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Lots of efforts for make_Credential.

Browse Source 
It DOES NOT pass tests yet.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>
This commit is contained in:
Pol Henarejos
2022-09-16 00:50:19 +02:00
parent 5da2af2c34
commit 20038b1586
3 changed files with 219 additions and 28 deletions
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217
src/fido/cbor_make_credential.c
View File

@@ -15,11 +15,16 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "common.h"
#include "mbedtls/chachapoly.h"
#include "ctap2_cbor.h"
#include "cbor_make_credential.h"
#include "fido.h"
#include "ctap.h"
#include "files.h"
#include "random.h"
#include "hsm.h"
#include <math.h>
bool credential_verify(CborByteString *cred_id, const uint8_t *rp_id_hash) {
if (cred_id->len < 4+12+16)
@@ -54,6 +59,9 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
size_t excludeList_len = 0;
CredOptions options = {0};
uint64_t pinUvAuthProtocol = 0, enterpriseAttestation = 0;
const bool *hmac_secret = NULL;
uint8_t *cred_id = NULL, *aut_data = NULL;
size_t resp_size = 0;
CBOR_CHECK(cbor_parser_init(data, len, 0, &parser, &map));
CBOR_PARSE_MAP_START(map, 1) {
@@ -113,7 +121,12 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
CBOR_PARSE_ARRAY_END(_f1, 2);
}
else if (val_u == 0x06) { // extensions
CBOR_ADVANCE(1);
CBOR_PARSE_MAP_START(_f1, 2) {
CBOR_FIELD_GET_KEY_TEXT(2);
CBOR_FIELD_KEY_TEXT_VAL_BOOL(2, "hmac-secret", hmac_secret);
CBOR_ADVANCE(2);
}
CBOR_PARSE_MAP_END(_f1, 2);
}
else if (val_u == 0x07) { // options
options.present = true;
@@ -140,29 +153,41 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
uint8_t rp_id_hash[32];
mbedtls_sha256((uint8_t *)rp.id.data, rp.id.len, rp_id_hash, 0);
int curve = 0, alg = 0;
for (int i = 0; i < pubKeyCredParams_len; i++) {
if (strcmp(pubKeyCredParams[i].type.data, "public-key") != 0)
continue;
if (pubKeyCredParams[i].alg != FIDO2_ALG_ES256 && pubKeyCredParams[i].alg != FIDO2_ALG_ES384 && pubKeyCredParams[i].alg != FIDO2_ALG_ES512)
CBOR_ERROR(CTAP2_ERR_UNSUPPORTED_ALGORITHM);
if (pubKeyCredParams[i].alg == FIDO2_ALG_ES256)
curve = FIDO2_CURVE_P256;
else if (pubKeyCredParams[i].alg == FIDO2_ALG_ES384)
curve = FIDO2_CURVE_P384;
else if (pubKeyCredParams[i].alg == FIDO2_ALG_ES512)
curve = FIDO2_CURVE_P521;
if (curve > 0) {
alg = pubKeyCredParams[i].alg;
break;
}
}
if (curve == 0)
CBOR_ERROR(CTAP2_ERR_UNSUPPORTED_ALGORITHM);
if (pinUvAuthParam.present == true) {
if (pinUvAuthParam.len == 0 || pinUvAuthParam.data == NULL) {
if (wait_button() == true)
CBOR_ERROR(CTAP2_ERR_OPERATION_DENIED);
if (!file_has_data(ef_pin))
CBOR_ERROR(CTAP2_ERR_PIN_NOT_SET);
else
CBOR_ERROR(CTAP2_ERR_PIN_INVALID);
}
else {
if (pinUvAuthProtocol == 0)
CBOR_ERROR(CTAP2_ERR_MISSING_PARAMETER);
if (pinUvAuthProtocol != 1 && pinUvAuthProtocol != 2)
CBOR_ERROR(CTAP1_ERR_INVALID_PARAMETER);
}
}
if (pinUvAuthParam.len == 0 || pinUvAuthParam.data == NULL) {
if (wait_button_pressed() == true)
CBOR_ERROR(CTAP2_ERR_OPERATION_DENIED);
if (!file_has_data(ef_pin))
CBOR_ERROR(CTAP2_ERR_PIN_NOT_SET);
else
CBOR_ERROR(CTAP2_ERR_PIN_INVALID);
}
else if (pinUvAuthParam.present == true) {
if (pinUvAuthProtocol == 0)
