From b415ee086d26045f90dfa32ecd422a7640f188f6 Mon Sep 17 00:00:00 2001
From: merlokk <807634+merlokk@users.noreply.github.com>
Date: Mon, 19 Jul 2021 19:54:51 +0300
Subject: [PATCH] remove double padding

---
 client/src/cmdhfmfdes.c         | 2 +-
 client/src/mifare/desfirecore.c | 7 +++----
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/client/src/cmdhfmfdes.c b/client/src/cmdhfmfdes.c
index 6b429cd47..8c59ff80f 100644
--- a/client/src/cmdhfmfdes.c
+++ b/client/src/cmdhfmfdes.c
@@ -4997,7 +4997,7 @@ static int CmdHF14ADesChangeKey(const char *Cmd) {
     }
 
     DesfireSetCommMode(&dctx, DCMEncryptedPlain);
-    res = DesfireChangeKey(&dctx, (appid == 0x000000), newkeynum, newkeytype, newkeyver, newkey, oldkeytype, oldkey, true);
+    res = DesfireChangeKey(&dctx, (appid == 0x000000) && (newkeynum == 0) && (dctx.keyNum == 0), newkeynum, newkeytype, newkeyver, newkey, oldkeytype, oldkey, true);
     if (res == PM3_SUCCESS) {
         PrintAndLogEx(SUCCESS, "Change key " _GREEN_("ok") " ");
     } else {
diff --git a/client/src/mifare/desfirecore.c b/client/src/mifare/desfirecore.c
index 476728505..47046095c 100644
--- a/client/src/mifare/desfirecore.c
+++ b/client/src/mifare/desfirecore.c
@@ -1163,15 +1163,14 @@ int DesfireChangeKey(DesfireContext *dctx, bool change_master_key, uint8_t newke
         }
     }
 
-    // get padded data length
-    size_t rlen = padded_data_length(cdatalen, desfire_get_key_block_length(newkeytype));
-
     // send command
     uint8_t resp[257] = {0};
     size_t resplen = 0;
-    int res = DesfireChangeKeyCmd(dctx, &pckcdata[1], rlen + 1, resp, &resplen);
+    int res = DesfireChangeKeyCmd(dctx, &pckcdata[1], cdatalen, resp, &resplen);
 
     // check response
+    if (res == 0 && resplen > 0)
+        res = -20;
 
     // clear auth
     if (newkeynum == dctx->keyNum)