linux/crypto/asymmetric_keys/public_key.c
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   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
  23MODULE_LICENSE("GPL");
  24
  25const char *const pkey_algo[PKEY_ALGO__LAST] = {
  26        [PKEY_ALGO_DSA]         = "DSA",
  27        [PKEY_ALGO_RSA]         = "RSA",
  28};
  29EXPORT_SYMBOL_GPL(pkey_algo);
  30
  31const 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};
  41EXPORT_SYMBOL_GPL(pkey_hash_algo);
  42
  43const char *const pkey_id_type[PKEY_ID_TYPE__LAST] = {
  44        [PKEY_ID_PGP]           = "PGP",
  45        [PKEY_ID_X509]          = "X509",
  46};
  47EXPORT_SYMBOL_GPL(pkey_id_type);
  48
  49/*
  50 * Provide a part of a description of the key for /proc/keys.
  51 */
  52static 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 */
  65void 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}
  76EXPORT_SYMBOL_GPL(public_key_destroy);
  77
  78/*
  79 * Verify a signature using a public key.
  80 */
  81static 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 */
 101struct 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};
 108EXPORT_SYMBOL_GPL(public_key_subtype);
 109
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