KEYS: Consolidate the concept of an 'index key' for key access

Consolidate the concept of an 'index key' for accessing keys.  The index key
is the search term needed to find a key directly - basically the key type and
the key description.  We can add to that the description length.

This will be useful when turning a keyring into an associative array rather
than just a pointer block.

Signed-off-by: David Howells <dhowells@redhat.com>

5 files changed, 83 insertions, 67 deletions

diff --git a/include/linux/key.h b/include/linux/key.h
index 51bce2950de4..d573e820a23d 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -82,6 +82,12 @@ struct key_owner;
 struct keyring_list;
 struct keyring_name;
 
+struct keyring_index_key {
+        struct key_type         *type;
+        const char              *description;
+        size_t                  desc_len;
+};
+
 /*****************************************************************************/
 /*
  * key reference with possession attribute handling
@@ -129,7 +135,6 @@ struct key {
                 struct list_head graveyard_link;
                 struct rb_node  serial_node;
         };
-        struct key_type         *type;          /* type of key */
         struct rw_semaphore     sem;            /* change vs change sem */
         struct key_user         *user;          /* owner of this key */
         void                    *security;      /* security data for this key */
@@ -163,12 +168,18 @@ struct key {
 #define KEY_FLAG_ROOT_CAN_CLEAR 6       /* set if key can be cleared by root without permission */
 #define KEY_FLAG_INVALIDATED    7       /* set if key has been invalidated */
 
-        /* the description string
-         * - this is used to match a key against search criteria
-         * - this should be a printable string
+        /* the key type and key description string
+         * - the desc is used to match a key against search criteria
+         * - it should be a printable string
          * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
          */
-        char                    *description;
+        union {
+                struct keyring_index_key index_key;
+                struct {
+                        struct key_type *type;          /* type of key */
+                        char            *description;
+                };
+        };
 
         /* type specific data
          * - this is used by the keyring type to index the name
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 490aef5ba34b..77441dd1f9d4 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -89,19 +89,17 @@ extern struct key_type *key_type_lookup(const char *type);
 extern void key_type_put(struct key_type *ktype);
 
 extern int __key_link_begin(struct key *keyring,
-                            const struct key_type *type,
-                            const char *description,
+                            const struct keyring_index_key *index_key,
                             unsigned long *_prealloc);
 extern int __key_link_check_live_key(struct key *keyring, struct key *key);
 extern void __key_link(struct key *keyring, struct key *key,
                        unsigned long *_prealloc);
 extern void __key_link_end(struct key *keyring,
-                           struct key_type *type,
+                           const struct keyring_index_key *index_key,
                            unsigned long prealloc);
 
 extern key_ref_t __keyring_search_one(key_ref_t keyring_ref,
-                                      const struct key_type *type,
-                                      const char *description,
+                                      const struct keyring_index_key *index_key,
                                       key_perm_t perm);
 
 extern struct key *keyring_search_instkey(struct key *keyring,
diff --git a/security/keys/key.c b/security/keys/key.c
index 8fb7c7bd4657..7e6bc396bb23 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -242,8 +242,8 @@ struct key *key_alloc(struct key_type *type, const char *desc,
                 }
         }
 
-        desclen = strlen(desc) + 1;
-        quotalen = desclen + type->def_datalen;
+        desclen = strlen(desc);
+        quotalen = desclen + 1 + type->def_datalen;
 
         /* get hold of the key tracking for this user */
         user = key_user_lookup(uid);
@@ -277,7 +277,8 @@ struct key *key_alloc(struct key_type *type, const char *desc,
                 goto no_memory_2;
 
         if (desc) {
-                key->description = kmemdup(desc, desclen, GFP_KERNEL);
+                key->index_key.desc_len = desclen;
+                key->index_key.description = kmemdup(desc, desclen + 1, GFP_KERNEL);
                 if (!key->description)
                         goto no_memory_3;
         }
@@ -285,7 +286,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
         atomic_set(&key->usage, 1);
         init_rwsem(&key->sem);
         lockdep_set_class(&key->sem, &type->lock_class);
-        key->type = type;
+        key->index_key.type = type;
         key->user = user;
         key->quotalen = quotalen;
         key->datalen = type->def_datalen;
@@ -489,8 +490,7 @@ int key_instantiate_and_link(struct key *key,
         }
 
