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Add support for PIN hash storage and MKEK.

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Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>
This commit is contained in:
Pol Henarejos
2025-01-03 01:20:58 +01:00
parent a70e259a90
commit 6a67800057
8 changed files with 308 additions and 46 deletions
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84
src/fido/cbor_client_pin.c
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@@ -37,6 +37,7 @@
#include "crypto_utils.h"
#include "pico_keys.h"
#include "apdu.h"
#include "kek.h"
uint32_t usage_timer = 0, initial_usage_time_limit = 0;
uint32_t max_usage_time_period = 600 * 1000;
@@ -279,6 +280,21 @@ int pinUvAuthTokenUsageTimerObserver() {
return 0;
}
int check_mkek_encrypted(const uint8_t *dhash) {
if (file_get_size(ef_mkek) == MKEK_IV_SIZE + MKEK_KEY_SIZE) {
hash_multi(dhash, 16, session_pin); // Only for storing MKEK
uint8_t mkek[MKEK_SIZE] = {0};
memcpy(mkek, file_get_data(ef_mkek), MKEK_IV_SIZE + MKEK_KEY_SIZE);
int ret = store_mkek(mkek);
mbedtls_platform_zeroize(mkek, sizeof(mkek));
mbedtls_platform_zeroize(session_pin, sizeof(session_pin));
if (ret != PICOKEY_OK) {
return CTAP2_ERR_PIN_AUTH_INVALID;
}
}
return PICOKEY_OK;
}
uint8_t new_pin_mismatches = 0;
int cbor_client_pin(const uint8_t *data, size_t len) {
@@ -415,12 +431,20 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
if (pin_len < minPin) {
CBOR_ERROR(CTAP2_ERR_PIN_POLICY_VIOLATION);
}
uint8_t hsh[34];
uint8_t hsh[34], dhash[32];
hsh[0] = MAX_PIN_RETRIES;
hsh[1] = pin_len;
mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), paddedNewPin, pin_len, hsh + 2);
file_put_data(ef_pin, hsh, 2 + 16);
mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), paddedNewPin, pin_len, dhash);
double_hash_pin(dhash, 16, hsh + 2);
file_put_data(ef_pin, hsh, 2 + 32);
low_flash_available();
ret = check_mkek_encrypted(dhash);
if (ret != PICOKEY_OK) {
CBOR_ERROR(ret);
}
mbedtls_platform_zeroize(hsh, sizeof(hsh));
mbedtls_platform_zeroize(dhash, sizeof(dhash));
goto err; //No return
}
else if (subcommand == 0x4) { //changePIN
@@ -462,8 +486,8 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
mbedtls_platform_zeroize(sharedSecret, sizeof(sharedSecret));
CBOR_ERROR(CTAP2_ERR_PIN_AUTH_INVALID);
}
uint8_t pin_data[18];
memcpy(pin_data, file_get_data(ef_pin), 18);
uint8_t pin_data[34];
memcpy(pin_data, file_get_data(ef_pin), 34);
pin_data[0] -= 1;
file_put_data(ef_pin, pin_data, sizeof(pin_data));
low_flash_available();
@@ -474,7 +498,9 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
mbedtls_platform_zeroize(sharedSecret, sizeof(sharedSecret));
CBOR_ERROR(CTAP2_ERR_PIN_AUTH_INVALID);
}
if (memcmp(paddedNewPin, file_get_data(ef_pin) + 2, 16) != 0) {
uint8_t dhash[32];
double_hash_pin(paddedNewPin, 16, dhash);
if (memcmp(dhash, file_get_data(ef_pin) + 2, 32) != 0) {
regenerate();
mbedtls_platform_zeroize(sharedSecret, sizeof(sharedSecret));
if (retries == 0) {
