dearsky/pico-fido
1
0
Fork 0
Code Issues 46 Pull Requests 1 Actions Packages Projects Releases 22 Wiki Activity

Finalizing get assertion.

Browse Source 
Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>
This commit is contained in:
Pol Henarejos
2022-09-21 14:29:28 +02:00
parent f71624f489
commit 99fc76a385
8 changed files with 213 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
src/fido/cbor.c
View File

@@ -44,6 +44,8 @@ int cbor_parse(const uint8_t *data, size_t len) {
return cbor_reset();
else if (data[0] == CTAP_CLIENT_PIN)
return cbor_client_pin(data + 1, len - 1);
else if (data[0] == CTAP_GET_ASSERTION)
return cbor_get_assertion(data + 1, len - 1);
return CTAP2_ERR_INVALID_CBOR;
}

173
src/fido/cbor_get_assertion.c
View File

@@ -27,14 +27,26 @@
#include "apdu.h"
#include "cbor_make_credential.h"
#include "credential.h"
#include <math.h>
int cbor_client_pin(const uint8_t *data, size_t len) {
CborCharString rpIdx = {0};
CborByteString pinUvAuthParamx = {0}, clientDataHashx = {0};
bool residentx = false;
Credential credsx[MAX_CREDENTIAL_COUNT_IN_LIST] = {0};
uint64_t pinUvAuthProtocolx = 0;
CredExtensions extensionx = {0};
CredOptions optionsx = {0};
uint8_t flagsx = 0;
uint8_t credentialCounter = 1;
uint8_t numberOfCredentialsx = 0;
int cbor_get_assertion(const uint8_t *data, size_t len) {
size_t resp_size = 0;
uint64_t pinUvAuthProtocol = 0;
CredOptions options = {0};
CredExtensions extensions = {0};
CborParser parser;
CborEncoder encoder, mapEncoder;
CborEncoder encoder, mapEncoder, mapEncoder2;
CborValue map;
CborError error = CborNoError;
CborByteString pinUvAuthParam = {0}, clientDataHash = {0};
@@ -42,6 +54,8 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
PublicKeyCredentialDescriptor allowList[MAX_CREDENTIAL_COUNT_IN_LIST] = {0};
Credential creds[MAX_CREDENTIAL_COUNT_IN_LIST] = {0};
size_t allowList_len = 0, creds_len = 0;
uint8_t *aut_data = NULL;
bool asserted = false;
CBOR_CHECK(cbor_parser_init(data, len, 0, &parser, &map));
uint64_t val_c = 1;
@@ -173,7 +187,8 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
int ret = credential_load(file_get_data(ef) + 32, file_get_size(ef) - 32, rp_id_hash, &creds[creds_len]);
if (ret != 0)
credential_free(&creds[creds_len]);
creds_len++;
else
creds_len++;
}
resident = true;
}
@@ -207,17 +222,157 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
clearUserVerifiedFlag();
clearPinUvAuthTokenPermissionsExceptLbw();
}
if (resident) {
if (numberOfCredentials == 0)
CBOR_ERROR(CTAP2_ERR_NO_CREDENTIALS);
Credential *selcred = NULL;
if (resident == false) {
selcred = &creds[0];
}
else {
if (numberOfCredentials == 1)
selcred = &creds[0];
else {
asserted = true;
rpIdx = rpId;
pinUvAuthParamx = pinUvAuthParamx;
clientDataHashx = clientDataHash;
residentx = resident;
for (int i = 0; i < MAX_CREDENTIAL_COUNT_IN_LIST; i++)
credsx[i] = creds[i];
numberOfCredentialsx = numberOfCredentials;
pinUvAuthProtocolx = pinUvAuthProtocol;
extensionx = extensions;
optionsx = options;
flagsx = flags;
}
}
uint8_t cred_id[MAX_CRED_ID_LENGTH];
size_t cred_id_len = 0;
if (credential_create_cred(selcred, cred_id, &cred_id_len) != 0)
CBOR_ERROR(CTAP2_ERR_INTEGRITY_FAILURE);
mbedtls_ecdsa_context ekey;
mbedtls_ecdsa_init(&ekey);
int ret = fido_load_key(selcred->curve, cred_id, &ekey);
if (ret != 0) {
mbedtls_ecdsa_free(&ekey);
CBOR_ERROR(CTAP1_ERR_OTHER);
}
size_t ext_len = 0;
uint8_t ext [512];
if (extensions.present == true) {
cbor_encoder_init(&encoder, ext, sizeof(ext), 0);
int l = 0;
if (extensions.hmac_secret != NULL)
l++;
if (extensions.credProtect != 0)
l++;
CBOR_CHECK(cbor_encoder_create_map(&encoder, &mapEncoder, l));
if (extensions.credProtect != 0) {
CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder, "credProtect"));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, extensions.credProtect));
}
if (extensions.hmac_secret != NULL) {
CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder, "hmac-secret"));