         if (keyring) {
-                ret = __key_link_begin(keyring, key->type, key->description,
-                                       &prealloc);
+                ret = __key_link_begin(keyring, &key->index_key, &prealloc);
                 if (ret < 0)
                         goto error_free_preparse;
         }
@@ -499,7 +499,7 @@ int key_instantiate_and_link(struct key *key,
                                          &prealloc);
 
         if (keyring)
-                __key_link_end(keyring, key->type, prealloc);
+                __key_link_end(keyring, &key->index_key, prealloc);
 
 error_free_preparse:
         if (key->type->preparse)
@@ -548,8 +548,7 @@ int key_reject_and_link(struct key *key,
         ret = -EBUSY;
 
         if (keyring)
-                link_ret = __key_link_begin(keyring, key->type,
-                                            key->description, &prealloc);
+                link_ret = __key_link_begin(keyring, &key->index_key, &prealloc);
 
         mutex_lock(&key_construction_mutex);
 
@@ -581,7 +580,7 @@ int key_reject_and_link(struct key *key,
         mutex_unlock(&key_construction_mutex);
 
         if (keyring)
-                __key_link_end(keyring, key->type, prealloc);
+                __key_link_end(keyring, &key->index_key, prealloc);
 
         /* wake up anyone waiting for a key to be constructed */
         if (awaken)
@@ -780,25 +779,27 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
                                key_perm_t perm,
                                unsigned long flags)
 {
-        unsigned long prealloc;
+        struct keyring_index_key index_key = {
+                .description    = description,
+        };
         struct key_preparsed_payload prep;
         const struct cred *cred = current_cred();
-        struct key_type *ktype;
+        unsigned long prealloc;
         struct key *keyring, *key = NULL;
         key_ref_t key_ref;
         int ret;
 
         /* look up the key type to see if it's one of the registered kernel
          * types */
-        ktype = key_type_lookup(type);
-        if (IS_ERR(ktype)) {
+        index_key.type = key_type_lookup(type);
+        if (IS_ERR(index_key.type)) {
                 key_ref = ERR_PTR(-ENODEV);
                 goto error;
         }
 
         key_ref = ERR_PTR(-EINVAL);
-        if (!ktype->match || !ktype->instantiate ||
-            (!description && !ktype->preparse))
+        if (!index_key.type->match || !index_key.type->instantiate ||
+            (!index_key.description && !index_key.type->preparse))
                 goto error_put_type;
 
         keyring = key_ref_to_ptr(keyring_ref);
@@ -812,21 +813,22 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
         memset(&prep, 0, sizeof(prep));
         prep.data = payload;
         prep.datalen = plen;
-        prep.quotalen = ktype->def_datalen;
-        if (ktype->preparse) {
-                ret = ktype->preparse(&prep);
+        prep.quotalen = index_key.type->def_datalen;
+        if (index_key.type->preparse) {
+                ret = index_key.type->preparse(&prep);
                 if (ret < 0) {
                         key_ref = ERR_PTR(ret);
                         goto error_put_type;
                 }
-                if (!description)
-                        description = prep.description;
+                if (!index_key.description)
+                        index_key.description = prep.description;
                 key_ref = ERR_PTR(-EINVAL);
-                if (!description)
+                if (!index_key.description)
                         goto error_free_prep;
         }
+        index_key.desc_len = strlen(index_key.description);
 
-        ret = __key_link_begin(keyring, ktype, description, &prealloc);
+        ret = __key_link_begin(keyring, &index_key, &prealloc);
         if (ret < 0) {
                 key_ref = ERR_PTR(ret);
                 goto error_free_prep;
@@ -844,9 +846,8 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
          * key of the same type and description in the destination keyring and
          * update that instead if possible
          */
-        if (ktype->update) {
-                key_ref = __keyring_search_one(keyring_ref, ktype, description,
-                                               0);
+        if (index_key.type->update) {
+                key_ref = __keyring_search_one(keyring_ref, &index_key, 0);
                 if (!IS_ERR(key_ref))
                         goto found_matching_key;
         }
@@ -856,16 +857,17 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
                 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
                 perm |= KEY_USR_VIEW;
 
