Adding support for clientPIN.

It does not pass the tests yet.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

CMakeLists.txt

@@ -39,6 +39,7 @@ target_sources(pico_fido PUBLIC
         ${CMAKE_CURRENT_LIST_DIR}/src/fido/cbor_get_info.c
         ${CMAKE_CURRENT_LIST_DIR}/src/fido/cbor_make_credential.c
         ${CMAKE_CURRENT_LIST_DIR}/src/fido/known_apps.c
+        ${CMAKE_CURRENT_LIST_DIR}/src/fido/cbor_client_pin.c
         )
 set(HSM_DRIVER "hid")
 include(pico-hsm-sdk/pico_hsm_sdk_import.cmake)

src/fido/cbor.c

@@ -39,5 +39,7 @@ int cbor_process(const uint8_t *data, size_t len) {
         return cbor_get_info();
     else if (data[0] == CTAP_RESET)
         return cbor_reset();
+    else if (data[0] == CTAP_CLIENT_PIN)
+        return cbor_client_pin(data+1, len-1);
     return -CTAP2_ERR_INVALID_CBOR;
 }

src/fido/cbor_make_credential.c

@@ -43,7 +43,7 @@ bool credential_verify(CborByteString *cred_id, const uint8_t *rp_id_hash) {
     return false;
 }
 
-int verify(CborByteString *clientDataHash, CborByteString *pinUvAuthParam) {
+int verify_user(CborByteString *clientDataHash, CborByteString *pinUvAuthParam) {
     return CborNoError;
 }
 
@@ -225,7 +225,7 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
         //Unfinished. See 6.1.2.9
     }
     if (pinUvAuthParam.present == true) { //11.1
-        int ret = verify(&clientDataHash, &pinUvAuthParam);
+        int ret = verify_user(&clientDataHash, &pinUvAuthParam);
         if (ret != CborNoError)
             CBOR_ERROR(CTAP2_ERR_PIN_AUTH_INVALID);
         //Check pinUvAuthToken permissions. See 6.1.2.11
@@ -272,7 +272,7 @@ int cbor_make_credential(const uint8_t *data, size_t len) {
     uint8_t key[32];
     memset(key, 0, sizeof(key));
     uint8_t iv[12];
-    memcpy(iv, random_bytes_get(sizeof(iv)), sizeof(iv));
+    random_gen_core0(NULL, iv, sizeof(12));
     mbedtls_chachapoly_context chatx;
     mbedtls_chachapoly_init(&chatx);
     mbedtls_chachapoly_setkey(&chatx, key);

src/fido/fido.c

@@ -24,6 +24,7 @@
 #include "file.h"
 #include "usb.h"
 #include "random.h"
+#include "bsp/board.h"
 #include "mbedtls/ecdsa.h"
 #include "mbedtls/x509_crt.h"
 #include "mbedtls/hkdf.h"
@@ -36,6 +37,8 @@ void init_fido();
 int fido_process_apdu();
 int fido_unload();
 
+pinUvAuthToken_t paut = {0};
+
 const uint8_t fido_aid[] = {
     8,
     0xA0, 0x00, 0x00, 0x06, 0x47, 0x2F, 0x00, 0x01
@@ -81,7 +84,7 @@ int x509_create_cert(mbedtls_ecdsa_context *ecdsa, uint8_t *buffer, size_t buffe
     mbedtls_x509write_crt_set_subject_key_identifier(&ctx);
     mbedtls_x509write_crt_set_authority_key_identifier(&ctx);
     mbedtls_x509write_crt_set_key_usage(&ctx, MBEDTLS_X509_KU_DIGITAL_SIGNATURE | MBEDTLS_X509_KU_KEY_CERT_SIGN);
-    int ret = mbedtls_x509write_crt_der(&ctx, buffer, buffer_size, random_gen, NULL);
+    int ret = mbedtls_x509write_crt_der(&ctx, buffer, buffer_size, random_gen_core0, NULL);
     return ret;
 }
 
