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/*
* QEMU Crypto akcipher algorithms
*
* Copyright (c) 2022 Bytedance
* Author: lei he <helei.sig11@bytedance.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include <nettle/rsa.h>
#include "qemu/osdep.h"
#include "qemu/host-utils.h"
#include "crypto/akcipher.h"
#include "crypto/random.h"
#include "qapi/error.h"
#include "sysemu/cryptodev.h"
#include "rsakey.h"
typedef struct QCryptoNettleRSA {
QCryptoAkCipher akcipher;
struct rsa_public_key pub;
struct rsa_private_key priv;
QCryptoRSAPaddingAlgorithm padding_alg;
QCryptoHashAlgorithm hash_alg;
} QCryptoNettleRSA;
static void qcrypto_nettle_rsa_free(QCryptoAkCipher *akcipher)
{
QCryptoNettleRSA *rsa = (QCryptoNettleRSA *)akcipher;
if (!rsa) {
return;
}
rsa_public_key_clear(&rsa->pub);
rsa_private_key_clear(&rsa->priv);
g_free(rsa);
}
static QCryptoAkCipher *qcrypto_nettle_rsa_new(
const QCryptoAkCipherOptionsRSA *opt,
QCryptoAkCipherKeyType type,
const uint8_t *key, size_t keylen,
Error **errp);
QCryptoAkCipher *qcrypto_akcipher_new(const QCryptoAkCipherOptions *opts,
QCryptoAkCipherKeyType type,
const uint8_t *key, size_t keylen,
Error **errp)
{
switch (opts->alg) {
case QCRYPTO_AKCIPHER_ALG_RSA:
return qcrypto_nettle_rsa_new(&opts->u.rsa, type, key, keylen, errp);
default:
error_setg(errp, "Unsupported algorithm: %u", opts->alg);
return NULL;
}
return NULL;
}
static void qcrypto_nettle_rsa_set_akcipher_size(QCryptoAkCipher *akcipher,
int key_size)
{
akcipher->max_plaintext_len = key_size;
akcipher->max_ciphertext_len = key_size;
akcipher->max_signature_len = key_size;
akcipher->max_dgst_len = key_size;
}
static int qcrypt_nettle_parse_rsa_private_key(QCryptoNettleRSA *rsa,
const uint8_t *key,
size_t keylen,
Error **errp)
{
g_autoptr(QCryptoAkCipherRSAKey) rsa_key = qcrypto_akcipher_rsakey_parse(
QCRYPTO_AKCIPHER_KEY_TYPE_PRIVATE, key, keylen, errp);
if (!rsa_key) {
return -1;
}
nettle_mpz_init_set_str_256_u(rsa->pub.n, rsa_key->n.len, rsa_key->n.data);
nettle_mpz_init_set_str_256_u(rsa->pub.e, rsa_key->e.len, rsa_key->e.data);
nettle_mpz_init_set_str_256_u(rsa->priv.d, rsa_key->d.len, rsa_key->d.data);
nettle_mpz_init_set_str_256_u(rsa->priv.p, rsa_key->p.len, rsa_key->p.data);
nettle_mpz_init_set_str_256_u(rsa->priv.q, rsa_key->q.len, rsa_key->q.data);
nettle_mpz_init_set_str_256_u(rsa->priv.a, rsa_key->dp.len,
rsa_key->dp.data);
nettle_mpz_init_set_str_256_u(rsa->priv.b, rsa_key->dq.len,
rsa_key->dq.data);
nettle_mpz_init_set_str_256_u(rsa->priv.c, rsa_key->u.len, rsa_key->u.data);
if (!rsa_public_key_prepare(&rsa->pub)) {
error_setg(errp, "Failed to check RSA key");
return -1;
}
/**
* Since in the kernel's unit test, the p, q, a, b, c of some
* private keys is 0, only the simplest length check is done here
*/
if (rsa_key->p.len > 1 &&
rsa_key->q.len > 1 &&
rsa_key->dp.len > 1 &&
rsa_key->dq.len > 1 &&
rsa_key->u.len > 1) {
if (!rsa_private_key_prepare(&rsa->priv)) {
error_setg(errp, "Failed to check RSA key");
return -1;
}
} else {
rsa->priv.size = rsa->pub.size;
}
qcrypto_nettle_rsa_set_akcipher_size(
(QCryptoAkCipher *)rsa, rsa->priv.size);
return 0;
}
static int qcrypt_nettle_parse_rsa_public_key(QCryptoNettleRSA *rsa,
const uint8_t *key,
size_t keylen,
Error **errp)
{
g_autoptr(QCryptoAkCipherRSAKey) rsa_key = qcrypto_akcipher_rsakey_parse(
QCRYPTO_AKCIPHER_KEY_TYPE_PUBLIC, key, keylen, errp);
if (!rsa_key) {
return -1;
}
nettle_mpz_init_set_str_256_u(rsa->pub.n, rsa_key->n.len, rsa_key->n.data);
nettle_mpz_init_set_str_256_u(rsa->pub.e, rsa_key->e.len, rsa_key->e.data);
if (!rsa_public_key_prepare(&rsa->pub)) {
error_setg(errp, "Failed to check RSA key");
return -1;
}
qcrypto_nettle_rsa_set_akcipher_size(
(QCryptoAkCipher *)rsa, rsa->pub.size);
