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solo1/ctap.c

1473 wiersze
40 KiB
C
Czysty Wina Historia

#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "cbor.h"
#include "ctap.h"
#include "ctap_errors.h"
#include "cose_key.h"
#include "crypto.h"
#include "util.h"
#include "log.h"
#define check_ret(r) _check_ret(r,__LINE__, __FILE__);\
if ((r) != CborNoError) return CTAP2_ERR_CBOR_PARSING;
#define PIN_TOKEN_SIZE 16
static uint8_t PIN_TOKEN[PIN_TOKEN_SIZE];
static CborEncoder * _ENCODER;
static void _check_ret(CborError ret, int line, const char * filename)
{
if (ret != CborNoError)
{
printf1("CborError: 0x%x: %s: %d: %s\n", ret, filename, line, cbor_error_string(ret));
/*exit(1);*/
}
}
static const char * cbor_value_get_type_string(const CborValue *value)
{
switch(cbor_value_get_type(value))
{
case CborIntegerType:
return "CborIntegerType";
break;
case CborByteStringType:
return "CborByteStringType";
break;
case CborTextStringType:
return "CborTextStringType";
break;
case CborArrayType:
return "CborArrayType";
break;
case CborMapType:
return "CborMapType";
break;
case CborTagType:
return "CborTagType";
break;
case CborSimpleType:
return "CborSimpleType";
break;
case CborBooleanType:
return "CborBooleanType";
break;
case CborNullType:
return "CborNullType";
break;
case CborUndefinedType:
return "CborUndefinedType";
break;
case CborHalfFloatType:
return "CborHalfFloatType";
break;
case CborFloatType:
return "CborFloatType";
break;
case CborDoubleType:
return "CborDoubleType";
break;
}
return "Invalid type";
}
/*static CborError cbor_value_map_find_value_by_int(const CborValue *map, const int key, CborValue * element)*/
/*{*/
/*size_t sz;*/
/*CborValue ckey, it;*/
/*int rkey;*/
/*int ret = cbor_value_get_map_length(map, &sz);*/
/*check_ret(ret);*/
/*cbor_value_enter_container(map, &it);*/
/*int i;*/
/*for (i = 0; i < sz; i++)*/
/*{*/
/*if (cbor_value_get_type(&it) == CborIntegerType)*/
/*{*/
/*ret = cbor_value_advance(&it);*/
/*check_ret(ret);*/
/*ret = cbor_value_get_int_checked(&it, &rkey);*/
/*check_ret(ret);*/
/*ret = cbor_value_advance(&it);*/
/*check_ret(ret);*/
/*}*/
/*else*/
/*{*/
/*cbor_value_advance(&it);*/
/*cbor_value_advance(&it);*/
/*}*/
/*}*/
/*return CborNoError;*/
/*}*/
uint8_t ctap_get_info(CborEncoder * encoder)
{
int ret;
CborEncoder array;
CborEncoder map;
CborEncoder options;
CborEncoder pins;
const int number_of_versions = 2;
ret = cbor_encoder_create_map(encoder, &map, 5);
check_ret(ret);
{
ret = cbor_encode_uint(&map, RESP_versions); // versions key
check_ret(ret);
{
ret = cbor_encoder_create_array(&map, &array, number_of_versions);
check_ret(ret);
{
ret = cbor_encode_text_stringz(&array, "U2F_V2");
check_ret(ret);
ret = cbor_encode_text_stringz(&array, "FIDO_2_0");
check_ret(ret);
}
ret = cbor_encoder_close_container(&map, &array);
check_ret(ret);
}
ret = cbor_encode_uint(&map, RESP_aaguid);
check_ret(ret);
{
ret = cbor_encode_byte_string(&map, CTAP_AAGUID, 16);
check_ret(ret);
}
ret = cbor_encode_uint(&map, RESP_maxMsgSize);
check_ret(ret);
{
ret = cbor_encode_int(&map, CTAP_MAX_MESSAGE_SIZE);
check_ret(ret);
}
ret = cbor_encode_uint(&map, RESP_pinProtocols);
check_ret(ret);
{
ret = cbor_encoder_create_array(&map, &pins, 1);
check_ret(ret);
{
ret = cbor_encode_int(&pins, 1);
check_ret(ret);
}
ret = cbor_encoder_close_container(&map, &pins);
check_ret(ret);
}
ret = cbor_encode_uint(&map, RESP_options);
check_ret(ret);
{
ret = cbor_encoder_create_map(&map, &options,4);
check_ret(ret);
{
ret = cbor_encode_text_string(&options, "plat", 4);
check_ret(ret);
{
ret = cbor_encode_boolean(&options, 0); // Not attached to platform
check_ret(ret);
}
ret = cbor_encode_text_string(&options, "rk", 2);
check_ret(ret);
{
ret = cbor_encode_boolean(&options, 0); // State-less device, requires allowList parameter.
