lib/image: Fix incorrect free of stbi-allocated buffer corrupting memmap

Author: Mintsuki

common/lib/image.c

@@ -40,7 +40,7 @@ struct image *image_open(struct file_handle *file) {
     if (image->img == NULL || x == 0 || y == 0) {
         if (image->img != NULL) {
             // stbi allocated but dimensions are degenerate
-            pmm_free(image->img, (size_t)x * (size_t)y * 4);
+            stbi_image_free(image->img);
         }
         pmm_free(image, sizeof(struct image));
         return NULL;
@@ -49,15 +49,15 @@ struct image *image_open(struct file_handle *file) {
     // Convert ABGR to XRGB
     uint32_t *pptr = (void *)image->img;
     size_t pixel_count = CHECKED_MUL((size_t)x, (size_t)y,
-        ({ pmm_free(image, sizeof(struct image)); return NULL; }));
+        ({ stbi_image_free(image->img); pmm_free(image, sizeof(struct image)); return NULL; }));
     for (size_t i = 0; i < pixel_count; i++) {
         pptr[i] = (pptr[i] & 0x0000ff00) | ((pptr[i] & 0x00ff0000) >> 16) | ((pptr[i] & 0x000000ff) << 16);
     }
 
     image->x_size = x;
     image->y_size = y;
     image->pitch = (int)CHECKED_MUL((size_t)x, 4,
-        ({ pmm_free(image, sizeof(struct image)); return NULL; }));
+        ({ stbi_image_free(image->img); pmm_free(image, sizeof(struct image)); return NULL; }));
     image->bpp = 32;
     image->img_width = x;
     image->img_height = y;