From 9dc3c39a95c0d06abfd5524339060c220ba56fba Mon Sep 17 00:00:00 2001
From: Matthias Konrath <office@inet-sec.at>
Date: Wed, 28 Aug 2019 09:45:11 +0200
Subject: [PATCH] Added additional checks to the from load dictionary returned
 data points.

---
 client/cmdhfmf.c    |  6 +++---
 client/cmdlft55xx.c | 11 ++---------
 2 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/client/cmdhfmf.c b/client/cmdhfmf.c
index 87fa500a8..66aca7421 100644
--- a/client/cmdhfmf.c
+++ b/client/cmdhfmf.c
@@ -1585,7 +1585,7 @@ static int CmdHF14AMfAutoPWN(const char *Cmd) {
     uint64_t key64 = 0;
     bool calibrate = true;
     // Attack key storage variables
-    uint8_t *keyBlock;
+    uint8_t *keyBlock = NULL;
     uint16_t key_cnt = 0;
     sector_t *e_sector;
     uint8_t sectors_cnt = MIFARE_1K_MAXSECTOR;
@@ -1787,9 +1787,9 @@ static int CmdHF14AMfAutoPWN(const char *Cmd) {
     // Load the dictionary
     if (strlen(filename) != 0) {
         int res = loadFileDICTIONARY_safe(filename, &keyBlock, 6, &key_cnt);
-        if (res != PM3_SUCCESS || key_cnt <= 0) {
+        if (res != PM3_SUCCESS || key_cnt <= 0 || keyBlock == NULL) {
             PrintAndLogEx(FAILED, "An error occurred while loading the dictionary! (we will use the default keys now)");
-            free(keyBlock); // free the memory, just in case an allocation happened
+            if (keyBlock != NULL) free(keyBlock);
             goto useDefaultKeys;
         }
     } else {
diff --git a/client/cmdlft55xx.c b/client/cmdlft55xx.c
index 3802beab9..f256a5ee3 100644
--- a/client/cmdlft55xx.c
+++ b/client/cmdlft55xx.c
@@ -2128,17 +2128,10 @@ static int CmdT55xxChkPwds(const char *Cmd) {
     if (use_pwd_file) {
         uint16_t keycount = 0;
 
-        // TODO, a way of reallocating memory if file was larger
-        keyBlock = calloc(4 * 200, sizeof(uint8_t));
-        if (keyBlock == NULL) {
-            PrintAndLogEx(ERR, "error, cannot allocate memory ");
-            return PM3_ESOFT;
-        }
-
         int res = loadFileDICTIONARY_safe(filename, &keyBlock, 4, &keycount);
-        if (res || keycount == 0) {
+        if (res || keycount == 0 || keyBlock == NULL) {
             PrintAndLogEx(WARNING, "No keys found in file");
-            free(keyBlock);
+            if (keyBlock != NULL) free(keyBlock);
             return PM3_ESOFT;
         }