fix endless loop (#782)

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index f5fcc91c49dbdd530c2b2b0f74499c3634e3fda9..50160798664d2f42c29e8e528cdd5af32d904220 100644 (file)
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -1955,7 +1955,7 @@ int iso14_apdu(uint8_t *cmd, uint16_t cmd_len, void *data, uint8_t *res) {
                return 0; //DATA LINK ERROR
        } else{
                // S-Block WTX 
-               while((data_bytes[0] & 0xF2) == 0xF2) {
+               while(len && ((data_bytes[0] & 0xF2) == 0xF2)) {
                        uint32_t save_iso14a_timeout = iso14a_get_timeout();
                        // temporarily increase timeout
                        iso14a_set_timeout(MAX((data_bytes[1] & 0x3f) * save_iso14a_timeout, MAX_ISO14A_TIMEOUT));
@@ -1994,12 +1994,14 @@ int iso14_apdu(uint8_t *cmd, uint16_t cmd_len, void *data, uint8_t *res) {
                
        }
        
-       // cut frame byte
-       len -= 1;
-       // memmove(data_bytes, data_bytes + 1, len);
-       for (int i = 0; i < len; i++)
-               data_bytes[i] = data_bytes[i + 1];
-       
+       if (len) {
+               // cut frame byte
+               len -= 1;
+               // memmove(data_bytes, data_bytes + 1, len);
+               for (int i = 0; i < len; i++)
+                       data_bytes[i] = data_bytes[i + 1];
+       }
+               
        return len;
 }