@@ -103,7 +106,9 @@ int derive_key(const uint8_t *app_id, bool new_key, uint8_t *key_handle, int cur
     for (int i = 0; i < KEY_PATH_ENTRIES; i++)
     {
         if (new_key == true) {
-            uint32_t val = 0x80000000 | *((uint32_t *)random_bytes_get(sizeof(uint32_t)));
+            uint32_t val = 0;
+            random_gen_core0(NULL, (uint8_t *) &val, sizeof(val));
+            val |= 0x80000000;
             memcpy(&key_handle[i*sizeof(uint32_t)], &val, sizeof(uint32_t));
         }
         r = mbedtls_hkdf(md_info, &key_handle[i * sizeof(uint32_t)], sizeof(uint32_t), outk, 32, outk + 32, 32, outk, sizeof(outk));
@@ -141,7 +146,7 @@ int derive_key(const uint8_t *app_id, bool new_key, uint8_t *key_handle, int cur
 int scan_files() {
     ef_keydev = search_by_fid(EF_KEY_DEV, NULL, SPECIFY_EF);
     if (ef_keydev) {
-        if (!ef_keydev->data) {
+        if (!file_has_data(ef_keydev)) {
             printf("KEY DEVICE is empty. Generating SECP256R1 curve...");
             mbedtls_ecdsa_context ecdsa;
             mbedtls_ecdsa_init(&ecdsa);
@@ -168,7 +173,7 @@ int scan_files() {
     }
     ef_certdev = search_by_fid(EF_EE_DEV, NULL, SPECIFY_EF);
     if (ef_certdev) {
-        if (file_get_size(ef_certdev) == 0 || !ef_certdev->data) {
+        if (!file_has_data(ef_certdev)) {
             uint8_t cert[4096];
             mbedtls_ecdsa_context key;
             mbedtls_ecdsa_init(&key);
@@ -188,7 +193,7 @@ int scan_files() {
     }
     ef_counter = search_by_fid(EF_COUNTER, NULL, SPECIFY_EF);
     if (ef_counter) {
-        if (file_get_size(ef_counter) == 0 || !ef_counter->data) {
+        if (!file_has_data(ef_counter)) {
             uint32_t v = 0;
             flash_write_data_to_file(ef_counter, (uint8_t *)&v, sizeof(v));
         }
@@ -197,6 +202,19 @@ int scan_files() {
         printf("FATAL ERROR: Global counter not found in memory!\r\n");
     }
     ef_pin = search_by_fid(EF_PIN, NULL, SPECIFY_EF);
+    ef_authtoken = search_by_fid(EF_AUTHTOKEN, NULL, SPECIFY_EF);
+    if (ef_authtoken) {
+        if (!file_has_data(ef_authtoken)) {
+            uint8_t t[32];
+            random_gen_core0(NULL, t, sizeof(t));
+            flash_write_data_to_file(ef_authtoken, t, sizeof(t));
+        }
+        paut.data = file_get_data(ef_authtoken);
+        paut.len = file_get_size(ef_authtoken);
+    }
+    else {
+        printf("FATAL ERROR: Auth Token not found in memory!\r\n");
+    }
     low_flash_available();
     return CCID_OK;
 }
@@ -218,6 +236,17 @@ bool wait_button_pressed() {
     return (val == EV_BUTTON_TIMEOUT);
 }
 
+uint32_t user_present_time_limit = 0;
+
+bool check_user_presence() {
+    if (user_present_time_limit == 0 || user_present_time_limit+TRANSPORT_TIME_LIMIT < board_millis()) {
+        if (wait_button() == true) //timeout
+            return false;
+        user_present_time_limit = board_millis();
+    }
+    return true;
+}
+
 typedef struct cmd
 {
   uint8_t ins;

src/fido/fido.h

@@ -54,6 +54,15 @@ extern CTAPHID_FRAME *ctap_req, *ctap_resp;
 #define FIDO2_AUT_FLAG_AT       0x40
 #define FIDO2_AUT_FLAG_ED       0x80
 
