crypto/asymmetric_keys/signature.c

   1 /* Signature verification with an asymmetric key
   2  *
   3  * See Documentation/security/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 #include <keys/asymmetric-subtype.h>
  15 #include <linux/module.h>
  16 #include <linux/err.h>
  17 #include <crypto/public_key.h>
  18 #include "asymmetric_keys.h"
  19
  20 /**
  21  * verify_signature - Initiate the use of an asymmetric key to verify a signature
  22  * @key: The asymmetric key to verify against
  23  * @sig: The signature to check
  24  *
  25  * Returns 0 if successful or else an error.
  26  */
  27 int verify_signature(const struct key *key,
  28                      const struct public_key_signature *sig)
  29 {
  30         const struct asymmetric_key_subtype *subtype;
  31         int ret;
  32
  33         pr_devel("==>%s()\n", __func__);
  34
  35         if (key->type != &key_type_asymmetric)
  36                 return -EINVAL;
  37         subtype = asymmetric_key_subtype(key);
  38         if (!subtype ||
  39             !key->payload.data)
  40                 return -EINVAL;
  41         if (!subtype->verify_signature)
  42                 return -ENOTSUPP;
  43
  44         ret = subtype->verify_signature(key, sig);
  45
  46         pr_devel("<==%s() = %d\n", __func__, ret);
  47         return ret;
  48 }
  49 EXPORT_SYMBOL_GPL(verify_signature);