selinux: move context hashing under sidtab

Now that context hash computation no longer depends on policydb, we can
simplify things by moving the context hashing completely under sidtab.
The hash is still cached in sidtab entries, but not for the in-flight
context structures.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/selinux/ss/context.h b/security/selinux/ss/context.h
index e7ae7e21449b8f97f5c84753d8831f4771f161c6..62990aa1ec9e7178a046a1de5067f35a61629983 100644 (file)
--- a/security/selinux/ss/context.h
+++ b/security/selinux/ss/context.h
@@ -31,7 +31,6 @@ struct context {
        u32 len;        /* length of string in bytes */
        struct mls_range range;
        char *str;      /* string representation if context cannot be mapped. */
-       u32 hash;       /* a hash of the string representation */
 };
 
 static inline void mls_context_init(struct context *c)
@@ -169,13 +168,12 @@ static inline int context_cpy(struct context *dst, struct context *src)
                kfree(dst->str);
                return rc;
        }
-       dst->hash = src->hash;
        return 0;
 }
 
 static inline void context_destroy(struct context *c)
 {
-       c->user = c->role = c->type = c->hash = 0;
+       c->user = c->role = c->type = 0;
        kfree(c->str);
        c->str = NULL;
        c->len = 0;
@@ -184,8 +182,6 @@ static inline void context_destroy(struct context *c)
 
 static inline int context_cmp(struct context *c1, struct context *c2)
 {
-       if (c1->hash && c2->hash && (c1->hash != c2->hash))
-               return 0;
        if (c1->len && c2->len)
                return (c1->len == c2->len && !strcmp(c1->str, c2->str));
        if (c1->len || c2->len)
@@ -198,10 +194,5 @@ static inline int context_cmp(struct context *c1, struct context *c2)
 
 u32 context_compute_hash(const struct context *c);
 
-static inline void context_add_hash(struct context *context)
-{
-       context->hash = context_compute_hash(context);
-}
-
 #endif /* _SS_CONTEXT_H_ */
 

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 2849bc362828c4379657d2039e06fb7c378b4620..dc6729860bd6e8940b2f2a5a987354a77f6b1a8c 100644 (file)
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -862,8 +862,6 @@ int policydb_load_isids(struct policydb *p, struct sidtab *s)
                if (!name)
                        continue;
 
-               context_add_hash(&c->context[0]);
-
                rc = sidtab_set_initial(s, sid, &c->context[0]);
                if (rc) {
                        pr_err("SELinux:  unable to load initial SID %s.\n",

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index ed330691430978ba685d18d0cf394591efcd8cef..b49a336b1e6e3c5a68d0a0501dcb299c62460699 100644 (file)
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -1490,17 +1490,6 @@ out:
        return rc;
 }
 
-static int context_struct_to_sid(struct selinux_state *state,
-                                struct context *context, u32 *sid)
-{
-       struct sidtab *sidtab = state->ss->sidtab;
-
-       if (!context->hash)
-               context_add_hash(context);
-
-       return sidtab_context_to_sid(sidtab, context, sid);
-}
-
 static int security_context_to_sid_core(struct selinux_state *state,
                                        const char *scontext, u32 scontext_len,
                                        u32 *sid, u32 def_sid, gfp_t gfp_flags,
@@ -1555,7 +1544,7 @@ static int security_context_to_sid_core(struct selinux_state *state,
                str = NULL;
        } else if (rc)
                goto out_unlock;
-       rc = context_struct_to_sid(state, &context, sid);
+       rc = sidtab_context_to_sid(sidtab, &context, sid);
        context_destroy(&context);
 out_unlock:
        read_unlock(&state->ss->policy_rwlock);
@@ -1865,7 +1854,7 @@ static int security_compute_sid(struct selinux_state *state,
                        goto out_unlock;
        }
        /* Obtain the sid for the context. */
-       rc = context_struct_to_sid(state, &newcontext, out_sid);
+       rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid);
 out_unlock:
        read_unlock(&state->ss->policy_rwlock);
        context_destroy(&newcontext);
@@ -2017,7 +2006,6 @@ static int convert_context(struct context *oldc, struct context *newc, void *p)
                        context_init(newc);
                        newc->str = s;
                        newc->len = oldc->len;
-                       newc->hash = oldc->hash;
                        return 0;
                }
                kfree(s);
@@ -2094,8 +2082,6 @@ static int convert_context(struct context *oldc, struct context *newc, void *p)
                        goto bad;
        }
 