CBOR_CHECK(cbor_encode_boolean(&mapEncoder, *extensions.hmac_secret));
}
CBOR_CHECK(cbor_encoder_close_container(&encoder, &mapEncoder));
ext_len = cbor_encoder_get_buffer_size(&encoder, ext);
flags |= FIDO2_AUT_FLAG_ED;
}
uint8_t pkey[66];
const mbedtls_ecp_curve_info *cinfo = mbedtls_ecp_curve_info_from_grp_id(ekey.grp.id);
if (cinfo == NULL)
CBOR_ERROR(CTAP1_ERR_OTHER);
size_t olen = 0, pkey_len = ceil((float)cinfo->bit_size/8);
uint32_t ctr = *(uint32_t *)file_get_data(ef_counter);
uint8_t cbor_buf[1024];
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, -selcred->alg));
CBOR_CHECK(cbor_encode_negative_int(&mapEncoder, 1));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, selcred->curve));
CBOR_CHECK(cbor_encode_negative_int(&mapEncoder, 2));
mbedtls_mpi_write_binary(&ekey.Q.X, pkey, pkey_len);
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder, pkey, pkey_len));
CBOR_CHECK(cbor_encode_negative_int(&mapEncoder, 3));
mbedtls_mpi_write_binary(&ekey.Q.Y, pkey, pkey_len);
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder, pkey, pkey_len));
CBOR_CHECK(cbor_encoder_close_container(&encoder, &mapEncoder));
size_t 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 + clientDataHash.len);
uint8_t *pa = aut_data;
memcpy(pa, rp_id_hash, 32); pa += 32;
*pa++ = flags;
*pa++ = ctr >> 24;
*pa++ = ctr >> 16;
*pa++ = ctr >> 8;
*pa++ = ctr & 0xff;
memcpy(pa, aaguid, 16); pa += 16;
*pa++ = cred_id_len >> 8;
*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;
if (pa-aut_data != aut_data_len)
CBOR_ERROR(CTAP1_ERR_OTHER);
memcpy(pa, clientDataHash.data, clientDataHash.len);
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+clientDataHash.len, hash);
ret = mbedtls_ecdsa_write_signature(&ekey, MBEDTLS_MD_SHA256, hash, 32, sig, sizeof(sig), &olen, random_gen, NULL);
mbedtls_ecdsa_free(&ekey);
uint8_t lfields = 3;
if (resident)
lfields++;
if (numberOfCredentials > 1)
lfields++;
cbor_encoder_init(&encoder, ctap_resp->init.data + 1, CTAP_MAX_PACKET_SIZE, 0);
CBOR_CHECK(cbor_encoder_create_map(&encoder, &mapEncoder, lfields));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 0x01));
CBOR_CHECK(cbor_encoder_create_map(&mapEncoder, &mapEncoder2, 2));
CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder2, "type"));
CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder2, "public-key"));
CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder2, "id"));
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder2, cred_id, cred_id_len));
CBOR_CHECK(cbor_encoder_close_container(&mapEncoder, &mapEncoder2));
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_encode_byte_string(&mapEncoder, sig, olen));
if (resident) {
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 0x04));
CBOR_CHECK(cbor_encoder_create_map(&mapEncoder, &mapEncoder2, 1));
CBOR_CHECK(cbor_encode_text_stringz(&mapEncoder2, "id"));
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder2, selcred->userId.data, selcred->userId.len));
CBOR_CHECK(cbor_encoder_close_container(&mapEncoder, &mapEncoder2));
}
if (numberOfCredentials > 1) {
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 0x05));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, numberOfCredentials));
}
CBOR_CHECK(cbor_encoder_close_container(&encoder, &mapEncoder));
res_APDU_size = cbor_encoder_get_buffer_size(&encoder, ctap_resp->init.data + 1);
err:
if (asserted == false) {
CBOR_FREE_BYTE_STRING(clientDataHash);
CBOR_FREE_BYTE_STRING(pinUvAuthParam);
CBOR_FREE_BYTE_STRING(rpId);
CBOR_FREE_BYTE_STRING(pinUvAuthParam);
CBOR_FREE_BYTE_STRING(rpId);
}
for (int m = 0; m < allowList_len; m++) {
CBOR_FREE_BYTE_STRING(allowList[m].type);
@@ -226,6 +381,8 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
CBOR_FREE_BYTE_STRING(allowList[m].transports[n]);
}
}
if (aut_data)
free(aut_data);
if (error != CborNoError) {
if (error == CborErrorImproperValue)
return CTAP2_ERR_CBOR_UNEXPECTED_TYPE;

