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authorStephen Smalley <stephen.smalley.work@gmail.com>2020-08-19 22:45:16 +0300
committerPaul Moore <paul@paul-moore.com>2020-08-25 15:34:47 +0300
commit1b8b31a2e6120b7b2bc99137c0ba1ae3e45dbd7d (patch)
tree7c263dfa7217f93b7b12ac5d1417d598ba874e36
parentc76a2f9ecdcb44cdcdb2de82e90d84283736aeb2 (diff)
downloadlinux-1b8b31a2e6120b7b2bc99137c0ba1ae3e45dbd7d.tar.xz
selinux: convert policy read-write lock to RCU
Convert the policy read-write lock to RCU. This is significantly simplified by the earlier work to encapsulate the policy data structures and refactor the policy load and boolean setting logic. Move the latest_granting sequence number into the selinux_policy structure so that it can be updated atomically with the policy. Since removing the policy rwlock and moving latest_granting reduces the selinux_ss structure to nothing more than a wrapper around the selinux_policy pointer, get rid of the extra layer of indirection. At present this change merely passes a hardcoded 1 to rcu_dereference_check() in the cases where we know we do not need to take rcu_read_lock(), with the preceding comment explaining why. Alternatively we could pass fsi->mutex down from selinuxfs and apply a lockdep check on it instead. Based in part on earlier attempts to convert the policy rwlock to RCU by Kaigai Kohei [1] and by Peter Enderborg [2]. [1] https://lore.kernel.org/selinux/6e2f9128-e191-ebb3-0e87-74bfccb0767f@tycho.nsa.gov/ [2] https://lore.kernel.org/selinux/20180530141104.28569-1-peter.enderborg@sony.com/ Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com> Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
-rw-r--r--security/selinux/hooks.c1
-rw-r--r--security/selinux/include/security.h5
-rw-r--r--security/selinux/ss/services.c487
-rw-r--r--security/selinux/ss/services.h5
4 files changed, 280 insertions, 218 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index e3fe5647a366..6f30ba1a38dc 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -7235,7 +7235,6 @@ static __init int selinux_init(void)
memset(&selinux_state, 0, sizeof(selinux_state));
enforcing_set(&selinux_state, selinux_enforcing_boot);
selinux_state.checkreqprot = selinux_checkreqprot_boot;
- selinux_ss_init(&selinux_state.ss);
selinux_avc_init(&selinux_state.avc);
mutex_init(&selinux_state.status_lock);
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index c68ed2beadff..505e51264d51 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -13,6 +13,7 @@
#include <linux/dcache.h>
#include <linux/magic.h>
#include <linux/types.h>
+#include <linux/rcupdate.h>
#include <linux/refcount.h>
#include <linux/workqueue.h>
#include "flask.h"
@@ -84,7 +85,6 @@ extern int selinux_enabled_boot;
#define POLICYDB_BOUNDS_MAXDEPTH 4
struct selinux_avc;
-struct selinux_ss;
struct selinux_policy;
struct selinux_state {
@@ -102,10 +102,9 @@ struct selinux_state {
struct mutex status_lock;
struct selinux_avc *avc;
- struct selinux_ss *ss;
+ struct selinux_policy __rcu *policy;
} __randomize_layout;
-void selinux_ss_init(struct selinux_ss **ss);
void selinux_avc_init(struct selinux_avc **avc);
extern struct selinux_state selinux_state;
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index a48fc1b337ba..838161462756 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -66,14 +66,6 @@
#include "audit.h"
#include "policycap_names.h"
-static struct selinux_ss selinux_ss;
-
-void selinux_ss_init(struct selinux_ss **ss)
-{
- rwlock_init(&selinux_ss.policy_rwlock);
- *ss = &selinux_ss;
-}
-
/* Forward declaration. */
static int context_struct_to_string(struct policydb *policydb,
struct context *context,
@@ -239,13 +231,15 @@ static void map_decision(struct selinux_map *map,
int security_mls_enabled(struct selinux_state *state)
{
int mls_enabled;
+ struct selinux_policy *policy;
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
- mls_enabled = state->ss->policy->policydb.mls_enabled;
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ mls_enabled = policy->policydb.mls_enabled;
+ rcu_read_unlock();
return mls_enabled;
}
