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Commit 24ed7fda authored by Ondrej Mosnacek's avatar Ondrej Mosnacek Committed by Paul Moore
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selinux: use separate table for initial SID lookup 



This moves handling of initial SIDs into a separate table. Note that the
SIDs stored in the main table are now shifted by SECINITSID_NUM and
converted to/from the actual SIDs transparently by helper functions.

This change doesn't make much sense on its own, but it simplifies
further sidtab overhaul in a succeeding patch.

Signed-off-by: default avatarOndrej Mosnacek <omosnace@redhat.com>
Reviewed-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
[PM: fixed some checkpatch warnings on line length, whitespace]
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 89f5bebc

security/selinux/ss/policydb.c

+9 −1
Original line number Diff line number Diff line
@@ -909,13 +909,21 @@ int policydb_load_isids(struct policydb *p, struct sidtab *s) 
		if (!c->context[0].user) {

			pr_err("SELinux:  SID %s was never defined.\n",

				c->u.name);

			sidtab_destroy(s);

			goto out;

		}

		if (c->sid[0] == SECSID_NULL || c->sid[0] > SECINITSID_NUM) {

			pr_err("SELinux:  Initial SID %s out of range.\n",

				c->u.name);

			sidtab_destroy(s);

			goto out;

		}



		rc = sidtab_insert(s, c->sid[0], &c->context[0]);

		rc = sidtab_set_initial(s, c->sid[0], &c->context[0]);

		if (rc) {

			pr_err("SELinux:  unable to load initial SID %s.\n",

				c->u.name);

			sidtab_destroy(s);

			goto out;

		}

	}

security/selinux/ss/services.c

+50 −38
Original line number Diff line number Diff line
@@ -776,7 +776,7 @@ static int security_compute_validatetrans(struct selinux_state *state, 
	read_lock(&state->ss->policy_rwlock);



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	if (!user)

		tclass = unmap_class(&state->ss->map, orig_tclass);
@@ -876,7 +876,7 @@ int security_bounded_transition(struct selinux_state *state, 
	read_lock(&state->ss->policy_rwlock);



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	rc = -EINVAL;

	old_context = sidtab_search(sidtab, old_sid);
@@ -1034,7 +1034,7 @@ void security_compute_xperms_decision(struct selinux_state *state, 
		goto allow;



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	scontext = sidtab_search(sidtab, ssid);

	if (!scontext) {
@@ -1123,7 +1123,7 @@ void security_compute_av(struct selinux_state *state, 
		goto allow;



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	scontext = sidtab_search(sidtab, ssid);

	if (!scontext) {
@@ -1177,7 +1177,7 @@ void security_compute_av_user(struct selinux_state *state, 
		goto allow;



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	scontext = sidtab_search(sidtab, ssid);

	if (!scontext) {
@@ -1315,7 +1315,7 @@ static int security_sid_to_context_core(struct selinux_state *state, 
	}

	read_lock(&state->ss->policy_rwlock);

	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;

	if (force)

		context = sidtab_search_force(sidtab, sid);

	else
@@ -1483,7 +1483,7 @@ static int security_context_to_sid_core(struct selinux_state *state, 
	}

	read_lock(&state->ss->policy_rwlock);

	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;

	rc = string_to_context_struct(policydb, sidtab, scontext2,

				      &context, def_sid);

	if (rc == -EINVAL && force) {
@@ -1668,7 +1668,7 @@ static int security_compute_sid(struct selinux_state *state, 
	}



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	scontext = sidtab_search(sidtab, ssid);

	if (!scontext) {
@@ -1925,10 +1925,7 @@ static int convert_context(u32 key, 
	struct user_datum *usrdatum;

	char *s;

	u32 len;

	int rc = 0;



	if (key <= SECINITSID_NUM)

		goto out;

	int rc;



	args = p;
@@ -2090,9 +2087,8 @@ static int security_preserve_bools(struct selinux_state *state, 
int security_load_policy(struct selinux_state *state, void *data, size_t len)

{

	struct policydb *policydb;

	struct sidtab *sidtab;

	struct sidtab *oldsidtab, *newsidtab;

	struct policydb *oldpolicydb, *newpolicydb;

	struct sidtab oldsidtab, newsidtab;

	struct selinux_mapping *oldmapping;

	struct selinux_map newmap;

	struct convert_context_args args;
@@ -2108,27 +2104,37 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len) 
	newpolicydb = oldpolicydb + 1;