check_ret(ret);
}
ret = cbor_encode_text_string(&options, "up", 2);
check_ret(ret);
{
ret = cbor_encode_boolean(&options, 1); // Capable of testing user presence
check_ret(ret);
}
ret = cbor_encode_text_string(&options, "uv", 2);
check_ret(ret);
{
ret = cbor_encode_boolean(&options, 0); // NOT [yet] capable of verifying user
check_ret(ret);
}
}
ret = cbor_encoder_close_container(&map, &options);
check_ret(ret);
}
}
ret = cbor_encoder_close_container(encoder, &map);
check_ret(ret);
return CTAP1_ERR_SUCCESS;
}
static uint8_t parse_client_data_hash(uint8_t * clientDataHash, CborValue * val)
{
size_t sz;
int ret;
if (cbor_value_get_type(val) != CborByteStringType)
{
printf2("error, wrong type\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_calculate_string_length(val, &sz);
check_ret(ret);
if (sz != CLIENT_DATA_HASH_SIZE)
{
printf2("error, wrong size for client data hash\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_copy_byte_string(val, clientDataHash, &sz, NULL);
check_ret(ret);
return 0;
}
static uint8_t parse_user(CTAP_makeCredential * MC, CborValue * val)
{
size_t sz, map_length;
uint8_t key[8];
int ret;
int i;
CborValue map;
if (cbor_value_get_type(val) != CborMapType)
{
printf2("error, wrong type\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_enter_container(val,&map);
check_ret(ret);
ret = cbor_value_get_map_length(val, &map_length);
check_ret(ret);
for (i = 0; i < map_length; i++)
{
if (cbor_value_get_type(&map) != CborTextStringType)
{
printf2("Error, expecting text string type for user map key, got %s\n", cbor_value_get_type_string(&map));
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
sz = sizeof(key);
ret = cbor_value_copy_text_string(&map, key, &sz, NULL);
if (ret == CborErrorOutOfMemory)
{
printf2("Error, rp map key is too large\n");
return CTAP2_ERR_LIMIT_EXCEEDED;
}
check_ret(ret);
key[sizeof(key) - 1] = 0;
ret = cbor_value_advance(&map);
check_ret(ret);
if (strcmp(key, "id") == 0)
{
if (cbor_value_get_type(&map) != CborByteStringType)
{
printf2("Error, expecting byte string type for rp map value\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
sz = USER_ID_MAX_SIZE;
ret = cbor_value_copy_byte_string(&map, MC->user.id, &sz, NULL);
if (ret == CborErrorOutOfMemory)
{
printf2("Error, USER_ID is too large\n");
return CTAP2_ERR_LIMIT_EXCEEDED;
}
MC->user.id_size = sz;
check_ret(ret);
}
else if (strcmp(key, "name") == 0)
{
sz = USER_NAME_LIMIT;
ret = cbor_value_copy_text_string(&map, MC->user.name, &sz, NULL);
if (ret != CborErrorOutOfMemory)
{ // Just truncate the name it's okay
check_ret(ret);
}
MC->user.name[USER_NAME_LIMIT - 1] = 0;
}
else
{
printf1("ignoring key %s for user map\n", key);
}
ret = cbor_value_advance(&map);
check_ret(ret);
}
MC->paramsParsed |= PARAM_user;
return 0;
}
static int parse_pub_key_cred_param(CborValue * val, uint8_t * cred_type, int32_t * alg_type)
{
CborValue map;
CborValue cred;
CborValue alg;
int ret;
uint8_t type_str[16];
size_t sz = sizeof(type_str);
if (cbor_value_get_type(val) != CborMapType)
{
printf2("error, expecting map type, got %s\n", cbor_value_get_type_string(val));
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_map_find_value(val, "type", &cred);
check_ret(ret);
ret = cbor_value_map_find_value(val, "alg", &alg);
check_ret(ret);
if (cbor_value_get_type(&cred) != CborTextStringType)
{
printf2("Error, parse_pub_key could not find credential param\n");
return CTAP2_ERR_MISSING_PARAMETER;
}
if (cbor_value_get_type(&alg) != CborIntegerType)
{
printf2("Error, parse_pub_key could not find alg param\n");
return CTAP2_ERR_MISSING_PARAMETER;
}
ret = cbor_value_copy_text_string(&cred, type_str, &sz, NULL);
check_ret(ret);
type_str[sizeof(type_str) - 1] = 0;
if (strcmp(type_str, "public-key") == 0)
{
*cred_type = PUB_KEY_CRED_PUB_KEY;
}
else
{
*cred_type = PUB_KEY_CRED_UNKNOWN;
}
ret = cbor_value_get_int_checked(&alg, alg_type);
check_ret(ret);
return 0;
}
// Check if public key credential+algorithm type is supported
static int pub_key_cred_param_supported(uint8_t cred, int32_t alg)
{
if (cred == PUB_KEY_CRED_PUB_KEY)
{
if (alg == COSE_ALG_ES256)
{
return CREDENTIAL_IS_SUPPORTED;
}
}
return CREDENTIAL_NOT_SUPPORTED;
}
static uint8_t parse_pub_key_cred_params(CTAP_makeCredential * MC, CborValue * val)
{
size_t sz, arr_length;
uint8_t cred_type;
int32_t alg_type;
uint8_t key[8];
int ret;
int i;
CborValue arr;
if (cbor_value_get_type(val) != CborArrayType)
{
printf2("error, expecting array type\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_enter_container(val,&arr);
check_ret(ret);
ret = cbor_value_get_array_length(val, &arr_length);
check_ret(ret);
for (i = 0; i < arr_length; i++)
{
if ((ret = parse_pub_key_cred_param(&arr, &cred_type, &alg_type)) == 0)
{
if (pub_key_cred_param_supported(cred_type, alg_type) == CREDENTIAL_IS_SUPPORTED)
{
MC->publicKeyCredentialType = cred_type;
MC->COSEAlgorithmIdentifier = alg_type;
MC->paramsParsed |= PARAM_pubKeyCredParams;
return 0;
}
}
else
{
// Continue? fail?
