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okcrypto.cpp
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okcrypto.cpp
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/*
* Copyright (c) 2015-2022, CryptoTrust LLC.
* All rights reserved.
*
* Author : Tim Steiner <t@crp.to>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by CryptoTrust LLC. for
* the OnlyKey Project (https://crp.to/ok)"
*
* 4. The names "OnlyKey" and "CryptoTrust" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* admin@crp.to.
*
* 5. Products derived from this software may not be called "OnlyKey"
* nor may "OnlyKey" or "CryptoTrust" appear in their names without
* specific prior written permission. For written permission, please
* contact admin@crp.to.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by CryptoTrust LLC. for
* the OnlyKey Project (https://crp.to/ok)"
*
* 7. Redistributions in any form must be accompanied by information on
* how to obtain complete source code for this software and any
* accompanying software that uses this software. The source code
* must either be included in the distribution or be available for
* no more than the cost of distribution plus a nominal fee, and must
* be freely redistributable under reasonable conditions. For a
* binary file, complete source code means the source code for all
* modules it contains.
*
* NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS
* ARE GRANTED BY THIS LICENSE. IF SOFTWARE RECIPIENT INSTITUTES PATENT
* LITIGATION AGAINST ANY ENTITY (INCLUDING A CROSS-CLAIM OR COUNTERCLAIM
* IN A LAWSUIT) ALLEGING THAT THIS SOFTWARE (INCLUDING COMBINATIONS OF THE
* SOFTWARE WITH OTHER SOFTWARE OR HARDWARE) INFRINGES SUCH SOFTWARE
* RECIPIENT'S PATENT(S), THEN SUCH SOFTWARE RECIPIENT'S RIGHTS GRANTED BY
* THIS LICENSE SHALL TERMINATE AS OF THE DATE SUCH LITIGATION IS FILED. IF
* ANY PROVISION OF THIS AGREEMENT IS INVALID OR UNENFORCEABLE UNDER
* APPLICABLE LAW, IT SHALL NOT AFFECT THE VALIDITY OR ENFORCEABILITY OF THE
* REMAINDER OF THE TERMS OF THIS AGREEMENT, AND WITHOUT FURTHER ACTION
* BY THE PARTIES HERETO, SUCH PROVISION SHALL BE REFORMED TO THE MINIMUM
* EXTENT NECESSARY TO MAKE SUCH PROVISION VALID AND ENFORCEABLE. ALL
* SOFTWARE RECIPIENT'S RIGHTS UNDER THIS AGREEMENT SHALL TERMINATE IF IT
* FAILS TO COMPLY WITH ANY OF THE MATERIAL TERMS OR CONDITIONS OF THIS
* AGREEMENT AND DOES NOT CURE SUCH FAILURE IN A REASONABLE PERIOD OF
* TIME AFTER BECOMING AWARE OF SUCH NONCOMPLIANCE. THIS SOFTWARE IS
* PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <cstring>
#include "Arduino.h"
#include "onlykey.h"
#ifdef STD_VERSION
#include <SoftTimer.h>
#include "T3MacLib.h"
#include <RNG.h>
#include <AES.h>
#include <CBC.h>
#include <GCM.h>
#include <ChaCha.h>
#include <Crypto.h>
#include "sha1.h"
#include "sha512.h"
#include "yubikey.h"
#include "device.h"
#include "okcrypto.h"
#if !defined(MBEDTLS_CONFIG_FILE)
#include "config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
#include "memory_buffer_alloc.h"
#endif
/*************************************/
//RSA assignments
/*************************************/
uint8_t rsa_publicN[MAX_RSA_KEY_SIZE];
uint8_t rsa_private_key[MAX_RSA_KEY_SIZE];
/*************************************/
//ECC Authentication assignments
/*************************************/
uint8_t ecc_public_key[(MAX_ECC_KEY_SIZE*2)+1];
uint8_t ecc_private_key[MAX_ECC_KEY_SIZE];
/*************************************/
//HMACSHA1 assignments
/*************************************/
extern uint8_t keyboard_buffer[KEYBOARD_BUFFER_SIZE];
/*************************************/
extern uint8_t Challenge_button1;
extern uint8_t Challenge_button2;
extern uint8_t Challenge_button3;
extern uint8_t CRYPTO_AUTH;
uint8_t type;
extern int large_buffer_offset;
