/*
* 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 <gcrypt.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 QCryptoGcryptRSA {
QCryptoAkCipher akcipher;
gcry_sexp_t key;
QCryptoRSAPaddingAlgorithm padding_alg;
QCryptoHashAlgorithm hash_alg;
} QCryptoGcryptRSA;
static void qcrypto_gcrypt_rsa_free(QCryptoAkCipher *akcipher)
{
QCryptoGcryptRSA *rsa = (QCryptoGcryptRSA *)akcipher;
if (!rsa) {
return;
}
gcry_sexp_release(rsa->key);
g_free(rsa);
}
static QCryptoGcryptRSA *qcrypto_gcrypt_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 (QCryptoAkCipher *)qcrypto_gcrypt_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_gcrypt_set_rsa_size(QCryptoAkCipher *akcipher, gcry_mpi_t n)
{
size_t key_size = (gcry_mpi_get_nbits(n) + 7) / 8;
akcipher->max_plaintext_len = key_size;
akcipher->max_ciphertext_len = key_size;
akcipher->max_dgst_len = key_size;
akcipher->max_signature_len = key_size;
}
static int qcrypto_gcrypt_parse_rsa_private_key(
QCryptoGcryptRSA *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);
gcry_mpi_t n = NULL, e = NULL, d = NULL, p = NULL, q = NULL, u = NULL;
bool compute_mul_inv = false;
int ret = -1;
gcry_error_t err;
if (!rsa_key) {
return ret;
}
err = gcry_mpi_scan(&n, GCRYMPI_FMT_STD,
rsa_key->n.data, rsa_key->n.len, NULL);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to parse RSA parameter n: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_mpi_scan(&e, GCRYMPI_FMT_STD,
rsa_key->e.data, rsa_key->e.len, NULL);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to parse RSA parameter e: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_mpi_scan(&d, GCRYMPI_FMT_STD,
rsa_key->d.data, rsa_key->d.len, NULL);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to parse RSA parameter d: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_mpi_scan(&p, GCRYMPI_FMT_STD,
rsa_key->p.data, rsa_key->p.len, NULL);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to parse RSA parameter p: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_mpi_scan(&q, GCRYMPI_FMT_STD,
rsa_key->q.data, rsa_key->q.len, NULL);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to parse RSA parameter q: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
if (gcry_mpi_cmp_ui(p, 0) > 0 && gcry_mpi_cmp_ui(q, 0) > 0) {
compute_mul_inv = true;
u = gcry_mpi_new(0);
if (gcry_mpi_cmp(p, q) > 0) {
gcry_mpi_swap(p, q);
}
gcry_mpi_invm(u, p, q);
}
if (compute_mul_inv) {
err = gcry_sexp_build(&rsa->key, NULL,
"(private-key (rsa (n %m) (e %m) (d %m) (p %m) (q %m) (u %m)))",
n, e, d, p, q, u);
} else {
err = gcry_sexp_build(&rsa->key, NULL,
"(private-key (rsa (n %m) (e %m) (d %m)))", n, e, d);
}
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to build RSA private key: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
qcrypto_gcrypt_set_rsa_size((QCryptoAkCipher *)rsa, n);
ret = 0;
cleanup:
gcry_mpi_release(n);
gcry_mpi_release(e);
gcry_mpi_release(d);
gcry_mpi_release(p);
gcry_mpi_release(q);
gcry_mpi_release(u);
return ret;
}
static int qcrypto_gcrypt_parse_rsa_public_key(QCryptoGcryptRSA *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);
gcry_mpi_t n = NULL, e = NULL;
int ret = -1;
gcry_error_t err;
if (!rsa_key) {
return ret;
}
err = gcry_mpi_scan(&n, GCRYMPI_FMT_STD,
rsa_key->n.data, rsa_key->n.len, NULL);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to parse RSA parameter n: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_mpi_scan(&e, GCRYMPI_FMT_STD,
rsa_key->e.data, rsa_key->e.len, NULL);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to parse RSA parameter e: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_sexp_build(&rsa->key, NULL,
"(public-key (rsa (n %m) (e %m)))", n, e);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to build RSA public key: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
qcrypto_gcrypt_set_rsa_size((QCryptoAkCipher *)rsa, n);
ret = 0;
cleanup:
gcry_mpi_release(n);
gcry_mpi_release(e);
return ret;
}
static int qcrypto_gcrypt_rsa_encrypt(QCryptoAkCipher *akcipher,
const void *in, size_t in_len,
void *out, size_t out_len,
Error **errp)
{
QCryptoGcryptRSA *rsa = (QCryptoGcryptRSA *)akcipher;
int ret = -1;
