diff --git a/src/DevTest.c b/src/DevTest.c
index df34186d..17b06c6d 100644
--- a/src/DevTest.c
+++ b/src/DevTest.c
@@ -250,6 +250,8 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
     unsigned char event = 0;
     unsigned int meta_length = 0;
     unsigned int i = 0;
+    unsigned long int input_length = midi_size;
+
     /*
     printf("Midi Data: ");
     for (i = 0; i < ((midi_size >= 32)? 32 : midi_size); i++) {
@@ -272,6 +274,7 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
         event = *midi_data++;
         midi_size--;
         rtn_cnt++;
+        input_length--;
     }
 
     switch (event >> 4) {
@@ -285,6 +288,7 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                 printf("Note Off: chan(%i) note(%i) vel(%i)\n",
                        (event & 0x0F), midi_data[0], midi_data[1]);
             rtn_cnt += 2;
+            input_length -= 2;
             check_notes[(event & 0x0F)][midi_data[0]] = 0;
             break;
         case 0x9:
@@ -297,6 +301,7 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                 printf("Note On: chan(%i) note(%i) vel(%i)\n",
                        (event & 0x0F), midi_data[0], midi_data[1]);
             rtn_cnt += 2;
+            input_length -= 2;
             if (midi_data[1] == 0) {
                 check_notes[(event & 0x0F)][midi_data[0]] = 0;
             } else {
@@ -313,6 +318,7 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                 printf("Aftertouch: chan(%i) note(%i) vel(%i)\n",
                        (event & 0x0F), midi_data[0], midi_data[1]);
             rtn_cnt += 2;
+            input_length -= 2;
             break;
         case 0xB:
             if (!(options & EVENT_DATA_8BIT)) {
@@ -387,6 +393,8 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                 printf("chan(%i) set(%i)\n", (event & 0x0F), midi_data[1]);
             }
             rtn_cnt += 2;
+            input_length -= 2;
+
             break;
         case 0xC:
             if ((midi_size == 0) || (*midi_data > 0x7F)) {
@@ -397,6 +405,7 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                 printf("Set Patch: chan(%i) patch(%i)\n", (event & 0x0F),
                        *midi_data);
             rtn_cnt++;
+            input_length--;
             break;
         case 0xD:
             if ((midi_size == 0) || (*midi_data > 0x7F)) {
@@ -407,6 +416,7 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                 printf("Channel Pressure: chan(%i) pres(%i)\n",
                        (event & 0x0F), *midi_data);
             rtn_cnt++;
+            input_length--;
             break;
         case 0xE:
             if ((midi_size < 2) || (midi_data[0] > 0x7F)
@@ -418,6 +428,7 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                 printf("Set Pitch: chan(%i) pitch(%i)\n", (event & 0x0F),
                        ((midi_data[0] << 7) | midi_data[1]));
             rtn_cnt += 2;
+            input_length -= 2;
             break;
         case 0xF:
             if ((event == 0xF0) || (event == 0xF7)) {
@@ -433,16 +444,21 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                     midi_data++;
                     midi_size--;
                     rtn_cnt++;
+                    input_length--;
                 }
                 sysex_size = (sysex_size << 7) | (*midi_data & 0x7F);
                 midi_data++;
                 midi_size--;
                 rtn_cnt++;
+                input_length--;
+
+                if (input_length < sysex_size){
+                    printf("Corrupt sysex size, was larger than rest of file.\n");
+                    return -1;
+                }
 
-                sysex_store = realloc(sysex_store,
-                                      (sysex_store_ofs + sysex_size));
-                memcpy(&sysex_store[sysex_store_ofs], midi_data,
-                       sysex_size);
+                sysex_store = realloc(sysex_store, (sysex_store_ofs + sysex_size));
+                memcpy(&sysex_store[sysex_store_ofs], midi_data, sysex_size);
                 sysex_store_ofs += sysex_size;
 
                 if (sysex_store[sysex_store_ofs - 1] == 0xF7) {
@@ -514,6 +530,7 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                 free(sysex_store);
                 sysex_store = NULL;
                 rtn_cnt += sysex_size;
+                input_length -= sysex_size;
             } else if ((event <= 0xFE) && (event >= 0xF1)) {
                 // Added just in case
                 printf("Realtime Event: 0x%.2x ** NOTE: Not expected in midi file type data\n",event);
@@ -652,11 +669,13 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                 midi_data++;
                 midi_size--;
                 rtn_cnt++;
+                input_length--;
                 meta_length = 0;
                 while (*midi_data > 0x7F) {
                     meta_length = (meta_length << 7) | (*midi_data & 0x7F);
                     midi_data++;
                     rtn_cnt++;
+                    input_length--;
                     if (midi_size == 0) {
                         printf("Data too short: Missing MIDI Data\n");
                         return -1;
@@ -667,6 +686,7 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                 midi_data++;
                 midi_size--;
                 rtn_cnt++;
+                input_length--;
 
                 if (midi_size < meta_length) {
                     printf("Data too short: Missing MIDI Data\n");
@@ -685,6 +705,7 @@ static int check_midi_event (unsigned char *midi_data, unsigned long int midi_si
                     printf("\n");
                 }
                 rtn_cnt += meta_length;
+                input_length -= meta_length;
             } else {
                 printf("Corrupt Midi, Unknown Event Data\n");
                 return -1;