extern uint8_t resp_buffer[64];
extern uint8_t* large_buffer;
extern uint8_t recv_buffer[64];
extern int large_buffer_len;
extern uint8_t profilekey[32];
extern uint8_t packet_buffer_details[5];
extern uint8_t* large_resp_buffer;
extern uint8_t outputmode;
extern uint8_t pending_operation;
extern uint8_t transit_key[32];
void okcrypto_sign (uint8_t *buffer) {
uECC_set_rng(&RNG2);
uint8_t features = 0;
#ifdef DEBUG
Serial.println();
Serial.println("OKSIGN MESSAGE RECEIVED");
#endif
if (buffer[5] < 101) { //Slot 101-132 are for ECC, 1-4 are for RSA
features = okcore_flashget_RSA ((int)buffer[5]);
if (type == 0) {
hidprint("Error no key set in this slot");
fadeoff(0);
return;
}
#ifdef DEBUG
Serial.print(features, BIN);
#endif
if (is_bit_set(features, 6)) {
okcrypto_rsasign(buffer);
} else {
#ifdef DEBUG
Serial.print("Error key not set as signature key");
#endif
hidprint("Error key not set as signature key");
fadeoff(0);
}
return;
}
else if (buffer[5] > 200 && buffer[5] < 205) { // SSH/GPG Derive Key
okcrypto_ecdsa_eddsa(buffer);
} else {
if (buffer[5] > 100 && buffer[5] < 117) { // Keys 117 - 132 reserved
features = okcore_flashget_ECC ((int)buffer[5]);
}
if (type == 0) {
hidprint("Error no key set in this slot");
fadeoff(0);
return;
}
#ifdef DEBUG
Serial.print(features, BIN);
#endif
if (is_bit_set(features, 6)) {
okcrypto_ecdsa_eddsa(buffer);
} else {
#ifdef DEBUG
Serial.print("Error key not set as signature key");
#endif
hidprint("Error key not set as signature key");
fadeoff(0);
return;
}
}
}
void okcrypto_getpubkey (uint8_t *buffer) {
#ifdef DEBUG
Serial.println();
Serial.println("OKGETPUBKEY MESSAGE RECEIVED");
#endif
if (buffer[5] < 5 && !buffer[6]) { //Slot 101-132 are for ECC, 1-4 are for RSA
if (okcore_flashget_RSA ((int)buffer[5])) okcrypto_getrsapubkey(buffer);
} else if (buffer[5] < 117) { //128-132 are reserved
if (okcore_flashget_ECC ((int)buffer[5])) okcrypto_geteccpubkey(buffer);
} else if (buffer[5] == RESERVED_KEY_DERIVATION && buffer[6] <= KEYTYPE_CURVE25519) { // Generate key using provided data, return public
okcrypto_derive_key(buffer[6], buffer+7, NULL);
send_transport_response(ecc_public_key, 64, false, false);
}
}
void okcrypto_decrypt (uint8_t *buffer){
uECC_set_rng(&RNG2);
uint8_t features = 0;
#ifdef DEBUG
Serial.println();
Serial.println("OKDECRYPT MESSAGE RECEIVED");
#endif
if (buffer[5] < 101) { //Slot 101-132 are for ECC, 1-4 are for RSA
features = okcore_flashget_RSA (buffer[5]);
if (type == 0) {
hidprint("Error no key set in this slot");
fadeoff(0);
return;
}
if (is_bit_set(features, 5)) {
okcrypto_rsadecrypt(buffer);
} else {
#ifdef DEBUG
Serial.print("Error key not set as decryption key");
#endif
hidprint("Error key not set as decryption key");
fadeoff(0);
return;
}
} else if (buffer[5] > 200 && buffer[5] < 205) { // SSH/GPG Derive Key
okcrypto_ecdh(buffer);
} else {
if (buffer[5] > 100 && buffer[5] < 117) { // Keys 117 - 132 reserved
features = okcore_flashget_ECC ((int)buffer[5]);
}
if (type == 0) {
hidprint("Error no key set in this slot");
fadeoff(0);
return;
}
if (is_bit_set(features, 5)) {
okcrypto_ecdh(buffer);
} else {
#ifdef DEBUG
Serial.print("Error key not set as decryption key");
#endif
hidprint("Error key not set as decryption key");
fadeoff(0);
return;
}
}
}
void okcrypto_generate_random_key (uint8_t *buffer) {
uECC_set_rng(&RNG2);
//uint8_t backupslot;
//uint8_t temp[64];
#ifdef DEBUG
Serial.println();
Serial.println("GENERATE KEY MESSAGE RECEIVED");
#endif
if (buffer[5] > 100) { //Slot 101-132 are for ECC, 1-4 are for RSA
if ((buffer[6] & 0x0F) == 1) {
crypto_box_keypair(ecc_public_key, buffer+7); //Curve25519
} else if ((buffer[6] & 0x0F) == 2) {
const struct uECC_Curve_t * curve = uECC_secp256r1(); //P-256
uECC_make_key(ecc_public_key, buffer+7, curve);