@@ -717,13 +711,14 @@ static void context_struct_compute_av(struct policydb *policydb,
}
static int security_validtrans_handle_fail(struct selinux_state *state,
- struct sidtab_entry *oentry,
- struct sidtab_entry *nentry,
- struct sidtab_entry *tentry,
- u16 tclass)
+ struct selinux_policy *policy,
+ struct sidtab_entry *oentry,
+ struct sidtab_entry *nentry,
+ struct sidtab_entry *tentry,
+ u16 tclass)
{
- struct policydb *p = &state->ss->policy->policydb;
- struct sidtab *sidtab = state->ss->policy->sidtab;
+ struct policydb *p = &policy->policydb;
+ struct sidtab *sidtab = policy->sidtab;
char *o = NULL, *n = NULL, *t = NULL;
u32 olen, nlen, tlen;
@@ -751,6 +746,7 @@ static int security_compute_validatetrans(struct selinux_state *state,
u32 oldsid, u32 newsid, u32 tasksid,
u16 orig_tclass, bool user)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
struct sidtab_entry *oentry;
@@ -765,13 +761,14 @@ static int security_compute_validatetrans(struct selinux_state *state,
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
+ rcu_read_lock();
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
if (!user)
- tclass = unmap_class(&state->ss->policy->map, orig_tclass);
+ tclass = unmap_class(&policy->map, orig_tclass);
else
tclass = orig_tclass;
@@ -814,17 +811,18 @@ static int security_compute_validatetrans(struct selinux_state *state,
rc = -EPERM;
else
rc = security_validtrans_handle_fail(state,
- oentry,
- nentry,
- tentry,
- tclass);
+ policy,
+ oentry,
+ nentry,
+ tentry,
+ tclass);
goto out;
}
constraint = constraint->next;
}
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
@@ -856,6 +854,7 @@ int security_validate_transition(struct selinux_state *state,
int security_bounded_transition(struct selinux_state *state,
u32 old_sid, u32 new_sid)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
struct sidtab_entry *old_entry, *new_entry;
@@ -866,10 +865,10 @@ int security_bounded_transition(struct selinux_state *state,
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
rc = -EINVAL;
old_entry = sidtab_search_entry(sidtab, old_sid);
@@ -930,17 +929,20 @@ int security_bounded_transition(struct selinux_state *state,
kfree(old_name);
}
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
-static void avd_init(struct selinux_state *state, struct av_decision *avd)
+static void avd_init(struct selinux_policy *policy, struct av_decision *avd)
{
avd->allowed = 0;
avd->auditallow = 0;
avd->auditdeny = 0xffffffff;
- avd->seqno = state->ss->latest_granting;
+ if (policy)
+ avd->seqno = policy->latest_granting;
+ else
+ avd->seqno = 0;
avd->flags = 0;
}
@@ -1005,6 +1007,7 @@ void security_compute_xperms_decision(struct selinux_state *state,
u8 driver,
struct extended_perms_decision *xpermd)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
u16 tclass;
@@ -1021,12 +1024,13 @@ void security_compute_xperms_decision(struct selinux_state *state,
memset(xpermd->auditallow->p, 0, sizeof(xpermd->auditallow->p));
memset(xpermd->dontaudit->p, 0, sizeof(xpermd->dontaudit->p));
- read_lock(&state->ss->policy_rwlock);
+ rcu_read_lock();
if (!selinux_initialized(state))
goto allow;
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
scontext = sidtab_search(sidtab, ssid);
if (!scontext) {
@@ -1042,7 +1046,7 @@ void security_compute_xperms_decision(struct selinux_state *state,
goto out;
}
- tclass = unmap_class(&state->ss->policy->map, orig_tclass);
+ tclass = unmap_class(&policy->map, orig_tclass);
if (unlikely(orig_tclass && !tclass)) {
if (policydb->allow_unknown)
goto allow;
@@ -1074,7 +1078,7 @@ void security_compute_xperms_decision(struct selinux_state *state,
}
}
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return;
allow:
memset(xpermd->allowed->p, 0xff, sizeof(xpermd->allowed->p));
@@ -1099,19 +1103,21 @@ void security_compute_av(struct selinux_state *state,
struct av_decision *avd,
struct extended_perms *xperms)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
u16 tclass;
struct context *scontext = NULL, *tcontext = NULL;
- read_lock(&state->ss->policy_rwlock);
- avd_init(state, avd);
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ avd_init(policy, avd);
xperms->len = 0;