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;



	newsidtab = kmalloc(sizeof(*newsidtab), GFP_KERNEL);

	if (!newsidtab) {

		rc = -ENOMEM;

		goto out;

	}



	if (!state->initialized) {

		rc = policydb_read(policydb, fp);

		if (rc)

		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, sidtab);

		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;
@@ -2141,13 +2147,17 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len) 
		goto out;

	}



	oldsidtab = state->ss->sidtab;



#if 0

	sidtab_hash_eval(sidtab, "sids");

	sidtab_hash_eval(oldsidtab, "sids");

#endif



	rc = policydb_read(newpolicydb, fp);

	if (rc)

	if (rc) {

		kfree(newsidtab);

		goto out;

	}



	newpolicydb->len = len;

	/* If switching between different policy types, log MLS status */
@@ -2156,10 +2166,11 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len) 
	else if (!policydb->mls_enabled && newpolicydb->mls_enabled)

		pr_info("SELinux: Enabling MLS support...\n");



	rc = policydb_load_isids(newpolicydb, &newsidtab);

	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;

	}
@@ -2180,7 +2191,7 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len) 
	args.state = state;

	args.oldp = policydb;

	args.newp = newpolicydb;

	rc = sidtab_convert(sidtab, &newsidtab, convert_context, &args);

	rc = sidtab_convert(oldsidtab, newsidtab, convert_context, &args);

	if (rc) {

		pr_err("SELinux:  unable to convert the internal"

			" representation of contexts in the new SID"
@@ -2190,12 +2201,11 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len) 


	/* Save the old policydb and SID table to free later. */

	memcpy(oldpolicydb, policydb, sizeof(*policydb));

	sidtab_set(&oldsidtab, sidtab);



	/* Install the new policydb and SID table. */

	write_lock_irq(&state->ss->policy_rwlock);

	memcpy(policydb, newpolicydb, sizeof(*policydb));

	sidtab_set(sidtab, &newsidtab);

	state->ss->sidtab = newsidtab;

	security_load_policycaps(state);

	oldmapping = state->ss->map.mapping;

	state->ss->map.mapping = newmap.mapping;
@@ -2205,7 +2215,8 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len) 


	/* Free the old policydb and SID table. */

	policydb_destroy(oldpolicydb);

	sidtab_destroy(&oldsidtab);

	sidtab_destroy(oldsidtab);

	kfree(oldsidtab);

	kfree(oldmapping);



	avc_ss_reset(state->avc, seqno);
@@ -2219,7 +2230,8 @@ int security_load_policy(struct selinux_state *state, void *data, size_t len) 


err:

	kfree(newmap.mapping);

	sidtab_destroy(&newsidtab);

	sidtab_destroy(newsidtab);

	kfree(newsidtab);

	policydb_destroy(newpolicydb);



out:
@@ -2256,7 +2268,7 @@ int security_port_sid(struct selinux_state *state, 
	read_lock(&state->ss->policy_rwlock);



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	c = policydb->ocontexts[OCON_PORT];

	while (c) {
@@ -2302,7 +2314,7 @@ int security_ib_pkey_sid(struct selinux_state *state, 
	read_lock(&state->ss->policy_rwlock);



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	c = policydb->ocontexts[OCON_IBPKEY];

	while (c) {
@@ -2348,7 +2360,7 @@ int security_ib_endport_sid(struct selinux_state *state, 
	read_lock(&state->ss->policy_rwlock);



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	c = policydb->ocontexts[OCON_IBENDPORT];

	while (c) {
@@ -2394,7 +2406,7 @@ int security_netif_sid(struct selinux_state *state, 
	read_lock(&state->ss->policy_rwlock);



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	c = policydb->ocontexts[OCON_NETIF];

	while (c) {
@@ -2459,7 +2471,7 @@ int security_node_sid(struct selinux_state *state, 
	read_lock(&state->ss->policy_rwlock);



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	switch (domain) {

	case AF_INET: {
@@ -2559,7 +2571,7 @@ int security_get_user_sids(struct selinux_state *state, 
	read_lock(&state->ss->policy_rwlock);



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	context_init(&usercon);
@@ -2661,7 +2673,7 @@ static inline int __security_genfs_sid(struct selinux_state *state, 
				       u32 *sid)

{

	struct policydb *policydb = &state->ss->policydb;

	struct sidtab *sidtab = &state->ss->sidtab;

	struct sidtab *sidtab = state->ss->sidtab;

	int len;

	u16 sclass;

	struct genfs *genfs;
@@ -2747,7 +2759,7 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb) 
	read_lock(&state->ss->policy_rwlock);



	policydb = &state->ss->policydb;

	sidtab = &state->ss->sidtab;

	sidtab = state->ss->sidtab;



	c = policydb->ocontexts[OCON_FSUSE];

	while (c) {
@@ -2953,7 +2965,7 @@ int security_sid_mls_copy(struct selinux_state *state, 
			  u32 sid, u32 mls_sid, u32 *new_sid)

{

	struct policydb *policydb = &state->ss->policydb;

	struct sidtab *sidtab = &state->ss->sidtab;

	struct sidtab *sidtab = state->ss->sidtab;

	struct context *context1;

	struct context *context2;

	struct context newcon;
@@ -3044,7 +3056,7 @@ int security_net_peersid_resolve(struct selinux_state *state, 
				 u32 *peer_sid)

{

	struct policydb *policydb = &state->ss->policydb;

	struct sidtab *sidtab = &state->ss->sidtab;

	struct sidtab *sidtab = state->ss->sidtab;

	int rc;

	struct context *nlbl_ctx;

	struct context *xfrm_ctx;
@@ -3405,7 +3417,7 @@ int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule, 
		goto out;

	}



	ctxt = sidtab_search(&state->ss->sidtab, sid);

	ctxt = sidtab_search(state->ss->sidtab, sid);

	if (unlikely(!ctxt)) {

		WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",

			  sid);
@@ -3568,7 +3580,7 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state, 
				   u32 *sid)

{

	struct policydb *policydb = &state->ss->policydb;

	struct sidtab *sidtab = &state->ss->sidtab;

	struct sidtab *sidtab = state->ss->sidtab;

	int rc;

	struct context *ctx;

	struct context ctx_new;
@@ -3646,7 +3658,7 @@ int security_netlbl_sid_to_secattr(struct selinux_state *state, 
	read_lock(&state->ss->policy_rwlock);



	rc = -ENOENT;

	ctx = sidtab_search(&state->ss->sidtab, sid);

	ctx = sidtab_search(state->ss->sidtab, sid);

	if (ctx == NULL)

		goto out;

security/selinux/ss/services.h

+1 −1
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ struct selinux_map { 
};



struct selinux_ss {

	struct sidtab sidtab;

	struct sidtab *sidtab;

	struct policydb policydb;

	rwlock_t policy_rwlock;

	u32 latest_granting;

security/selinux/ss/sidtab.c

+103 −65
Original line number Diff line number Diff line
@@ -22,16 +22,24 @@ int sidtab_init(struct sidtab *s) 
	s->htable = kmalloc_array(SIDTAB_SIZE, sizeof(*s->htable), GFP_ATOMIC);

	if (!s->htable)

		return -ENOMEM;



	for (i = 0; i < SECINITSID_NUM; i++)

		s->isids[i].set = 0;



	for (i = 0; i < SIDTAB_SIZE; i++)

		s->htable[i] = NULL;



	for (i = 0; i < SIDTAB_CACHE_LEN; i++)

		s->cache[i] = NULL;



	s->nel = 0;

	s->next_sid = 1;

	s->next_sid = 0;

	s->shutdown = 0;

	spin_lock_init(&s->lock);

	return 0;

}



int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)

static int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)

{

	int hvalue;

	struct sidtab_node *prev, *cur, *newnode;
@@ -76,34 +84,62 @@ int sidtab_insert(struct sidtab *s, u32 sid, struct context *context) 
	return 0;

}



static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force)

int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context)

{

	struct sidtab_isid_entry *entry;

	int rc;



	if (sid == 0 || sid > SECINITSID_NUM)

		return -EINVAL;



	entry = &s->isids[sid - 1];



	rc = context_cpy(&entry->context, context);

	if (rc)

		return rc;



	entry->set = 1;

	return 0;

