kfree_sensitive(mk);
}
+static void clear_mk_users(struct fscrypt_master_key *mk);
+
void fscrypt_put_master_key(struct fscrypt_master_key *mk)
{
if (!refcount_dec_and_test(&mk->mk_struct_refs))
return;
/*
- * No structural references left, so free ->mk_users, and also free the
+ * No structural references left, so clear ->mk_users, and also free the
* fscrypt_master_key struct itself after an RCU grace period ensures
* that concurrent keyring lookups can no longer find it.
*/
WARN_ON_ONCE(refcount_read(&mk->mk_active_refs) != 0);
- if (mk->mk_users) {
- /* Clear the keyring so the quota gets released right away. */
- keyring_clear(mk->mk_users);
- key_put(mk->mk_users);
- mk->mk_users = NULL;
- }
+ clear_mk_users(mk);
call_rcu(&mk->mk_rcu_head, fscrypt_free_master_key);
}
}
/*
- * Type of key in ->mk_users. Each key of this type represents a particular
- * user who has added a particular master key.
+ * Type of fscrypt_master_key_user::quota_key. This contains no secret; it
+ * exists solely to charge a user's key quota.
*
* Note that the name of this key type really should be something like
* ".fscrypt-user" instead of simply ".fscrypt". But the shorter name is chosen
.describe = fscrypt_user_key_describe,
};
-#define FSCRYPT_MK_USERS_DESCRIPTION_SIZE \
- (CONST_STRLEN("fscrypt-") + 2 * FSCRYPT_KEY_IDENTIFIER_SIZE + \
- CONST_STRLEN("-users") + 1)
-
#define FSCRYPT_MK_USER_DESCRIPTION_SIZE \
(2 * FSCRYPT_KEY_IDENTIFIER_SIZE + CONST_STRLEN(".uid.") + 10 + 1)
-static void format_mk_users_keyring_description(
- char description[FSCRYPT_MK_USERS_DESCRIPTION_SIZE],
- const u8 mk_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
-{
- sprintf(description, "fscrypt-%*phN-users",
- FSCRYPT_KEY_IDENTIFIER_SIZE, mk_identifier);
-}
-
-static void format_mk_user_description(
- char description[FSCRYPT_MK_USER_DESCRIPTION_SIZE],
- const u8 mk_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
-{
-
- sprintf(description, "%*phN.uid.%u", FSCRYPT_KEY_IDENTIFIER_SIZE,
- mk_identifier, __kuid_val(current_fsuid()));
-}
-
/* Create ->s_master_keys if needed. Synchronized by fscrypt_add_key_mutex. */
static int allocate_filesystem_keyring(struct super_block *sb)
{
return mk;
}
-static int allocate_master_key_users_keyring(struct fscrypt_master_key *mk)
-{
- char description[FSCRYPT_MK_USERS_DESCRIPTION_SIZE];
- struct key *keyring;
-
- format_mk_users_keyring_description(description,
- mk->mk_spec.u.identifier);
- keyring = keyring_alloc(description, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
- current_cred(), KEY_POS_SEARCH |
- KEY_USR_SEARCH | KEY_USR_READ | KEY_USR_VIEW,
- KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
- if (IS_ERR(keyring))
- return PTR_ERR(keyring);
-
- mk->mk_users = keyring;
- return 0;
-}
-
-/*
- * Find the current user's "key" in the master key's ->mk_users.
- * Returns ERR_PTR(-ENOKEY) if not found.
- */
-static struct key *find_master_key_user(struct fscrypt_master_key *mk)
+/* Find the current user's claim in ->mk_users. ->mk_sem must be held. */
+static struct fscrypt_master_key_user *
+find_master_key_user(struct fscrypt_master_key *mk)
{
- char description[FSCRYPT_MK_USER_DESCRIPTION_SIZE];
- key_ref_t keyref;
+ struct fscrypt_master_key_user *mk_user;
+ kuid_t uid = current_fsuid();
- format_mk_user_description(description, mk->mk_spec.u.identifier);
-
- /*
- * We need to mark the keyring reference as "possessed" so that we
- * acquire permission to search it, via the KEY_POS_SEARCH permission.