if (!selinux_initialized(state))
goto allow;
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
scontext = sidtab_search(sidtab, ssid);
if (!scontext) {
@@ -1131,7 +1137,7 @@ void security_compute_av(struct selinux_state *state,
goto out;
}
- tclass = unmap_class(&state->ss->policy->map, orig_tclass);
+ tclass = unmap_class(&policy->map, orig_tclass);
if (unlikely(orig_tclass && !tclass)) {
if (policydb->allow_unknown)
goto allow;
@@ -1139,10 +1145,10 @@ void security_compute_av(struct selinux_state *state,
}
context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
xperms);
- map_decision(&state->ss->policy->map, orig_tclass, avd,
+ map_decision(&policy->map, orig_tclass, avd,
policydb->allow_unknown);
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return;
allow:
avd->allowed = 0xffffffff;
@@ -1155,17 +1161,19 @@ void security_compute_av_user(struct selinux_state *state,
u16 tclass,
struct av_decision *avd)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
struct context *scontext = NULL, *tcontext = NULL;
- read_lock(&state->ss->policy_rwlock);
- avd_init(state, avd);
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ avd_init(policy, avd);
if (!selinux_initialized(state))
goto allow;
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
scontext = sidtab_search(sidtab, ssid);
if (!scontext) {
@@ -1194,7 +1202,7 @@ void security_compute_av_user(struct selinux_state *state,
context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
NULL);
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return;
allow:
avd->allowed = 0xffffffff;
@@ -1279,6 +1287,7 @@ static int sidtab_entry_to_string(struct policydb *p,
int security_sidtab_hash_stats(struct selinux_state *state, char *page)
{
+ struct selinux_policy *policy;
int rc;
if (!selinux_initialized(state)) {
@@ -1287,9 +1296,10 @@ int security_sidtab_hash_stats(struct selinux_state *state, char *page)
return -EINVAL;
}
- read_lock(&state->ss->policy_rwlock);
- rc = sidtab_hash_stats(state->ss->policy->sidtab, page);
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ rc = sidtab_hash_stats(policy->sidtab, page);
+ rcu_read_unlock();
return rc;
}
@@ -1306,6 +1316,7 @@ static int security_sid_to_context_core(struct selinux_state *state,
u32 *scontext_len, int force,
int only_invalid)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
struct sidtab_entry *entry;
@@ -1335,9 +1346,10 @@ static int security_sid_to_context_core(struct selinux_state *state,
"load_policy on unknown SID %d\n", __func__, sid);
return -EINVAL;
}
- read_lock(&state->ss->policy_rwlock);
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
if (force)
entry = sidtab_search_entry_force(sidtab, sid);
@@ -1356,7 +1368,7 @@ static int security_sid_to_context_core(struct selinux_state *state,
scontext_len);
out_unlock:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
@@ -1491,6 +1503,7 @@ static int security_context_to_sid_core(struct selinux_state *state,
u32 *sid, u32 def_sid, gfp_t gfp_flags,
int force)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
char *scontext2, *str = NULL;
@@ -1529,9 +1542,10 @@ static int security_context_to_sid_core(struct selinux_state *state,
if (!str)
goto out;
}
- read_lock(&state->ss->policy_rwlock);
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
rc = string_to_context_struct(policydb, sidtab, scontext2,
&context, def_sid);
if (rc == -EINVAL && force) {
@@ -1543,7 +1557,7 @@ static int security_context_to_sid_core(struct selinux_state *state,
rc = sidtab_context_to_sid(sidtab, &context, sid);
context_destroy(&context);
out_unlock:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
out:
kfree(scontext2);
kfree(str);
@@ -1613,13 +1627,14 @@ int security_context_to_sid_force(struct selinux_state *state,
static int compute_sid_handle_invalid_context(
struct selinux_state *state,
+ struct selinux_policy *policy,
struct sidtab_entry *sentry,
struct sidtab_entry *tentry,
u16 tclass,
struct context *newcontext)
{
- struct policydb *policydb = &state->ss->policy->policydb;
- struct sidtab *sidtab = state->ss->policy->sidtab;
+ struct policydb *policydb = &policy->policydb;
