ -1801,12 +1791,6 @@ int policydb_read(struct policydb *p, void *fp)
p->policyvers);
goto bad;
}
} else {
if (ss_initialized && selinux_mls_enabled) {
printk(KERN_ERR "SELinux: Cannot switch between MLS and"
" non-MLS policies\n");
goto bad;
}
}
p->reject_unknown = !!(le32_to_cpu(buf[1]) & REJECT_UNKNOWN);
p->allow_unknown = !!(le32_to_cpu(buf[1]) & ALLOW_UNKNOWN);

4
security/selinux/ss/policydb.h
View File

@ -27,6 +27,8 @@
#include "symtab.h"
#include "avtab.h"
#include "sidtab.h"
#include "ebitmap.h"
#include "mls_types.h"
#include "context.h"
#include "constraint.h"
@ -185,6 +187,8 @@ struct genfs {
/* The policy database */
struct policydb {
int mls_enabled;
/* symbol tables */
struct symtab symtab[SYM_NUM];
#define p_commons symtab[SYM_COMMONS]

62
security/selinux/ss/services.c
View File

@ -26,6 +26,10 @@
*
* 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.
@ -232,6 +236,10 @@ static void map_decision(u16 tclass, struct av_decision *avd,
}
}
int security_mls_enabled(void)
{
return policydb.mls_enabled;
}
/*
* Return the boolean value of a constraint expression
@ -1550,6 +1558,8 @@ static int convert_context(u32 key,
{
struct convert_context_args *args;
struct context oldc;
struct ocontext *oc;
struct mls_range *range;
struct role_datum *role;
struct type_datum *typdatum;
struct user_datum *usrdatum;
@ -1620,9 +1630,39 @@ static int convert_context(u32 key,
goto bad;
c->type = typdatum->value;
rc = mls_convert_context(args->oldp, args->newp, c);
if (rc)
goto bad;
/* 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, c);
if (rc)
goto bad;
} else if (args->oldp->mls_enabled && !args->newp->mls_enabled) {
/*
* Switching between MLS and non-MLS policy:
* free any storage used by the MLS fields in the
* context for all existing entries in the sidtab.
*/
mls_context_destroy(c);
} 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;
if (!oc) {
printk(KERN_ERR "SELinux: unable to look up"
" the initial SIDs list\n");
goto bad;
}
range = &oc->context[0].range;
rc = mls_range_set(c, range);
if (rc)
goto bad;
}
/* Check the validity of the new context. */
if (!policydb_context_isvalid(args->newp, c)) {
@ -1718,6 +1758,12 @@ int security_load_policy(void *data, size_t len)
if (policydb_read(&newpolicydb, fp))
return -EINVAL;
/* If switching between different policy types, log MLS status */
if (policydb.mls_enabled && !newpolicydb.mls_enabled)
printk(KERN_INFO "SELinux: Disabling MLS support...\n");
else if (!policydb.mls_enabled && newpolicydb.mls_enabled)
printk(KERN_INFO "SELinux: Enabling MLS support...\n");
rc = policydb_load_isids(&newpolicydb, &newsidtab);
if (rc) {
printk(KERN_ERR "SELinux: unable to load the initial SIDs\n");
@ -1749,8 +1795,12 @@ int security_load_policy(void *data, size_t len)
args.oldp = &policydb;
args.newp = &newpolicydb;
rc = sidtab_map(&newsidtab, convert_context, &args);
if (rc)
if (rc) {
printk(KERN_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);
@ -2346,7 +2396,7 @@ int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid)
u32 len;
int rc = 0;
if (!ss_initialized || !selinux_mls_enabled) {
if (!ss_initialized || !policydb.mls_enabled) {
*new_sid = sid;
goto out;
}
@ -2447,7 +2497,7 @@ int security_net_peersid_resolve(u32 nlbl_sid, u32 nlbl_type,
/* 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) {
if (!policydb.mls_enabled) {
*peer_sid = SECSID_NULL;
return 0;
}