@@ -488,6 +514,7 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
CBOR_ERROR(CTAP2_ERR_PIN_INVALID);
}
}
hash_multi(paddedNewPin, 16, session_pin);
pin_data[0] = MAX_PIN_RETRIES;
file_put_data(ef_pin, pin_data, sizeof(pin_data));
low_flash_available();
@@ -515,12 +542,33 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
uint8_t hsh[34];
hsh[0] = MAX_PIN_RETRIES;
hsh[1] = pin_len;
mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), paddedNewPin, pin_len, hsh + 2);
mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), paddedNewPin, pin_len, dhash);
double_hash_pin(dhash, 16, hsh + 2);
if (file_has_data(ef_minpin) && file_get_data(ef_minpin)[1] == 1 &&
memcmp(hsh + 2, file_get_data(ef_pin) + 2, 16) == 0) {
memcmp(hsh + 2, file_get_data(ef_pin) + 2, 32) == 0) {
CBOR_ERROR(CTAP2_ERR_PIN_POLICY_VIOLATION);
}
file_put_data(ef_pin, hsh, 2 + 16);
uint8_t mkek[MKEK_SIZE] = {0};
ret = load_mkek(mkek);
if (ret != PICOKEY_OK) {
CBOR_ERROR(ret);
}
file_put_data(ef_pin, hsh, 2 + 32);
ret = check_mkek_encrypted(dhash);
if (ret != PICOKEY_OK) {
CBOR_ERROR(ret);
}
hash_multi(dhash, 16, session_pin);
ret = store_mkek(mkek);
mbedtls_platform_zeroize(mkek, sizeof(mkek));
if (ret != PICOKEY_OK) {
CBOR_ERROR(ret);
}
mbedtls_platform_zeroize(hsh, sizeof(hsh));
mbedtls_platform_zeroize(dhash, sizeof(dhash));
if (file_has_data(ef_minpin) && file_get_data(ef_minpin)[1] == 1) {
uint8_t *tmpf = (uint8_t *) calloc(1, file_get_size(ef_minpin));
memcpy(tmpf, file_get_data(ef_minpin), file_get_size(ef_minpin));
@@ -570,8 +618,8 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
mbedtls_platform_zeroize(sharedSecret, sizeof(sharedSecret));
CBOR_ERROR(CTAP1_ERR_INVALID_PARAMETER);
}
uint8_t pin_data[18];
memcpy(pin_data, file_get_data(ef_pin), 18);
uint8_t pin_data[34];
memcpy(pin_data, file_get_data(ef_pin), 34);
pin_data[0] -= 1;
file_put_data(ef_pin, pin_data, sizeof(pin_data));
low_flash_available();
@@ -582,7 +630,9 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
mbedtls_platform_zeroize(sharedSecret, sizeof(sharedSecret));
CBOR_ERROR(CTAP2_ERR_PIN_AUTH_INVALID);
}
if (memcmp(paddedNewPin, file_get_data(ef_pin) + 2, 16) != 0) {
uint8_t dhash[32];
double_hash_pin(paddedNewPin, 16, dhash);
if (memcmp(dhash, file_get_data(ef_pin) + 2, 32) != 0) {
regenerate();
mbedtls_platform_zeroize(sharedSecret, sizeof(sharedSecret));
if (retries == 0) {
@@ -596,9 +646,19 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
CBOR_ERROR(CTAP2_ERR_PIN_INVALID);
}
}
ret = check_mkek_encrypted(paddedNewPin);
if (ret != PICOKEY_OK) {
CBOR_ERROR(ret);
}
hash_multi(paddedNewPin, 16, session_pin);
pin_data[0] = MAX_PIN_RETRIES;
new_pin_mismatches = 0;
file_put_data(ef_pin, pin_data, sizeof(pin_data));
mbedtls_platform_zeroize(pin_data, sizeof(pin_data));
mbedtls_platform_zeroize(dhash, sizeof(dhash));
low_flash_available();
file_t *ef_minpin = search_by_fid(EF_MINPINLEN, NULL, SPECIFY_EF);
if (file_has_data(ef_minpin) && file_get_data(ef_minpin)[1] == 1) {