- */
- keyref = keyring_search(make_key_ref(mk->mk_users, true /*possessed*/),
- &key_type_fscrypt_user, description, false);
- if (IS_ERR(keyref)) {
- if (PTR_ERR(keyref) == -EAGAIN || /* not found */
- PTR_ERR(keyref) == -EKEYREVOKED) /* recently invalidated */
- keyref = ERR_PTR(-ENOKEY);
- return ERR_CAST(keyref);
+ list_for_each_entry(mk_user, &mk->mk_users, link) {
+ if (uid_eq(mk_user->uid, uid))
+ return mk_user;
}
- return key_ref_to_ptr(keyref);
+ return NULL;
}
/*
- * Give the current user a "key" in ->mk_users. This charges the user's quota
+ * Give the current user a claim in ->mk_users. This charges the user's quota
* and marks the master key as added by the current user, so that it cannot be
* removed by another user with the key. Either ->mk_sem must be held for
* write, or the master key must be still undergoing initialization.
*/
static int add_master_key_user(struct fscrypt_master_key *mk)
{
+ kuid_t uid = current_fsuid();
char description[FSCRYPT_MK_USER_DESCRIPTION_SIZE];
- struct key *mk_user;
+ struct key *quota_key;
+ struct fscrypt_master_key_user *mk_user;
int err;
- format_mk_user_description(description, mk->mk_spec.u.identifier);
- mk_user = key_alloc(&key_type_fscrypt_user, description,
- current_fsuid(), current_gid(), current_cred(),
- KEY_POS_SEARCH | KEY_USR_VIEW, 0, NULL);
- if (IS_ERR(mk_user))
- return PTR_ERR(mk_user);
+ snprintf(description, sizeof(description), "%*phN.uid.%u",
+ FSCRYPT_KEY_IDENTIFIER_SIZE, mk->mk_spec.u.identifier,
+ __kuid_val(uid));
+ quota_key = key_alloc(&key_type_fscrypt_user, description, uid,
+ current_gid(), current_cred(),
+ KEY_POS_SEARCH | KEY_USR_VIEW, 0, NULL);
+ if (IS_ERR(quota_key))
+ return PTR_ERR(quota_key);
+
+ err = key_instantiate_and_link(quota_key, NULL, 0, NULL, NULL);
+ if (err) {
+ key_put(quota_key);
+ return err;
+ }
- err = key_instantiate_and_link(mk_user, NULL, 0, mk->mk_users, NULL);
- key_put(mk_user);
- return err;
+ mk_user = kzalloc_obj(*mk_user);
+ if (!mk_user) {
+ key_put(quota_key);
+ return -ENOMEM;
+ }
+ mk_user->uid = uid;
+ mk_user->quota_key = quota_key;
+ list_add(&mk_user->link, &mk->mk_users);
+ return 0;
+}
+
+static void unlink_and_free_mk_user(struct fscrypt_master_key_user *mk_user)
+{
+ list_del(&mk_user->link);
+ key_put(mk_user->quota_key);
+ kfree(mk_user);
}
/*
- * Remove the current user's "key" from ->mk_users.
+ * Remove the current user's claim from ->mk_users.
* ->mk_sem must be held for write.
*
- * Returns 0 if removed, -ENOKEY if not found, or another -errno code.
+ * Returns 0 if removed or -ENOKEY if not found.
*/
static int remove_master_key_user(struct fscrypt_master_key *mk)
{
- struct key *mk_user;
- int err;
+ struct fscrypt_master_key_user *mk_user;
mk_user = find_master_key_user(mk);
- if (IS_ERR(mk_user))
- return PTR_ERR(mk_user);
- err = key_unlink(mk->mk_users, mk_user);
- key_put(mk_user);
- return err;
+ if (!mk_user)
+ return -ENOKEY;
+ unlink_and_free_mk_user(mk_user);
+ return 0;
+}
+
+/*
+ * Clear ->mk_users. Either ->mk_sem must be held for write, or 'mk' must have
+ * no structural references left.