CBOR_ERROR(CTAP2_ERR_MISSING_PARAMETER);
if (pinUvAuthProtocol != 1 && pinUvAuthProtocol != 2)
CBOR_ERROR(CTAP1_ERR_INVALID_PARAMETER);
}
bool *rup = pfalse;
if (options.present) {
if (options.uv == ptrue) { //5.3
CBOR_ERROR(CTAP2_ERR_INVALID_OPTION);
@@ -170,8 +195,8 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
if (options.up == pfalse) { //5.6
CBOR_ERROR(CTAP2_ERR_INVALID_OPTION);
}
else if (options.up == NULL) //5.7
rup = ptrue;
//else if (options.up == NULL) //5.7
//rup = ptrue;
}
if (pinUvAuthParam.present == false && options.uv == pfalse && file_has_data(ef_pin)) { //8.1
CBOR_ERROR(CTAP2_ERR_PUAT_REQUIRED);
@@ -199,8 +224,149 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
if (pinUvAuthParam.present && options.up == ptrue) { //14.1
if (wait_button_pressed() == true)
CBOR_ERROR(CTAP2_ERR_OPERATION_DENIED);
rup = ptrue;
//rup = ptrue;
}
CborEncoder encoder, mapEncoder, mapEncoder2;
uint8_t cbor_buf[1024];
cbor_encoder_init(&encoder, cbor_buf, sizeof(cbor_buf), 0);
CBOR_CHECK(cbor_encoder_create_map(&encoder, &mapEncoder, CborIndefiniteLength));
CBOR_APPEND_KEY_UINT_VAL_STRING(mapEncoder, 0x01, rp.id);
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 0x02));
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder, rp_id_hash, 32));
CBOR_APPEND_KEY_UINT_VAL_BYTES(mapEncoder, 0x03, user.id);
CBOR_APPEND_KEY_UINT_VAL_STRING(mapEncoder, 0x04, user.displayName);
CBOR_APPEND_KEY_UINT_VAL_UINT(mapEncoder, 0x05, 1);
CBOR_APPEND_KEY_UINT_VAL_PBOOL(mapEncoder, 0x06, hmac_secret);
if (alg != FIDO2_ALG_ES256 || curve != FIDO2_CURVE_P256) {
CBOR_APPEND_KEY_UINT_VAL_UINT(mapEncoder, 0x07, alg);
CBOR_APPEND_KEY_UINT_VAL_UINT(mapEncoder, 0x08, curve);
}
CBOR_CHECK(cbor_encoder_close_container(&encoder, &mapEncoder));
size_t rs = cbor_encoder_get_buffer_size(&encoder, cbor_buf);
size_t cred_id_len = 4 + 12 + rs + 16;
cred_id = (uint8_t *)calloc(1, 4 + 12 + rs + 16);
uint8_t key[32];
memset(key, 0, sizeof(key));
uint8_t iv[12];
memcpy(iv, random_bytes_get(sizeof(iv)), sizeof(iv));
mbedtls_chachapoly_context chatx;
mbedtls_chachapoly_init(&chatx);
mbedtls_chachapoly_setkey(&chatx, key);
int ret = mbedtls_chachapoly_encrypt_and_tag(&chatx, rs, iv, rp_id_hash, 32, cbor_buf, cred_id + 4 + 12, cred_id + 4 + 12 + rs);
if (ret != 0) {
CBOR_ERROR(CTAP1_ERR_OTHER);
}
memcpy(cred_id, "\xf1\xd0\x02\x00", 4);
memcpy(cred_id + 4, iv, 12);
const mbedtls_ecp_curve_info *cinfo = mbedtls_ecp_curve_info_from_grp_id(curve);
if (cinfo == NULL) {
CBOR_ERROR(CTAP1_ERR_OTHER);
}
mbedtls_ecdsa_context ekey;
mbedtls_ecdsa_init(&ekey);
uint8_t key_path[KEY_PATH_LEN];
memcpy(key_path, cred_id, KEY_PATH_LEN);
*(uint32_t *)key_path = 0x80000000 | 10022;
for (int i = 1; i < KEY_PATH_ENTRIES; i++)
*(uint32_t *)(key_path+i*sizeof(uint32_t)) |= 0x80000000;
ret = derive_key(NULL, false, key_path, curve, &ekey);
if (ret != 0) {
mbedtls_ecdsa_free(&ekey);
CBOR_ERROR(CTAP1_ERR_OTHER);
}
uint8_t flags = FIDO2_AUT_FLAG_UP | FIDO2_AUT_FLAG_AT;
size_t ext_len = 0;
uint8_t *ext = NULL;
if (hmac_secret == ptrue) {
ext_len = 14;
ext = (uint8_t *)"\xA1\x6B\x68\x6D\x61\x63\x2D\x73\x65\x63\x72\x65\x74\xF5";
flags |= FIDO2_AUT_FLAG_ED;
}
uint8_t pkey[2 * 66 + 1];
size_t olen = 0;
