include/linux/key-type.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /* Definitions for key type implementations
   3  *
   4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #ifndef _LINUX_KEY_TYPE_H
   9 #define _LINUX_KEY_TYPE_H
  10
  11 #include <linux/key.h>
  12 #include <linux/errno.h>
  13
  14 #ifdef CONFIG_KEYS
  15
  16 struct kernel_pkey_query;
  17 struct kernel_pkey_params;
  18
  19 /*
  20  * Pre-parsed payload, used by key add, update and instantiate.
  21  *
  22  * This struct will be cleared and data and datalen will be set with the data
  23  * and length parameters from the caller and quotalen will be set from
  24  * def_datalen from the key type.  Then if the preparse() op is provided by the
  25  * key type, that will be called.  Then the struct will be passed to the
  26  * instantiate() or the update() op.
  27  *
  28  * If the preparse() op is given, the free_preparse() op will be called to
  29  * clear the contents.
  30  */
  31 struct key_preparsed_payload {
  32         char            *description;   /* Proposed key description (or NULL) */
  33         union key_payload payload;      /* Proposed payload */
  34         const void      *data;          /* Raw data */
  35         size_t          datalen;        /* Raw datalen */
  36         size_t          quotalen;       /* Quota length for proposed payload */
  37         time64_t        expiry;         /* Expiry time of key */
  38 } __randomize_layout;
  39
  40 typedef int (*request_key_actor_t)(struct key *auth_key, void *aux);
  41
  42 /*
  43  * Preparsed matching criterion.
  44  */
  45 struct key_match_data {
  46         /* Comparison function, defaults to exact description match, but can be
  47          * overridden by type->match_preparse().  Should return true if a match
  48          * is found and false if not.
  49          */
  50         bool (*cmp)(const struct key *key,
  51                     const struct key_match_data *match_data);
  52
  53         const void      *raw_data;      /* Raw match data */
  54         void            *preparsed;     /* For ->match_preparse() to stash stuff */
  55         unsigned        lookup_type;    /* Type of lookup for this search. */
  56 #define KEYRING_SEARCH_LOOKUP_DIRECT    0x0000  /* Direct lookup by description. */
  57 #define KEYRING_SEARCH_LOOKUP_ITERATE   0x0001  /* Iterative search. */
  58 };
  59
  60 /*
  61  * kernel managed key type definition
  62  */
  63 struct key_type {
  64         /* name of the type */
  65         const char *name;
  66
  67         /* default payload length for quota precalculation (optional)
  68          * - this can be used instead of calling key_payload_reserve(), that
  69          *   function only needs to be called if the real datalen is different
  70          */
  71         size_t def_datalen;
  72
  73         /* vet a description */
  74         int (*vet_description)(const char *description);
  75
  76         /* Preparse the data blob from userspace that is to be the payload,
  77          * generating a proposed description and payload that will be handed to
  78          * the instantiate() and update() ops.
  79          */
  80         int (*preparse)(struct key_preparsed_payload *prep);
  81
  82         /* Free a preparse data structure.
  83          */
  84         void (*free_preparse)(struct key_preparsed_payload *prep);
  85
  86         /* instantiate a key of this type
  87          * - this method should call key_payload_reserve() to determine if the
  88          *   user's quota will hold the payload
  89          */
  90         int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
  91
  92         /* update a key of this type (optional)
  93          * - this method should call key_payload_reserve() to recalculate the
  94          *   quota consumption
  95          * - the key must be locked against read when modifying
  96          */
  97         int (*update)(struct key *key, struct key_preparsed_payload *prep);
  98
  99         /* Preparse the data supplied to ->match() (optional).  The
 100          * data to be preparsed can be found in match_data->raw_data.
 101          * The lookup type can also be set by this function.
 102          */
 103         int (*match_preparse)(struct key_match_data *match_data);
 104
 105         /* Free preparsed match data (optional).  This should be supplied it
 106          * ->match_preparse() is supplied. */
 107         void (*match_free)(struct key_match_data *match_data);
 108
 109         /* clear some of the data from a key on revokation (optional)
 110          * - the key's semaphore will be write-locked by the caller
 111          */
 112         void (*revoke)(struct key *key);
 113
 114         /* clear the data from a key (optional) */
 115         void (*destroy)(struct key *key);
 116
 117         /* describe a key */
 118         void (*describe)(const struct key *key, struct seq_file *p);
 119
 120         /* read a key's data (optional)
 121          * - permission checks will be done by the caller
 122          * - the key's semaphore will be readlocked by the caller
 123          * - should return the amount of data that could be read, no matter how
 124          *   much is copied into the buffer
 125          * - shouldn't do the copy if the buffer is NULL
 126          */
 127         long (*read)(const struct key *key, char __user *buffer, size_t buflen);
 128
 129         /* handle request_key() for this type instead of invoking
 130          * /sbin/request-key (optional)
 131          * - key is the key to instantiate
 132          * - authkey is the authority to assume when instantiating this key
 133          * - op is the operation to be done, usually "create"
 134          * - the call must not return until the instantiation process has run
 135          *   its course
 136          */
 137         request_key_actor_t request_key;
 138
 139         /* Look up a keyring access restriction (optional)
 140          *
 141          * - NULL is a valid return value (meaning the requested restriction
 142          *   is known but will never block addition of a key)
 143          * - should return -EINVAL if the restriction is unknown
 144          */
 145         struct key_restriction *(*lookup_restriction)(const char *params);
 146
 147         /* Asymmetric key accessor functions. */
 148         int (*asym_query)(const struct kernel_pkey_params *params,
 149                           struct kernel_pkey_query *info);
 150         int (*asym_eds_op)(struct kernel_pkey_params *params,
 151                            const void *in, void *out);
 152         int (*asym_verify_signature)(struct kernel_pkey_params *params,
 153                                      const void *in, const void *in2);
 154
 155         /* internal fields */
 156         struct list_head        link;           /* link in types list */
 157         struct lock_class_key   lock_class;     /* key->sem lock class */
 158 } __randomize_layout;
 159
 160 extern struct key_type key_type_keyring;
 161
 162 extern int register_key_type(struct key_type *ktype);
 163 extern void unregister_key_type(struct key_type *ktype);
 164
 165 extern int key_payload_reserve(struct key *key, size_t datalen);
 166 extern int key_instantiate_and_link(struct key *key,
 167                                     const void *data,
 168                                     size_t datalen,
 169                                     struct key *keyring,
 170                                     struct key *authkey);
 171 extern int key_reject_and_link(struct key *key,
 172                                unsigned timeout,
 173                                unsigned error,
 174                                struct key *keyring,
 175                                struct key *authkey);
 176 extern void complete_request_key(struct key *authkey, int error);
 177
 178 static inline int key_negate_and_link(struct key *key,
 179                                       unsigned timeout,
 180                                       struct key *keyring,
 181                                       struct key *authkey)
 182 {
 183         return key_reject_and_link(key, timeout, ENOKEY, keyring, authkey);
 184 }
 185
 186 extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);
 187
 188 #endif /* CONFIG_KEYS */
 189 #endif /* _LINUX_KEY_TYPE_H */