+ struct sidtab *sidtab = policy->sidtab;
char *s = NULL, *t = NULL, *n = NULL;
u32 slen, tlen, nlen;
struct audit_buffer *ab;
@@ -1686,6 +1701,7 @@ static int security_compute_sid(struct selinux_state *state,
u32 *out_sid,
bool kern)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
struct class_datum *cladatum = NULL;
@@ -1712,19 +1728,21 @@ static int security_compute_sid(struct selinux_state *state,
context_init(&newcontext);
- read_lock(&state->ss->policy_rwlock);
+ rcu_read_lock();
+
+ policy = rcu_dereference(state->policy);
if (kern) {
- tclass = unmap_class(&state->ss->policy->map, orig_tclass);
+ tclass = unmap_class(&policy->map, orig_tclass);
sock = security_is_socket_class(orig_tclass);
} else {
tclass = orig_tclass;
- sock = security_is_socket_class(map_class(&state->ss->policy->map,
+ sock = security_is_socket_class(map_class(&policy->map,
tclass));
}
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
sentry = sidtab_search_entry(sidtab, ssid);
if (!sentry) {
@@ -1844,15 +1862,16 @@ static int security_compute_sid(struct selinux_state *state,
/* Check the validity of the context. */
if (!policydb_context_isvalid(policydb, &newcontext)) {
- rc = compute_sid_handle_invalid_context(state, sentry, tentry,
- tclass, &newcontext);
+ rc = compute_sid_handle_invalid_context(state, policy, sentry,
+ tentry, 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);
+ rcu_read_unlock();
context_destroy(&newcontext);
out:
return rc;
@@ -1939,9 +1958,9 @@ int security_change_sid(struct selinux_state *state,
static inline int convert_context_handle_invalid_context(
struct selinux_state *state,
+ struct policydb *policydb,
struct context *context)
{
- struct policydb *policydb = &state->ss->policy->policydb;
char *s;
u32 len;
@@ -2073,7 +2092,9 @@ static int convert_context(struct context *oldc, struct context *newc, void *p)
/* Check the validity of the new context. */
if (!policydb_context_isvalid(args->newp, newc)) {
- rc = convert_context_handle_invalid_context(args->state, oldc);
+ rc = convert_context_handle_invalid_context(args->state,
+ args->oldp,
+ oldc);
if (rc)
goto bad;
}
@@ -2092,15 +2113,14 @@ bad:
return 0;
}
-static void security_load_policycaps(struct selinux_state *state)
+static void security_load_policycaps(struct selinux_state *state,
+ struct selinux_policy *policy)
{
struct policydb *p;
unsigned int i;
struct ebitmap_node *node;
- read_lock(&state->ss->policy_rwlock);
-
- p = &state->ss->policy->policydb;
+ p = &policy->policydb;
for (i = 0; i < ARRAY_SIZE(state->policycap); i++)
state->policycap[i] = ebitmap_get_bit(&p->policycaps, i);
@@ -2115,12 +2135,10 @@ static void security_load_policycaps(struct selinux_state *state)
pr_info("SELinux: unknown policy capability %u\n",
i);
}
-
- read_unlock(&state->ss->policy_rwlock);
}
-static int security_preserve_bools(struct selinux_state *state,
- struct policydb *newpolicydb);
+static int security_preserve_bools(struct selinux_policy *oldpolicy,
+ struct selinux_policy *newpolicy);
static void selinux_policy_free(struct selinux_policy *policy)
{
@@ -2134,10 +2152,26 @@ static void selinux_policy_free(struct selinux_policy *policy)
kfree(policy);
}
+static void selinux_policy_cond_free(struct selinux_policy *policy)
+{
+ cond_policydb_destroy_dup(&policy->policydb);
+ kfree(policy);
+}
+
void selinux_policy_cancel(struct selinux_state *state,
struct selinux_policy *policy)
{
- sidtab_cancel_convert(state->ss->policy->sidtab);
+ struct selinux_policy *oldpolicy;
+
+ /*
+ * NOTE: We do not need to take the rcu read lock
+ * around the code below because other policy-modifying
+ * operations are already excluded by selinuxfs via
+ * fsi->mutex.
+ */
+ oldpolicy = rcu_dereference_check(state->policy, 1);
+
+ sidtab_cancel_convert(oldpolicy->sidtab);
selinux_policy_free(policy);
}
@@ -2159,14 +2193,14 @@ void selinux_policy_commit(struct selinux_state *state,
u32 seqno;
/*
- * NOTE: We do not need to take the policy read-lock
+ * NOTE: We do not need to take the rcu read lock
* around the code below because other policy-modifying
* operations are already excluded by selinuxfs via
* fsi->mutex.