}



static struct context *sidtab_lookup(struct sidtab *s, u32 sid)

{

	int hvalue;

	struct sidtab_node *cur;



	if (!s)

		return NULL;



	hvalue = SIDTAB_HASH(sid);

	cur = s->htable[hvalue];

	while (cur && sid > cur->sid)

		cur = cur->next;



	if (force && cur && sid == cur->sid && cur->context.len)

	if (!cur || sid != cur->sid)

		return NULL;



	return &cur->context;

}



	if (!cur || sid != cur->sid || cur->context.len) {

		/* Remap invalid SIDs to the unlabeled SID. */

		sid = SECINITSID_UNLABELED;

		hvalue = SIDTAB_HASH(sid);

		cur = s->htable[hvalue];

		while (cur && sid > cur->sid)

			cur = cur->next;

		if (!cur || sid != cur->sid)

static struct context *sidtab_lookup_initial(struct sidtab *s, u32 sid)

{

	return s->isids[sid - 1].set ? &s->isids[sid - 1].context : NULL;

}



static struct context *sidtab_search_core(struct sidtab *s, u32 sid, int force)

{

	struct context *context;



	if (!s)

		return NULL;



	if (sid != 0) {

		if (sid > SECINITSID_NUM)

			context = sidtab_lookup(s, sid - (SECINITSID_NUM + 1));

		else

			context = sidtab_lookup_initial(s, sid);

		if (context && (!context->len || force))

			return context;

	}



	return &cur->context;

	return sidtab_lookup_initial(s, SECINITSID_UNLABELED);

}



struct context *sidtab_search(struct sidtab *s, u32 sid)
@@ -145,11 +181,7 @@ static int sidtab_map(struct sidtab *s, 
static int clone_sid(u32 sid, struct context *context, void *arg)

{

	struct sidtab *s = arg;



	if (sid > SECINITSID_NUM)

	return sidtab_insert(s, sid, context);

	else

		return 0;

}



int sidtab_convert(struct sidtab *s, struct sidtab *news,
@@ -183,8 +215,8 @@ static void sidtab_update_cache(struct sidtab *s, struct sidtab_node *n, int loc 
	s->cache[0] = n;

}



static inline u32 sidtab_search_context(struct sidtab *s,

						  struct context *context)

static inline int sidtab_search_context(struct sidtab *s,

					struct context *context, u32 *sid)

{

	int i;

	struct sidtab_node *cur;
@@ -194,15 +226,17 @@ static inline u32 sidtab_search_context(struct sidtab *s, 
		while (cur) {

			if (context_cmp(&cur->context, context)) {

				sidtab_update_cache(s, cur, SIDTAB_CACHE_LEN - 1);

				return cur->sid;

				*sid = cur->sid;

				return 0;

			}

			cur = cur->next;

		}

	}

	return 0;

	return -ENOENT;

}



static inline u32 sidtab_search_cache(struct sidtab *s, struct context *context)

static inline int sidtab_search_cache(struct sidtab *s, struct context *context,

				      u32 *sid)

{

	int i;

	struct sidtab_node *node;
@@ -210,54 +244,69 @@ static inline u32 sidtab_search_cache(struct sidtab *s, struct context *context) 
	for (i = 0; i < SIDTAB_CACHE_LEN; i++) {

		node = s->cache[i];

		if (unlikely(!node))

			return 0;

			return -ENOENT;

		if (context_cmp(&node->context, context)) {

			sidtab_update_cache(s, node, i);

			return node->sid;

			*sid = node->sid;

			return 0;

		}

	}

	return 0;

	return -ENOENT;

}



int sidtab_context_to_sid(struct sidtab *s,

			  struct context *context,

			  u32 *out_sid)

static int sidtab_reverse_lookup(struct sidtab *s, struct context *context,

				 u32 *sid)

{

	u32 sid;

	int ret = 0;

	int ret;

	unsigned long flags;



	*out_sid = SECSID_NULL;



	sid  = sidtab_search_cache(s, context);

	if (!sid)

		sid = sidtab_search_context(s, context);

	if (!sid) {

	ret = sidtab_search_cache(s, context, sid);

	if (ret)

		ret = sidtab_search_context(s, context, sid);

	if (ret) {

		spin_lock_irqsave(&s->lock, flags);