gcry_sexp_t data_sexp = NULL, cipher_sexp = NULL;
gcry_sexp_t cipher_sexp_item = NULL;
gcry_mpi_t cipher_mpi = NULL;
const char *result;
gcry_error_t err;
size_t actual_len;
if (in_len > akcipher->max_plaintext_len) {
error_setg(errp, "Plaintext length is greater than key size: %d",
akcipher->max_plaintext_len);
return ret;
}
err = gcry_sexp_build(&data_sexp, NULL,
"(data (flags %s) (value %b))",
QCryptoRSAPaddingAlgorithm_str(rsa->padding_alg),
in_len, in);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to build plaintext: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_pk_encrypt(&cipher_sexp, data_sexp, rsa->key);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to encrypt: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
/* S-expression of cipher: (enc-val (rsa (a a-mpi))) */
cipher_sexp_item = gcry_sexp_find_token(cipher_sexp, "a", 0);
if (!cipher_sexp_item || gcry_sexp_length(cipher_sexp_item) != 2) {
error_setg(errp, "Invalid ciphertext result");
goto cleanup;
}
if (rsa->padding_alg == QCRYPTO_RSA_PADDING_ALG_RAW) {
cipher_mpi = gcry_sexp_nth_mpi(cipher_sexp_item, 1, GCRYMPI_FMT_USG);
if (!cipher_mpi) {
error_setg(errp, "Invalid ciphertext result");
goto cleanup;
}
err = gcry_mpi_print(GCRYMPI_FMT_USG, out, out_len,
&actual_len, cipher_mpi);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to print MPI: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
if (actual_len > out_len) {
error_setg(errp, "Ciphertext buffer length is too small");
goto cleanup;
}
/* We always padding leading-zeros for RSA-RAW */
if (actual_len < out_len) {
memmove((uint8_t *)out + (out_len - actual_len), out, actual_len);
memset(out, 0, out_len - actual_len);
}
ret = out_len;
} else {
result = gcry_sexp_nth_data(cipher_sexp_item, 1, &actual_len);
if (!result) {
error_setg(errp, "Invalid ciphertext result");
goto cleanup;
}
if (actual_len > out_len) {
error_setg(errp, "Ciphertext buffer length is too small");
goto cleanup;
}
memcpy(out, result, actual_len);
ret = actual_len;
}
cleanup:
gcry_sexp_release(data_sexp);
gcry_sexp_release(cipher_sexp);
gcry_sexp_release(cipher_sexp_item);
gcry_mpi_release(cipher_mpi);
return ret;
}
static int qcrypto_gcrypt_rsa_decrypt(QCryptoAkCipher *akcipher,
const void *in, size_t in_len,
void *out, size_t out_len,
Error **errp)
{
QCryptoGcryptRSA *rsa = (QCryptoGcryptRSA *)akcipher;
int ret = -1;
gcry_sexp_t data_sexp = NULL, cipher_sexp = NULL;
gcry_mpi_t data_mpi = NULL;
gcry_error_t err;
size_t actual_len;
const char *result;
if (in_len > akcipher->max_ciphertext_len) {
error_setg(errp, "Ciphertext length is greater than key size: %d",
akcipher->max_ciphertext_len);
return ret;
}
err = gcry_sexp_build(&cipher_sexp, NULL,
"(enc-val (flags %s) (rsa (a %b) ))",
QCryptoRSAPaddingAlgorithm_str(rsa->padding_alg),
in_len, in);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to build ciphertext: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_pk_decrypt(&data_sexp, cipher_sexp, rsa->key);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to decrypt: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
/* S-expression of plaintext: (value plaintext) */
if (rsa->padding_alg == QCRYPTO_RSA_PADDING_ALG_RAW) {
data_mpi = gcry_sexp_nth_mpi(data_sexp, 1, GCRYMPI_FMT_USG);
if (!data_mpi) {
error_setg(errp, "Invalid plaintext result");
goto cleanup;
}
err = gcry_mpi_print(GCRYMPI_FMT_USG, out, out_len,
&actual_len, data_mpi);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to print MPI: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
if (actual_len > out_len) {
error_setg(errp, "Plaintext buffer length is too small");
goto cleanup;
}
/* We always padding leading-zeros for RSA-RAW */
if (actual_len < out_len) {
memmove((uint8_t *)out + (out_len - actual_len), out, actual_len);
memset(out, 0, out_len - actual_len);
}
ret = out_len;
} else {
result = gcry_sexp_nth_data(data_sexp, 1, &actual_len);
if (!result) {
error_setg(errp, "Invalid plaintext result");
goto cleanup;
}
if (actual_len > out_len) {
error_setg(errp, "Plaintext buffer length is too small");
goto cleanup;
}
memcpy(out, result, actual_len);
ret = actual_len;
}
cleanup:
gcry_sexp_release(cipher_sexp);