*/
+ oldpolicy = rcu_dereference_check(state->policy, 1);
/* If switching between different policy types, log MLS status */
- oldpolicy = state->ss->policy;
if (oldpolicy) {
if (oldpolicy->policydb.mls_enabled && !newpolicy->policydb.mls_enabled)
pr_info("SELinux: Disabling MLS support...\n");
@@ -2174,14 +2208,18 @@ void selinux_policy_commit(struct selinux_state *state,
pr_info("SELinux: Enabling MLS support...\n");
}
+ /* Set latest granting seqno for new policy. */
+ if (oldpolicy)
+ newpolicy->latest_granting = oldpolicy->latest_granting + 1;
+ else
+ newpolicy->latest_granting = 1;
+ seqno = newpolicy->latest_granting;
+
/* Install the new policy. */
- write_lock_irq(&state->ss->policy_rwlock);
- state->ss->policy = newpolicy;
- seqno = ++state->ss->latest_granting;
- write_unlock_irq(&state->ss->policy_rwlock);
+ rcu_assign_pointer(state->policy, newpolicy);
/* Load the policycaps from the new policy */
- security_load_policycaps(state);
+ security_load_policycaps(state, newpolicy);
if (!selinux_initialized(state)) {
/*
@@ -2194,6 +2232,7 @@ void selinux_policy_commit(struct selinux_state *state,
}
/* Free the old policy */
+ synchronize_rcu();
selinux_policy_free(oldpolicy);
/* Notify others of the policy change */
@@ -2213,7 +2252,7 @@ void selinux_policy_commit(struct selinux_state *state,
int security_load_policy(struct selinux_state *state, void *data, size_t len,
struct selinux_policy **newpolicyp)
{
- struct selinux_policy *newpolicy;
+ struct selinux_policy *newpolicy, *oldpolicy;
struct sidtab_convert_params convert_params;
struct convert_context_args args;
int rc = 0;
@@ -2250,8 +2289,16 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len,
return 0;
}
+ /*
+ * NOTE: We do not need to take the rcu read lock
+ * around the code below because other policy-modifying
+ * operations are already excluded by selinuxfs via
+ * fsi->mutex.
+ */
+ oldpolicy = rcu_dereference_check(state->policy, 1);
+
/* Preserve active boolean values from the old policy */
- rc = security_preserve_bools(state, &newpolicy->policydb);
+ rc = security_preserve_bools(oldpolicy, newpolicy);
if (rc) {
pr_err("SELinux: unable to preserve booleans\n");
goto err;
@@ -2260,21 +2307,16 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len,
/*
* Convert the internal representations of contexts
* in the new SID table.
- *
- * NOTE: We do not need to take the policy read-lock
- * around the code below because other policy-modifying
- * operations are already excluded by selinuxfs via
- * fsi->mutex.
*/
args.state = state;
- args.oldp = &state->ss->policy->policydb;
+ args.oldp = &oldpolicy->policydb;
args.newp = &newpolicy->policydb;
convert_params.func = convert_context;
convert_params.args = &args;
convert_params.target = newpolicy->sidtab;
- rc = sidtab_convert(state->ss->policy->sidtab, &convert_params);
+ rc = sidtab_convert(oldpolicy->sidtab, &convert_params);
if (rc) {
pr_err("SELinux: unable to convert the internal"
" representation of contexts in the new SID"
@@ -2291,14 +2333,16 @@ err:
size_t security_policydb_len(struct selinux_state *state)
{
+ struct selinux_policy *policy;
size_t len;
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
- len = state->ss->policy->policydb.len;
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ len = policy->policydb.len;
+ rcu_read_unlock();
return len;
}
@@ -2312,6 +2356,7 @@ size_t security_policydb_len(struct selinux_state *state)
int security_port_sid(struct selinux_state *state,
u8 protocol, u16 port, u32 *out_sid)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
struct ocontext *c;
@@ -2322,10 +2367,10 @@ int security_port_sid(struct selinux_state *state,
return 0;
}
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
c = policydb->ocontexts[OCON_PORT];
while (c) {
@@ -2349,7 +2394,7 @@ int security_port_sid(struct selinux_state *state,
}
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
@@ -2362,6 +2407,7 @@ out:
int security_ib_pkey_sid(struct selinux_state *state,
u64 subnet_prefix, u16 pkey_num, u32 *out_sid)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
struct ocontext *c;
@@ -2372,10 +2418,10 @@ int security_ib_pkey_sid(struct selinux_state *state,
return 0;
}
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
c = policydb->ocontexts[OCON_IBPKEY];
while (c) {
@@ -2400,7 +2446,7 @@ int security_ib_pkey_sid(struct selinux_state *state,
*out_sid = SECINITSID_UNLABELED;
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
@@ -2413,6 +2459,7 @@ out:
int security_ib_endport_sid(struct selinux_state *state,
const char *dev_name, u8 port_num, u32 *out_sid)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
struct ocontext *c;
@@ -2423,10 +2470,10 @@ int security_ib_endport_sid(struct selinux_state *state,
return 0;
}
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
c = policydb->ocontexts[OCON_IBENDPORT];