return 0;
}
static void wrap_nettle_random_func(void *ctx, size_t len, uint8_t *out)
{
qcrypto_random_bytes(out, len, &error_abort);
}
static int qcrypto_nettle_rsa_encrypt(QCryptoAkCipher *akcipher,
const void *data, size_t data_len,
void *enc, size_t enc_len,
Error **errp)
{
QCryptoNettleRSA *rsa = (QCryptoNettleRSA *)akcipher;
mpz_t c;
int ret = -1;
if (data_len > rsa->pub.size) {
error_setg(errp, "Plaintext length %zu is greater than key size: %zu",
data_len, rsa->pub.size);
return ret;
}
if (enc_len < rsa->pub.size) {
error_setg(errp, "Ciphertext buffer length %zu is less than "
"key size: %zu", enc_len, rsa->pub.size);
return ret;
}
/* Nettle do not support RSA encryption without any padding */
switch (rsa->padding_alg) {
case QCRYPTO_RSA_PADDING_ALG_RAW:
error_setg(errp, "RSA with raw padding is not supported");
break;
case QCRYPTO_RSA_PADDING_ALG_PKCS1:
mpz_init(c);
if (rsa_encrypt(&rsa->pub, NULL, wrap_nettle_random_func,
data_len, (uint8_t *)data, c) != 1) {
error_setg(errp, "Failed to encrypt");
} else {
nettle_mpz_get_str_256(enc_len, (uint8_t *)enc, c);
ret = nettle_mpz_sizeinbase_256_u(c);
}
mpz_clear(c);
break;
default:
error_setg(errp, "Unknown padding");
}
return ret;
}
static int qcrypto_nettle_rsa_decrypt(QCryptoAkCipher *akcipher,
const void *enc, size_t enc_len,
void *data, size_t data_len,
Error **errp)
{
QCryptoNettleRSA *rsa = (QCryptoNettleRSA *)akcipher;
mpz_t c;
int ret = -1;
if (enc_len > rsa->priv.size) {
error_setg(errp, "Ciphertext length %zu is greater than key size: %zu",
enc_len, rsa->priv.size);
return ret;
}
switch (rsa->padding_alg) {
case QCRYPTO_RSA_PADDING_ALG_RAW:
error_setg(errp, "RSA with raw padding is not supported");
break;
case QCRYPTO_RSA_PADDING_ALG_PKCS1:
nettle_mpz_init_set_str_256_u(c, enc_len, enc);
if (!rsa_decrypt(&rsa->priv, &data_len, (uint8_t *)data, c)) {
error_setg(errp, "Failed to decrypt");
} else {
ret = data_len;
}
mpz_clear(c);
break;
default:
error_setg(errp, "Unknown padding algorithm: %d", rsa->padding_alg);
}
return ret;
}
static int qcrypto_nettle_rsa_sign(QCryptoAkCipher *akcipher,
const void *data, size_t data_len,
void *sig, size_t sig_len, Error **errp)
{
QCryptoNettleRSA *rsa = (QCryptoNettleRSA *)akcipher;
int ret = -1, rv;
mpz_t s;
/**
* The RSA algorithm cannot be used for signature/verification
* without padding.
*/
if (rsa->padding_alg == QCRYPTO_RSA_PADDING_ALG_RAW) {
error_setg(errp, "Try to make signature without padding");
return ret;
}
if (data_len > rsa->priv.size) {
error_setg(errp, "Data length %zu is greater than key size: %zu",
data_len, rsa->priv.size);
return ret;
}
if (sig_len < rsa->priv.size) {
error_setg(errp, "Signature buffer length %zu is less than "
"key size: %zu", sig_len, rsa->priv.size);
return ret;
}
mpz_init(s);
switch (rsa->hash_alg) {
case QCRYPTO_HASH_ALG_MD5:
rv = rsa_md5_sign_digest(&rsa->priv, data, s);
break;
case QCRYPTO_HASH_ALG_SHA1:
rv = rsa_sha1_sign_digest(&rsa->priv, data, s);
break;
case QCRYPTO_HASH_ALG_SHA256:
rv = rsa_sha256_sign_digest(&rsa->priv, data, s);
break;
case QCRYPTO_HASH_ALG_SHA512:
rv = rsa_sha512_sign_digest(&rsa->priv, data, s);
break;
default:
error_setg(errp, "Unknown hash algorithm: %d", rsa->hash_alg);
goto cleanup;
}
if (rv != 1) {
error_setg(errp, "Failed to make signature");
goto cleanup;
}
nettle_mpz_get_str_256(sig_len, (uint8_t *)sig, s);
ret = nettle_mpz_sizeinbase_256_u(s);
cleanup:
mpz_clear(s);
return ret;
}
static int qcrypto_nettle_rsa_verify(QCryptoAkCipher *akcipher,
const void *sig, size_t sig_len,
const void *data, size_t data_len,
Error **errp)
{
QCryptoNettleRSA *rsa = (QCryptoNettleRSA *)akcipher;
int ret = -1, rv;
mpz_t s;
/**
* The RSA algorithm cannot be used for signature/verification
* without padding.