gcry_sexp_release(data_sexp);
gcry_mpi_release(data_mpi);
return ret;
}
static int qcrypto_gcrypt_rsa_sign(QCryptoAkCipher *akcipher,
const void *in, size_t in_len,
void *out, size_t out_len, Error **errp)
{
QCryptoGcryptRSA *rsa = (QCryptoGcryptRSA *)akcipher;
int ret = -1;
gcry_sexp_t dgst_sexp = NULL, sig_sexp = NULL;
gcry_sexp_t sig_sexp_item = NULL;
const char *result;
gcry_error_t err;
size_t actual_len;
if (in_len > akcipher->max_dgst_len) {
error_setg(errp, "Data length is greater than key size: %d",
akcipher->max_dgst_len);
return ret;
}
if (rsa->padding_alg != QCRYPTO_RSA_PADDING_ALG_PKCS1) {
error_setg(errp, "Invalid padding %u", rsa->padding_alg);
return ret;
}
err = gcry_sexp_build(&dgst_sexp, NULL,
"(data (flags pkcs1) (hash %s %b))",
QCryptoHashAlgorithm_str(rsa->hash_alg),
in_len, in);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to build dgst: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_pk_sign(&sig_sexp, dgst_sexp, rsa->key);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to make signature: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
/* S-expression of signature: (sig-val (rsa (s s-mpi))) */
sig_sexp_item = gcry_sexp_find_token(sig_sexp, "s", 0);
if (!sig_sexp_item || gcry_sexp_length(sig_sexp_item) != 2) {
error_setg(errp, "Invalid signature result");
goto cleanup;
}
result = gcry_sexp_nth_data(sig_sexp_item, 1, &actual_len);
if (!result) {
error_setg(errp, "Invalid signature result");
goto cleanup;
}
if (actual_len > out_len) {
error_setg(errp, "Signature buffer length is too small");
goto cleanup;
}
memcpy(out, result, actual_len);
ret = actual_len;
cleanup:
gcry_sexp_release(dgst_sexp);
gcry_sexp_release(sig_sexp);
gcry_sexp_release(sig_sexp_item);
return ret;
}
static int qcrypto_gcrypt_rsa_verify(QCryptoAkCipher *akcipher,
const void *in, size_t in_len,
const void *in2, size_t in2_len,
Error **errp)
{
QCryptoGcryptRSA *rsa = (QCryptoGcryptRSA *)akcipher;
int ret = -1;
gcry_sexp_t sig_sexp = NULL, dgst_sexp = NULL;
gcry_error_t err;
if (in_len > akcipher->max_signature_len) {
error_setg(errp, "Signature length is greater than key size: %d",
akcipher->max_signature_len);
return ret;
}
if (in2_len > akcipher->max_dgst_len) {
error_setg(errp, "Data length is greater than key size: %d",
akcipher->max_dgst_len);
return ret;
}
if (rsa->padding_alg != QCRYPTO_RSA_PADDING_ALG_PKCS1) {
error_setg(errp, "Invalid padding %u", rsa->padding_alg);
return ret;
}
err = gcry_sexp_build(&sig_sexp, NULL,
"(sig-val (rsa (s %b)))", in_len, in);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to build signature: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_sexp_build(&dgst_sexp, NULL,
"(data (flags pkcs1) (hash %s %b))",
QCryptoHashAlgorithm_str(rsa->hash_alg),
in2_len, in2);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to build dgst: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
err = gcry_pk_verify(sig_sexp, dgst_sexp, rsa->key);
if (gcry_err_code(err) != 0) {
error_setg(errp, "Failed to verify signature: %s/%s",
gcry_strsource(err), gcry_strerror(err));
goto cleanup;
}
ret = 0;
cleanup:
gcry_sexp_release(dgst_sexp);
gcry_sexp_release(sig_sexp);
return ret;
}
QCryptoAkCipherDriver gcrypt_rsa = {
.encrypt = qcrypto_gcrypt_rsa_encrypt,
.decrypt = qcrypto_gcrypt_rsa_decrypt,
.sign = qcrypto_gcrypt_rsa_sign,
.verify = qcrypto_gcrypt_rsa_verify,
.free = qcrypto_gcrypt_rsa_free,
};
static QCryptoGcryptRSA *qcrypto_gcrypt_rsa_new(
const QCryptoAkCipherOptionsRSA *opt,
QCryptoAkCipherKeyType type,
const uint8_t *key, size_t keylen,
Error **errp)
{
QCryptoGcryptRSA *rsa = g_new0(QCryptoGcryptRSA, 1);
rsa->padding_alg = opt->padding_alg;
rsa->hash_alg = opt->hash_alg;
rsa->akcipher.driver = &gcrypt_rsa;
switch (type) {
case QCRYPTO_AKCIPHER_KEY_TYPE_PRIVATE:
if (qcrypto_gcrypt_parse_rsa_private_key(rsa, key, keylen, errp) != 0) {
goto error;
}
break;
case QCRYPTO_AKCIPHER_KEY_TYPE_PUBLIC:
if (qcrypto_gcrypt_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 rsa;
error:
qcrypto_gcrypt_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_RAW:
return true;
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;
}
default:
return false;
}
default:
return true;
}
}