} else if ((buffer[6] & 0x0F) == 3) {
const struct uECC_Curve_t * curve = uECC_secp256k1();
uECC_make_key(ecc_public_key, buffer+7, curve);
}
memset(ecc_public_key, 0, sizeof(ecc_public_key));
}
return;
}
void okcrypto_getrsapubkey (uint8_t *buffer) {
#ifdef DEBUG
byteprint(rsa_publicN, (type*128));
#endif
send_transport_response(rsa_publicN, (type*128), true, true);
}
void okcrypto_rsasign (uint8_t *buffer) {
uint8_t rsa_signature[(type*128)];
uint8_t rsa_signaturetemp[64];
char code[6];
if(!CRYPTO_AUTH) {
process_packets (buffer, 0, 0);
pending_operation=OKSIGN_ERR_USER_ACTION_PENDING;
}
else if (CRYPTO_AUTH == 4) {
if (large_buffer_offset != 28 && large_buffer_offset != 32 && large_buffer_offset != 48 && large_buffer_offset != 64) {
hidprint("Error with RSA data to sign invalid size");
#ifdef DEBUG
Serial.println("Error with RSA data to sign invalid size");
Serial.println(large_buffer_offset);
#endif
fadeoff(1);
large_buffer_offset = 0;
memset(large_buffer, 0, LARGE_BUFFER_SIZE); //wipe buffer
return;
}
okcore_aes_gcm_decrypt(large_buffer, packet_buffer_details[0], packet_buffer_details[1], profilekey, large_buffer_offset);
#ifdef DEBUG
Serial.println();
Serial.printf("RSA data to sign size=%d", large_buffer_offset);
Serial.println();
byteprint(large_buffer, large_buffer_offset);
#endif
pending_operation=CTAP2_ERR_OPERATION_PENDING;
memcpy(rsa_signaturetemp, large_buffer, large_buffer_offset);
memset(large_buffer, 0, LARGE_BUFFER_SIZE);
if (rsa_sign (large_buffer_offset, rsa_signaturetemp, rsa_signature) == 0) {
pending_operation=CTAP2_ERR_DATA_READY;
#ifdef DEBUG
Serial.print("Signature = ");
byteprint(rsa_signature, sizeof(rsa_signature));
#endif
outputmode=packet_buffer_details[2]; // Outputmode set at start of operation
if (outputmode == WEBAUTHN) {
send_transport_response(rsa_signature, (type*128), true, true);
}
else {
send_transport_response(rsa_signature, (type*128), false, false);
wipetasks();
}
} else {
pending_operation=0;
hidprint("Error with RSA signing");
}
fadeoff(85);
memset(rsa_signature, 0, sizeof(rsa_signature));
if (outputmode != WEBAUTHN) memset(large_resp_buffer, 0, LARGE_RESP_BUFFER_SIZE);
return;
} else {
#ifdef DEBUG
Serial.println("Waiting for challenge buttons to be pressed");
#endif
pending_operation=CTAP2_ERR_USER_ACTION_PENDING;
}
}
void okcrypto_rsadecrypt (uint8_t *buffer) {
unsigned int plaintext_len = 0;
if(!CRYPTO_AUTH) {
process_packets (buffer, 0, 0);
pending_operation=OKDECRYPT_ERR_USER_ACTION_PENDING;
}
else if (CRYPTO_AUTH == 4) {
if (large_buffer_offset != (type*128)) {
hidprint("Error with RSA data to decrypt invalid size");
#ifdef DEBUG
Serial.println("Error with RSA data to decrypt invalid size");
Serial.println(large_buffer_offset);
#endif
fadeoff(1);
large_buffer_offset = 0;
memset(large_buffer, 0, LARGE_BUFFER_SIZE); //wipe buffer
return;
}
okcore_aes_gcm_decrypt(large_buffer, packet_buffer_details[0], packet_buffer_details[1], profilekey, large_buffer_offset);
#ifdef DEBUG
Serial.println();
Serial.printf("RSA ciphertext blob size=%d", large_buffer_offset);
Serial.println();
byteprint(large_buffer, large_buffer_offset);
#endif
// decrypt ciphertext in large_buffer to temp_buffer
pending_operation=CTAP2_ERR_OPERATION_PENDING;
uint8_t rsa_decrypttemp[(type*128)];
memcpy(rsa_decrypttemp, large_buffer, large_buffer_offset);
memset(large_buffer, 0, LARGE_BUFFER_SIZE);
if (rsa_decrypt (&plaintext_len, rsa_decrypttemp, large_resp_buffer) == 0) {
pending_operation=CTAP2_ERR_DATA_READY;
#ifdef DEBUG
Serial.println();
Serial.print("Plaintext len = ");
Serial.println(plaintext_len);
Serial.print("Plaintext = ");
byteprint(large_resp_buffer, plaintext_len);
Serial.println();
#endif
outputmode=packet_buffer_details[2]; // Outputmode set at start of operation
