From 7303dd8c5dfafccbb9eaf70687ef1ef7a60c504d Mon Sep 17 00:00:00 2001
From: iceman1001 <iceman@iuse.se>
Date: Tue, 28 Apr 2020 14:51:47 +0200
Subject: [PATCH] coverity fix 279922 , div by zero

---
 client/src/mifare/desfire_crypto.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/client/src/mifare/desfire_crypto.c b/client/src/mifare/desfire_crypto.c
index e4caaae26..a0e066b44 100644
--- a/client/src/mifare/desfire_crypto.c
+++ b/client/src/mifare/desfire_crypto.c
@@ -281,6 +281,10 @@ void cmac_generate_subkeys(desfirekey_t key) {
 
 void cmac(const desfirekey_t key, uint8_t *ivect, const uint8_t *data, size_t len, uint8_t *cmac) {
     int kbs = key_block_size(key);
+    if (kbs == 0) {
+       return;
+    }
+
     uint8_t *buffer = malloc(padded_data_length(len, kbs));
 
     memcpy(buffer, data, len);