return ret;
}
ret = cbor_value_advance(&arr);
check_ret(ret);
}
printf2("Error, no public key credential parameters are supported!\n");
return CTAP2_ERR_UNSUPPORTED_ALGORITHM;
}
static int parse_rp_id(struct rpId * rp, CborValue * val)
{
size_t sz = DOMAIN_NAME_MAX_SIZE;
int ret = cbor_value_copy_text_string(val, rp->id, &sz, NULL);
if (ret == CborErrorOutOfMemory)
{
printf2("Error, RP_ID is too large\n");
return CTAP2_ERR_LIMIT_EXCEEDED;
}
rp->id[DOMAIN_NAME_MAX_SIZE] = 0; // Extra byte defined in struct.
rp->size = sz;
check_ret(ret);
return 0;
}
static uint8_t parse_rp(struct rpId * rp, CborValue * val)
{
size_t sz, map_length;
uint8_t key[8];
int ret;
int i;
CborValue map;
if (cbor_value_get_type(val) != CborMapType)
{
printf2("error, wrong type\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_enter_container(val,&map);
check_ret(ret);
ret = cbor_value_get_map_length(val, &map_length);
check_ret(ret);
rp->size = 0;
for (i = 0; i < map_length; i++)
{
if (cbor_value_get_type(&map) != CborTextStringType)
{
printf2("Error, expecting text string type for rp map key, got %s\n", cbor_value_get_type_string(&map));
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
sz = sizeof(key);
ret = cbor_value_copy_text_string(&map, key, &sz, NULL);
if (ret == CborErrorOutOfMemory)
{
printf2("Error, rp map key is too large\n");
return CTAP2_ERR_LIMIT_EXCEEDED;
}
check_ret(ret);
key[sizeof(key) - 1] = 0;
ret = cbor_value_advance(&map);
check_ret(ret);
if (cbor_value_get_type(&map) != CborTextStringType)
{
printf2("Error, expecting text string type for rp map value\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
if (strcmp(key, "id") == 0)
{
ret = parse_rp_id(rp, &map);
if (ret != 0)
{
return ret;
}
}
else if (strcmp(key, "name") == 0)
{
sz = RP_NAME_LIMIT;
ret = cbor_value_copy_text_string(&map, rp->name, &sz, NULL);
if (ret != CborErrorOutOfMemory)
{ // Just truncate the name it's okay
check_ret(ret);
}
rp->name[RP_NAME_LIMIT - 1] = 0;
}
else
{
printf1("ignoring key %s for RP map\n", key);
}
ret = cbor_value_advance(&map);
check_ret(ret);
}
if (rp->size == 0)
{
printf2("Error, no RPID provided\n");
return CTAP2_ERR_MISSING_PARAMETER;
}
return 0;
}
static uint8_t ctap_parse_make_credential(CTAP_makeCredential * MC, CborEncoder * encoder, uint8_t * request, int length)
{
int ret;
int i;
int key;
size_t map_length;
size_t sz;
CborParser parser;
CborValue it,map;
memset(MC, 0, sizeof(CTAP_makeCredential));
ret = cbor_parser_init(request, length, CborValidateCanonicalFormat, &parser, &it);
check_ret(ret);
CborType type = cbor_value_get_type(&it);
if (type != CborMapType)
{
printf2("Error, expecting cbor map\n");
return CTAP2_ERR_CBOR_UNEXPECTED_TYPE;
}
ret = cbor_value_enter_container(&it,&map);
check_ret(ret);
ret = cbor_value_get_map_length(&it, &map_length);
check_ret(ret);
printf1("map has %d elements\n",map_length);
for (i = 0; i < map_length; i++)
{
type = cbor_value_get_type(&map);
if (type != CborIntegerType)
{
printf2("Error, expecting int for map key\n");
return CTAP2_ERR_CBOR_UNEXPECTED_TYPE;
}
ret = cbor_value_get_int_checked(&map, &key);
check_ret(ret);
ret = cbor_value_advance(&map);
check_ret(ret);
ret = 0;
switch(key)
{
case MC_clientDataHash:
printf1("CTAP_clientDataHash\n");
ret = parse_client_data_hash(MC->clientDataHash, &map);
if (ret == 0)
{
MC->paramsParsed |= PARAM_clientDataHash;
}
printf1(" "); dump_hex(MC->clientDataHash, 32);
break;
case MC_rp:
printf1("CTAP_rp\n");
ret = parse_rp(&MC->rp, &map);
if (ret == 0)
{
MC->paramsParsed |= PARAM_rp;
}
printf1(" ID: %s\n", MC->rp.id);
printf1(" name: %s\n", MC->rp.name);
break;
case MC_user:
printf1("CTAP_user\n");
ret = parse_user(MC, &map);
printf1(" ID: "); dump_hex(MC->user.id, MC->user.id_size);
printf1(" name: %s\n", MC->user.name);
break;
case MC_pubKeyCredParams:
printf1("CTAP_pubKeyCredParams\n");
ret = parse_pub_key_cred_params(MC, &map);
printf1(" cred_type: 0x%02x\n", MC->publicKeyCredentialType);
printf1(" alg_type: %d\n", MC->COSEAlgorithmIdentifier);
break;
case MC_excludeList:
printf1("CTAP_excludeList\n");
break;
case MC_extensions:
printf1("CTAP_extensions\n");
break;
case MC_options:
printf1("CTAP_options\n");
break;
case MC_pinAuth:
printf1("CTAP_pinAuth\n");
break;
case MC_pinProtocol:
printf1("CTAP_pinProtocol\n");
break;
default:
printf1("invalid key %d\n", key);
}
if (ret != 0)
{
return ret;
}
cbor_value_advance(&map);
check_ret(ret);
}
return 0;
}
static int ctap_generate_cose_key(CborEncoder * cose_key, uint8_t * hmac_input, int len, uint8_t credtype, int32_t algtype)
{
uint8_t x[32], y[32];
int ret;
CborEncoder map;
ret = cbor_encoder_create_map(cose_key, &map, 5);
int extra = cbor_encoder_get_extra_bytes_needed(&map);
printf1(" extra? %d\n", extra);
check_ret(ret);
if (credtype != PUB_KEY_CRED_PUB_KEY)
{
printf2("Error, pubkey credential type not supported\n");
return -1;
}
switch(algtype)
{
case COSE_ALG_ES256:
crypto_ecc256_init();
crypto_ecc256_derive_public_key(hmac_input, len, x, y);
break;
default:
printf2("Error, COSE alg %d not supported\n", algtype);
return -1;
}
{
ret = cbor_encode_int(&map, COSE_KEY_LABEL_KTY);
check_ret(ret);
ret = cbor_encode_int(&map, COSE_KEY_KTY_EC2);
check_ret(ret);
}
{
ret = cbor_encode_int(&map, COSE_KEY_LABEL_ALG);
check_ret(ret);
ret = cbor_encode_int(&map, algtype);
check_ret(ret);
}
{
ret = cbor_encode_int(&map, COSE_KEY_LABEL_CRV);
check_ret(ret);
ret = cbor_encode_int(&map, COSE_KEY_CRV_P256);
check_ret(ret);
}
{
ret = cbor_encode_int(&map, COSE_KEY_LABEL_X);
check_ret(ret);
ret = cbor_encode_byte_string(&map, x, 32);
check_ret(ret);
}
{
ret = cbor_encode_int(&map, COSE_KEY_LABEL_Y);
check_ret(ret);
ret = cbor_encode_byte_string(&map, y, 32);
check_ret(ret);
}
ret = cbor_encoder_close_container(cose_key, &map);
check_ret(ret);
}
void make_auth_tag(struct rpId * rp, CTAP_userEntity * user, uint32_t count, uint8_t * tag)
{
uint8_t hashbuf[32];
crypto_sha256_init();
crypto_sha256_update(rp->id, rp->size);
crypto_sha256_update(user->id, user->id_size);
crypto_sha256_update(user->name, strnlen(user->name, USER_NAME_LIMIT));
crypto_sha256_update((uint8_t*)&count, 4);
crypto_sha256_update_secret();
crypto_sha256_final(hashbuf);
memmove(tag, hashbuf, CREDENTIAL_TAG_SIZE);
}
static int ctap_make_auth_data(struct rpId * rp, CborEncoder * map, uint8_t * auth_data_buf, int len, CTAP_userEntity * user, uint8_t credtype, int32_t algtype)
{
CborEncoder cose_key;
int auth_data_sz, ret;
uint32_t count;
CTAP_authData * authData = (CTAP_authData *)auth_data_buf;
uint8_t * cose_key_buf = auth_data_buf + sizeof(CTAP_authData);
if((sizeof(CTAP_authData) - sizeof(CTAP_attestHeader)) > len)
{
printf1("assertion fail, auth_data_buf must be at least %d bytes\n", sizeof(CTAP_authData) - sizeof(CTAP_attestHeader));
exit(1);
}
crypto_sha256_init();
crypto_sha256_update(rp->id, rp->size);
crypto_sha256_final(authData->rpIdHash);
authData->flags = (ctap_user_presence_test() << 0);
authData->flags |= (ctap_user_verification(0) << 2);
count = ctap_atomic_count( 0 );
authData->signCount = ntohl(count);
if (credtype != 0)
{
// add attestedCredentialData
authData->flags |= (1 << 6);//include attestation data
cbor_encoder_init(&cose_key, cose_key_buf, len - sizeof(CTAP_authData), 0);
_ENCODER = &cose_key;
memmove(authData->attest.aaguid, CTAP_AAGUID, 16);
authData->attest.credLenL = CREDENTIAL_ID_SIZE & 0x00FF;
authData->attest.credLenH = (CREDENTIAL_ID_SIZE & 0xFF00) >> 8;
#if CREDENTIAL_ID_SIZE != 150
#error "need to update credential ID layout"
#else
memset(authData->attest.credential.id, 0, CREDENTIAL_ID_SIZE);
// Make a tag we can later check to make sure this is a token we made
make_auth_tag(rp, user, count, authData->attest.credential.fields.tag);
memmove(&authData->attest.credential.fields.user, user, sizeof(CTAP_userEntity)); //TODO encrypt this
authData->attest.credential.fields.count = count;
ctap_generate_cose_key(&cose_key, authData->attest.credential.id, CREDENTIAL_ID_SIZE, credtype, algtype);
printf1("COSE_KEY: "); dump_hex(cose_key_buf, cbor_encoder_get_buffer_size(&cose_key, cose_key_buf));
auth_data_sz = sizeof(CTAP_authData) + cbor_encoder_get_buffer_size(&cose_key, cose_key_buf);
#endif
}
else
{
auth_data_sz = sizeof(CTAP_authData) - sizeof(CTAP_attestHeader);
}
{
ret = cbor_encode_int(map,RESP_authData);
check_ret(ret);
ret = cbor_encode_byte_string(map, auth_data_buf, auth_data_sz);
check_ret(ret);
}
return auth_data_sz;
}
// require load_key prior to this
// @data data to hash before signature
// @clientDataHash for signature
// @tmp buffer for hash. (can be same as data if data >= 32 bytes)
// @sigbuf location to deposit signature (must be 64 bytes)
// @sigder location to deposit der signature (must be 72 bytes)
// @return length of der signature
int ctap_calculate_signature(uint8_t * data, int datalen, uint8_t * clientDataHash, uint8_t * hashbuf, uint8_t * sigbuf, uint8_t * sigder)
{
// calculate attestation sig
crypto_sha256_init();
crypto_sha256_update(data, datalen);
crypto_sha256_update(clientDataHash, CLIENT_DATA_HASH_SIZE);
crypto_sha256_final(hashbuf);
crypto_ecc256_sign(hashbuf, 32, sigbuf);
/*printf1("signature hash: "); dump_hex(hashbuf, 32);*/
/*printf1("R: "); dump_hex(sigbuf, 32);*/
/*printf1("S: "); dump_hex(sigbuf+32, 32);*/
// Need to caress into dumb der format ..
uint8_t pad_s = (sigbuf[32] & 0x80) == 0x80;
uint8_t pad_r = (sigbuf[0] & 0x80) == 0x80;
sigder[0] = 0x30;
sigder[1] = 0x44 + pad_s + pad_r;
sigder[2] = 0x02;
sigder[3 + pad_r] = 0;
sigder[3] = 0x20 + pad_r;
memmove(sigder + 4 + pad_r, sigbuf, 32);
sigder[4 + 32 + pad_r] = 0x02;
sigder[5 + 32 + pad_r + pad_s] = 0;
sigder[5 + 32 + pad_r] = 0x20 + pad_s;
memmove(sigder + 6 + 32 + pad_r + pad_s, sigbuf + 32, 32);
//
return 0x46 + pad_s + pad_r;
}
uint8_t ctap_add_attest_statement(CborEncoder * map, uint8_t * sigder, int len)
{
int ret;
CborEncoder stmtmap;
CborEncoder x5carr;
ret = cbor_encode_int(map,RESP_attStmt);
check_ret(ret);
ret = cbor_encoder_create_map(map, &stmtmap, 3);
check_ret(ret);
{
ret = cbor_encode_text_stringz(&stmtmap,"alg");
check_ret(ret);
ret = cbor_encode_int(&stmtmap,COSE_ALG_ES256);
check_ret(ret);
}
{
ret = cbor_encode_text_stringz(&stmtmap,"sig");
check_ret(ret);
ret = cbor_encode_byte_string(&stmtmap, sigder, len);
check_ret(ret);
}
{
ret = cbor_encode_text_stringz(&stmtmap,"x5c");
check_ret(ret);
ret = cbor_encoder_create_array(&stmtmap, &x5carr, 1);
check_ret(ret);
{
ret = cbor_encode_byte_string(&x5carr, attestation_cert_der, attestation_cert_der_size);
check_ret(ret);
ret = cbor_encoder_close_container(&stmtmap, &x5carr);
check_ret(ret);
}
}
ret = cbor_encoder_close_container(map, &stmtmap);
check_ret(ret);
}
uint8_t ctap_make_credential(CborEncoder * encoder, uint8_t * request, int length)
{
CTAP_makeCredential MC;
int ret;
uint8_t auth_data_buf[300];
uint8_t * hashbuf = auth_data_buf + 0;
uint8_t * sigbuf = auth_data_buf + 32;
uint8_t * sigder = auth_data_buf + 32 + 64;
ret = ctap_parse_make_credential(&MC,encoder,request,length);
if (ret != 0)
{
printf2("error, parse_make_credential failed\n");
return ret;
}
if ((MC.paramsParsed & MC_requiredMask) != MC_requiredMask)
{
printf2("error, required parameter(s) for makeCredential are missing\n");
return CTAP2_ERR_MISSING_PARAMETER;
}
CborEncoder map;
ret = cbor_encoder_create_map(encoder, &map, 3);
check_ret(ret);
int auth_data_sz = ctap_make_auth_data(&MC.rp, &map, auth_data_buf, sizeof(auth_data_buf),
&MC.user, MC.publicKeyCredentialType, MC.COSEAlgorithmIdentifier);
crypto_ecc256_load_attestation_key();
int sigder_sz = ctap_calculate_signature(auth_data_buf, auth_data_sz, MC.clientDataHash, auth_data_buf, sigbuf, sigder);
printf1("der sig [%d]: ", sigder_sz); dump_hex(sigder, sigder_sz);
ret = ctap_add_attest_statement(&map, sigder, sigder_sz);
check_ret(ret);
{
ret = cbor_encode_int(&map,RESP_fmt);
check_ret(ret);
ret = cbor_encode_text_stringz(&map, "packed");
check_ret(ret);
}
ret = cbor_encoder_close_container(encoder, &map);
check_ret(ret);
return CTAP1_ERR_SUCCESS;
}
static int parse_allow_list(CTAP_getAssertion * GA, CborValue * it)
{
CborValue arr, val;
size_t len,buflen;
uint8_t type[12];
int i,ret;
if (cbor_value_get_type(it) != CborArrayType)
{
printf2("Error, expecting cbor array\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_enter_container(it,&arr);
check_ret(ret);
ret = cbor_value_get_array_length(it, &len);
check_ret(ret);
GA->credLen = 0;
for(i = 0; i < len; i++)
{
if (i >= ALLOW_LIST_MAX_SIZE)
{
printf1("Error, out of memory for allow list.\n");
return CTAP2_ERR_TOO_MANY_ELEMENTS;
}
GA->credLen += 1;
if (cbor_value_get_type(&arr) != CborMapType)
{
printf2("Error, CborMapType expected in allow_list\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_map_find_value(&arr, "id", &val);
check_ret(ret);
if (cbor_value_get_type(&val) != CborByteStringType)
{
printf2("Error, No valid ID field (%s)\n", cbor_value_get_type_string(&val));
return CTAP2_ERR_MISSING_PARAMETER;
}
buflen = CREDENTIAL_ID_SIZE;
cbor_value_copy_byte_string(&val, GA->creds[i].credential.id, &buflen, NULL);
if (buflen != CREDENTIAL_ID_SIZE)
{
printf2("Error, credential is incorrect length\n");
return CTAP2_ERR_CBOR_UNEXPECTED_TYPE; // maybe just skip it instead of fail?
}
ret = cbor_value_map_find_value(&arr, "type", &val);
check_ret(ret);
if (cbor_value_get_type(&val) != CborTextStringType)
{
printf2("Error, No valid type field\n");
return CTAP2_ERR_MISSING_PARAMETER;
}
buflen = sizeof(type);
cbor_value_copy_text_string(&val, type, &buflen, NULL);
if (strcmp(type, "public-key") == 0)
{
GA->creds[i].type = PUB_KEY_CRED_PUB_KEY;
}
else
{
GA->creds[i].type = PUB_KEY_CRED_UNKNOWN;
}
ret = cbor_value_advance(&arr);
check_ret(ret);
}
return 0;
}
// Return 1 if credential belongs to this token
int ctap_authenticate_credential(struct rpId * rp, CTAP_credentialDescriptor * desc)
{
uint8_t tag[16];
if (desc->type != PUB_KEY_CRED_PUB_KEY)
{
printf1("unsupported credential type: %d\n", desc->type);
return 0;
}
make_auth_tag(rp, &desc->credential.fields.user, desc->credential.fields.count, tag);
return (memcmp(desc->credential.fields.tag, tag, CREDENTIAL_TAG_SIZE) == 0);
}
int ctap_parse_get_assertion(CTAP_getAssertion * GA, uint8_t * request, int length)
{
int ret;
int i,j;
int key;
size_t map_length;
size_t sz;
CborParser parser;
CborValue it,map;
memset(GA, 0, sizeof(CTAP_getAssertion));
ret = cbor_parser_init(request, length, CborValidateCanonicalFormat, &parser, &it);
check_ret(ret);
CborType type = cbor_value_get_type(&it);
if (type != CborMapType)
{
printf2("Error, expecting cbor map\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_enter_container(&it,&map);
check_ret(ret);
ret = cbor_value_get_map_length(&it, &map_length);
check_ret(ret);
printf1("GA map has %d elements\n",map_length);
for (i = 0; i < map_length; i++)
{
type = cbor_value_get_type(&map);
if (type != CborIntegerType)
{
printf2("Error, expecting int for map key\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_get_int_checked(&map, &key);
check_ret(ret);
ret = cbor_value_advance(&map);
check_ret(ret);
ret = 0;
switch(key)
{
case GA_clientDataHash:
printf1("GA_clientDataHash\n");
ret = parse_client_data_hash(GA->clientDataHash, &map);
printf1(" "); dump_hex(GA->clientDataHash, 32);
break;
case GA_rpId:
printf1("GA_rpId\n");
ret = parse_rp_id(&GA->rp, &map);
printf1(" ID: %s\n", GA->rp.id);
break;
case GA_allowList:
printf1("GA_allowList\n");
ret = parse_allow_list(GA, &map);
if (ret == 0)
{
for (j = 0; j < GA->credLen; j++)
{
printf1("CRED ID (# %d): ", GA->creds[j].credential.fields.count);
dump_hex(GA->creds[j].credential.id, CREDENTIAL_ID_SIZE);
if (ctap_authenticate_credential(&GA->rp, &GA->creds[j])) // warning encryption will break this
{
printf1(" Authenticated.\n");
}
else
{
printf1(" NOT authentic.\n");
}
}
}
break;
case GA_extensions:
printf1("GA_extensions\n");
break;
case GA_options:
printf1("GA_options\n");
break;
case GA_pinAuth:
printf1("GA_pinAuth\n");
break;
case GA_pinProtocol:
printf1("GA_pinProtocol\n");
break;
default:
printf1("invalid key %d\n", key);
}
if (ret != 0)
{
printf2("error, parsing failed\n");
return ret;
}
cbor_value_advance(&map);
check_ret(ret);
}
return 0;
}
static int pick_first_authentic_credential(CTAP_getAssertion * GA)
{
int i;
for (i = 0; i < GA->credLen; i++)
{
if (ctap_authenticate_credential(&GA->rp, &GA->creds[i]))
{
return i;
}
}
return -1;
}
static uint8_t ctap_add_credential_descriptor(CborEncoder * map, CTAP_credentialDescriptor * cred)
{
CborEncoder desc;
int ret = cbor_encode_int(map, RESP_credential);
check_ret(ret);
ret = cbor_encoder_create_map(map, &desc, 2);
check_ret(ret);
{
ret = cbor_encode_text_string(&desc, "type", 4);
check_ret(ret);
ret = cbor_encode_int(&desc, cred->type);
check_ret(ret);
}
{
ret = cbor_encode_text_string(&desc, "id", 2);
check_ret(ret);
ret = cbor_encode_byte_string(&desc, cred->credential.id, CREDENTIAL_ID_SIZE);
check_ret(ret);
}
ret = cbor_encoder_close_container(map, &desc);
check_ret(ret);
return 0;
}
uint8_t ctap_add_user_entity(CborEncoder * map, CTAP_userEntity * user)
{
CborEncoder entity;
int ret = cbor_encode_int(map, RESP_publicKeyCredentialUserEntity);
check_ret(ret);
ret = cbor_encoder_create_map(map, &entity, 2);
check_ret(ret);
{
ret = cbor_encode_text_string(&entity, "id", 2);
check_ret(ret);
ret = cbor_encode_byte_string(&entity, user->id, user->id_size);
check_ret(ret);
}
{
ret = cbor_encode_text_string(&entity, "displayName", 11);
check_ret(ret);
ret = cbor_encode_text_stringz(&entity, user->name);
check_ret(ret);
}
ret = cbor_encoder_close_container(map, &entity);
check_ret(ret);
return 0;
}
uint8_t ctap_get_assertion(CborEncoder * encoder, uint8_t * request, int length)
{
CTAP_getAssertion GA;
uint8_t auth_data_buf[32 + 1 + 4];
uint8_t sigbuf[64];
uint8_t sigder[72];
int ret = ctap_parse_get_assertion(&GA,request,length);
if (ret != 0)
{
printf2("error, parse_get_assertion failed\n");
return ret;
}
CborEncoder map;
ret = cbor_encoder_create_map(encoder, &map, 5);
check_ret(ret);
ctap_make_auth_data(&GA.rp, &map, auth_data_buf, sizeof(auth_data_buf), NULL, 0,0);
int pick = pick_first_authentic_credential(&GA); // TODO let this handle decryption? lazy?