if (outputmode == WEBAUTHN) {
send_transport_response(large_resp_buffer, plaintext_len, true, true);
}
else {
send_transport_response(large_resp_buffer, plaintext_len, false, false);
wipetasks();
}
} else {
pending_operation=0;
hidprint("Error with RSA decryption");
}
fadeoff(85);
if (outputmode != WEBAUTHN) memset(large_resp_buffer, 0, LARGE_RESP_BUFFER_SIZE);
return;
} else {
#ifdef DEBUG
Serial.println("Waiting for challenge buttons to be pressed");
#endif
pending_operation=CTAP2_ERR_USER_ACTION_PENDING;
}
}
void okcrypto_geteccpubkey (uint8_t *buffer) {
uint8_t pubkeylen = 64;
okcore_flashget_ECC (buffer[5]);
if (type==KEYTYPE_NACL && buffer[6]==KEYTYPE_CURVE25519) {
type = KEYTYPE_CURVE25519;
okcrypto_compute_pubkey();
}
#ifdef DEBUG
Serial.println("okcrypto_geteccpubkey MESSAGE RECEIVED");
byteprint(ecc_public_key, sizeof(ecc_public_key));
#endif
if (type==KEYTYPE_CURVE25519 || type==KEYTYPE_ED25519) pubkeylen = 32;
send_transport_response(ecc_public_key, pubkeylen, true, true);
memset(ecc_public_key, 0, MAX_ECC_KEY_SIZE*2); //wipe buffer
memset(ecc_private_key, 0, MAX_ECC_KEY_SIZE); //wipe buffer
}
void okcrypto_derive_key (uint8_t ktype, uint8_t *data, uint8_t slot) {
if (!slot) { //SHA256 KDF used for SSH and challenge-response
okcore_flashget_ECC (RESERVED_KEY_DERIVATION); //Default Key stored in ECC slot 32
memset(ecc_public_key, 0, sizeof(ecc_public_key));
SHA256_CTX ekey;
sha256_init(&ekey);
sha256_update(&ekey, ecc_private_key, 32); //Add default key to ekey
sha256_update(&ekey, data, 32); //Add provided data to ekey
sha256_final(&ekey, ecc_private_key); //Create hash and store
#ifdef DEBUG
Serial.println();
Serial.println("Agent derivation private key");
byteprint(ecc_private_key,32);
#endif
} else if (slot==RESERVED_KEY_WEB_DERIVATION) { //HMAC SHA256 KDF used for web requests
okcore_flashget_ECC (slot);
#ifdef DEBUG
Serial.println();
Serial.println("Web derivation key");
byteprint(ecc_private_key,32);
Serial.println("Other data");
byteprint(data,33);
#endif
// HKDF Reference: RFC5869 - https://tools.ietf.org/html/rfc5869
okcrypto_hkdf(data, ecc_private_key, ecc_private_key, 32);
#ifdef DEBUG
Serial.println();
Serial.println("HKDF Key");
byteprint(ecc_private_key,32);
#endif
}
type=ktype;
okcrypto_compute_pubkey();
}
void okcrypto_ecdsa_eddsa(uint8_t *buffer)
{
uint8_t ecc_signature[64];
uint8_t hash[64];
uint8_t len = 0;
#ifdef DEBUG
Serial.println();
Serial.println("OKECDSA_EDDSA SIGN MESSAGE RECEIVED");
#endif
if (!CRYPTO_AUTH) {
process_packets (buffer, 0, 0);
pending_operation=OKSIGN_ERR_USER_ACTION_PENDING;
}
else if (CRYPTO_AUTH == 4) {
//if (outputmode == RAW_USB && !derived_key_challenge_mode && !stored_key_challenge_mod) {
//}
okcore_aes_gcm_decrypt(large_buffer, packet_buffer_details[0], packet_buffer_details[1], profilekey, large_buffer_offset);
#ifdef DEBUG
Serial.println();
Serial.print("ECC blob size of ");
Serial.println(large_buffer_offset);
byteprint(large_buffer, large_buffer_offset);
#endif
uint8_t tmp[32 + 32 + 64];
SHA256_HashContext ectx = {{&init_SHA256, &update_SHA256, &finish_SHA256, 64, 32, tmp}};
if (buffer[5] > 200) {
if (buffer[5] == 201) {
//Used by SSH, old version used 132, new version uses 201 for type 1
okcrypto_derive_key(1, large_buffer+(large_buffer_offset-32), NULL);
}
else if (buffer[5] == 202) {
okcrypto_derive_key(2, large_buffer+(large_buffer_offset-32), NULL);
}
else if (buffer[5] == 203) {
okcrypto_derive_key(3, large_buffer+(large_buffer_offset-32), NULL);
} else if (buffer[5] == 211) {
okcrypto_derive_key(1, large_buffer+(large_buffer_offset-32), RESERVED_KEY_WEB_DERIVATION);
}
else if (buffer[5] == 212) {
okcrypto_derive_key(2, large_buffer+(large_buffer_offset-32), RESERVED_KEY_WEB_DERIVATION);
}
else if (buffer[5] == 213) {
