1/*
  2 * RSA key extract helper
  3 *
  4 * Copyright (c) 2015, Intel Corporation
  5 * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
  6 *
  7 * This program is free software; you can redistribute it and/or modify it
  8 * under the terms of the GNU General Public License as published by the Free
  9 * Software Foundation; either version 2 of the License, or (at your option)
 10 * any later version.
 11 *
 12 */
 13#include <linux/kernel.h>
 14#include <linux/export.h>
 15#include <linux/err.h>
 16#include <linux/fips.h>
 17#include <crypto/internal/rsa.h>
 18#include "rsapubkey-asn1.h"
 19#include "rsaprivkey-asn1.h"
 20
 21int rsa_get_n(void *context, size_t hdrlen, unsigned char tag,
 22	      const void *value, size_t vlen)
 23{
 24	struct rsa_key *key = context;
 25
 26	key->n = mpi_read_raw_data(value, vlen);
 27
 28	if (!key->n)
 29		return -ENOMEM;
 30
 31	/* In FIPS mode only allow key size 2K & 3K */
 32	if (fips_enabled && (mpi_get_size(key->n) != 256 &&
 33			     mpi_get_size(key->n) != 384)) {
 34		pr_err("RSA: key size not allowed in FIPS mode\n");
 35		mpi_free(key->n);
 36		key->n = NULL;
 37		return -EINVAL;
 38	}
 39	return 0;
 40}
 41
 42int rsa_get_e(void *context, size_t hdrlen, unsigned char tag,
 43	      const void *value, size_t vlen)
 44{
 45	struct rsa_key *key = context;
 46
 47	key->e = mpi_read_raw_data(value, vlen);
 48
 49	if (!key->e)
 50		return -ENOMEM;
 51
 52	return 0;
 53}
 54
 55int rsa_get_d(void *context, size_t hdrlen, unsigned char tag,
 56	      const void *value, size_t vlen)
 57{
 58	struct rsa_key *key = context;
 59
 60	key->d = mpi_read_raw_data(value, vlen);
 61
 62	if (!key->d)
 63		return -ENOMEM;
 64
 65	/* In FIPS mode only allow key size 2K & 3K */
 66	if (fips_enabled && (mpi_get_size(key->d) != 256 &&
 67			     mpi_get_size(key->d) != 384)) {
 68		pr_err("RSA: key size not allowed in FIPS mode\n");
 69		mpi_free(key->d);
 70		key->d = NULL;
 71		return -EINVAL;
 72	}
 73	return 0;
 74}
 75
 76static void free_mpis(struct rsa_key *key)
 77{
 78	mpi_free(key->n);
 79	mpi_free(key->e);
 80	mpi_free(key->d);
 81	key->n = NULL;
 82	key->e = NULL;
 83	key->d = NULL;
 84}
 85
 86/**
 87 * rsa_free_key() - frees rsa key allocated by rsa_parse_key()
 88 *
 89 * @rsa_key:	struct rsa_key key representation
 90 */
 91void rsa_free_key(struct rsa_key *key)
 92{
 93	free_mpis(key);
 94}
 95EXPORT_SYMBOL_GPL(rsa_free_key);
 96
 97/**
 98 * rsa_parse_pub_key() - extracts an rsa public key from BER encoded buffer
 99 *			 and stores it in the provided struct rsa_key
100 *
101 * @rsa_key:	struct rsa_key key representation
102 * @key:	key in BER format
103 * @key_len:	length of key
104 *
105 * Return:	0 on success or error code in case of error
106 */
107int rsa_parse_pub_key(struct rsa_key *rsa_key, const void *key,
108		      unsigned int key_len)
109{
110	int ret;
111
112	free_mpis(rsa_key);
113	ret = asn1_ber_decoder(&rsapubkey_decoder, rsa_key, key, key_len);
114	if (ret < 0)
115		goto error;
116
117	return 0;
118error:
119	free_mpis(rsa_key);
120	return ret;
121}
122EXPORT_SYMBOL_GPL(rsa_parse_pub_key);
123
124/**
125 * rsa_parse_pub_key() - extracts an rsa private key from BER encoded buffer
126 *			 and stores it in the provided struct rsa_key
127 *
128 * @rsa_key:	struct rsa_key key representation
129 * @key:	key in BER format
130 * @key_len:	length of key
131 *
132 * Return:	0 on success or error code in case of error
133 */
134int rsa_parse_priv_key(struct rsa_key *rsa_key, const void *key,
135		       unsigned int key_len)
136{
137	int ret;
138
139	free_mpis(rsa_key);
140	ret = asn1_ber_decoder(&rsaprivkey_decoder, rsa_key, key, key_len);
141	if (ret < 0)
142		goto error;
143
144	return 0;
145error:
146	free_mpis(rsa_key);
147	return ret;
148}
149EXPORT_SYMBOL_GPL(rsa_parse_priv_key);