enforce 10s window where device reset is possible

Fixes issue found by @My1: https://github.com/solokeys/solo/issues/407

fido2/ctap.c

@@ -31,6 +31,7 @@ uint8_t PIN_TOKEN[PIN_TOKEN_SIZE];
 uint8_t KEY_AGREEMENT_PUB[64];
 static uint8_t KEY_AGREEMENT_PRIV[32];
 static int8_t PIN_BOOT_ATTEMPTS_LEFT = PIN_BOOT_ATTEMPTS;
+static uint32_t BOOT_TIME = 0;
 
 AuthenticatorState STATE;
 
@@ -1587,18 +1588,15 @@ static int scan_for_next_rk(int index, uint8_t * initialRpIdHash){
 
     if (initialRpIdHash != NULL) {
         memmove(lastRpIdHash, initialRpIdHash, 32);
-        index = 0;
+        index = -1;
     }
     else
     {
         ctap_load_rk(index, &rk);
         memmove(lastRpIdHash, rk.id.rpIdHash, 32);
-        index++;
     }
 
-    ctap_load_rk(index, &rk);
-
-    while ( memcmp( rk.id.rpIdHash, lastRpIdHash, 32 ) != 0 )
+    do
     {
         index++;
         if ((unsigned int)index >= ctap_rk_size()) 
@@ -1607,6 +1605,7 @@ static int scan_for_next_rk(int index, uint8_t * initialRpIdHash){
         }
         ctap_load_rk(index, &rk);
     }
+    while ( memcmp( rk.id.rpIdHash, lastRpIdHash, 32 ) != 0 );
 
     return index;
 }
@@ -2287,11 +2286,18 @@ uint8_t ctap_request(uint8_t * pkt_raw, int length, CTAP_RESPONSE * resp)
             break;
         case CTAP_RESET:
             printf1(TAG_CTAP,"CTAP_RESET\n");
+            if ((millis() - BOOT_TIME) > 10 * 1000)
+            {
+                status = CTAP2_ERR_NOT_ALLOWED;
+            }
+            else
+            {
                 status = ctap2_user_presence_test();
                 if (status == CTAP1_ERR_SUCCESS)
                 {
                     ctap_reset();
                 }
+            }
             break;
         case GET_NEXT_ASSERTION:
             printf1(TAG_CTAP,"CTAP_NEXT_ASSERTION\n");
@@ -2384,6 +2390,7 @@ void ctap_init()
             firmware_version.major, firmware_version.minor, firmware_version.patch, firmware_version.reserved,
             firmware_version.major, firmware_version.minor, firmware_version.patch, firmware_version.reserved
             );
+    BOOT_TIME = millis();
     crypto_ecc256_init();
 
     int is_init = authenticator_read_state(&STATE);