return SW_WRONG_LENGTH for incorrect lc

fido2/apdu.c

@@ -9,7 +9,7 @@
 
 #include "apdu.h"
 
-int apdu_decode(uint8_t *data, size_t len, APDU_STRUCT *apdu) 
+uint16_t apdu_decode(uint8_t *data, size_t len, APDU_STRUCT *apdu) 
 {
     EXT_APDU_HEADER *hapdu = (EXT_APDU_HEADER *)data;
     
@@ -63,6 +63,11 @@ int apdu_decode(uint8_t *data, size_t len, APDU_STRUCT *apdu)
     {
         uint16_t extlen = (hapdu->lc[1] << 8) + hapdu->lc[2];
 
+        if (len - 7 < extlen)
+        {
+            return SW_WRONG_LENGTH;
+        }
+        
          // case 2E (Le) - extended
         if (len == 7)
         {
@@ -103,9 +108,18 @@ int apdu_decode(uint8_t *data, size_t len, APDU_STRUCT *apdu)
             apdu->le = 0x10000;
         }
     }
+    else
+    {
+        if ((len > 5) && (len - 5 < hapdu->lc[0]))
+        {
+            return SW_WRONG_LENGTH;
+        }
+    }
     
     if (!apdu->case_type)
-        return 1;
+    {
+        return SW_COND_USE_NOT_SATISFIED;
+    }
     
     if (apdu->lc)
     {

fido2/apdu.h

@@ -36,7 +36,7 @@ typedef struct
     uint8_t case_type;
 } __attribute__((packed)) APDU_STRUCT;
 
-extern int apdu_decode(uint8_t *data, size_t len, APDU_STRUCT *apdu);
+extern uint16_t apdu_decode(uint8_t *data, size_t len, APDU_STRUCT *apdu);
 
 #define APDU_FIDO_U2F_REGISTER        0x01
 #define APDU_FIDO_U2F_AUTHENTICATE    0x02

targets/stm32l432/src/nfc.c

@@ -784,9 +784,10 @@ void nfc_process_iblock(uint8_t * buf, int len)
     }
     
     APDU_STRUCT apdu;
-    if (apdu_decode(buf + block_offset, len - block_offset, &apdu)) {
+    uint16_t ret = apdu_decode(buf + block_offset, len - block_offset, &apdu);
+    if (ret != 0) {
         printf1(TAG_NFC,"apdu decode error\r\n");
-        nfc_write_response(buf[0], SW_COND_USE_NOT_SATISFIED);
+        nfc_write_response(buf[0], ret);
         return;
     }
     printf1(TAG_NFC,"apdu ok. %scase=%02x cla=%02x ins=%02x p1=%02x p2=%02x lc=%d le=%d\r\n",