-       context_add_hash(newc);
-
        return 0;
 bad:
        /* Map old representation to string and save it. */
@@ -2105,7 +2091,6 @@ bad:
        context_destroy(newc);
        newc->str = s;
        newc->len = len;
-       context_add_hash(newc);
        pr_info("SELinux:  Context %s became invalid (unmapped).\n",
                newc->str);
        return 0;
@@ -2322,12 +2307,14 @@ int security_port_sid(struct selinux_state *state,
                      u8 protocol, u16 port, u32 *out_sid)
 {
        struct policydb *policydb;
+       struct sidtab *sidtab;
        struct ocontext *c;
        int rc = 0;
 
        read_lock(&state->ss->policy_rwlock);
 
        policydb = &state->ss->policydb;
+       sidtab = state->ss->sidtab;
 
        c = policydb->ocontexts[OCON_PORT];
        while (c) {
@@ -2340,7 +2327,7 @@ int security_port_sid(struct selinux_state *state,
 
        if (c) {
                if (!c->sid[0]) {
-                       rc = context_struct_to_sid(state, &c->context[0],
+                       rc = sidtab_context_to_sid(sidtab, &c->context[0],
                                                   &c->sid[0]);
                        if (rc)
                                goto out;
@@ -2365,12 +2352,14 @@ int security_ib_pkey_sid(struct selinux_state *state,
                         u64 subnet_prefix, u16 pkey_num, u32 *out_sid)
 {
        struct policydb *policydb;
+       struct sidtab *sidtab;
        struct ocontext *c;
        int rc = 0;
 
        read_lock(&state->ss->policy_rwlock);
 
        policydb = &state->ss->policydb;
+       sidtab = state->ss->sidtab;
 
        c = policydb->ocontexts[OCON_IBPKEY];
        while (c) {
@@ -2384,7 +2373,7 @@ int security_ib_pkey_sid(struct selinux_state *state,
 
        if (c) {
                if (!c->sid[0]) {
-                       rc = context_struct_to_sid(state,
+                       rc = sidtab_context_to_sid(sidtab,
                                                   &c->context[0],
                                                   &c->sid[0]);
                        if (rc)
@@ -2409,12 +2398,14 @@ int security_ib_endport_sid(struct selinux_state *state,
                            const char *dev_name, u8 port_num, u32 *out_sid)
 {
        struct policydb *policydb;
+       struct sidtab *sidtab;
        struct ocontext *c;
        int rc = 0;
 
        read_lock(&state->ss->policy_rwlock);
 
        policydb = &state->ss->policydb;
+       sidtab = state->ss->sidtab;
 
        c = policydb->ocontexts[OCON_IBENDPORT];
        while (c) {
@@ -2429,7 +2420,7 @@ int security_ib_endport_sid(struct selinux_state *state,
 
        if (c) {
                if (!c->sid[0]) {
-                       rc = context_struct_to_sid(state, &c->context[0],
+                       rc = sidtab_context_to_sid(sidtab, &c->context[0],
                                                   &c->sid[0]);
                        if (rc)
                                goto out;
@@ -2452,12 +2443,14 @@ int security_netif_sid(struct selinux_state *state,
                       char *name, u32 *if_sid)
 {
        struct policydb *policydb;
+       struct sidtab *sidtab;
        int rc = 0;
        struct ocontext *c;
 
        read_lock(&state->ss->policy_rwlock);
 
        policydb = &state->ss->policydb;
+       sidtab = state->ss->sidtab;
 
        c = policydb->ocontexts[OCON_NETIF];
        while (c) {
@@ -2468,11 +2461,11 @@ int security_netif_sid(struct selinux_state *state,
 
        if (c) {
                if (!c->sid[0] || !c->sid[1]) {
-                       rc = context_struct_to_sid(state, &c->context[0],
+                       rc = sidtab_context_to_sid(sidtab, &c->context[0],
                                                   &c->sid[0]);
                        if (rc)
                                goto out;
-                       rc = context_struct_to_sid(state, &c->context[1],
+                       rc = sidtab_context_to_sid(sidtab, &c->context[1],
                                                   &c->sid[1]);
                        if (rc)
                                goto out;
@@ -2513,12 +2506,14 @@ int security_node_sid(struct selinux_state *state,
                      u32 *out_sid)
 {
        struct policydb *policydb;
+       struct sidtab *sidtab;
        int rc;
        struct ocontext *c;
 
