Merge v6.18.39linux-rolling-lts

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 105 insertions, 134 deletions

diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 3adbd7167055..4ea4ee5cfc64 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -65,36 +65,33 @@ static void fscrypt_free_master_key(struct rcu_head *head)
 	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);
 }
 
 void fscrypt_put_master_key_activeref(struct super_block *sb,
 				      struct fscrypt_master_key *mk)
 {
-	size_t i;
+	struct fscrypt_mode_key *node, *tmp;
 
 	if (!refcount_dec_and_test(&mk->mk_active_refs))
 		return;
 	/*
 	 * No active references left, so complete the full removal of this
 	 * fscrypt_master_key struct by removing it from the keyring and
-	 * destroying any subkeys embedded in it.
+	 * destroying any non-file-scoped subkeys.
 	 */
 
 	if (WARN_ON_ONCE(!sb->s_master_keys))
@@ -110,13 +107,16 @@ void fscrypt_put_master_key_activeref(struct super_block *sb,
 	WARN_ON_ONCE(mk->mk_present);
 	WARN_ON_ONCE(!list_empty(&mk->mk_decrypted_inodes));
 
-	for (i = 0; i <= FSCRYPT_MODE_MAX; i++) {
-		fscrypt_destroy_prepared_key(
-				sb, &mk->mk_direct_keys[i]);
-		fscrypt_destroy_prepared_key(
-				sb, &mk->mk_iv_ino_lblk_64_keys[i]);
-		fscrypt_destroy_prepared_key(
-				sb, &mk->mk_iv_ino_lblk_32_keys[i]);
+	/*
+	 * Destroy any non-file-scoped subkeys.  Since ->mk_active_refs == 0,
+	 * they're no longer referenced by any inodes.  Nor can key setup run
+	 * and use them again.  So they're no longer needed.  (This implies no
+	 * concurrent readers, so we don't need list_del_rcu() for example.)
+	 */
+	list_for_each_entry_safe(node, tmp, &mk->mk_mode_keys, link) {
+		fscrypt_destroy_prepared_key(sb, &node->key);
+		list_del(&node->link);
+		kfree(node);
 	}
 	memzero_explicit(&mk->mk_ino_hash_key,
 			 sizeof(mk->mk_ino_hash_key));
@@ -162,8 +162,8 @@ static void fscrypt_user_key_describe(const struct key *key, struct seq_file *m)
 }
 
 /*
- * 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
@@ -177,30 +177,9 @@ static struct key_type key_type_fscrypt_user = {
 	.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)
 {
@@ -335,91 +314,94 @@ out:
 	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;
-
-	format_mk_user_description(description, mk->mk_spec.u.identifier);
+	struct fscrypt_master_key_user *mk_user;
+	kuid_t uid = current_fsuid();
 
-	/*
-	 * 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);
 }
 
 /*
@@ -442,13 +424,14 @@ static int add_new_master_key(struct super_block *sb,
 	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;
@@ -477,19 +460,13 @@ static int add_existing_master_key(struct fscrypt_master_key *mk,
 	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;
@@ -888,7 +865,6 @@ int fscrypt_verify_key_added(struct super_block *sb,
 {
 	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;
@@ -900,13 +876,10 @@ int fscrypt_verify_key_added(struct super_block *sb,
 		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:
@@ -1098,16 +1071,18 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
 	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
@@ -1193,6 +1168,8 @@ int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg)
 	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)))
@@ -1225,19 +1202,13 @@ int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg)
 	}
 
 	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: