From 9a3bb81337becf05c32d6638769d0438aa8f07a8 Mon Sep 17 00:00:00 2001
From: IFAKA <99131130+IFAKA@users.noreply.github.com>
Date: Sun, 21 Dec 2025 03:36:59 +0100
Subject: [PATCH] fix: add NULL checks after malloc in drawBmp() (#80)

## Problem
`drawBmp()` allocates two row buffers via `malloc()` but doesn't check
if allocations succeed. On low memory, this causes a crash when the NULL
pointers are dereferenced.

## Fix
Add NULL check after both `malloc()` calls. If either fails, log error
and return early.

Changed `lib/GfxRenderer/GfxRenderer.cpp`.

## Test
- Defensive addition only - no logic changes
- Manual device testing appreciated
---
 lib/GfxRenderer/GfxRenderer.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/GfxRenderer/GfxRenderer.cpp b/lib/GfxRenderer/GfxRenderer.cpp
index b1a98c7..a4b9369 100644
--- a/lib/GfxRenderer/GfxRenderer.cpp
+++ b/lib/GfxRenderer/GfxRenderer.cpp
@@ -136,6 +136,13 @@ void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, con
   auto* outputRow = static_cast<uint8_t*>(malloc(outputRowSize));
   auto* rowBytes = static_cast<uint8_t*>(malloc(bitmap.getRowBytes()));
 
+  if (!outputRow || !rowBytes) {
+    Serial.printf("[%lu] [GFX] !! Failed to allocate BMP row buffers\n", millis());
+    free(outputRow);
+    free(rowBytes);
+    return;
+  }
+
   for (int bmpY = 0; bmpY < bitmap.getHeight(); bmpY++) {
     // The BMP's (0, 0) is the bottom-left corner (if the height is positive, top-left if negative).
     // Screen's (0, 0) is the top-left corner.