ret = mbedtls_ecp_point_write_binary(&ekey.grp, &ekey.Q, MBEDTLS_ECP_PF_UNCOMPRESSED, &olen, pkey, sizeof(pkey));
if (ret != 0) {
mbedtls_ecdsa_free(&ekey);
CBOR_ERROR(CTAP1_ERR_OTHER);
}
uint32_t ctr = *(uint32_t *)file_get_data(ef_counter);
cbor_encoder_init(&encoder, cbor_buf, sizeof(cbor_buf), 0);
CBOR_CHECK(cbor_encoder_create_map(&encoder, &mapEncoder, 5));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 1));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 2));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 3));
CBOR_CHECK(cbor_encode_negative_int(&mapEncoder, -alg));
CBOR_CHECK(cbor_encode_negative_int(&mapEncoder, 1));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, curve));
CBOR_CHECK(cbor_encode_negative_int(&mapEncoder, 2));
mbedtls_mpi_write_binary(&ekey.Q.X, pkey, sizeof(pkey));
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder, pkey, sizeof(pkey)));
CBOR_CHECK(cbor_encode_negative_int(&mapEncoder, 3));
mbedtls_mpi_write_binary(&ekey.Q.Y, pkey, sizeof(pkey));
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder, pkey, sizeof(pkey)));
CBOR_CHECK(cbor_encoder_close_container(&encoder, &mapEncoder));
rs = cbor_encoder_get_buffer_size(&encoder, cbor_buf);
size_t aut_data_len = 32 + 1 + 4 + (16 + 2 + cred_id_len + rs) + ext_len;
aut_data = (uint8_t *)calloc(1, aut_data_len);
uint8_t *pa = aut_data;
memcpy(pa, rp_id_hash, 32); pa += 32;
memcpy(pa, &flags, 1); pa++;
*pa++ = ctr >> 24;
*pa++ = ctr >> 16;
*pa++ = ctr >> 8;
*pa++ = ctr & 0xff;
memcpy(pa, aaguid, 16); pa += 16;
*pa++ = cred_id_len >> 16;
*pa++ = cred_id_len & 0xff;
memcpy(pa, cred_id, cred_id_len); pa += cred_id_len;
memcpy(pa, cbor_buf, rs); pa += rs;
memcpy(pa, ext, ext_len); pa += ext_len;
const known_app_t *ka = find_app_by_rp_id_hash(rp_id_hash);
uint8_t hash[32], sig[MBEDTLS_ECDSA_MAX_LEN];
ret = mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), aut_data, aut_data_len, hash);
bool self_attestation = true;
if (ka && ka->use_self_attestation == pfalse)
{
mbedtls_ecdsa_free(&ekey);
mbedtls_ecdsa_init(&ekey);
ret = mbedtls_ecp_read_key(MBEDTLS_ECP_DP_SECP256R1, &ekey, file_get_data(ef_keydev), 32);
self_attestation = false;
}
ret = mbedtls_ecdsa_write_signature(&ekey, MBEDTLS_MD_SHA256, hash, 32, sig, sizeof(sig), &olen, random_gen, NULL);
mbedtls_ecdsa_free(&ekey);
cbor_encoder_init(&encoder, ctap_resp->init.data + 1, CTAP_MAX_PACKET_SIZE, 0);
CBOR_CHECK(cbor_encoder_create_map(&encoder, &mapEncoder, 3));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 0x01));
CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder, "packed"));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 0x02));
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder, aut_data, aut_data_len));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 0x03));
CBOR_CHECK(cbor_encoder_create_map(&mapEncoder, &mapEncoder2, self_attestation == false ? 3 : 2));
CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder2, "alg"));
CBOR_CHECK(cbor_encode_negative_int(&mapEncoder2, self_attestation ? -alg : -FIDO2_ALG_ES256));
CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder2, "sig"));
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder2, sig, olen));
if (self_attestation == false) {
CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder2, "x5c"));
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder2, file_get_data(ef_certdev), file_get_size(ef_certdev)));
}
CBOR_CHECK(cbor_encoder_close_container(&mapEncoder, &mapEncoder2));
CBOR_CHECK(cbor_encoder_close_container(&encoder, &mapEncoder));
resp_size = cbor_encoder_get_buffer_size(&encoder, ctap_resp->init.data + 1);
err:
CBOR_FREE_BYTE_STRING(clientDataHash);
CBOR_FREE_BYTE_STRING(pinUvAuthParam);
@@ -220,8 +386,13 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
CBOR_FREE_BYTE_STRING(excludeList[m].transports[n]);
}
}
if (aut_data)
free(aut_data);
if (cred_id)
free(cred_id);
if (error != CborNoError)
return -CTAP2_ERR_INVALID_CBOR;
driver_exec_finished(1);
driver_exec_finished(1+resp_size);
return 0;
}

6
src/fido/cbor_make_credential.h
View File

@@ -57,9 +57,9 @@ typedef struct PublicKeyCredentialDescriptor {
} PublicKeyCredentialDescriptor;
typedef struct CredOptions {
bool *rk;
bool *up;
bool *uv;
const bool *rk;
const bool *up;
const bool *uv;
bool present;
} CredOptions;

24
src/fido/ctap2_cbor.h
View File

@@ -31,7 +31,9 @@ extern int cbor_get_info();
extern int cbor_make_credential(const uint8_t *data, size_t len);
extern const uint8_t aaguid[16];
extern bool *ptrue, *pfalse;
extern const bool _btrue, _bfalse;
#define ptrue (&_btrue)
#define pfalse (&_bfalse)
#define CBOR_CHECK(f) \
do \
@@ -164,6 +166,7 @@ typedef struct CborCharString {
CBOR_ASSERT(cbor_value_is_text_string(&_f##_n) == true); \
CBOR_CHECK(cbor_value_dup_text_string(&(_f##_n), &(_v).data, &(_v).len, &(_f##_n))); \
(_v).present = true; \
continue; \
}
#define CBOR_FIELD_KEY_TEXT_VAL_BYTES(_n, _t, _v) \
@@ -171,16 +174,19 @@ typedef struct CborCharString {
CBOR_ASSERT(cbor_value_is_byte_string(&_f##_n) == true); \
CBOR_CHECK(cbor_value_dup_byte_string(&(_f##_n), &(_v).data, &(_v).len, &(_f##_n))); \
(_v).present = true; \
continue; \
}
#define CBOR_FIELD_KEY_TEXT_VAL_INT(_n, _t, _v) \
if (strcmp(_fd##_n, _t) == 0) { \
CBOR_FIELD_GET_INT(_v, _n);\
continue; \
}
#define CBOR_FIELD_KEY_TEXT_VAL_BOOL(_n, _t, _v) \
if (strcmp(_fd##_n, _t) == 0) { \
CBOR_FIELD_GET_BOOL(_v, _n);\
continue; \
}
#define CBOR_PARSE_MAP_END(_p,_n) \
@@ -190,13 +196,21 @@ typedef struct CborCharString {
#define CBOR_ADVANCE(_n) CBOR_CHECK(cbor_value_advance(&_f##_n));
#define CBOR_APPEND_KEY_UINT_VAL_TEXT(p, k, v) \
#define CBOR_APPEND_KEY_UINT_VAL_BYTES(p, k, v) \
do { \
if ((v).data && (v).len > 0) { \
CBOR_CHECK(cbor_encode_uint(&(p), (k))); \
CBOR_CHECK(cbor_encode_byte_string(&(p), (v).data, (v).len)); \
} } while(0)
#define CBOR_APPEND_KEY_UINT_VAL_STRING(p, k, v) \
do { \
if ((v).data && (v).len > 0) { \
CBOR_CHECK(cbor_encode_uint(&(p), (k))); \
CBOR_CHECK(cbor_encode_text_stringz(&(p), (v).data)); \
} } while(0)
#define CBOR_APPEND_KEY_UINT_VAL_UINT(p, k, v) \
do { \
CBOR_CHECK(cbor_encode_uint(&(p), (k))); \
@@ -209,5 +223,11 @@ typedef struct CborCharString {
CBOR_CHECK(cbor_encode_boolean(&(p), (v))); \
} while(0)
#define CBOR_APPEND_KEY_UINT_VAL_PBOOL(p, k, v) \
do { \
if (v != NULL) {\
CBOR_CHECK(cbor_encode_uint(&(p), (k))); \
CBOR_CHECK(cbor_encode_boolean(&(p), v == ptrue ? true : false)); \
} } while(0)
#endif //_CTAP2_CBOR_H_