rsa_helper.c
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/*
* RSA key extract helper
*
* Copyright (c) 2015, Intel Corporation
* Authors: Tadeusz Struk <tadeusz.struk@intel.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/fips.h>
#include <crypto/internal/rsa.h>
#include "rsapubkey-asn1.h"
#include "rsaprivkey-asn1.h"
int rsa_get_n(void *context, size_t hdrlen, unsigned char tag,
const void *value, size_t vlen)
{
struct rsa_key *key = context;
key->n = mpi_read_raw_data(value, vlen);
if (!key->n)
return -ENOMEM;
/* In FIPS mode only allow key size 2K & 3K */
if (fips_enabled && (mpi_get_size(key->n) != 256 &&
mpi_get_size(key->n) != 384)) {
pr_err("RSA: key size not allowed in FIPS mode\n");
mpi_free(key->n);
key->n = NULL;
return -EINVAL;
}
return 0;
}
int rsa_get_e(void *context, size_t hdrlen, unsigned char tag,
const void *value, size_t vlen)
{
struct rsa_key *key = context;
key->e = mpi_read_raw_data(value, vlen);
if (!key->e)
return -ENOMEM;
return 0;
}
int rsa_get_d(void *context, size_t hdrlen, unsigned char tag,
const void *value, size_t vlen)
{
struct rsa_key *key = context;
key->d = mpi_read_raw_data(value, vlen);
if (!key->d)
return -ENOMEM;
/* In FIPS mode only allow key size 2K & 3K */
if (fips_enabled && (mpi_get_size(key->d) != 256 &&
mpi_get_size(key->d) != 384)) {
pr_err("RSA: key size not allowed in FIPS mode\n");
mpi_free(key->d);
key->d = NULL;
return -EINVAL;
}
return 0;
}
static void free_mpis(struct rsa_key *key)
{
mpi_free(key->n);
mpi_free(key->e);
mpi_free(key->d);
key->n = NULL;
key->e = NULL;
key->d = NULL;
}
/**
* rsa_free_key() - frees rsa key allocated by rsa_parse_key()
*
* @rsa_key: struct rsa_key key representation
*/
void rsa_free_key(struct rsa_key *key)
{
free_mpis(key);
}
EXPORT_SYMBOL_GPL(rsa_free_key);
/**
* rsa_parse_pub_key() - extracts an rsa public key from BER encoded buffer
* and stores it in the provided struct rsa_key
*
* @rsa_key: struct rsa_key key representation
* @key: key in BER format
* @key_len: length of key
*
* Return: 0 on success or error code in case of error
*/
int rsa_parse_pub_key(struct rsa_key *rsa_key, const void *key,
unsigned int key_len)
{
int ret;
free_mpis(rsa_key);
ret = asn1_ber_decoder(&rsapubkey_decoder, rsa_key, key, key_len);
if (ret < 0)
goto error;
return 0;
error:
free_mpis(rsa_key);
return ret;
}
EXPORT_SYMBOL_GPL(rsa_parse_pub_key);
/**
* rsa_parse_pub_key() - extracts an rsa private key from BER encoded buffer
* and stores it in the provided struct rsa_key
*
* @rsa_key: struct rsa_key key representation
* @key: key in BER format
* @key_len: length of key
*
* Return: 0 on success or error code in case of error
*/
int rsa_parse_priv_key(struct rsa_key *rsa_key, const void *key,
unsigned int key_len)
{
int ret;
free_mpis(rsa_key);
ret = asn1_ber_decoder(&rsaprivkey_decoder, rsa_key, key, key_len);
if (ret < 0)
goto error;
return 0;
error:
free_mpis(rsa_key);
return ret;
}
EXPORT_SYMBOL_GPL(rsa_parse_priv_key);