crypto/asymmetric_keys/public_key.c

   1 /* In-software asymmetric public-key crypto subtype
   2  *
   3  * See Documentation/crypto/asymmetric-keys.txt
   4  *
   5  * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
   6  * Written by David Howells (dhowells@redhat.com)
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public Licence
  10  * as published by the Free Software Foundation; either version
  11  * 2 of the Licence, or (at your option) any later version.
  12  */
  13
  14 #define pr_fmt(fmt) "PKEY: "fmt
  15 #include <linux/module.h>
  16 #include <linux/export.h>
  17 #include <linux/kernel.h>
  18 #include <linux/slab.h>
  19 #include <linux/seq_file.h>
  20 #include <keys/asymmetric-subtype.h>
  21 #include "public_key.h"
  22
  23 MODULE_LICENSE("GPL");
  24
  25 const char *const pkey_algo[PKEY_ALGO__LAST] = {
  26         [PKEY_ALGO_DSA]         = "DSA",
  27         [PKEY_ALGO_RSA]         = "RSA",
  28 };
  29 EXPORT_SYMBOL_GPL(pkey_algo);
  30
  31 const char *const pkey_hash_algo[PKEY_HASH__LAST] = {
  32         [PKEY_HASH_MD4]         = "md4",
  33         [PKEY_HASH_MD5]         = "md5",
  34         [PKEY_HASH_SHA1]        = "sha1",
  35         [PKEY_HASH_RIPE_MD_160] = "rmd160",
  36         [PKEY_HASH_SHA256]      = "sha256",
  37         [PKEY_HASH_SHA384]      = "sha384",
  38         [PKEY_HASH_SHA512]      = "sha512",
  39         [PKEY_HASH_SHA224]      = "sha224",
  40 };
  41 EXPORT_SYMBOL_GPL(pkey_hash_algo);
  42
  43 const char *const pkey_id_type[PKEY_ID_TYPE__LAST] = {
  44         [PKEY_ID_PGP]           = "PGP",
  45         [PKEY_ID_X509]          = "X509",
  46 };
  47 EXPORT_SYMBOL_GPL(pkey_id_type);
  48
  49 /*
  50  * Provide a part of a description of the key for /proc/keys.
  51  */
  52 static void public_key_describe(const struct key *asymmetric_key,
  53                                 struct seq_file *m)
  54 {
  55         struct public_key *key = asymmetric_key->payload.data;
  56
  57         if (key)
  58                 seq_printf(m, "%s.%s",
  59                            pkey_id_type[key->id_type], key->algo->name);
  60 }
  61
  62 /*
  63  * Destroy a public key algorithm key.
  64  */
  65 void public_key_destroy(void *payload)
  66 {
  67         struct public_key *key = payload;
  68         int i;
  69
  70         if (key) {
  71                 for (i = 0; i < ARRAY_SIZE(key->mpi); i++)
  72                         mpi_free(key->mpi[i]);
  73                 kfree(key);
  74         }
  75 }
  76 EXPORT_SYMBOL_GPL(public_key_destroy);
  77
  78 /*
  79  * Verify a signature using a public key.
  80  */
  81 static int public_key_verify_signature(const struct key *key,
  82                                        const struct public_key_signature *sig)
  83 {
  84         const struct public_key *pk = key->payload.data;
  85
  86         if (!pk->algo->verify_signature)
  87                 return -ENOTSUPP;
  88
  89         if (sig->nr_mpi != pk->algo->n_sig_mpi) {
  90                 pr_debug("Signature has %u MPI not %u\n",
  91                          sig->nr_mpi, pk->algo->n_sig_mpi);
  92                 return -EINVAL;
  93         }
  94
  95         return pk->algo->verify_signature(pk, sig);
  96 }
  97
  98 /*
  99  * Public key algorithm asymmetric key subtype
 100  */
 101 struct asymmetric_key_subtype public_key_subtype = {
 102         .owner                  = THIS_MODULE,
 103         .name                   = "public_key",
 104         .describe               = public_key_describe,
 105         .destroy                = public_key_destroy,
 106         .verify_signature       = public_key_verify_signature,
 107 };
 108 EXPORT_SYMBOL_GPL(public_key_subtype);