/* SPDX-License-Identifier: GPL-2.0-or-later */

  /* Definitions for key type implementations
   *
   * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)

   */
  
  #ifndef _LINUX_KEY_TYPE_H
  #define _LINUX_KEY_TYPE_H
  
  #include <linux/key.h>

  #include <linux/errno.h>

  
  #ifdef CONFIG_KEYS

  struct kernel_pkey_query;
  struct kernel_pkey_params;

  /*

   * Pre-parsed payload, used by key add, update and instantiate.
   *
   * This struct will be cleared and data and datalen will be set with the data
   * and length parameters from the caller and quotalen will be set from
   * def_datalen from the key type.  Then if the preparse() op is provided by the
   * key type, that will be called.  Then the struct will be passed to the
   * instantiate() or the update() op.
   *
   * If the preparse() op is given, the free_preparse() op will be called to
   * clear the contents.
   */
  struct key_preparsed_payload {
  	char		*description;	/* Proposed key description (or NULL) */

  	union key_payload payload;	/* Proposed payload */

  	const void	*data;		/* Raw data */
  	size_t		datalen;	/* Raw datalen */
  	size_t		quotalen;	/* Quota length for proposed payload */

  	time64_t	expiry;		/* Expiry time of key */

  } __randomize_layout;

  typedef int (*request_key_actor_t)(struct key *auth_key, void *aux);

  
  /*

   * Preparsed matching criterion.
   */
  struct key_match_data {

  	/* Comparison function, defaults to exact description match, but can be
  	 * overridden by type->match_preparse().  Should return true if a match
  	 * is found and false if not.
  	 */
  	bool (*cmp)(const struct key *key,
  		    const struct key_match_data *match_data);

  
  	const void	*raw_data;	/* Raw match data */
  	void		*preparsed;	/* For ->match_preparse() to stash stuff */
  	unsigned	lookup_type;	/* Type of lookup for this search. */
  #define KEYRING_SEARCH_LOOKUP_DIRECT	0x0000	/* Direct lookup by description. */
  #define KEYRING_SEARCH_LOOKUP_ITERATE	0x0001	/* Iterative search. */
  };
  
  /*

   * kernel managed key type definition
   */
  struct key_type {
  	/* name of the type */
  	const char *name;
  
  	/* default payload length for quota precalculation (optional)
  	 * - this can be used instead of calling key_payload_reserve(), that
  	 *   function only needs to be called if the real datalen is different
  	 */
  	size_t def_datalen;

  	unsigned int flags;
  #define KEY_TYPE_NET_DOMAIN	0x00000001 /* Keys of this type have a net namespace domain */

  	/* vet a description */
  	int (*vet_description)(const char *description);

  	/* Preparse the data blob from userspace that is to be the payload,
  	 * generating a proposed description and payload that will be handed to
  	 * the instantiate() and update() ops.
  	 */
  	int (*preparse)(struct key_preparsed_payload *prep);
  
  	/* Free a preparse data structure.
  	 */
  	void (*free_preparse)(struct key_preparsed_payload *prep);

  	/* instantiate a key of this type
  	 * - this method should call key_payload_reserve() to determine if the
  	 *   user's quota will hold the payload
  	 */

  	int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);

  
  	/* update a key of this type (optional)
  	 * - this method should call key_payload_reserve() to recalculate the
  	 *   quota consumption
  	 * - the key must be locked against read when modifying
  	 */

  	int (*update)(struct key *key, struct key_preparsed_payload *prep);

  	/* Preparse the data supplied to ->match() (optional).  The
  	 * data to be preparsed can be found in match_data->raw_data.
  	 * The lookup type can also be set by this function.
  	 */
  	int (*match_preparse)(struct key_match_data *match_data);

  	/* Free preparsed match data (optional).  This should be supplied it
  	 * ->match_preparse() is supplied. */
  	void (*match_free)(struct key_match_data *match_data);

  
  	/* clear some of the data from a key on revokation (optional)
  	 * - the key's semaphore will be write-locked by the caller
  	 */
  	void (*revoke)(struct key *key);
  
  	/* clear the data from a key (optional) */
  	void (*destroy)(struct key *key);
  
  	/* describe a key */
  	void (*describe)(const struct key *key, struct seq_file *p);
  
  	/* read a key's data (optional)
  	 * - permission checks will be done by the caller
  	 * - the key's semaphore will be readlocked by the caller
  	 * - should return the amount of data that could be read, no matter how
  	 *   much is copied into the buffer
  	 * - shouldn't do the copy if the buffer is NULL
  	 */

  	long (*read)(const struct key *key, char *buffer, size_t buflen);

  
  	/* handle request_key() for this type instead of invoking
  	 * /sbin/request-key (optional)
  	 * - key is the key to instantiate
  	 * - authkey is the authority to assume when instantiating this key
  	 * - op is the operation to be done, usually "create"
  	 * - the call must not return until the instantiation process has run
  	 *   its course
  	 */
  	request_key_actor_t request_key;

  	/* Look up a keyring access restriction (optional)
  	 *
  	 * - NULL is a valid return value (meaning the requested restriction
  	 *   is known but will never block addition of a key)
  	 * - should return -EINVAL if the restriction is unknown
  	 */
  	struct key_restriction *(*lookup_restriction)(const char *params);

  	/* Asymmetric key accessor functions. */
  	int (*asym_query)(const struct kernel_pkey_params *params,
  			  struct kernel_pkey_query *info);
  	int (*asym_eds_op)(struct kernel_pkey_params *params,
  			   const void *in, void *out);
  	int (*asym_verify_signature)(struct kernel_pkey_params *params,
  				     const void *in, const void *in2);

  	/* internal fields */
  	struct list_head	link;		/* link in types list */

  	struct lock_class_key	lock_class;	/* key->sem lock class */

  } __randomize_layout;

  
  extern struct key_type key_type_keyring;
  
  extern int register_key_type(struct key_type *ktype);
  extern void unregister_key_type(struct key_type *ktype);
  
  extern int key_payload_reserve(struct key *key, size_t datalen);
  extern int key_instantiate_and_link(struct key *key,
  				    const void *data,
  				    size_t datalen,
  				    struct key *keyring,

  				    struct key *authkey);

  extern int key_reject_and_link(struct key *key,

  			       unsigned timeout,

  			       unsigned error,

  			       struct key *keyring,

  			       struct key *authkey);
  extern void complete_request_key(struct key *authkey, int error);

  static inline int key_negate_and_link(struct key *key,
  				      unsigned timeout,
  				      struct key *keyring,

  				      struct key *authkey)

  {

  	return key_reject_and_link(key, timeout, ENOKEY, keyring, authkey);

  }

  extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);

  #endif /* CONFIG_KEYS */
  #endif /* _LINUX_KEY_TYPE_H */