while (c) {
@@ -2451,7 +2498,7 @@ int security_ib_endport_sid(struct selinux_state *state,
*out_sid = SECINITSID_UNLABELED;
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
@@ -2463,6 +2510,7 @@ out:
int security_netif_sid(struct selinux_state *state,
char *name, u32 *if_sid)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
int rc = 0;
@@ -2473,10 +2521,10 @@ int security_netif_sid(struct selinux_state *state,
return 0;
}
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
c = policydb->ocontexts[OCON_NETIF];
while (c) {
@@ -2501,7 +2549,7 @@ int security_netif_sid(struct selinux_state *state,
*if_sid = SECINITSID_NETIF;
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
@@ -2531,6 +2579,7 @@ int security_node_sid(struct selinux_state *state,
u32 addrlen,
u32 *out_sid)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
int rc;
@@ -2541,10 +2590,10 @@ int security_node_sid(struct selinux_state *state,
return 0;
}
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
switch (domain) {
case AF_INET: {
@@ -2599,7 +2648,7 @@ int security_node_sid(struct selinux_state *state,
rc = 0;
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
@@ -2625,6 +2674,7 @@ int security_get_user_sids(struct selinux_state *state,
u32 **sids,
u32 *nel)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
struct context *fromcon, usercon;
@@ -2641,10 +2691,10 @@ int security_get_user_sids(struct selinux_state *state,
if (!selinux_initialized(state))
goto out;
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
context_init(&usercon);
@@ -2695,7 +2745,7 @@ int security_get_user_sids(struct selinux_state *state,
}
rc = 0;
out_unlock:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
if (rc || !mynel) {
kfree(mysids);
goto out;
@@ -2806,6 +2856,7 @@ int security_genfs_sid(struct selinux_state *state,
u16 orig_sclass,
u32 *sid)
{
+ struct selinux_policy *policy;
int retval;
if (!selinux_initialized(state)) {
@@ -2813,10 +2864,11 @@ int security_genfs_sid(struct selinux_state *state,
return 0;
}
- read_lock(&state->ss->policy_rwlock);
- retval = __security_genfs_sid(state->ss->policy,
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ retval = __security_genfs_sid(policy,
fstype, path, orig_sclass, sid);
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return retval;
}
@@ -2836,6 +2888,7 @@ int selinux_policy_genfs_sid(struct selinux_policy *policy,
*/
int security_fs_use(struct selinux_state *state, struct super_block *sb)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
int rc = 0;
@@ -2849,10 +2902,10 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb)
return 0;
}
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
c = policydb->ocontexts[OCON_FSUSE];
while (c) {
@@ -2871,7 +2924,7 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb)
}
sbsec->sid = c->sid[0];
} else {
- rc = __security_genfs_sid(state->ss->policy, fstype, "/",
+ rc = __security_genfs_sid(policy, fstype, "/",
SECCLASS_DIR, &sbsec->sid);
if (rc) {
sbsec->behavior = SECURITY_FS_USE_NONE;
@@ -2882,7 +2935,7 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb)
}
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
@@ -2949,23 +3002,22 @@ int security_set_bools(struct selinux_state *state, u32 len, int *values)
return -EINVAL;
/*
- * NOTE: We do not need to take the policy read-lock
+ * NOTE: We do not need to take the rcu read lock
* around the code below because other policy-modifying
* operations are already excluded by selinuxfs via
* fsi->mutex.
*/
+ oldpolicy = rcu_dereference_check(state->policy, 1);
+
/* Consistency check on number of booleans, should never fail */
- if (WARN_ON(len != state->ss->policy->policydb.p_bools.nprim))
+ if (WARN_ON(len != oldpolicy->policydb.p_bools.nprim))
return -EINVAL;
- newpolicy = kmemdup(state->ss->policy, sizeof(*newpolicy),
- GFP_KERNEL);
+ newpolicy = kmemdup(oldpolicy, sizeof(*newpolicy), GFP_KERNEL);
if (!newpolicy)
return -ENOMEM;
- oldpolicy = state->ss->policy;
-
/*
* Deep copy only the parts of the policydb that might be
* modified as a result of changing booleans.
@@ -2997,20 +3049,20 @@ int security_set_bools(struct selinux_state *state, u32 len, int *values)
/* Re-evaluate the conditional rules in the copy */
evaluate_cond_nodes(&newpolicy->policydb);
+ /* Set latest granting seqno for new policy */
+ newpolicy->latest_granting = oldpolicy->latest_granting + 1;
+ seqno = newpolicy->latest_granting;
+
/* Install the new policy */
- write_lock_irq(&state->ss->policy_rwlock);
- state->ss->policy = newpolicy;
- seqno = ++state->ss->latest_granting;
- write_unlock_irq(&state->ss->policy_rwlock);
+ rcu_assign_pointer(state->policy, newpolicy);
/*
* Free the conditional portions of the old policydb
- * that were copied for the new policy.
+ * that were copied for the new policy, and the oldpolicy
+ * structure itself but not what it references.