okcrypto_derive_key(3, large_buffer+(large_buffer_offset-32), RESERVED_KEY_WEB_DERIVATION);
}
large_buffer_offset = large_buffer_offset - 32;
}
else if (buffer[5] >= 101 && buffer[5] <= 116) {
// Not using derived key, using stored key
okcore_flashget_ECC (buffer[5]); //Default Key stored in ECC slot 32
} else {
return;
}
if (large_buffer_offset == 32 || large_buffer_offset == 64) { // Hash and sign data if larger than 32 bytes, if 32 bytes sign data
memcpy(hash, large_buffer, large_buffer_offset);
} else {
SHA256_CTX msghash;
sha256_init(&msghash);
sha256_update(&msghash, large_buffer, large_buffer_offset);
sha256_final(&msghash, hash); //Create hash and store
if (type!=0x01) large_buffer_offset = 32;
}
#ifdef DEBUG
Serial.println("Signature Hash ");
byteprint(hash, large_buffer_offset);
Serial.print("Type");
Serial.println(type);
Serial.println("Private ");
byteprint(ecc_private_key, sizeof(ecc_private_key));
#endif
pending_operation=CTAP2_ERR_OPERATION_PENDING;
if (type==0x01) Ed25519::sign(ecc_signature, ecc_private_key, ecc_public_key, large_buffer, large_buffer_offset);
else if (type==0x02) {
const struct uECC_Curve_t * curve = uECC_secp256r1(); //P-256
if (!uECC_sign_deterministic(ecc_private_key,
hash,
large_buffer_offset,
&ectx.uECC,
ecc_signature,
curve)) {
#ifdef DEBUG
Serial.println("Signature Failed ");
#endif
}
}
else if (type==0x03) {
const struct uECC_Curve_t * curve = uECC_secp256k1();
if (!uECC_sign_deterministic(ecc_private_key,
hash,
large_buffer_offset,
&ectx.uECC,
ecc_signature,
curve)) {
#ifdef DEBUG
Serial.println("Signature Failed ");
#endif
}
}
#ifdef DEBUG
Serial.print("Signature=");
byteprint(ecc_signature, 64);
#endif
pending_operation=CTAP2_ERR_DATA_READY;
outputmode=packet_buffer_details[2]; // Outputmode set at start of operation
if (outputmode == WEBAUTHN) {
send_transport_response (ecc_signature, 64, true, true);
}
else {
send_transport_response (ecc_signature, 64, true, true);
wipetasks();
}
// Stop the fade in
fadeoff(85);
memset(large_buffer, 0, LARGE_BUFFER_SIZE);
memset(ecc_public_key, 0, sizeof(ecc_public_key)); //wipe buffer
memset(ecc_private_key, 0, sizeof(ecc_private_key)); //wipe buffer
return;
} else {
#ifdef DEBUG
Serial.println("Waiting for challenge buttons to be pressed");
#endif
pending_operation=CTAP2_ERR_USER_ACTION_PENDING;
}
}
void okcrypto_ecdh(uint8_t *buffer) {
uint8_t temp[65] = {0};
uint8_t resplen = 64;
#ifdef DEBUG
Serial.println();
Serial.println("OKECDH MESSAGE RECEIVED");
#endif
if(!CRYPTO_AUTH) {
process_packets (buffer, 0, 0);
pending_operation=OKDECRYPT_ERR_USER_ACTION_PENDING;
}
else if (CRYPTO_AUTH == 4) {
okcore_aes_gcm_decrypt(large_buffer, packet_buffer_details[0], packet_buffer_details[1], profilekey, large_buffer_offset);
#ifdef DEBUG
Serial.println();
Serial.print("ECC blob size of ");
Serial.println(large_buffer_offset);
byteprint(large_buffer, large_buffer_offset);
#endif
if (buffer[5] > 201) {
if (buffer[5] == 202) {
okcrypto_derive_key(2, large_buffer+(large_buffer_offset-32), NULL);
}
else if (buffer[5] == 203) {
okcrypto_derive_key(3, large_buffer+(large_buffer_offset-32), NULL);
}
else if (buffer[5] == 204) {
okcrypto_derive_key(4, large_buffer+(large_buffer_offset-32), NULL);
} else if (buffer[5] == 212) {
okcrypto_derive_key(2, large_buffer+(large_buffer_offset-32), RESERVED_KEY_WEB_DERIVATION);
}
else if (buffer[5] == 213) {
okcrypto_derive_key(3, large_buffer+(large_buffer_offset-32), RESERVED_KEY_WEB_DERIVATION);
}
else if (buffer[5] == 214) {
okcrypto_derive_key(4, large_buffer+(large_buffer_offset-32), RESERVED_KEY_WEB_DERIVATION);
}
large_buffer_offset = large_buffer_offset - 32; //Remove derivation data hash
}
else if (buffer[5] >= 101 && buffer[5] <= 116) {
// Not using derived key, using stored key