*/
if (rsa->padding_alg == QCRYPTO_RSA_PADDING_ALG_RAW) {
error_setg(errp, "Try to verify signature without padding");
return ret;
}
if (data_len > rsa->pub.size) {
error_setg(errp, "Data length %zu is greater than key size: %zu",
data_len, rsa->pub.size);
return ret;
}
if (sig_len < rsa->pub.size) {
error_setg(errp, "Signature length %zu is greater than key size: %zu",
sig_len, rsa->pub.size);
return ret;
}
nettle_mpz_init_set_str_256_u(s, sig_len, sig);
switch (rsa->hash_alg) {
case QCRYPTO_HASH_ALG_MD5:
rv = rsa_md5_verify_digest(&rsa->pub, data, s);
break;
case QCRYPTO_HASH_ALG_SHA1:
rv = rsa_sha1_verify_digest(&rsa->pub, data, s);
break;
case QCRYPTO_HASH_ALG_SHA256:
rv = rsa_sha256_verify_digest(&rsa->pub, data, s);
break;
case QCRYPTO_HASH_ALG_SHA512:
rv = rsa_sha512_verify_digest(&rsa->pub, data, s);
break;
default:
error_setg(errp, "Unsupported hash algorithm: %d", rsa->hash_alg);
goto cleanup;
}
if (rv != 1) {
error_setg(errp, "Failed to verify signature");
goto cleanup;
}
ret = 0;
cleanup:
mpz_clear(s);
return ret;
}
QCryptoAkCipherDriver nettle_rsa = {
.encrypt = qcrypto_nettle_rsa_encrypt,
.decrypt = qcrypto_nettle_rsa_decrypt,
.sign = qcrypto_nettle_rsa_sign,
.verify = qcrypto_nettle_rsa_verify,
.free = qcrypto_nettle_rsa_free,
};
static QCryptoAkCipher *qcrypto_nettle_rsa_new(
const QCryptoAkCipherOptionsRSA *opt,
QCryptoAkCipherKeyType type,
const uint8_t *key, size_t keylen,
Error **errp)
{
QCryptoNettleRSA *rsa = g_new0(QCryptoNettleRSA, 1);
rsa->padding_alg = opt->padding_alg;
rsa->hash_alg = opt->hash_alg;
rsa->akcipher.driver = &nettle_rsa;
rsa_public_key_init(&rsa->pub);
rsa_private_key_init(&rsa->priv);
switch (type) {
case QCRYPTO_AKCIPHER_KEY_TYPE_PRIVATE:
if (qcrypt_nettle_parse_rsa_private_key(rsa, key, keylen, errp) != 0) {
goto error;
}
break;
case QCRYPTO_AKCIPHER_KEY_TYPE_PUBLIC:
if (qcrypt_nettle_parse_rsa_public_key(rsa, key, keylen, errp) != 0) {
goto error;
}
break;
default:
error_setg(errp, "Unknown akcipher key type %d", type);
goto error;
}
return (QCryptoAkCipher *)rsa;
error:
qcrypto_nettle_rsa_free((QCryptoAkCipher *)rsa);
return NULL;
}
bool qcrypto_akcipher_supports(QCryptoAkCipherOptions *opts)
{
switch (opts->alg) {
case QCRYPTO_AKCIPHER_ALG_RSA:
switch (opts->u.rsa.padding_alg) {
case QCRYPTO_RSA_PADDING_ALG_PKCS1:
switch (opts->u.rsa.hash_alg) {
case QCRYPTO_HASH_ALG_MD5:
case QCRYPTO_HASH_ALG_SHA1:
case QCRYPTO_HASH_ALG_SHA256:
case QCRYPTO_HASH_ALG_SHA512:
return true;
default:
return false;
}
case QCRYPTO_RSA_PADDING_ALG_RAW:
default:
return false;
}
break;
default:
return false;
}
}