        read_lock(&state->ss->policy_rwlock);
 
        policydb = &state->ss->policydb;
+       sidtab = state->ss->sidtab;
 
        switch (domain) {
        case AF_INET: {
@@ -2560,7 +2555,7 @@ int security_node_sid(struct selinux_state *state,
 
        if (c) {
                if (!c->sid[0]) {
-                       rc = context_struct_to_sid(state,
+                       rc = sidtab_context_to_sid(sidtab,
                                                   &c->context[0],
                                                   &c->sid[0]);
                        if (rc)
@@ -2644,17 +2639,12 @@ int security_get_user_sids(struct selinux_state *state,
                usercon.role = i + 1;
                ebitmap_for_each_positive_bit(&role->types, tnode, j) {
                        usercon.type = j + 1;
-                       /*
-                        * The same context struct is reused here so the hash
-                        * must be reset.
-                        */
-                       usercon.hash = 0;
 
                        if (mls_setup_user_range(policydb, fromcon, user,
                                                 &usercon))
                                continue;
 
-                       rc = context_struct_to_sid(state, &usercon, &sid);
+                       rc = sidtab_context_to_sid(sidtab, &usercon, &sid);
                        if (rc)
                                goto out_unlock;
                        if (mynel < maxnel) {
@@ -2725,6 +2715,7 @@ static inline int __security_genfs_sid(struct selinux_state *state,
                                       u32 *sid)
 {
        struct policydb *policydb = &state->ss->policydb;
+       struct sidtab *sidtab = state->ss->sidtab;
        int len;
        u16 sclass;
        struct genfs *genfs;
@@ -2759,7 +2750,7 @@ static inline int __security_genfs_sid(struct selinux_state *state,
                goto out;
 
        if (!c->sid[0]) {
-               rc = context_struct_to_sid(state, &c->context[0], &c->sid[0]);
+               rc = sidtab_context_to_sid(sidtab, &c->context[0], &c->sid[0]);
                if (rc)
                        goto out;
        }
@@ -2801,6 +2792,7 @@ int security_genfs_sid(struct selinux_state *state,
 int security_fs_use(struct selinux_state *state, struct super_block *sb)
 {
        struct policydb *policydb;
+       struct sidtab *sidtab;
        int rc = 0;
        struct ocontext *c;
        struct superblock_security_struct *sbsec = sb->s_security;
@@ -2809,6 +2801,7 @@ 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;
 
        c = policydb->ocontexts[OCON_FSUSE];
        while (c) {
@@ -2820,7 +2813,7 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb)
        if (c) {
                sbsec->behavior = c->v.behavior;
                if (!c->sid[0]) {
-                       rc = context_struct_to_sid(state, &c->context[0],
+                       rc = sidtab_context_to_sid(sidtab, &c->context[0],
                                                   &c->sid[0]);
                        if (rc)
                                goto out;
@@ -3068,7 +3061,7 @@ int security_sid_mls_copy(struct selinux_state *state,
                        goto out_unlock;
                }
        }
-       rc = context_struct_to_sid(state, &newcon, new_sid);
+       rc = sidtab_context_to_sid(sidtab, &newcon, new_sid);
 out_unlock:
        read_unlock(&state->ss->policy_rwlock);
        context_destroy(&newcon);
@@ -3661,7 +3654,7 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state,
                if (!mls_context_isvalid(policydb, &ctx_new))
                        goto out_free;
 
-               rc = context_struct_to_sid(state, &ctx_new, sid);
+               rc = sidtab_context_to_sid(sidtab, &ctx_new, sid);
                if (rc)
                        goto out_free;
 

diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
index 98d5ea3fcde4cdd27cc3b165721d240a7cf65ac4..eb6d27b5aeb45631057518f5329e6de5b2a5f1e3 100644 (file)
--- a/security/selinux/ss/sidtab.c
+++ b/security/selinux/ss/sidtab.c
@@ -54,14 +54,15 @@ int sidtab_init(struct sidtab *s)
        return 0;
 }
 
