diff --git a/backend/code.c b/backend/code.c
index 2aa63709..63fccc5e 100644
--- a/backend/code.c
+++ b/backend/code.c
@@ -259,7 +259,7 @@ int pharmazentral(struct zint_symbol *symbol, unsigned char source[])
 	
 	int i, error_number;
 	unsigned int h, count, check_digit;
-	char localstr[8], checkstr[3];
+	char localstr[10], checkstr[3];
 	int zeroes;
 	
 	error_number = 0;
@@ -371,19 +371,20 @@ int c93(struct zint_symbol *symbol, unsigned char source[])
 	strcpy(buffer, "");
 	int ascii_value;
 	char dest[1000];
+	unsigned char local_source[47];
 	
 	error_number = 0;
 	strcpy(dest, "");
 
-	if(ustrlen(source) > 45) {
+	if(ustrlen(local_source) > 45) {
 		/* This stops rediculously long input - the actual length of the barcode
 		depends on the type of data */
 		strcpy(symbol->errtxt, "Input too long");
 		return ERROR_TOO_LONG;
 	}
 	
-	for(i = 0; i < ustrlen(source); i++) {
-		if(source[i] > 127) {
+	for(i = 0; i < ustrlen(local_source); i++) {
+		if(local_source[i] > 127) {
 			/* Cannot encode extended ASCII */
 			strcpy(symbol->errtxt, "Invalid characters in input data");
 			return ERROR_INVALID_DATA;
@@ -394,8 +395,8 @@ int c93(struct zint_symbol *symbol, unsigned char source[])
 	concat(dest, "111141");
 
 	/* Message Content */
-	for(i = 0; i < ustrlen(source); i++) {
-		ascii_value = source[i];
+	for(i = 0; i < ustrlen(local_source); i++) {
+		ascii_value = local_source[i];
 		if(ascii_value == symbol->nullchar) {
 			concat(buffer, C93Ctrl[0]);
 		} else {
@@ -463,12 +464,12 @@ int c93(struct zint_symbol *symbol, unsigned char source[])
 	/* Stop character */
 	concat(dest, "1111411");
 	
-	h = ustrlen(source);
-	source[h] = set_copy[c];
-	source[h + 1] = set_copy[k];
-	source[h + 2] = '\0';
+	h = ustrlen(local_source);
+	local_source[h] = set_copy[c];
+	local_source[h + 1] = set_copy[k];
+	local_source[h + 2] = '\0';
 	expand(symbol, dest);
-	ustrcpy(symbol->text, source);
+	ustrcpy(symbol->text, local_source);
 	for(i = 0; i < ustrlen(symbol->text); i++) {
 		if(symbol->text[i] == symbol->nullchar) {
 			symbol->text[i] = ' ';
diff --git a/backend/dmatrix.c b/backend/dmatrix.c
index 45b3f7ce..ac7031d5 100644
--- a/backend/dmatrix.c
+++ b/backend/dmatrix.c
@@ -43,11 +43,11 @@ void crc_machine(char data_prefix_bitstream[], int scheme, unsigned char source[
 	input_length = ustrlen(source);
 	char xor_register[17];
 #ifndef _MSC_VER
-	char precrc_bitstream[(input_length * 8) + 16];
-	char precrc_bitstream_reversed[(input_length * 8) + 16];
+	char precrc_bitstream[(input_length * 8) + 18];
+	char precrc_bitstream_reversed[(input_length * 8) + 18];
 #else
-        char* precrc_bitstream = (char*)_alloca((input_length * 8) + 16);
-	char* precrc_bitstream_reversed = (char*)_alloca((input_length * 8) + 16);
+        char* precrc_bitstream = (char*)_alloca((input_length * 8) + 18);
+	char* precrc_bitstream_reversed = (char*)_alloca((input_length * 8) + 18);
 #endif
 	int machine_cycles;
 	char input_bit, out1, out2, out3;
diff --git a/backend/postal.c b/backend/postal.c
index 69651e39..b0510221 100644
--- a/backend/postal.c
+++ b/backend/postal.c
@@ -206,7 +206,7 @@ int korea_post(struct zint_symbol *symbol, unsigned char source[])
 { /* Korean Postal Authority */
 
 	int total, h, loop, check, zeroes, error_number;
-	char localstr[7], checkstr[3], dest[80];
+	char localstr[8], checkstr[3], dest[80];
 
 	error_number = 0;
 	h = ustrlen(source);
@@ -499,19 +499,16 @@ int flattermarken(struct zint_symbol *symbol, unsigned char source[])
 int japan_post(struct zint_symbol *symbol, unsigned char source[])
 { /* Japanese Postal Code (Kasutama Barcode) */
 	int input_length, error_number;
-	char pattern[65];
-	int writer, loopey, inter_posn, i, inter_length, sum, check;
+	char pattern[69];
+	int writer, loopey, inter_posn, i, sum, check;
 	char check_char;
+	char inter[23];
 
 	input_length = ustrlen(source);
-	inter_length = input_length * 2;
-	if(inter_length < 20) { inter_length = 20; }
 #ifndef _MSC_VER
-	char inter[inter_length];
-        char local_source[input_length];
+        char local_source[input_length + 1];
 #else
-	char* inter = (char*)_alloca(inter_length);
-        char* local_source = (char*)_alloca(inter_length);
+        char* local_source = (char*)_alloca(input_length + 1);
 #endif
 	
 	inter_posn = 0;
@@ -526,11 +523,14 @@ int japan_post(struct zint_symbol *symbol, unsigned char source[])
 		return error_number;
 	}
 
-	for(i = 0; i < inter_length; i++) {
+	for(i = 0; i < 20; i++) {
 		inter[i] = 'd'; /* Pad character CC4 */
 	}
+	inter[20] = '\0';
 
-	for(i = 0; i < input_length; i++) {
+	i = 0;
+	inter_posn = 0;
+	do {
 		if(((local_source[i] >= '0') && (local_source[i] <= '9')) || (local_source[i] == '-')) {
 			inter[inter_posn] = local_source[i];
 			inter_posn++;
@@ -551,7 +551,9 @@ int japan_post(struct zint_symbol *symbol, unsigned char source[])
 				inter_posn += 2;
 			}
 		}
-	}
+		i++;
+	}while((i < input_length) && (inter_posn < 20));
+	inter[20] = '\0';
 
 	strcpy(pattern, "13"); /* Start */