mirror of
https://github.com/Mbed-TLS/mbedtls.git
synced 2024-12-29 09:21:19 +00:00
289 lines
8.3 KiB
C
289 lines
8.3 KiB
C
/*
|
|
* Diffie-Hellman-Merkle key exchange (client side)
|
|
*
|
|
* Copyright The Mbed TLS Contributors
|
|
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
|
|
*/
|
|
|
|
#include "mbedtls/build_info.h"
|
|
|
|
#include "mbedtls/platform.h"
|
|
/* md.h is included this early since MD_CAN_XXX macros are defined there. */
|
|
#include "mbedtls/md.h"
|
|
|
|
#if defined(MBEDTLS_AES_C) && defined(MBEDTLS_DHM_C) && \
|
|
defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_NET_C) && \
|
|
defined(MBEDTLS_RSA_C) && defined(MBEDTLS_SHA256_C) && \
|
|
defined(MBEDTLS_FS_IO) && defined(MBEDTLS_CTR_DRBG_C)
|
|
#include "mbedtls/net_sockets.h"
|
|
#include "mbedtls/aes.h"
|
|
#include "mbedtls/dhm.h"
|
|
#include "mbedtls/rsa.h"
|
|
#include "mbedtls/sha256.h"
|
|
#include "mbedtls/entropy.h"
|
|
#include "mbedtls/ctr_drbg.h"
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#endif
|
|
|
|
#define SERVER_NAME "localhost"
|
|
#define SERVER_PORT "11999"
|
|
|
|
#if !defined(MBEDTLS_AES_C) || !defined(MBEDTLS_DHM_C) || \
|
|
!defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_NET_C) || \
|
|
!defined(MBEDTLS_RSA_C) || !defined(MBEDTLS_SHA256_C) || \
|
|
!defined(MBEDTLS_FS_IO) || !defined(MBEDTLS_CTR_DRBG_C)
|
|
int main(void)
|
|
{
|
|
mbedtls_printf("MBEDTLS_AES_C and/or MBEDTLS_DHM_C and/or MBEDTLS_ENTROPY_C "
|
|
"and/or MBEDTLS_NET_C and/or MBEDTLS_RSA_C and/or "
|
|
"PSA_WANT_ALG_SHA_256 and/or MBEDTLS_FS_IO and/or "
|
|
"MBEDTLS_CTR_DRBG_C and/or MBEDTLS_SHA1_C not defined.\n");
|
|
mbedtls_exit(0);
|
|
}
|
|
|
|
#elif defined(MBEDTLS_BLOCK_CIPHER_NO_DECRYPT)
|
|
int main(void)
|
|
{
|
|
mbedtls_printf("MBEDTLS_BLOCK_CIPHER_NO_DECRYPT defined.\n");
|
|
mbedtls_exit(0);
|
|
}
|
|
#else
|
|
|
|
|
|
int main(void)
|
|
{
|
|
FILE *f;
|
|
|
|
int ret = 1;
|
|
int exit_code = MBEDTLS_EXIT_FAILURE;
|
|
unsigned int mdlen;
|
|
size_t n, buflen;
|
|
mbedtls_net_context server_fd;
|
|
|
|
unsigned char *p, *end;
|
|
unsigned char buf[2048];
|
|
unsigned char hash[MBEDTLS_MD_MAX_SIZE];
|
|
mbedtls_mpi N, E;
|
|
const char *pers = "dh_client";
|
|
|
|
mbedtls_entropy_context entropy;
|
|
mbedtls_ctr_drbg_context ctr_drbg;
|
|
mbedtls_rsa_context rsa;
|
|
mbedtls_dhm_context dhm;
|
|
mbedtls_aes_context aes;
|
|
|
|
mbedtls_net_init(&server_fd);
|
|
mbedtls_dhm_init(&dhm);
|
|
mbedtls_aes_init(&aes);
|
|
mbedtls_ctr_drbg_init(&ctr_drbg);
|
|
mbedtls_mpi_init(&N);
|
|
mbedtls_mpi_init(&E);
|
|
|
|
/*
|
|
* 1. Setup the RNG
|
|
*/
|
|
mbedtls_printf("\n . Seeding the random number generator");
|
|
fflush(stdout);
|
|
|
|
mbedtls_entropy_init(&entropy);
|
|
if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy,
|
|
(const unsigned char *) pers,
|
|
strlen(pers))) != 0) {
|
|