-static u32 context_to_sid(struct sidtab *s, struct context *context)
+static u32 context_to_sid(struct sidtab *s, struct context *context, u32 hash)
 {
        struct sidtab_entry *entry;
        u32 sid = 0;
 
        rcu_read_lock();
-       hash_for_each_possible_rcu(s->context_to_sid, entry, list,
-                                  context->hash) {
+       hash_for_each_possible_rcu(s->context_to_sid, entry, list, hash) {
+               if (entry->hash != hash)
+                       continue;
                if (context_cmp(&entry->context, context)) {
                        sid = entry->sid;
                        break;
@@ -74,6 +75,7 @@ static u32 context_to_sid(struct sidtab *s, struct context *context)
 int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context)
 {
        struct sidtab_isid_entry *isid;
+       u32 hash;
        int rc;
 
        if (sid == 0 || sid > SECINITSID_NUM)
@@ -90,15 +92,18 @@ int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context)
 #endif
        isid->set = 1;
 
+       hash = context_compute_hash(context);
+
        /*
         * Multiple initial sids may map to the same context. Check that this
         * context is not already represented in the context_to_sid hashtable
         * to avoid duplicate entries and long linked lists upon hash
         * collision.
         */
-       if (!context_to_sid(s, context)) {
+       if (!context_to_sid(s, context, hash)) {
                isid->entry.sid = sid;
-               hash_add(s->context_to_sid, &isid->entry.list, context->hash);
+               isid->entry.hash = hash;
+               hash_add(s->context_to_sid, &isid->entry.list, hash);
        }
 
        return 0;
@@ -259,12 +264,12 @@ int sidtab_context_to_sid(struct sidtab *s, struct context *context,
                          u32 *sid)
 {
        unsigned long flags;
-       u32 count;
+       u32 count, hash = context_compute_hash(context);
        struct sidtab_convert_params *convert;
        struct sidtab_entry *dst, *dst_convert;
        int rc;
 
-       *sid = context_to_sid(s, context);
+       *sid = context_to_sid(s, context, hash);
        if (*sid)
                return 0;
 
@@ -272,7 +277,7 @@ int sidtab_context_to_sid(struct sidtab *s, struct context *context,
        spin_lock_irqsave(&s->lock, flags);
 
        rc = 0;
-       *sid = context_to_sid(s, context);
+       *sid = context_to_sid(s, context, hash);
        if (*sid)
                goto out_unlock;
 
@@ -291,6 +296,7 @@ int sidtab_context_to_sid(struct sidtab *s, struct context *context,
                goto out_unlock;
 
        dst->sid = index_to_sid(count);
+       dst->hash = hash;
 
        rc = context_cpy(&dst->context, context);
        if (rc)
@@ -315,10 +321,11 @@ int sidtab_context_to_sid(struct sidtab *s, struct context *context,
                        goto out_unlock;
                }
                dst_convert->sid = index_to_sid(count);
+               dst_convert->hash = context_compute_hash(&dst_convert->context);
                convert->target->count = count + 1;
 
                hash_add_rcu(convert->target->context_to_sid,
-                            &dst_convert->list, dst_convert->context.hash);
+                            &dst_convert->list, dst_convert->hash);
        }
 
        if (context->len)
@@ -329,7 +336,7 @@ int sidtab_context_to_sid(struct sidtab *s, struct context *context,
 
        /* write entries before updating count */
        smp_store_release(&s->count, count + 1);
-       hash_add_rcu(s->context_to_sid, &dst->list, dst->context.hash);
+       hash_add_rcu(s->context_to_sid, &dst->list, dst->hash);
 
        rc = 0;
 out_unlock:
@@ -345,10 +352,9 @@ static void sidtab_convert_hashtable(struct sidtab *s, u32 count)
        for (i = 0; i < count; i++) {
                entry = sidtab_do_lookup(s, i, 0);
                entry->sid = index_to_sid(i);
+               entry->hash = context_compute_hash(&entry->context);
 
-               hash_add_rcu(s->context_to_sid, &entry->list,
-                            entry->context.hash);
-
+               hash_add_rcu(s->context_to_sid, &entry->list, entry->hash);
        }
 }
 

diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h
index 3311d9f236c00b9f4a5b144c791b674b86c6111f..f2a84560b8b3cc12b0c7e4fd3137849f29cacfc5 100644 (file)
--- a/security/selinux/ss/sidtab.h
+++ b/security/selinux/ss/sidtab.h
@@ -19,6 +19,7 @@
 
 struct sidtab_entry {
        u32 sid;
+       u32 hash;
        struct context context;
 #if CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0
        struct sidtab_str_cache __rcu *cache;