linux/crypto/asymmetric_keys/signature.c

69 lines
1.7 KiB
C

/* Signature verification with an asymmetric key
*
* See Documentation/security/asymmetric-keys.txt
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#define pr_fmt(fmt) "SIG: "fmt
#include <keys/asymmetric-subtype.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <crypto/public_key.h>
#include "asymmetric_keys.h"
/*
* Destroy a public key signature.
*/
void public_key_signature_free(struct public_key_signature *sig)
{
int i;
if (sig) {
for (i = 0; i < ARRAY_SIZE(sig->auth_ids); i++)
kfree(sig->auth_ids[i]);
kfree(sig->s);
kfree(sig->digest);
kfree(sig);
}
}
EXPORT_SYMBOL_GPL(public_key_signature_free);
/**
* verify_signature - Initiate the use of an asymmetric key to verify a signature
* @key: The asymmetric key to verify against
* @sig: The signature to check
*
* Returns 0 if successful or else an error.
*/
int verify_signature(const struct key *key,
const struct public_key_signature *sig)
{
const struct asymmetric_key_subtype *subtype;
int ret;
pr_devel("==>%s()\n", __func__);
if (key->type != &key_type_asymmetric)
return -EINVAL;
subtype = asymmetric_key_subtype(key);
if (!subtype ||
!key->payload.data[0])
return -EINVAL;
if (!subtype->verify_signature)
return -ENOTSUPP;
ret = subtype->verify_signature(key, sig);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
EXPORT_SYMBOL_GPL(verify_signature);