-                if (ktype->read)
+                if (index_key.type->read)
                         perm |= KEY_POS_READ;
 
-                if (ktype == &key_type_keyring || ktype->update)
+                if (index_key.type == &key_type_keyring ||
+                    index_key.type->update)
                         perm |= KEY_POS_WRITE;
         }
 
         /* allocate a new key */
-        key = key_alloc(ktype, description, cred->fsuid, cred->fsgid, cred,
-                        perm, flags);
+        key = key_alloc(index_key.type, index_key.description,
+                        cred->fsuid, cred->fsgid, cred, perm, flags);
         if (IS_ERR(key)) {
                 key_ref = ERR_CAST(key);
                 goto error_link_end;
@@ -882,12 +884,12 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
         key_ref = make_key_ref(key, is_key_possessed(keyring_ref));
 
 error_link_end:
-        __key_link_end(keyring, ktype, prealloc);
+        __key_link_end(keyring, &index_key, prealloc);
 error_free_prep:
-        if (ktype->preparse)
-                ktype->free_preparse(&prep);
+        if (index_key.type->preparse)
+                index_key.type->free_preparse(&prep);
 error_put_type:
-        key_type_put(ktype);
+        key_type_put(index_key.type);
 error:
         return key_ref;
 
@@ -895,7 +897,7 @@ error:
         /* we found a matching key, so we're going to try to update it
          * - we can drop the locks first as we have the key pinned
          */
-        __key_link_end(keyring, ktype, prealloc);
+        __key_link_end(keyring, &index_key, prealloc);
 
         key_ref = __key_update(key_ref, &prep);
         goto error_free_prep;
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index f78406372ebe..c7f59f9dd7b6 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -538,8 +538,7 @@ EXPORT_SYMBOL(keyring_search);
  * to the returned key reference.
  */
 key_ref_t __keyring_search_one(key_ref_t keyring_ref,
-                               const struct key_type *ktype,
-                               const char *description,
+                               const struct keyring_index_key *index_key,
                                key_perm_t perm)
 {
         struct keyring_list *klist;
@@ -558,9 +557,9 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref,
                 smp_rmb();
                 for (loop = 0; loop < nkeys ; loop++) {
                         key = rcu_dereference(klist->keys[loop]);
-                        if (key->type == ktype &&
+                        if (key->type == index_key->type &&
                             (!key->type->match ||
-                             key->type->match(key, description)) &&
+                             key->type->match(key, index_key->description)) &&
                             key_permission(make_key_ref(key, possessed),
                                            perm) == 0 &&
                             !(key->flags & ((1 << KEY_FLAG_INVALIDATED) |
@@ -747,8 +746,8 @@ static void keyring_unlink_rcu_disposal(struct rcu_head *rcu)
 /*
  * Preallocate memory so that a key can be linked into to a keyring.
  */
-int __key_link_begin(struct key *keyring, const struct key_type *type,
-                     const char *description, unsigned long *_prealloc)
+int __key_link_begin(struct key *keyring, const struct keyring_index_key *index_key,
+                     unsigned long *_prealloc)
         __acquires(&keyring->sem)
         __acquires(&keyring_serialise_link_sem)
 {
@@ -759,7 +758,8 @@ int __key_link_begin(struct key *keyring, const struct key_type *type,
         size_t size;
         int loop, lru, ret;
 
-        kenter("%d,%s,%s,", key_serial(keyring), type->name, description);
+        kenter("%d,%s,%s,",
+               key_serial(keyring), index_key->type->name, index_key->description);
 
         if (keyring->type != &key_type_keyring)
                 return -ENOTDIR;
@@ -772,7 +772,7 @@ int __key_link_begin(struct key *keyring, const struct key_type *type,
 