+ */
+static void clear_mk_users(struct fscrypt_master_key *mk)
+{
+ struct fscrypt_master_key_user *mk_user, *tmp;
+
+ list_for_each_entry_safe(mk_user, tmp, &mk->mk_users, link)
+ unlink_and_free_mk_user(mk_user);
}
/*
refcount_set(&mk->mk_struct_refs, 1);
mk->mk_spec = *mk_spec;
+ INIT_LIST_HEAD(&mk->mk_users);
+
INIT_LIST_HEAD(&mk->mk_decrypted_inodes);
spin_lock_init(&mk->mk_decrypted_inodes_lock);
INIT_LIST_HEAD(&mk->mk_mode_keys);
if (mk_spec->type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) {
- err = allocate_master_key_users_keyring(mk);
- if (err)
- goto out_put;
err = add_master_key_user(mk);
if (err)
goto out_put;
int err;
/*
- * If the current user is already in ->mk_users, then there's nothing to
- * do. Otherwise, we need to add the user to ->mk_users. (Neither is
- * applicable for v1 policy keys, which have NULL ->mk_users.)
+ * For v2 policy keys (FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER): If the current
+ * user is already in ->mk_users, then there's nothing to do.
+ * Otherwise, add the user to ->mk_users.
*/
- if (mk->mk_users) {
- struct key *mk_user = find_master_key_user(mk);
-
- if (mk_user != ERR_PTR(-ENOKEY)) {
- if (IS_ERR(mk_user))
- return PTR_ERR(mk_user);
- key_put(mk_user);
+ if (mk->mk_spec.type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) {
+ if (find_master_key_user(mk) != NULL)
return 0;
- }
err = add_master_key_user(mk);
if (err)
return err;
{
struct fscrypt_key_specifier mk_spec;
struct fscrypt_master_key *mk;
- struct key *mk_user;
int err;
mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
goto out;
}
down_read(&mk->mk_sem);
- mk_user = find_master_key_user(mk);
- if (IS_ERR(mk_user)) {
- err = PTR_ERR(mk_user);
- } else {
- key_put(mk_user);
+ if (find_master_key_user(mk) != NULL)
err = 0;
- }
+ else
+ err = -ENOKEY;
up_read(&mk->mk_sem);
fscrypt_put_master_key(mk);
out:
down_write(&mk->mk_sem);
/* If relevant, remove current user's (or all users) claim to the key */
- if (mk->mk_users && mk->mk_users->keys.nr_leaves_on_tree != 0) {
- if (all_users)
- err = keyring_clear(mk->mk_users);
- else
+ if (!list_empty(&mk->mk_users)) {
+ if (all_users) {
+ clear_mk_users(mk);
+ err = 0;
+ } else {
err = remove_master_key_user(mk);
+ }
if (err) {
up_write(&mk->mk_sem);
goto out_put_key;
}
- if (mk->mk_users->keys.nr_leaves_on_tree != 0) {
+ if (!list_empty(&mk->mk_users)) {
/*
* Other users have still added the key too. We removed
* the current user's claim to the key, but we still
struct super_block *sb = file_inode(filp)->i_sb;
struct fscrypt_get_key_status_arg arg;
struct fscrypt_master_key *mk;
+ kuid_t uid;
+ const struct fscrypt_master_key_user *mk_user;
int err;
if (copy_from_user(&arg, uarg, sizeof(arg)))
}
arg.status = FSCRYPT_KEY_STATUS_PRESENT;
- if (mk->mk_users) {
- struct key *mk_user;
- arg.user_count = mk->mk_users->keys.nr_leaves_on_tree;
- mk_user = find_master_key_user(mk);
- if (!IS_ERR(mk_user)) {
+ uid = current_fsuid();
+ list_for_each_entry(mk_user, &mk->mk_users, link) {
+ arg.user_count++;
+ if (uid_eq(mk_user->uid, uid))
arg.status_flags |=
FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF;
- key_put(mk_user);
- } else if (mk_user != ERR_PTR(-ENOKEY)) {
- err = PTR_ERR(mk_user);
- goto out_release_key;
- }
}
err = 0;
out_release_key:
projects / thirdparty / kernel / linux.git / commitdiff