+#define FIDO2_PERMISSION_MC     0x1
+#define FIDO2_PERMISSION_GA     0x2
+#define FIDO2_PERMISSION_CM     0x4
+#define FIDO2_PERMISSION_BE     0x8
+#define FIDO2_PERMISSION_LBW    0x10
+#define FIDO2_PERMISSION_ACFG   0x20
+
+#define MAX_PIN_RETRIES 3
+
 typedef struct known_app {
     const uint8_t *rp_id_hash;
     const char *label;
@@ -63,4 +72,20 @@ typedef struct known_app {
 
 extern const known_app_t *find_app_by_rp_id_hash(const uint8_t *rp_id_hash);
 
+#define TRANSPORT_TIME_LIMIT (30*1000) //USB
+
+bool check_user_presence();
+
+typedef struct pinUvAuthToken {
+    uint8_t *data;
+    size_t len;
+    bool in_use;
+    uint8_t permissions;
+    uint8_t rp_id_hash[32];
+} pinUvAuthToken_t;
+
+extern uint32_t user_present_time_limit;
+
+extern pinUvAuthToken_t paut;
+
 #endif //_FIDO_H

src/fido/files.c

@@ -23,7 +23,8 @@ file_t file_entries[] = {
     {.fid = EF_KEY_DEV, .parent = 0, .name = NULL, .type = FILE_TYPE_INTERNAL_EF | FILE_DATA_FLASH | FILE_PERSISTENT, .data = NULL, .ef_structure = FILE_EF_TRANSPARENT, .acl = {0xff}},  // Device Key
     {.fid = EF_EE_DEV,  .parent = 0, .name = NULL, .type = FILE_TYPE_INTERNAL_EF | FILE_DATA_FLASH | FILE_PERSISTENT, .data = NULL, .ef_structure = FILE_EF_TRANSPARENT, .acl = {0xff}},   // End Entity Certificate Device
     {.fid = EF_COUNTER,  .parent = 0, .name = NULL, .type = FILE_TYPE_INTERNAL_EF | FILE_DATA_FLASH, .data = NULL, .ef_structure = FILE_EF_TRANSPARENT, .acl = {0xff}},   // Global counter
-    {.fid = EF_PIN,  .parent = 0, .name = NULL, .type = FILE_TYPE_INTERNAL_EF | FILE_DATA_FLASH, .data = NULL, .ef_structure = FILE_EF_TRANSPARENT, .acl = {0xff}},   // Global counter
+    {.fid = EF_PIN,  .parent = 0, .name = NULL, .type = FILE_TYPE_INTERNAL_EF | FILE_DATA_FLASH, .data = NULL, .ef_structure = FILE_EF_TRANSPARENT, .acl = {0xff}},   // PIN
+    {.fid = EF_AUTHTOKEN,  .parent = 0, .name = NULL, .type = FILE_TYPE_INTERNAL_EF | FILE_DATA_FLASH, .data = NULL, .ef_structure = FILE_EF_TRANSPARENT, .acl = {0xff}},   // AUTH TOKEN
     { .fid = 0x0000, .parent = 0xff, .name = NULL, .type = FILE_TYPE_UNKNOWN, .data = NULL, .ef_structure = 0, .acl = {0} } //end
 };
 
@@ -33,3 +34,4 @@ file_t *ef_keydev = NULL;
 file_t *ef_certdev = NULL;
 file_t *ef_counter = NULL;
 file_t *ef_pin = NULL;
+file_t *ef_authtoken = NULL;

src/fido/files.h

@@ -24,10 +24,12 @@
 #define EF_EE_DEV       0xCE00
 #define EF_COUNTER      0xC000
 #define EF_PIN          0x1080
+#define EF_AUTHTOKEN    0x1090
 
 extern file_t *ef_keydev;
 extern file_t *ef_certdev;
 extern file_t *ef_counter;
 extern file_t *ef_pin;
+extern file_t *ef_authtoken;
 
 #endif //_FILES_H_