okcore_flashget_ECC (buffer[5]);
} else {
return;
}
if (type==2 || type==3) type+=100; // Different shared secret method required, multiply points and return x and y
if (type==1) {
type=4; // Use Curve25519 scalar multiply
resplen = 32;
okcrypto_compute_pubkey();
}
if (large_buffer_offset == 33 || large_buffer_offset == 65) { // Remove public key first byte 0x04 or 0x40 for Trezor agent
large_buffer_offset--;
memcpy(ecc_public_key, large_buffer+1, large_buffer_offset);
} else if (large_buffer_offset == 32 || large_buffer_offset == 64) {
memcpy(ecc_public_key, large_buffer, large_buffer_offset);
}
pending_operation=CTAP2_ERR_USER_ACTION_PENDING;
// Use ecc_private_key and provided pubkey to generate shared secret
if (large_buffer_offset == 64 || large_buffer_offset == 32) { // Public key sizes
if (okcrypto_shared_secret (ecc_public_key, temp)) {
//Error
}
}
#ifdef DEBUG
Serial.println("Input public");
byteprint(ecc_public_key, large_buffer_offset);
Serial.println("Private");
byteprint(ecc_private_key, sizeof(ecc_private_key));
Serial.print("Type");
Serial.println(type);
Serial.print("Shared Secret =");
byteprint(temp, large_buffer_offset);
#endif
pending_operation=CTAP2_ERR_DATA_READY;
outputmode=packet_buffer_details[2]; // Outputmode set at start of operation
if (outputmode == WEBAUTHN) {
send_transport_response (temp, resplen, true, true);
}
else {
send_transport_response (temp, resplen, true, true);
wipetasks();
}
// Stop the fade in
fadeoff(85);
memset(large_buffer, 0, LARGE_BUFFER_SIZE);
memset(ecc_public_key, 0, sizeof(ecc_public_key)); //wipe buffer
memset(ecc_private_key, 0, sizeof(ecc_private_key)); //wipe buffer
return;
} else {
#ifdef DEBUG
Serial.println("Waiting for challenge buttons to be pressed");
#endif
}
}
void okcrypto_hmacsha1 () {
uint8_t temp[32];
uint8_t inputlen;
uint8_t slot = keyboard_buffer[64];
uint16_t crc;
extern uint8_t setBuffer[9];
uint8_t *ptr;
#ifdef DEBUG
Serial.println();
Serial.println("GENERATE HMACSHA1 MESSAGE RECEIVED");
Serial.print("SLOT = ");
Serial.println(slot);
#endif
if (CRYPTO_AUTH == 4) {
if(!check_crc(keyboard_buffer)) {
memset(setBuffer, 0, 9);
memset(keyboard_buffer, 0, KEYBOARD_BUFFER_SIZE);
return;
}
outputmode=RAW_USB;
if (slot == 0x38) { //HMAC Slot 2 selected, 0x08 for slot 2, 0x00 for slot 1
okcore_flashget_ECC (RESERVED_KEY_HMACSHA1_2); //ECC slot 129 reserved for HMAC Slot 2 key
} else if (slot == 0x30){ //HMAC Slot 2 selected, 0x00 for slot 1
okcore_flashget_ECC (RESERVED_KEY_HMACSHA1_1); //ECC slot 130 reserved for HMAC Slot 1 key
} else if (slot >= 1 && slot <= 24) {
okcore_flashget_hmac(ecc_private_key, slot);
}
if (type == 0) { //Generate a key using the default key in slot 132 if there is no key set in slot
// Derive key from SHA256 hash of default key and added data temp
for(int i=0; i<32; i++) {
temp[i] = i + slot;
}
okcrypto_derive_key(0, temp, NULL);
}
outputmode=KEYBOARD_USB;
// Variable buffer size
// Any challenge less than 16 bytes in size is treated as 16 bytes, this means response will be different than Yubikey response
if (keyboard_buffer[57] == 0x20 && keyboard_buffer[58] == 0x20 && keyboard_buffer[59] == 0x20 && keyboard_buffer[60] == 0x20 && keyboard_buffer[61] == 0x20 && keyboard_buffer[62] == 0x20 && keyboard_buffer[63] == 0x20) {
inputlen = 32; //KeepassXC uses 0x20 for empty buffer
} else {
int i;
for (i = 63; i >= 15; i--) {
if (keyboard_buffer[i] != 0) { //YubiKey personalization tool uses 0 for empty buffer
break;
}
}
inputlen = i+1;
}
#ifdef DEBUG
Serial.print("HMACSHA1 Input = ");
byteprint(keyboard_buffer, 70);
Serial.print("Input Length");
Serial.println(inputlen);
#endif
//Load HMAC Key
Sha1.initHmac(ecc_private_key, 20);
//Generate HMACSHA1
Sha1.write(keyboard_buffer, inputlen);
ptr=keyboard_buffer;