         /* serialise link/link calls to prevent parallel calls causing a cycle
          * when linking two keyring in opposite orders */
-        if (type == &key_type_keyring)
+        if (index_key->type == &key_type_keyring)
                 down_write(&keyring_serialise_link_sem);
 
         klist = rcu_dereference_locked_keyring(keyring);
@@ -784,8 +784,8 @@ int __key_link_begin(struct key *keyring, const struct key_type *type,
                 for (loop = klist->nkeys - 1; loop >= 0; loop--) {
                         struct key *key = rcu_deref_link_locked(klist, loop,
                                                                 keyring);
-                        if (key->type == type &&
-                            strcmp(key->description, description) == 0) {
+                        if (key->type == index_key->type &&
+                            strcmp(key->description, index_key->description) == 0) {
                                 /* Found a match - we'll replace the link with
                                  * one to the new key.  We record the slot
                                  * position.
@@ -865,7 +865,7 @@ error_quota:
         key_payload_reserve(keyring,
                             keyring->datalen - KEYQUOTA_LINK_BYTES);
 error_sem:
-        if (type == &key_type_keyring)
+        if (index_key->type == &key_type_keyring)
                 up_write(&keyring_serialise_link_sem);
 error_krsem:
         up_write(&keyring->sem);
@@ -957,16 +957,17 @@ void __key_link(struct key *keyring, struct key *key,
  *
  * Must be called with __key_link_begin() having being called.
  */
-void __key_link_end(struct key *keyring, struct key_type *type,
+void __key_link_end(struct key *keyring,
+                    const struct keyring_index_key *index_key,
                     unsigned long prealloc)
         __releases(&keyring->sem)
         __releases(&keyring_serialise_link_sem)
 {
-        BUG_ON(type == NULL);
-        BUG_ON(type->name == NULL);
-        kenter("%d,%s,%lx", keyring->serial, type->name, prealloc);
+        BUG_ON(index_key->type == NULL);
+        BUG_ON(index_key->type->name == NULL);
+        kenter("%d,%s,%lx", keyring->serial, index_key->type->name, prealloc);
 
-        if (type == &key_type_keyring)
+        if (index_key->type == &key_type_keyring)
                 up_write(&keyring_serialise_link_sem);
 
         if (prealloc) {
@@ -1007,12 +1008,12 @@ int key_link(struct key *keyring, struct key *key)
         key_check(keyring);
         key_check(key);
 
-        ret = __key_link_begin(keyring, key->type, key->description, &prealloc);
+        ret = __key_link_begin(keyring, &key->index_key, &prealloc);
         if (ret == 0) {
                 ret = __key_link_check_live_key(keyring, key);
                 if (ret == 0)
                         __key_link(keyring, key, &prealloc);
-                __key_link_end(keyring, key->type, prealloc);
+                __key_link_end(keyring, &key->index_key, prealloc);
         }
 
         return ret;
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 172115b38054..586cb79ee82d 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -352,6 +352,11 @@ static int construct_alloc_key(struct key_type *type,
                                struct key_user *user,
                                struct key **_key)
 {
+        const struct keyring_index_key index_key = {
+                .type           = type,
+                .description    = description,
+                .desc_len       = strlen(description),
+        };
         const struct cred *cred = current_cred();
         unsigned long prealloc;
         struct key *key;
@@ -379,8 +384,7 @@ static int construct_alloc_key(struct key_type *type,
         set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
 
         if (dest_keyring) {
-                ret = __key_link_begin(dest_keyring, type, description,
-                                       &prealloc);
+                ret = __key_link_begin(dest_keyring, &index_key, &prealloc);
                 if (ret < 0)
                         goto link_prealloc_failed;
         }
@@ -400,7 +404,7 @@ static int construct_alloc_key(struct key_type *type,
 
         mutex_unlock(&key_construction_mutex);
         if (dest_keyring)
-                __key_link_end(dest_keyring, type, prealloc);
+                __key_link_end(dest_keyring, &index_key, prealloc);
         mutex_unlock(&user->cons_lock);
         *_key = key;
         kleave(" = 0 [%d]", key_serial(key));
@@ -416,7 +420,7 @@ key_already_present:
                 ret = __key_link_check_live_key(dest_keyring, key);
                 if (ret == 0)
                         __key_link(dest_keyring, key, &prealloc);
-                __key_link_end(dest_keyring, type, prealloc);
+                __key_link_end(dest_keyring, &index_key, prealloc);
                 if (ret < 0)
                         goto link_check_failed;
         }