25
src/fido/cbor_make_credential.c
View File

@@ -244,30 +244,9 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
CBOR_CHECK(credential_create(&rp.id, &user.id, &user.parent.name, &user.displayName, &extensions, (!ka || ka->use_sign_count == ptrue), alg, curve, cred_id, &cred_id_len));
mbedtls_ecp_group_id mbedtls_curve = MBEDTLS_ECP_DP_SECP256R1;
if (curve == FIDO2_CURVE_P256)
mbedtls_curve = MBEDTLS_ECP_DP_SECP256R1;
else if (curve == FIDO2_CURVE_P384)
mbedtls_curve = MBEDTLS_ECP_DP_SECP384R1;
else if (curve == FIDO2_CURVE_P521)
mbedtls_curve = MBEDTLS_ECP_DP_SECP521R1;
else if (curve == FIDO2_CURVE_P256K1)
mbedtls_curve = MBEDTLS_ECP_DP_SECP256K1;
else if (curve == FIDO2_CURVE_X25519)
mbedtls_curve = MBEDTLS_ECP_DP_CURVE25519;
else if (curve == FIDO2_CURVE_X448)
mbedtls_curve = MBEDTLS_ECP_DP_CURVE448;
else
CBOR_ERROR(CTAP2_ERR_UNSUPPORTED_ALGORITHM);
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;
int ret = derive_key(NULL, false, key_path, mbedtls_curve, &ekey);
int ret = fido_load_key(curve, cred_id, &ekey);
if (ret != 0) {
mbedtls_ecdsa_free(&ekey);
CBOR_ERROR(CTAP1_ERR_OTHER);
@@ -301,7 +280,7 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
flags |= FIDO2_AUT_FLAG_ED;
}
uint8_t pkey[66];
const mbedtls_ecp_curve_info *cinfo = mbedtls_ecp_curve_info_from_grp_id(mbedtls_curve);
const mbedtls_ecp_curve_info *cinfo = mbedtls_ecp_curve_info_from_grp_id(ekey.grp.id);
if (cinfo == NULL)
CBOR_ERROR(CTAP1_ERR_OTHER);
size_t olen = 0, pkey_len = ceil((float)cinfo->bit_size/8);

8
src/fido/credential.c
View File

@@ -38,6 +38,10 @@ int credential_verify(uint8_t *cred_id, size_t cred_id_len, const uint8_t *rp_id
return mbedtls_chachapoly_auth_decrypt(&chatx, cred_id_len - (4 + 12 + 16), iv, rp_id_hash, 32, tag, cipher, cipher);
}
int credential_create_cred(Credential *cred, uint8_t *cred_id, size_t *cred_id_len) {
return credential_create(&cred->rpId, &cred->userId, &cred->userName, &cred->userDisplayName, &cred->extensions, cred->use_sign_count, cred->alg, cred->curve, cred_id, cred_id_len);
}
int credential_create(CborCharString *rpId, CborByteString *userId, CborCharString *userName, CborCharString *userDisplayName, CredExtensions *extensions, bool use_sign_count, int alg, int curve, uint8_t *cred_id, size_t *cred_id_len) {
CborEncoder encoder, mapEncoder, mapEncoder2;
CborError error = CborNoError;
@@ -108,6 +112,8 @@ int credential_load(const uint8_t *cred_id, size_t cred_id_len, const uint8_t *r
CborValue map;
CborError error;
memset(cred, 0, sizeof(Credential));
cred->curve = FIDO2_CURVE_P256;
cred->alg = FIDO2_ALG_ES256;
CBOR_CHECK(cbor_parser_init(copy_cred_id + 4 + 12, cred_id_len - (4 + 12 + 16), 0, &parser, &map));
CBOR_PARSE_MAP_START(map, 1) {
uint64_t val_u = 0;
@@ -160,6 +166,8 @@ int credential_load(const uint8_t *cred_id, size_t cred_id_len, const uint8_t *r
void credential_free(Credential *cred) {
CBOR_FREE_BYTE_STRING(cred->rpId);
CBOR_FREE_BYTE_STRING(cred->userId);
CBOR_FREE_BYTE_STRING(cred->userName);
CBOR_FREE_BYTE_STRING(cred->userDisplayName);
cred->present = false;
cred->extensions.present = false;
}

