From 0b6546012a446abe7d3c5d8c2319097800f8f3af Mon Sep 17 00:00:00 2001
From: merlokk <807634+merlokk@users.noreply.github.com>
Date: Tue, 27 Jul 2021 18:28:41 +0300
Subject: [PATCH] fix crc search with padding

---
 client/src/mifare/desfirecrypto.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/client/src/mifare/desfirecrypto.c b/client/src/mifare/desfirecrypto.c
index 79604f5eb..e1015c2d8 100644
--- a/client/src/mifare/desfirecrypto.c
+++ b/client/src/mifare/desfirecrypto.c
@@ -124,7 +124,8 @@ size_t DesfireSearchCRCPos(uint8_t *data, size_t datalen, uint8_t respcode, uint
 
     uint8_t crcdata[1024] = {0};
     size_t crcposfound = 0;
-    for (int i = 0; i < crclen + 1; i++) {
+    // crc may be 00..00 and at the end of file may be padding 0x80. so we search from last zero to crclen + 2 (one for crc=0 and one for padding 0x80)
+    for (int i = 0; i < crclen + 2; i++) {
         if (crcpos - i == 0)
             break;
         if (crcpos - i + crclen > datalen)