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|
/* RSA asymmetric public-key algorithm [RFC3447]
*
* 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 Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/module.h>
#include <crypto/internal/rsa.h>
#include <crypto/internal/akcipher.h>
#include <crypto/akcipher.h>
/*
* RSAEP function [RFC3447 sec 5.1.1]
* c = m^e mod n;
*/
static int _rsa_enc(const struct rsa_key *key, MPI c, MPI m)
{
/* (1) Validate 0 <= m < n */
if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
return -EINVAL;
/* (2) c = m^e mod n */
return mpi_powm(c, m, key->e, key->n);
}
/*
* RSADP function [RFC3447 sec 5.1.2]
* m = c^d mod n;
*/
static int _rsa_dec(const struct rsa_key *key, MPI m, MPI c)
{
/* (1) Validate 0 <= c < n */
if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)
return -EINVAL;
/* (2) m = c^d mod n */
return mpi_powm(m, c, key->d, key->n);
}
/*
* RSASP1 function [RFC3447 sec 5.2.1]
* s = m^d mod n
*/
static int _rsa_sign(const struct rsa_key *key, MPI s, MPI m)
{
/* (1) Validate 0 <= m < n */
if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
return -EINVAL;
/* (2) s = m^d mod n */
return mpi_powm(s, m, key->d, key->n);
}
/*
* RSAVP1 function [RFC3447 sec 5.2.2]
* m = s^e mod n;
*/
static int _rsa_verify(const struct rsa_key *key, MPI m, MPI s)
{
/* (1) Validate 0 <= s < n */
if (mpi_cmp_ui(s, 0) < 0 || mpi_cmp(s, key->n) >= 0)
return -EINVAL;
/* (2) m = s^e mod n */
return mpi_powm(m, s, key->e, key->n);
}
static inline struct rsa_key *rsa_get_key(struct crypto_akcipher *tfm)
{
return akcipher_tfm_ctx(tfm);
}
static int rsa_enc(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
const struct rsa_key *pkey = rsa_get_key(tfm);
MPI m, c = mpi_alloc(0);
int ret = 0;
int sign;
if (!c)
return -ENOMEM;
if (unlikely(!pkey->n || !pkey->e)) {
ret = -EINVAL;
goto err_free_c;
}
ret = -ENOMEM;
m = mpi_read_raw_from_sgl(req->src, req->src_len);
if (!m)
goto err_free_c;
ret = _rsa_enc(pkey, c, m);
if (ret)
goto err_free_m;
ret = mpi_write_to_sgl(c, req->dst, &req->dst_len, &sign);
if (ret)
goto err_free_m;
if (sign < 0)
ret = -EBADMSG;
err_free_m:
mpi_free(m);
err_free_c:
mpi_free(c);
return ret;
}
static int rsa_dec(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
const struct rsa_key *pkey = rsa_get_key(tfm);
MPI c, m = mpi_alloc(0);
int ret = 0;
int sign;
if (!m)
return -ENOMEM;
if (unlikely(!pkey->n || !pkey->d)) {
ret = -EINVAL;
goto err_free_m;
}
ret = -ENOMEM;
c = mpi_read_raw_from_sgl(req->src, req->src_len);
if (!c)
goto err_free_m;
ret = _rsa_dec(pkey, m, c);
if (ret)
goto err_free_c;
ret = mpi_write_to_sgl(m, req->dst, &req->dst_len, &sign);
if (ret)
goto err_free_c;
if (sign < 0)
ret = -EBADMSG;
err_free_c:
mpi_free(c);
err_free_m:
mpi_free(m);
return ret;
}
static int rsa_sign(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
const struct rsa_key *pkey = rsa_get_key(tfm);
MPI m, s = mpi_alloc(0);
int ret = 0;
int sign;
if (!s)
return -ENOMEM;
if (unlikely(!pkey->n || !pkey->d)) {
ret = -EINVAL;
goto err_free_s;
}
ret = -ENOMEM;
m = mpi_read_raw_from_sgl(req->src, req->src_len);
if (!m)
goto err_free_s;
ret = _rsa_sign(pkey, s, m);
if (ret)
goto err_free_m;
ret = mpi_write_to_sgl(s, req->dst, &req->dst_len, &sign);
if (ret)
goto err_free_m;
if (sign < 0)
ret = -EBADMSG;
err_free_m:
mpi_free(m);
err_free_s:
mpi_free(s);
return ret;
}
static int rsa_verify(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
const struct rsa_key *pkey = rsa_get_key(tfm);
MPI s, m = mpi_alloc(0);
int ret = 0;
int sign;
if (!m)
return -ENOMEM;
if (unlikely(!pkey->n || !pkey->e)) {
ret = -EINVAL;
goto err_free_m;
}
ret = -ENOMEM;
s = mpi_read_raw_from_sgl(req->src, req->src_len);
if (!s) {
ret = -ENOMEM;
goto err_free_m;
}
ret = _rsa_verify(pkey, m, s);
if (ret)
goto err_free_s;
ret = mpi_write_to_sgl(m, req->dst, &req->dst_len, &sign);
if (ret)
goto err_free_s;
if (sign < 0)
ret = -EBADMSG;
err_free_s:
mpi_free(s);
err_free_m:
mpi_free(m);
return ret;
}
static int rsa_check_key_length(unsigned int len)
{
switch (len) {
case 512:
case 1024:
case 1536:
case 2048:
case 3072:
case 4096:
return 0;
}
return -EINVAL;
}
static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
unsigned int keylen)
{
struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
int ret;
ret = rsa_parse_pub_key(pkey, key, keylen);
if (ret)
return ret;
if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
rsa_free_key(pkey);
ret = -EINVAL;
}
return ret;
}
static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
unsigned int keylen)
{
struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
int ret;
ret = rsa_parse_priv_key(pkey, key, keylen);
if (ret)
return ret;
if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
rsa_free_key(pkey);
ret = -EINVAL;
}
return ret;
}
static int rsa_max_size(struct crypto_akcipher *tfm)
{
struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
return pkey->n ? mpi_get_size(pkey->n) : -EINVAL;
}
static void rsa_exit_tfm(struct crypto_akcipher *tfm)
{
struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
rsa_free_key(pkey);
}
static struct akcipher_alg rsa = {
.encrypt = rsa_enc,
.decrypt = rsa_dec,
.sign = rsa_sign,
.verify = rsa_verify,
.set_priv_key = rsa_set_priv_key,
.set_pub_key = rsa_set_pub_key,
.max_size = rsa_max_size,
.exit = rsa_exit_tfm,
.base = {
.cra_name = "rsa",
.cra_driver_name = "rsa-generic",
.cra_priority = 100,
.cra_module = THIS_MODULE,
.cra_ctxsize = sizeof(struct rsa_key),
},
};
static int rsa_init(void)
{
return crypto_register_akcipher(&rsa);
}
static void rsa_exit(void)
{
crypto_unregister_akcipher(&rsa);
}
module_init(rsa_init);
module_exit(rsa_exit);
MODULE_ALIAS_CRYPTO("rsa");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RSA generic algorithm");
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