3
src/fido/credential.h
View File

@@ -37,6 +37,8 @@ typedef struct Credential
{
CborCharString rpId;
CborByteString userId;
CborCharString userName;
CborCharString userDisplayName;
uint64_t creation;
CredExtensions extensions;
const bool *use_sign_count;
@@ -54,5 +56,6 @@ extern int credential_create(CborCharString *rpId, CborByteString *userId, CborC
extern void credential_free(Credential *cred);
extern int credential_store(const uint8_t *cred_id, size_t cred_id_len, const uint8_t *rp_id_hash);
extern int credential_load(const uint8_t *cred_id, size_t cred_id_len, const uint8_t *rp_id_hash, Credential *cred);
extern int credential_create_cred(Credential *cred, uint8_t *cred_id, size_t *cred_id_len);
#endif // _CREDENTIAL_H_

1
src/fido/ctap2_cbor.h
View File

@@ -30,6 +30,7 @@ extern int cbor_reset();
extern int cbor_get_info();
extern int cbor_make_credential(const uint8_t *data, size_t len);
extern int cbor_client_pin(const uint8_t *data, size_t len);
extern int cbor_get_assertion(const uint8_t *data, size_t len);
extern const uint8_t aaguid[16];
extern const bool _btrue, _bfalse;

32
src/fido/fido.c
View File

@@ -62,6 +62,34 @@ int fido_unload() {
return CCID_OK;
}
mbedtls_ecp_group_id fido_curve_to_mbedtls(int curve) {
if (curve == FIDO2_CURVE_P256)
return MBEDTLS_ECP_DP_SECP256R1;
else if (curve == FIDO2_CURVE_P384)
return MBEDTLS_ECP_DP_SECP384R1;
else if (curve == FIDO2_CURVE_P521)
return MBEDTLS_ECP_DP_SECP521R1;
else if (curve == FIDO2_CURVE_P256K1)
return MBEDTLS_ECP_DP_SECP256K1;
else if (curve == FIDO2_CURVE_X25519)
return MBEDTLS_ECP_DP_CURVE25519;
else if (curve == FIDO2_CURVE_X448)
return MBEDTLS_ECP_DP_CURVE448;
return MBEDTLS_ECP_DP_NONE;
}
int fido_load_key(int curve, const uint8_t *cred_id, mbedtls_ecdsa_context *key) {
mbedtls_ecp_group_id mbedtls_curve = fido_curve_to_mbedtls(curve);
if (mbedtls_curve == MBEDTLS_ECP_DP_NONE)
return CTAP2_ERR_UNSUPPORTED_ALGORITHM;
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;
return derive_key(NULL, false, key_path, mbedtls_curve, key);
}
int x509_create_cert(mbedtls_ecdsa_context *ecdsa, uint8_t *buffer, size_t buffer_size) {
mbedtls_x509write_cert ctx;
mbedtls_x509write_crt_init(&ctx);
@@ -107,7 +135,7 @@ int derive_key(const uint8_t *app_id, bool new_key, uint8_t *key_handle, int cur
{
if (new_key == true) {
uint32_t val = 0;
random_gen_core0(NULL, (uint8_t *) &val, sizeof(val));
random_gen(NULL, (uint8_t *) &val, sizeof(val));
val |= 0x80000000;
memcpy(&key_handle[i*sizeof(uint32_t)], &val, sizeof(uint32_t));
}
@@ -137,7 +165,7 @@ int derive_key(const uint8_t *app_id, bool new_key, uint8_t *key_handle, int cur
mbedtls_platform_zeroize(outk, sizeof(outk));
if (r != 0)
return r;
return mbedtls_ecp_mul(&key->grp, &key->Q, &key->d, &key->grp.G, random_gen_core0, NULL);
return mbedtls_ecp_mul(&key->grp, &key->Q, &key->d, &key->grp.G, random_gen, NULL);
}
mbedtls_platform_zeroize(outk, sizeof(outk));
return r;

2
src/fido/fido.h
View File

@@ -35,6 +35,8 @@ extern int derive_key(const uint8_t *app_id, bool new_key, uint8_t *key_handle,
extern bool wait_button_pressed();
extern CTAPHID_FRAME *ctap_req, *ctap_resp;
extern void init_fido();
extern mbedtls_ecp_group_id fido_curve_to_mbedtls(int curve);
extern int fido_load_key(int curve, const uint8_t *cred_id, mbedtls_ecdsa_context *key);
#define FIDO2_ALG_ES256 -7 //ECDSA-SHA256 P256
#define FIDO2_ALG_EDDSA -8 //EdDSA