mbedtls_printf(" failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
/*
|
|
* 2. Read the server's public RSA key
|
|
*/
|
|
mbedtls_printf("\n . Reading public key from rsa_pub.txt");
|
|
fflush(stdout);
|
|
|
|
if ((f = fopen("rsa_pub.txt", "rb")) == NULL) {
|
|
mbedtls_printf(" failed\n ! Could not open rsa_pub.txt\n" \
|
|
" ! Please run rsa_genkey first\n\n");
|
|
goto exit;
|
|
}
|
|
|
|
mbedtls_rsa_init(&rsa);
|
|
if ((ret = mbedtls_mpi_read_file(&N, 16, f)) != 0 ||
|
|
(ret = mbedtls_mpi_read_file(&E, 16, f)) != 0 ||
|
|
(ret = mbedtls_rsa_import(&rsa, &N, NULL, NULL, NULL, &E) != 0)) {
|
|
mbedtls_printf(" failed\n ! mbedtls_mpi_read_file returned %d\n\n", ret);
|
|
fclose(f);
|
|
goto exit;
|
|
}
|
|
fclose(f);
|
|
|
|
/*
|
|
* 3. Initiate the connection
|
|
*/
|
|
mbedtls_printf("\n . Connecting to tcp/%s/%s", SERVER_NAME,
|
|
SERVER_PORT);
|
|
fflush(stdout);
|
|
|
|
if ((ret = mbedtls_net_connect(&server_fd, SERVER_NAME,
|
|
SERVER_PORT, MBEDTLS_NET_PROTO_TCP)) != 0) {
|
|
mbedtls_printf(" failed\n ! mbedtls_net_connect returned %d\n\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
/*
|
|
* 4a. First get the buffer length
|
|
*/
|
|
mbedtls_printf("\n . Receiving the server's DH parameters");
|
|
fflush(stdout);
|
|
|
|
memset(buf, 0, sizeof(buf));
|
|
|
|
if ((ret = mbedtls_net_recv(&server_fd, buf, 2)) != 2) {
|
|
mbedtls_printf(" failed\n ! mbedtls_net_recv returned %d\n\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
n = buflen = (buf[0] << 8) | buf[1];
|
|
if (buflen < 1 || buflen > sizeof(buf)) {
|
|
mbedtls_printf(" failed\n ! Got an invalid buffer length\n\n");
|
|
goto exit;
|
|
}
|
|
|
|
/*
|
|
* 4b. Get the DHM parameters: P, G and Ys = G^Xs mod P
|
|
*/
|
|
memset(buf, 0, sizeof(buf));
|
|
|
|
if ((ret = mbedtls_net_recv(&server_fd, buf, n)) != (int) n) {
|
|
mbedtls_printf(" failed\n ! mbedtls_net_recv returned %d\n\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
p = buf, end = buf + buflen;
|
|
|
|
if ((ret = mbedtls_dhm_read_params(&dhm, &p, end)) != 0) {
|
|
mbedtls_printf(" failed\n ! mbedtls_dhm_read_params returned %d\n\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
n = mbedtls_dhm_get_len(&dhm);
|
|
if (n < 64 || n > 512) {
|
|
mbedtls_printf(" failed\n ! Invalid DHM modulus size\n\n");
|
|
goto exit;
|
|
}
|
|
|
|
/*
|
|
* 5. Check that the server's RSA signature matches
|
|
* the SHA-256 hash of (P,G,Ys)
|
|
*/
|
|
mbedtls_printf("\n . Verifying the server's RSA signature");
|
|
fflush(stdout);
|
|
|
|
p += 2;
|
|
|
|
if ((n = (size_t) (end - p)) != mbedtls_rsa_get_len(&rsa)) {
|
|
mbedtls_printf(" failed\n ! Invalid RSA signature size\n\n");
|
|
goto exit;
|
|
}
|
|
|
|
mdlen = (unsigned int) mbedtls_md_get_size(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256));
|
|
if (mdlen == 0) {
|
|
mbedtls_printf(" failed\n ! Invalid digest type\n\n");
