LXR linux/crypto/asymmetric

   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#define pr_fmt(fmt) "SIG: "fmt
  15#include <keys/asymmetric-subtype.h>
  16#include <linux/export.h>
  17#include <linux/err.h>
  18#include <crypto/public_key.h>
  19#include "asymmetric_keys.h"
  20
  21/**
  22 * verify_signature - Initiate the use of an asymmetric key to verify a signature
  23 * @key: The asymmetric key to verify against
  24 * @sig: The signature to check
  25 *
  26 * Returns 0 if successful or else an error.
  27 */
  28int verify_signature(const struct key *key,
  29                     const struct public_key_signature *sig)
  30{
  31        const struct asymmetric_key_subtype *subtype;
  32        int ret;
  33
  34        pr_devel("==>%s()\n", __func__);
  35
  36        if (key->type != &key_type_asymmetric)
  37                return -EINVAL;
  38        subtype = asymmetric_key_subtype(key);
  39        if (!subtype ||
  40            !key->payload.data[0])
  41                return -EINVAL;
  42        if (!subtype->verify_signature)
  43                return -ENOTSUPP;
  44
  45        ret = subtype->verify_signature(key, sig);
  46
  47        pr_devel("<==%s() = %d\n", __func__, ret);
  48        return ret;
  49}
  50EXPORT_SYMBOL_GPL(verify_signature);
  51