fix: check return values of malloc in xbm2fb and realloc in cfg_desc_append (#132)

- Switch malloc+memset to calloc in xbm2fb(); return early on NULL
- Guard cfg_desc_append() against realloc failure using temp pointer
- Add PRINT diagnostic on allocation failure
- Include debug.h in setup.c and xbm.c

Author: Rampage270906

src/usb/setup.c

@@ -1,5 +1,5 @@
 #include <stdlib.h>
-
+#include "../debug.h"
 #include "CH58x_common.h"
 
 #include "utils.h"
@@ -30,7 +30,12 @@ void cfg_desc_append(void *desc)
 		cfg_len = ((USB_CFG_DESCR *)cfg_desc)->wTotalLength;
 	uint8_t newlen = cfg_len + len;
 
-	cfg_desc = realloc(cfg_desc, newlen); // TODO: add a safe check here
+	uint8_t *tmp = realloc(cfg_desc, newlen);
+	if (!tmp) {
+		printf("cfg_desc_append: out of memory\n");
+		return;
+	}
+	cfg_desc = tmp;
 
 	memcpy(cfg_desc + cfg_len, desc, len);
 

src/xbm.c

@@ -1,6 +1,7 @@
 #include "xbm.h"
 #include <stdlib.h>
 #include <memory.h>
+#include "debug.h"
 
 /**
  * Draw bitmap file to fb at (col, row)
@@ -9,9 +10,11 @@
 void xbm2fb(xbm_t *xbm, uint16_t *fb, int col, int row)
 {
 	int W = ALIGN_8BIT(xbm->w);
-	uint16_t *tmpfb = malloc(W * sizeof(uint16_t));
-	memset(tmpfb, 0, W * sizeof(uint16_t));
-
+	uint16_t *tmpfb = calloc(W, sizeof(*tmpfb));
+	if (!tmpfb) {
+		printf("xbm2fb: out of memory\n");
+		return;
+	}
 	if ((xbm->h + row) >= 0 && col >= 0) {
 
 		for (int h = 0; h < xbm->h; h++) {