if (pick == -1)
{
printf2("Error, no authentic credential\n");
return CTAP2_ERR_CREDENTIAL_NOT_VALID;
}
ret = ctap_add_credential_descriptor(&map, &GA.creds[pick]);
check_ret(ret);
ret = ctap_add_user_entity(&map, &GA.creds[pick].credential.fields.user);
check_ret(ret);
crypto_ecc256_load_key(GA.creds[pick].credential.id, CREDENTIAL_ID_SIZE);
int sigder_sz = ctap_calculate_signature(auth_data_buf, sizeof(auth_data_buf), GA.clientDataHash, auth_data_buf, sigbuf, sigder);
{
ret = cbor_encode_int(&map, RESP_signature);
check_ret(ret);
ret = cbor_encode_byte_string(&map, sigder, sigder_sz);
check_ret(ret);
}
{
ret = cbor_encode_int(&map, RESP_numberOfCredentials);
check_ret(ret);
ret = cbor_encode_int(&map, GA.credLen);
check_ret(ret);
}
ret = cbor_encoder_close_container(encoder, &map);
check_ret(ret);
}
int ctap_parse_client_pin(CTAP_clientPin * CP, uint8_t * request, int length)
{
int ret;
int i,j;
int key;
size_t map_length;
size_t sz;
CborParser parser;
CborValue it,map;
memset(CP, 0, sizeof(CTAP_clientPin));
ret = cbor_parser_init(request, length, CborValidateCanonicalFormat, &parser, &it);
check_ret(ret);
CborType type = cbor_value_get_type(&it);
if (type != CborMapType)
{
printf2("Error, expecting cbor map\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_enter_container(&it,&map);
check_ret(ret);
ret = cbor_value_get_map_length(&it, &map_length);
check_ret(ret);
printf1("CP map has %d elements\n",map_length);
for (i = 0; i < map_length; i++)
{
type = cbor_value_get_type(&map);
if (type != CborIntegerType)
{
printf2("Error, expecting int for map key\n");
return CTAP2_ERR_INVALID_CBOR_TYPE;
}
ret = cbor_value_get_int_checked(&map, &key);
check_ret(ret);
ret = cbor_value_advance(&map);
check_ret(ret);
ret = 0;
switch(key)
{
case CP_pinProtocol:
printf("CP_pinProtocol\n");
break;
case CP_subCommand:
printf("CP_subCommand\n");
break;
case CP_keyAgreement:
printf("CP_keyAgreement\n");
break;
case CP_pinAuth:
printf("CP_pinAuth\n");
break;
case CP_newPinEnc:
printf("CP_newPinEnc\n");
break;
case CP_pinHashEnc:
printf("CP_pinHashEnc\n");
break;
case CP_getKeyAgreement:
printf("CP_getKeyAgreement\n");
break;
case CP_getRetries:
printf("CP_getRetries\n");
break;
default:
printf1("Unknown key %d\n", key);
}
ret = cbor_value_advance(&map);
check_ret(ret);
}
return 0;
}
uint8_t ctap_client_pin(CborEncoder * encoder, uint8_t * request, int length)
{
CTAP_clientPin CP;
int ret = ctap_parse_client_pin(&CP,request,length);
if (ret != 0)
{
printf2("error, parse_client_pin failed\n");
return ret;
}
return 0;
}
uint8_t ctap_handle_packet(uint8_t * pkt_raw, int length, CTAP_RESPONSE * resp)
{
uint8_t status = 0;
uint8_t cmd = *pkt_raw;
pkt_raw++;
length--;
static uint8_t buf[1024];
memset(buf,0,sizeof(buf));
resp->data = buf;
resp->length = 0;
CborEncoder encoder;
cbor_encoder_init(&encoder, buf, sizeof(buf), 0);
_ENCODER = &encoder;
printf1("cbor req: "); dump_hex(pkt_raw, length);
switch(cmd)
{
case CTAP_MAKE_CREDENTIAL:
printf1("CTAP_MAKE_CREDENTIAL\n");
status = ctap_make_credential(&encoder, pkt_raw, length);
dump_hex(buf, cbor_encoder_get_buffer_size(&encoder, buf));
resp->length = cbor_encoder_get_buffer_size(&encoder, buf);
break;
case CTAP_GET_ASSERTION:
printf1("CTAP_GET_ASSERTION\n");
status = ctap_get_assertion(&encoder, pkt_raw, length);
resp->length = cbor_encoder_get_buffer_size(&encoder, buf);
printf1("cbor [%d]: \n", cbor_encoder_get_buffer_size(&encoder, buf));
dump_hex(buf, cbor_encoder_get_buffer_size(&encoder, buf));
break;
case CTAP_CANCEL:
printf1("CTAP_CANCEL\n");
break;
case CTAP_GET_INFO:
printf1("CTAP_GET_INFO\n");
status = ctap_get_info(&encoder);
resp->length = cbor_encoder_get_buffer_size(&encoder, buf);
dump_hex(buf, cbor_encoder_get_buffer_size(&encoder, buf));
break;
case CTAP_CLIENT_PIN:
printf1("CTAP_CLIENT_PIN\n");
status = ctap_client_pin(&encoder, pkt_raw, length);
break;
case CTAP_RESET:
printf1("CTAP_RESET\n");
break;
case GET_NEXT_ASSERTION:
printf1("CTAP_NEXT_ASSERTION\n");
break;
default:
status = CTAP1_ERR_INVALID_COMMAND;
printf2("error, invalid cmd\n");
}
if (status != CTAP1_ERR_SUCCESS)
{
resp->length = 0;
}
printf1("cbor input structure: %d bytes\n", length);
printf1("cbor output structure: %d bytes\n", resp->length);
return status;
}
void ctap_init()
{
if (ctap_generate_rng(PIN_TOKEN, PIN_TOKEN_SIZE) != 1)
{
printf2("Error, rng failed\n");
exit(1);
}
}
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