*/
- cond_policydb_destroy_dup(&oldpolicy->policydb);
-
- /* Free the old policy structure but not what it references. */
- kfree(oldpolicy);
+ synchronize_rcu();
+ selinux_policy_cond_free(oldpolicy);
/* Notify others of the policy change */
selinux_notify_policy_change(state, seqno);
@@ -3020,6 +3072,7 @@ int security_set_bools(struct selinux_state *state, u32 len, int *values)
int security_get_bool_value(struct selinux_state *state,
u32 index)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
int rc;
u32 len;
@@ -3027,9 +3080,9 @@ int security_get_bool_value(struct selinux_state *state,
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
rc = -EFAULT;
len = policydb->p_bools.nprim;
@@ -3038,29 +3091,28 @@ int security_get_bool_value(struct selinux_state *state,
rc = policydb->bool_val_to_struct[index]->state;
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
-static int security_preserve_bools(struct selinux_state *state,
- struct policydb *policydb)
+static int security_preserve_bools(struct selinux_policy *oldpolicy,
+ struct selinux_policy *newpolicy)
{
int rc, *bvalues = NULL;
char **bnames = NULL;
struct cond_bool_datum *booldatum;
u32 i, nbools = 0;
- read_lock(&state->ss->policy_rwlock);
- rc = security_get_bools(state->ss->policy, &nbools, &bnames, &bvalues);
- read_unlock(&state->ss->policy_rwlock);
+ rc = security_get_bools(oldpolicy, &nbools, &bnames, &bvalues);
if (rc)
goto out;
for (i = 0; i < nbools; i++) {
- booldatum = symtab_search(&policydb->p_bools, bnames[i]);
+ booldatum = symtab_search(&newpolicy->policydb.p_bools,
+ bnames[i]);
if (booldatum)
booldatum->state = bvalues[i];
}
- evaluate_cond_nodes(policydb);
+ evaluate_cond_nodes(&newpolicy->policydb);
out:
if (bnames) {
@@ -3079,6 +3131,7 @@ out:
int security_sid_mls_copy(struct selinux_state *state,
u32 sid, u32 mls_sid, u32 *new_sid)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
struct context *context1;
@@ -3096,10 +3149,10 @@ int security_sid_mls_copy(struct selinux_state *state,
context_init(&newcon);
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
if (!policydb->mls_enabled) {
*new_sid = sid;
@@ -3131,7 +3184,8 @@ int security_sid_mls_copy(struct selinux_state *state,
/* Check the validity of the new context. */
if (!policydb_context_isvalid(policydb, &newcon)) {
- rc = convert_context_handle_invalid_context(state, &newcon);
+ rc = convert_context_handle_invalid_context(state, policydb,
+ &newcon);
if (rc) {
if (!context_struct_to_string(policydb, &newcon, &s,
&len)) {
@@ -3152,7 +3206,7 @@ int security_sid_mls_copy(struct selinux_state *state,
}
rc = sidtab_context_to_sid(sidtab, &newcon, new_sid);
out_unlock:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
context_destroy(&newcon);
out:
return rc;
@@ -3183,6 +3237,7 @@ int security_net_peersid_resolve(struct selinux_state *state,
u32 xfrm_sid,
u32 *peer_sid)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
int rc;
@@ -3209,10 +3264,10 @@ int security_net_peersid_resolve(struct selinux_state *state,
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
/*
* We don't need to check initialized here since the only way both
@@ -3249,7 +3304,7 @@ int security_net_peersid_resolve(struct selinux_state *state,
* expressive */
*peer_sid = xfrm_sid;
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
@@ -3353,27 +3408,31 @@ err:
int security_get_reject_unknown(struct selinux_state *state)
{
+ struct selinux_policy *policy;
int value;
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
- value = state->ss->policy->policydb.reject_unknown;
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ value = policy->policydb.reject_unknown;
+ rcu_read_unlock();
return value;
}
int security_get_allow_unknown(struct selinux_state *state)
{
+ struct selinux_policy *policy;
int value;
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
- value = state->ss->policy->policydb.allow_unknown;
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ value = policy->policydb.allow_unknown;
+ rcu_read_unlock();
return value;
}
@@ -3390,14 +3449,16 @@ int security_get_allow_unknown(struct selinux_state *state)
int security_policycap_supported(struct selinux_state *state,
unsigned int req_cap)
{
+ struct selinux_policy *policy;
int rc;
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
- rc = ebitmap_get_bit(&state->ss->policy->policydb.policycaps, req_cap);
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ rc = ebitmap_get_bit(&policy->policydb.policycaps, req_cap);
+ rcu_read_unlock();
return rc;
}
