限制视觉绑定处理图的解码规模

在解码前限制 base64 字节数并校验图像宽高，避免异常响应造成过量内存分配。

apps/ai-game-creator-shell/src-tauri/src/ui_editor/commands/separation/image_preprocess.rs

@@ -1,11 +1,13 @@
 use super::area::MIN_VISIBLE_ALPHA;
 use base64::Engine as _;
-use image::{ImageFormat, Rgba, RgbaImage};
+use image::{ImageFormat, ImageReader, Rgba, RgbaImage};
 use std::fs;
 use std::io::Cursor;
 use std::path::{Path, PathBuf};
 
 pub(crate) const VISUAL_BINDING_TRANSPARENT_MARKER_RGBA: [u8; 4] = [255, 0, 255, 255];
+const MAX_PROCESSED_IMAGE_BYTES: usize = 64 * 1024 * 1024;
+const MAX_PROCESSED_IMAGE_DIMENSION: u32 = 2880;
 
 pub(crate) async fn preprocess_for_visual_binding(
     processed_url: String,
@@ -29,6 +31,21 @@ fn preprocess_for_visual_binding_blocking(
     let bytes = base64::engine::general_purpose::STANDARD
         .decode(encoded.trim())
         .map_err(|error| format!("解析处理图失败：{error}"))?;
+    if bytes.len() > MAX_PROCESSED_IMAGE_BYTES {
+        return Err(format!(
+            "处理图超过 {} MiB 字节上限",
+            MAX_PROCESSED_IMAGE_BYTES / 1024 / 1024
+        ));
+    }
+    let dimensions = ImageReader::new(Cursor::new(&bytes))
+        .with_guessed_format()
+        .map_err(|error| format!("解析处理图格式失败：{error}"))?
+        .into_dimensions()
+        .map_err(|error| format!("读取处理图尺寸失败：{error}"))?;
+    if dimensions.0 > MAX_PROCESSED_IMAGE_DIMENSION || dimensions.1 > MAX_PROCESSED_IMAGE_DIMENSION
+    {
+        return Err("处理图尺寸超出上限".to_string());
+    }
     let mut image = image::load_from_memory(&bytes)
         .map_err(|error| format!("解码处理图失败：{error}"))?
         .to_rgba8();