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         const char      *orig_description; /* Actual or proposed description (maybe NULL) */
  33         char            *description;   /* Proposed key description (or NULL) */
  34         union key_payload payload;      /* Proposed payload */
  35         const void      *data;          /* Raw data */
  36         size_t          datalen;        /* Raw datalen */
  37         size_t          quotalen;       /* Quota length for proposed payload */
  38         time64_t        expiry;         /* Expiry time of key */
  39 } __randomize_layout;
  40
  41 typedef int (*request_key_actor_t)(struct key *auth_key, void *aux);
  42
  43 /*
  44  * Preparsed matching criterion.
  45  */
  46 struct key_match_data {
  47         /* Comparison function, defaults to exact description match, but can be
  48          * overridden by type->match_preparse().  Should return true if a match
  49          * is found and false if not.
  50          */
  51         bool (*cmp)(const struct key *key,
  52                     const struct key_match_data *match_data);
  53
  54         const void      *raw_data;      /* Raw match data */
  55         void            *preparsed;     /* For ->match_preparse() to stash stuff */
  56         unsigned        lookup_type;    /* Type of lookup for this search. */
  57 #define KEYRING_SEARCH_LOOKUP_DIRECT    0x0000  /* Direct lookup by description. */
  58 #define KEYRING_SEARCH_LOOKUP_ITERATE   0x0001  /* Iterative search. */
  59 };
  60
  61 /*
  62  * kernel managed key type definition
  63  */
  64 struct key_type {
  65         /* name of the type */
  66         const char *name;
  67
  68         /* default payload length for quota precalculation (optional)
  69          * - this can be used instead of calling key_payload_reserve(), that
  70          *   function only needs to be called if the real datalen is different
  71          */
  72         size_t def_datalen;
  73
  74         unsigned int flags;
  75 #define KEY_TYPE_NET_DOMAIN     0x00000001 /* Keys of this type have a net namespace domain */
  76 #define KEY_TYPE_INSTANT_REAP   0x00000002 /* Keys of this type don't have a delay after expiring */
  77
  78         /* vet a description */
  79         int (*vet_description)(const char *description);
  80
  81         /* Preparse the data blob from userspace that is to be the payload,
  82          * generating a proposed description and payload that will be handed to
  83          * the instantiate() and update() ops.
  84          */
  85         int (*preparse)(struct key_preparsed_payload *prep);
  86
  87         /* Free a preparse data structure.
  88          */
  89         void (*free_preparse)(struct key_preparsed_payload *prep);
  90
  91         /* instantiate a key of this type
  92          * - this method should call key_payload_reserve() to determine if the
  93          *   user's quota will hold the payload
  94          */
  95         int (*instantiate)(struct key *key, struct key_preparsed_payload *prep);
  96
  97         /* update a key of this type (optional)
  98          * - this method should call key_payload_reserve() to recalculate the
  99          *   quota consumption
 100          * - the key must be locked against read when modifying
 101          */
 102         int (*update)(struct key *key, struct key_preparsed_payload *prep);
 103
 104         /* Preparse the data supplied to ->match() (optional).  The
 105          * data to be preparsed can be found in match_data->raw_data.
 106          * The lookup type can also be set by this function.
 107          */
 108         int (*match_preparse)(struct key_match_data *match_data);
 109
 110         /* Free preparsed match data (optional).  This should be supplied it
 111          * ->match_preparse() is supplied. */
 112         void (*match_free)(struct key_match_data *match_data);
 113
 114         /* clear some of the data from a key on revokation (optional)
 115          * - the key's semaphore will be write-locked by the caller
 116          */
 117         void (*revoke)(struct key *key);
 118
 119         /* clear the data from a key (optional) */
 120         void (*destroy)(struct key *key);
 121
 122         /* describe a key */
 123         void (*describe)(const struct key *key, struct seq_file *p);
 124
 125         /* read a key's data (optional)
 126          * - permission checks will be done by the caller
 127          * - the key's semaphore will be readlocked by the caller
 128          * - should return the amount of data that could be read, no matter how
 129          *   much is copied into the buffer
 130          * - shouldn't do the copy if the buffer is NULL
 131          */
 132         long (*read)(const struct key *key, char *buffer, size_t buflen);
 133
 134         /* handle request_key() for this type instead of invoking
 135          * /sbin/request-key (optional)
 136          * - key is the key to instantiate
 137          * - authkey is the authority to assume when instantiating this key
 138          * - op is the operation to be done, usually "create"
 139          * - the call must not return until the instantiation process has run
 140          *   its course
 141          */
 142         request_key_actor_t request_key;
 143
 144         /* Look up a keyring access restriction (optional)
 145          *
 146          * - NULL is a valid return value (meaning the requested restriction
 147          *   is known but will never block addition of a key)
 148          * - should return -EINVAL if the restriction is unknown
 149          */
 150         struct key_restriction *(*lookup_restriction)(const char *params);
 151
 152         /* Asymmetric key accessor functions. */
 153         int (*asym_query)(const struct kernel_pkey_params *params,
 154                           struct kernel_pkey_query *info);
 155         int (*asym_eds_op)(struct kernel_pkey_params *params,
 156                            const void *in, void *out);
 157         int (*asym_verify_signature)(struct kernel_pkey_params *params,
 158                                      const void *in, const void *in2);
 159
 160         /* internal fields */
 161         struct list_head        link;           /* link in types list */
 162         struct lock_class_key   lock_class;     /* key->sem lock class */
 163 } __randomize_layout;
 164
 165 extern struct key_type key_type_keyring;
 166
 167 extern int register_key_type(struct key_type *ktype);
 168 extern void unregister_key_type(struct key_type *ktype);
 169
 170 extern int key_payload_reserve(struct key *key, size_t datalen);
 171 extern int key_instantiate_and_link(struct key *key,
 172                                     const void *data,
 173                                     size_t datalen,
 174                                     struct key *keyring,
 175                                     struct key *authkey);
 176 extern int key_reject_and_link(struct key *key,
 177                                unsigned timeout,
 178                                unsigned error,
 179                                struct key *keyring,
 180                                struct key *authkey);
 181 extern void complete_request_key(struct key *authkey, int error);
 182
 183 static inline int key_negate_and_link(struct key *key,
 184                                       unsigned timeout,
 185                                       struct key *keyring,
 186                                       struct key *authkey)
 187 {
 188         return key_reject_and_link(key, timeout, ENOKEY, keyring, authkey);
 189 }
 190
 191 extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep);
 192
 193 #endif /* CONFIG_KEYS */
 194 #endif /* _LINUX_KEY_TYPE_H */