ptr = Sha1.resultHmac();
memcpy(temp, ptr, 20);
memset(ecc_private_key, 0, 32);
#ifdef DEBUG
Serial.print("HMAC for CRC Input = ");
byteprint(temp, 20);
#endif
//Generate CRC of Output
crc = yubikey_crc16 (temp, 20);
memcpy(keyboard_buffer, temp, 7);
keyboard_buffer[7] = 0xC0; //Part 1 of HMAC
memcpy(keyboard_buffer+8, temp+7, 7);
keyboard_buffer[15] = 0xC1; //Part 2 of HMAC
memcpy(keyboard_buffer+16, temp+14, 6);
keyboard_buffer[23] = 0xC2; //Part 3 of HMAC
memset(keyboard_buffer +24, 0, KEYBOARD_BUFFER_SIZE-24);
// CRC Bytes expected are CRC-16/X-25 but yubikey_crc16 generates CRC-16/MCRF4XX,
// Weird that firmware uses a different CRC-16 than https://github.com/Yubico/yubikey-personalization/blob/master/ykcore/
// We can XOR CRC-16/MCRF4XX output to convert to CRC-16/X-25
crc ^= 0xFFFF;
keyboard_buffer[22] = crc & 0xFF;
keyboard_buffer[24] = crc >> 8;
keyboard_buffer[31] = 0xC3; //Part 4 contains part of CRC and mystery byte keyboard_buffer[28]
keyboard_buffer[28] = 0x4B;
#ifdef DEBUG
Serial.print("HMACSHA1 Output = ");
byteprint(keyboard_buffer, KEYBOARD_BUFFER_SIZE);
Serial.print("CRC = ");
Serial.println(crc);
#endif
return;
} else {
#ifdef DEBUG
Serial.println("Waiting for challenge buttons to be pressed");
#endif
}
}
int okcrypto_shared_secret (uint8_t *pub, uint8_t *secret) {
const struct uECC_Curve_t * curve;
switch (type) {
case KEYTYPE_NACL:
if (crypto_box_beforenm(secret, pub, ecc_private_key)) return 1;
else return 0;
case KEYTYPE_P256R1:
curve = uECC_secp256r1();
if (uECC_shared_secret(pub, ecc_private_key, secret, curve)) {
return 0;
}
else return 1;
case KEYTYPE_P256K1:
curve = uECC_secp256k1();
if (uECC_shared_secret(pub, ecc_private_key, secret, curve)) {
return 0;
}
else return 1;
case KEYTYPE_CURVE25519:
Curve25519::eval(secret, ecc_private_key, pub);
return 0;
case KEYTYPE_ECDH_P256R:
curve = uECC_secp256r1();
if (uECC_shared_secret2(pub, ecc_private_key, secret, curve)) {
return 0;
}
case KEYTYPE_ECDH_P256K:
curve = uECC_secp256k1();
if (uECC_shared_secret2(pub, ecc_private_key, secret, curve)) {
return 0;
}
default:
hidprint("Error ECC type incorrect");
return 1;
}
}
mbedtls_md_context_t sha512_ctx;
void crypto_sha512_init() {
mbedtls_md_type_t md_type = MBEDTLS_MD_SHA512;
mbedtls_md_init (&sha512_ctx);
mbedtls_md_setup(&sha512_ctx, mbedtls_md_info_from_type(md_type), 0); // 0 = not using HMAC
}
void crypto_sha512_update(const uint8_t * data, size_t len) {
mbedtls_md_update (&sha512_ctx, data, len);
}
void crypto_sha512_final(uint8_t * hash) {
mbedtls_md_finish (&sha512_ctx, hash);
mbedtls_md_free (&sha512_ctx);
}
void okcrypto_aes_crypto_box (uint8_t *buffer, int len, bool open) {
uint8_t iv[12];
memset(iv, 0, 12);
//msgcount++;
//int ctr = ((msgcount>>24)&0xff) | // move byte 3 to byte 0
// ((msgcount<<8)&0xff0000) | // move byte 1 to byte 2
// ((msgcount>>8)&0xff00) | // move byte 2 to byte 1
// ((msgcount<<24)&0xff000000); // byte 0 to byte 3
//memcpy(iv, &ctr, 4);
#ifdef DEBUG
Serial.print("IV");
byteprint(iv, 12);
#endif
#ifdef DEBUG
Serial.print("Key");
byteprint(transit_key, 32);
#endif
#ifdef DEBUG
Serial.print("buffer");
byteprint(buffer, len);
#endif
if (open) {
okcrypto_aes_gcm_decrypt2 (buffer, iv, transit_key, len, false);
}
else {
okcrypto_aes_gcm_encrypt2 (buffer, iv, transit_key, len, false);
}
}
int rsa_sign (int mlen, const uint8_t *msg, uint8_t *out)
{
//mbedtls_rsa_self_test(1);
mbedtls_md_type_t md_type = MBEDTLS_MD_NONE;
int ret = 0;
static mbedtls_rsa_context rsa;
uint8_t rsa_ciphertext[(type*128)];
mbedtls_mpi P1, Q1, H;
mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 );
mbedtls_mpi_init (&P1); mbedtls_mpi_init (&Q1); mbedtls_mpi_init (&H);
rsa.len = (type*128);
MBEDTLS_MPI_CHK( mbedtls_mpi_lset (&rsa.E, 0x10001) );
