1 files changed, 21 insertions, 3 deletions
diff --git a/usb-i2c-sl018/tuer-rfid.c b/usb-i2c-sl018/tuer-rfid.c
index 664e810..698f2b7 100644
--- a/usb-i2c-sl018/tuer-rfid.c
+++ b/usb-i2c-sl018/tuer-rfid.c
@@ -95,6 +95,19 @@ const char* SL018_tagtype_tostring(const uint8_t type)
   }
 }
 
+uint8_t SL018_tagtype_to_uidlen(const uint8_t type) 
+{
+  switch(type) {
+  case 0x1:
+  case 0x4: return 4;
+  case 0x2:
+  case 0x3:
+  case 0x5:
+  case 0x6: return 7;
+  default: return 0;
+  }
+}
+
 const uint8_t SL018_CMD_ComSelectCard[]         = {1,0x01};
 const uint8_t SL018_CMD_ComRedLedOn[]           = {2,0x40,1};
 const uint8_t SL018_CMD_ComRedLedOff[]          = {2,0x40,0};
@@ -371,13 +384,18 @@ void handle_card(void)
   {
     uint8_t uid_len = twi_recv_msg->len - sizeof(twi_recv_msg->command) - sizeof(twi_recv_msg->status) - 1;
     if(uid_len == 255 || uid_len > sizeof(keyslot_t) - 1) {
-      fprintf(stdio," Invalid uid length received %d\n\r", uid_len);
+      fprintf(stdio," received UID length (%d) is to big for keystore \n\r", uid_len);
       return;
     }
+    uint8_t type = twi_recv_msg->data[uid_len];
+    uint8_t expected_uid_len = SL018_tagtype_to_uidlen(type);
+    if(expected_uid_len != uid_len) {
+      fprintf(stdio," Invalid uid length (%d) for tag type: %s\n\r", uid_len, SL018_tagtype_tostring(type));
+      return;
+    }    
+
     for (uint8_t pos=0; pos<uid_len; pos++)
       fprintf(stdio,"%02X",twi_recv_msg->data[uid_len-pos-1]);
-
-    uint8_t type = twi_recv_msg->data[uid_len];
     fprintf(stdio, ", %s\n\r", SL018_tagtype_tostring(type));
 
     if (0 < type && type < 7) {