@@ -3420,6 +3481,7 @@ void selinux_audit_rule_free(void *vrule)
int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
{
struct selinux_state *state = &selinux_state;
+ struct selinux_policy *policy;
struct policydb *policydb;
struct selinux_audit_rule *tmprule;
struct role_datum *roledatum;
@@ -3463,11 +3525,11 @@ int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
context_init(&tmprule->au_ctxt);
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
- tmprule->au_seqno = state->ss->latest_granting;
+ tmprule->au_seqno = policy->latest_granting;
switch (field) {
case AUDIT_SUBJ_USER:
@@ -3506,7 +3568,7 @@ int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
}
rc = 0;
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
if (rc) {
selinux_audit_rule_free(tmprule);
@@ -3546,6 +3608,7 @@ int selinux_audit_rule_known(struct audit_krule *rule)
int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
{
struct selinux_state *state = &selinux_state;
+ struct selinux_policy *policy;
struct context *ctxt;
struct mls_level *level;
struct selinux_audit_rule *rule = vrule;
@@ -3559,14 +3622,16 @@ int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
+ rcu_read_lock();
+
+ policy = rcu_dereference(state->policy);
- if (rule->au_seqno < state->ss->latest_granting) {
+ if (rule->au_seqno < policy->latest_granting) {
match = -ESTALE;
goto out;
}
- ctxt = sidtab_search(state->ss->policy->sidtab, sid);
+ ctxt = sidtab_search(policy->sidtab, sid);
if (unlikely(!ctxt)) {
WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",
sid);
@@ -3650,7 +3715,7 @@ int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
}
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return match;
}
@@ -3728,6 +3793,7 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state,
struct netlbl_lsm_secattr *secattr,
u32 *sid)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
struct sidtab *sidtab;
int rc;
@@ -3739,10 +3805,10 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state,
return 0;
}
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
- sidtab = state->ss->policy->sidtab;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
+ sidtab = policy->sidtab;
if (secattr->flags & NETLBL_SECATTR_CACHE)
*sid = *(u32 *)secattr->cache->data;
@@ -3778,12 +3844,12 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state,
} else
*sid = SECSID_NULL;
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return 0;
out_free:
ebitmap_destroy(&ctx_new.range.level[0].cat);
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
@@ -3800,6 +3866,7 @@ out:
int security_netlbl_sid_to_secattr(struct selinux_state *state,
u32 sid, struct netlbl_lsm_secattr *secattr)
{
+ struct selinux_policy *policy;
struct policydb *policydb;
int rc;
struct context *ctx;
@@ -3807,12 +3874,12 @@ int security_netlbl_sid_to_secattr(struct selinux_state *state,
if (!selinux_initialized(state))
return 0;
- read_lock(&state->ss->policy_rwlock);
-
- policydb = &state->ss->policy->policydb;
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ policydb = &policy->policydb;
rc = -ENOENT;
- ctx = sidtab_search(state->ss->policy->sidtab, sid);
+ ctx = sidtab_search(policy->sidtab, sid);
if (ctx == NULL)
goto out;
@@ -3827,7 +3894,7 @@ int security_netlbl_sid_to_secattr(struct selinux_state *state,
mls_export_netlbl_lvl(policydb, ctx, secattr);
rc = mls_export_netlbl_cat(policydb, ctx, secattr);
out:
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_unlock();
return rc;
}
#endif /* CONFIG_NETLABEL */
@@ -3841,6 +3908,7 @@ out:
int security_read_policy(struct selinux_state *state,
void **data, size_t *len)
{
+ struct selinux_policy *policy;
int rc;
struct policy_file fp;
@@ -3856,9 +3924,10 @@ int security_read_policy(struct selinux_state *state,
fp.data = *data;
fp.len = *len;
- read_lock(&state->ss->policy_rwlock);
- rc = policydb_write(&state->ss->policy->policydb, &fp);
- read_unlock(&state->ss->policy_rwlock);
+ rcu_read_lock();
+ policy = rcu_dereference(state->policy);
+ rc = policydb_write(&policy->policydb, &fp);
+ rcu_read_unlock();
if (rc)
return rc;
diff --git a/security/selinux/ss/services.h b/security/selinux/ss/services.h
index 06931e34cb24..9555ad074303 100644
--- a/security/selinux/ss/services.h
+++ b/security/selinux/ss/services.h
@@ -26,12 +26,7 @@ struct selinux_policy {
struct sidtab *sidtab;
struct policydb policydb;
struct selinux_map map;
-};
-
-struct selinux_ss {
- rwlock_t policy_rwlock;
u32 latest_granting;
- struct selinux_policy *policy;
} __randomize_layout;
void services_compute_xperms_drivers(struct extended_perms *xperms,