|
|
goto exit;
|
|
}
|
|
|
|
if ((ret = mbedtls_sha256(buf, (int) (p - 2 - buf), hash, 0)) != 0) {
|
|
mbedtls_printf(" failed\n ! mbedtls_sha256 returned %d\n\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
if ((ret = mbedtls_rsa_pkcs1_verify(&rsa, MBEDTLS_MD_SHA256,
|
|
mdlen, hash, p)) != 0) {
|
|
mbedtls_printf(" failed\n ! mbedtls_rsa_pkcs1_verify returned %d\n\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
/*
|
|
* 6. Send our public value: Yc = G ^ Xc mod P
|
|
*/
|
|
mbedtls_printf("\n . Sending own public value to server");
|
|
fflush(stdout);
|
|
|
|
n = mbedtls_dhm_get_len(&dhm);
|
|
if ((ret = mbedtls_dhm_make_public(&dhm, (int) n, buf, n,
|
|
mbedtls_ctr_drbg_random, &ctr_drbg)) != 0) {
|
|
mbedtls_printf(" failed\n ! mbedtls_dhm_make_public returned %d\n\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
if ((ret = mbedtls_net_send(&server_fd, buf, n)) != (int) n) {
|
|
mbedtls_printf(" failed\n ! mbedtls_net_send returned %d\n\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
/*
|
|
* 7. Derive the shared secret: K = Ys ^ Xc mod P
|
|
*/
|
|
mbedtls_printf("\n . Shared secret: ");
|
|
fflush(stdout);
|
|
|
|
if ((ret = mbedtls_dhm_calc_secret(&dhm, buf, sizeof(buf), &n,
|
|
mbedtls_ctr_drbg_random, &ctr_drbg)) != 0) {
|
|
mbedtls_printf(" failed\n ! mbedtls_dhm_calc_secret returned %d\n\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
for (n = 0; n < 16; n++) {
|
|
mbedtls_printf("%02x", buf[n]);
|
|
}
|
|
|
|
/*
|
|
* 8. Setup the AES-256 decryption key
|
|
*
|
|
* This is an overly simplified example; best practice is
|
|
* to hash the shared secret with a random value to derive
|
|
* the keying material for the encryption/decryption keys,
|
|
* IVs and MACs.
|
|
*/
|
|
mbedtls_printf("...\n . Receiving and decrypting the ciphertext");
|
|
fflush(stdout);
|
|
|
|
ret = mbedtls_aes_setkey_dec(&aes, buf, 256);
|
|
if (ret != 0) {
|
|
goto exit;
|
|
}
|
|
|
|
memset(buf, 0, sizeof(buf));
|
|
|
|
if ((ret = mbedtls_net_recv(&server_fd, buf, 16)) != 16) {
|
|
mbedtls_printf(" failed\n ! mbedtls_net_recv returned %d\n\n", ret);
|
|
goto exit;
|
|
}
|
|
|
|
ret = mbedtls_aes_crypt_ecb(&aes, MBEDTLS_AES_DECRYPT, buf, buf);
|
|
if (ret != 0) {
|
|
goto exit;
|
|
}
|
|
buf[16] = '\0';
|
|
mbedtls_printf("\n . Plaintext is \"%s\"\n\n", (char *) buf);
|
|
|
|
exit_code = MBEDTLS_EXIT_SUCCESS;
|
|
|
|
exit:
|
|
|
|
mbedtls_net_free(&server_fd);
|
|
|
|
mbedtls_aes_free(&aes);
|
|
mbedtls_rsa_free(&rsa);
|
|
mbedtls_dhm_free(&dhm);
|
|
mbedtls_ctr_drbg_free(&ctr_drbg);
|
|
mbedtls_entropy_free(&entropy);
|
|
mbedtls_mpi_free(&N);
|
|
mbedtls_mpi_free(&E);
|
|
|
|
mbedtls_exit(exit_code);
|
|
}
|
|
#endif /* MBEDTLS_AES_C && MBEDTLS_DHM_C && MBEDTLS_ENTROPY_C &&
|
|
MBEDTLS_NET_C && MBEDTLS_RSA_C && PSA_WANT_ALG_SHA_256 &&
|
|
MBEDTLS_FS_IO && MBEDTLS_CTR_DRBG_C */
|