		/* Rescan now that we hold the lock. */

		sid = sidtab_search_context(s, context);

		if (sid)

		ret = sidtab_search_context(s, context, sid);

		if (!ret)

			goto unlock_out;

		/* No SID exists for the context.  Allocate a new one. */

		if (s->next_sid == UINT_MAX || s->shutdown) {

		if (s->next_sid == (UINT_MAX - SECINITSID_NUM - 1) ||

		    s->shutdown) {

			ret = -ENOMEM;

			goto unlock_out;

		}

		sid = s->next_sid++;

		*sid = s->next_sid++;

		if (context->len)

			pr_info("SELinux:  Context %s is not valid (left unmapped).\n",

			       context->str);

		ret = sidtab_insert(s, sid, context);

		ret = sidtab_insert(s, *sid, context);

		if (ret)

			s->next_sid--;

unlock_out:

		spin_unlock_irqrestore(&s->lock, flags);

	}



	if (ret)

	return ret;

}



	*out_sid = sid;

int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid)

{

	int rc;

	u32 i;



	for (i = 0; i < SECINITSID_NUM; i++) {

		struct sidtab_isid_entry *entry = &s->isids[i];



		if (entry->set && context_cmp(context, &entry->context)) {

			*sid = i + 1;

			return 0;

		}

	}



	rc = sidtab_reverse_lookup(s, context, sid);

	if (rc)

		return rc;

	*sid += SECINITSID_NUM + 1;

	return 0;

}
@@ -296,6 +345,10 @@ void sidtab_destroy(struct sidtab *s) 
	if (!s)

		return;



	for (i = 0; i < SECINITSID_NUM; i++)

		if (s->isids[i].set)

			context_destroy(&s->isids[i].context);



	for (i = 0; i < SIDTAB_SIZE; i++) {

		cur = s->htable[i];

		while (cur) {
@@ -311,18 +364,3 @@ void sidtab_destroy(struct sidtab *s) 
	s->nel = 0;

	s->next_sid = 1;

}
 


void sidtab_set(struct sidtab *dst, struct sidtab *src)

{

	unsigned long flags;

	int i;



	spin_lock_irqsave(&src->lock, flags);

	dst->htable = src->htable;

	dst->nel = src->nel;

	dst->next_sid = src->next_sid;

	dst->shutdown = 0;

	for (i = 0; i < SIDTAB_CACHE_LEN; i++)

		dst->cache[i] = NULL;

	spin_unlock_irqrestore(&src->lock, flags);

}

security/selinux/ss/sidtab.h

+10 −5
Original line number Diff line number Diff line
@@ -22,6 +22,11 @@ struct sidtab_node { 


#define SIDTAB_SIZE SIDTAB_HASH_BUCKETS



struct sidtab_isid_entry {

	int set;

	struct context context;

};



struct sidtab {

	struct sidtab_node **htable;

	unsigned int nel;	/* number of elements */
@@ -30,10 +35,13 @@ struct sidtab { 
#define SIDTAB_CACHE_LEN	3

	struct sidtab_node *cache[SIDTAB_CACHE_LEN];

	spinlock_t lock;



	/* index == SID - 1 (no entry for SECSID_NULL) */

	struct sidtab_isid_entry isids[SECINITSID_NUM];

};



int sidtab_init(struct sidtab *s);

int sidtab_insert(struct sidtab *s, u32 sid, struct context *context);

int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context);

struct context *sidtab_search(struct sidtab *s, u32 sid);

struct context *sidtab_search_force(struct sidtab *s, u32 sid);
@@ -43,13 +51,10 @@ int sidtab_convert(struct sidtab *s, struct sidtab *news, 
				void *args),

		   void *args);



int sidtab_context_to_sid(struct sidtab *s,

			  struct context *context,

			  u32 *sid);

int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid);



void sidtab_hash_eval(struct sidtab *h, char *tag);

void sidtab_destroy(struct sidtab *s);

void sidtab_set(struct sidtab *dst, struct sidtab *src);



#endif	/* _SS_SIDTAB_H_ */