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary (&rsa.P, &rsa_private_key[0], ((type*128) / 2) ));
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary (&rsa.Q, &rsa_private_key[((type*128) / 2)], ((type*128) / 2) ));
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi (&rsa.N, &rsa.P, &rsa.Q) );
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int (&P1, &rsa.P, 1) );
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int (&Q1, &rsa.Q, 1) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi (&H, &P1, &Q1) );
MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod (&rsa.D , &rsa.E, &H) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi (&rsa.DP, &rsa.D, &P1) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi (&rsa.DQ, &rsa.D, &Q1) );
MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod (&rsa.QP, &rsa.Q, &rsa.P) );
#ifdef DEBUG
Serial.printf( "\nRSA len = " );
Serial.println(rsa.len);
#endif
ret = mbedtls_rsa_check_privkey( &rsa );
cleanup:
mbedtls_mpi_free (&P1); mbedtls_mpi_free (&Q1); mbedtls_mpi_free (&H);
if( ret != 0 ) {
#ifdef DEBUG
Serial.printf("Error with key check =%d", ret);
#endif
hidprint("Error invalid key, key check failed");
return -1;
}
if (ret == 0) {
#ifdef DEBUG
Serial.print("RSA sign messege length = ");
Serial.println(mlen);
#endif
if (mlen > ((type*128)-11)) mlen = ((type*128)-11);
switch (mlen) {
case 64:
md_type = MBEDTLS_MD_SHA512;
break;
case 48:
md_type = MBEDTLS_MD_SHA384;
break;
case 32:
md_type = MBEDTLS_MD_SHA256;
break;
case 28:
md_type = MBEDTLS_MD_SHA224;
break;
//case 20:
// md_type = MBEDTLS_MD_RIPEMD160;
//break;
default:
break;
}
ret = mbedtls_rsa_rsassa_pkcs1_v15_sign (&rsa, mbedtls_rand, NULL, MBEDTLS_RSA_PRIVATE, md_type, mlen, msg, rsa_ciphertext);
#ifdef DEBUG
Serial.print("Hash Value = ");
byteprint((uint8_t *)msg, mlen);
#endif
memcpy (out, rsa_ciphertext, (type*128));
/*int ret2 = mbedtls_rsa_rsassa_pkcs1_v15_verify ( &rsa, NULL, NULL, MBEDTLS_RSA_PUBLIC, MBEDTLS_MD_NONE, mlen, msg, rsa_ciphertext );
#ifdef DEBUG
Serial.print("Hash Value = ");
byteprint((uint8_t *)msg, mlen);
#endif
if( ret2 != 0 ) {
#ifdef DEBUG
Serial.print("Signature Verification Failed ");
Serial.println(ret2);
#endif
return -1;
}*/
}
mbedtls_rsa_free (&rsa);
if (ret == 0) {
#ifdef DEBUG
Serial.println("completed successfully");
#endif
return 0;
}
else {
#ifdef DEBUG
Serial.print("MBEDTLS_ERR_RSA_XXX error code ");
Serial.println(ret);
#endif
hidprint("invalid data, or data does not match key");
return -1;
}
}
int rsa_decrypt (unsigned int *olen, const uint8_t *in, uint8_t *out) {
mbedtls_mpi P1, Q1, H;
int ret = 0;
static mbedtls_rsa_context rsa;
#ifdef DEBUG
Serial.printf ("\nRSA decrypt:");
Serial.println ((uint32_t)&ret);
#endif
mbedtls_rsa_init (&rsa, MBEDTLS_RSA_PKCS_V15, 0);
mbedtls_mpi_init (&P1); mbedtls_mpi_init (&Q1); mbedtls_mpi_init (&H);
rsa.len = (type*128);
MBEDTLS_MPI_CHK( mbedtls_mpi_lset (&rsa.E, 0x10001) );
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary (&rsa.P, &rsa_private_key[0], ((type*128) / 2) ));
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary (&rsa.Q, &rsa_private_key[((type*128) / 2)], ((type*128) / 2) ));
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi (&rsa.N, &rsa.P, &rsa.Q) );
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int (&P1, &rsa.P, 1) );
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int (&Q1, &rsa.Q, 1) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi (&H, &P1, &Q1) );
MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod (&rsa.D , &rsa.E, &H) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi (&rsa.DP, &rsa.D, &P1) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi (&rsa.DQ, &rsa.D, &Q1) );
MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod (&rsa.QP, &rsa.Q, &rsa.P) );
#ifdef DEBUG