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: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
[PM: fixed some checkpatch warnings on line length, whitespace]
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index b63ef86..a50d625 100644 (file)
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -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;
                }
        }

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 0458f4c..4ff4b0e 100644 (file)
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -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;
 

diff --git a/security/selinux/ss/services.h b/security/selinux/ss/services.h
index 24c7bdc..9a36de8 100644 (file)
--- a/security/selinux/ss/services.h
+++ b/security/selinux/ss/services.h
@@ -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;

diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
index ccc0ea2..e44e7ce 100644 (file)
--- a/security/selinux/ss/sidtab.c
+++ b/security/selinux/ss/sidtab.c
@@ -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)
-               return &cur->context;
+       if (!cur || sid != cur->sid)
+               return NULL;
 
-       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)
-                       return NULL;
+       return &cur->context;
+}
+
+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 @@ out:
 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;
+       return sidtab_insert(s, sid, context);
 }
 
 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;
+       return ret;
+}
+
+int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid)
+{
+       int rc;
+       u32 i;
 
-       *out_sid = sid;
+       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);
-}

diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h
index e1d1f0b..e657ae6 100644 (file)
--- a/security/selinux/ss/sidtab.h
+++ b/security/selinux/ss/sidtab.h
@@ -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_ */