wolfssl-examples/pk/srp/srp.c

278 lines
7.5 KiB
C

/* srp.c
*
* Copyright (C) 2006-2020 wolfSSL Inc.
*
* This file is part of wolfSSL. (formerly known as CyaSSL)
*
* wolfSSL is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* wolfSSL 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#ifndef WOLFSSL_USER_SETTINGS
#include <wolfssl/options.h>
#endif
#include <wolfssl/wolfcrypt/settings.h>
#include <wolfssl/ssl.h>
#include <wolfssl/wolfcrypt/srp.h>
#include <wolfssl/wolfcrypt/error-crypt.h>
#include "srp_params.h"
#include "srp_store.h"
#include <stdio.h>
#ifdef WOLFCRYPT_HAVE_SRP
/* Create a client side SRP object */
static int client_init(Srp** srp)
{
int ret = 0;
*srp = XMALLOC(sizeof(Srp), NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (*srp == NULL) {
ret = MEMORY_E;
}
if (ret == 0) {
ret = wc_SrpInit(*srp, SRP_TYPE_SHA, SRP_CLIENT_SIDE);
}
return ret;
}
/* Calcuate the client's public key */
static int client_calc_public(Srp* srp, const char* username, char* password,
byte* salt, word32 saltSz, byte* pubKey,
word32* pubKeySz)
{
int ret;
ret = wc_SrpSetUsername(srp, (byte*)username, XSTRLEN(username));
if (ret == 0) {
ret = wc_SrpSetParams(srp, srp_n_640, sizeof(srp_n_640),
srp_g_640, sizeof(srp_g_640),
salt, saltSz);
}
if (ret == 0) {
ret = wc_SrpSetPassword(srp, (byte*)password, XSTRLEN(password));
}
if (ret == 0) {
ret = wc_SrpGetPublic(srp, pubKey, pubKeySz);
}
return ret;
}
/* Compute the client's proof */
static int client_compute_proof(Srp *srp, byte* clientPubKey,
word32 clientPubKeySz, byte* serverPubKey,
word32 serverPubKeySz, byte* proof,
word32* proofSz)
{
int ret;
ret = wc_SrpComputeKey(srp, clientPubKey, clientPubKeySz, serverPubKey,
serverPubKeySz);
if (ret == 0) {
ret = wc_SrpGetProof(srp, proof, proofSz);
}
return ret;
}
/* Verify the server's proof */
static int client_verify_proof(Srp *srp, byte* proof, word32 proofSz)
{
return wc_SrpVerifyPeersProof(srp, proof, proofSz);
}
/* Create a server side SRP object */
static int server_init(Srp** srp)
{
int ret = 0;
*srp = XMALLOC(sizeof(Srp), NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (*srp == NULL) {
ret = MEMORY_E;
}
if (ret == 0) {
ret = wc_SrpInit(*srp, SRP_TYPE_SHA, SRP_SERVER_SIDE);
}
return ret;
}
/* Calcuate the server's public key */
static int server_calc_public(Srp* srp, const char* username, byte* salt,
word32 saltSz, byte* verifier, word32 vSz,
byte* pubKey, word32* pubKeySz)
{
int ret;
ret = wc_SrpSetUsername(srp, (byte*)username, XSTRLEN(username));
if (ret == 0) {
ret = wc_SrpSetParams(srp, srp_n_640, sizeof(srp_n_640),
srp_g_640, sizeof(srp_g_640),
salt, saltSz);
}
if (ret == 0) {
ret = wc_SrpSetVerifier(srp, verifier, vSz);
}
if (ret == 0) {
ret = wc_SrpGetPublic(srp, pubKey, pubKeySz);
}
return ret;
}
/* Check the client's proof and generate the server's proof */
static int server_compute_proof(Srp *srp, byte* clientPubKey,
word32 clientPubKeySz, byte* serverPubKey,
word32 serverPubKeySz, byte* clientProof,
word32 clientProofSz, byte* proof,
word32* proofSz)
{
int ret;
ret = wc_SrpComputeKey(srp, clientPubKey, clientPubKeySz, serverPubKey,
serverPubKeySz);
if (ret == 0) {
ret = wc_SrpVerifyPeersProof(srp, clientProof, clientProofSz);
}
if (ret == 0) {
ret = wc_SrpGetProof(srp, proof, proofSz);
}
return ret;
}
/* Dispose of the SRP object */
static void srp_free(Srp* srp)
{
if (srp != NULL) {
wc_SrpTerm(srp);
XFREE(srp, NULL, DYNAMIC_TYPE_TMP_BUFFER);
}
}
/* Main entry point. */
int main(int argc, char* argv[])
{
int ret = 0;
Srp* cli = NULL;
Srp* srv = NULL;
char* password = NULL;
char* username = NULL;
byte serverPubKey[80];
word32 serverPubKeySz = (word32)sizeof(serverPubKey);
byte clientPubKey[80];
word32 clientPubKeySz = (word32)sizeof(clientPubKey);
byte clientProof[SRP_MAX_DIGEST_SIZE];
word32 clientProofSz = (word32)sizeof(clientProof);
byte serverProof[SRP_MAX_DIGEST_SIZE];
word32 serverProofSz = (word32)sizeof(serverProof);
if (argc < 3) {
fprintf(stderr, "Usage: srp <username> <password>\n");
return 1;
}
username = argv[1];
password = argv[2];
/* Initialize wolfSSL library. */
wolfSSL_Init();
if (XSTRNCMP(username, srp_username, XSTRLEN(srp_username)) != 0) {
printf("Username does not match stored verfier\n");
ret = -1;
}
if (ret == 0) {
ret = client_init(&cli);
}
if (ret == 0) {
ret = client_calc_public(cli, username, password, (byte*)salt,
sizeof(salt), clientPubKey, &clientPubKeySz);
}
if (ret == 0) {
ret = server_init(&srv);
}
if (ret == 0) {
ret = server_calc_public(srv, username, (byte*)salt, sizeof(salt),
(byte*)verifier, sizeof(verifier),
serverPubKey, &serverPubKeySz);
}
if (ret == 0) {
ret = client_compute_proof(cli, clientPubKey, clientPubKeySz,
serverPubKey, serverPubKeySz, clientProof,
&clientProofSz);
}
if (ret == 0) {
ret = server_compute_proof(srv, clientPubKey, clientPubKeySz,
serverPubKey, serverPubKeySz, clientProof,
clientProofSz, serverProof, &serverProofSz);
if (ret == 0) {
printf("Server verified client proof\n");
}
else {
printf("Server could not verify client proof\n");
}
}
if (ret == 0) {
ret = client_verify_proof(cli, serverProof, serverProofSz);
if (ret == 0) {
printf("Client verified server proof\n");
}
else {
printf("Client could not verify server proof\n");
}
}
srp_free(cli);
srp_free(srv);
/* Cleanup wolfSSL library. */
wolfSSL_Cleanup();
if (ret == 0)
printf("Done\n");
else {
char buffer[80];
printf("Error: %d, %s\n", ret, wolfSSL_ERR_error_string(ret, buffer));
}
return (ret == 0) ? 0 : 1;
}
#else
int main(int argc, char* argv[])
{
(void)argc;
(void)argv;
fprintf(stderr, "Must build wolfSSL with SRP enabled for this example\n");
return 0;
}
#endif