fix: prevent read tool from opening binary files and corrupting session (#1425)

1 files changed, 13 insertions, 0 deletions

diff --git a/packages/opencode/src/tool/read.ts b/packages/opencode/src/tool/read.ts
index f93840afb..c66716413 100644
--- a/packages/opencode/src/tool/read.ts
+++ b/packages/opencode/src/tool/read.ts
@@ -48,6 +48,8 @@ export const ReadTool = Tool.define("read", {
     const offset = params.offset || 0
     const isImage = isImageFile(filePath)
     if (isImage) throw new Error(`This is an image file of type: ${isImage}\nUse a different tool to process images`)
+    const isBinary = await isBinaryFile(file)
+    if (isBinary) throw new Error(`Cannot read binary file: ${filePath}`)
     const lines = await file.text().then((text) => text.split("\n"))
     const raw = lines.slice(offset, offset + limit).map((line) => {
       return line.length > MAX_LINE_LENGTH ? line.substring(0, MAX_LINE_LENGTH) + "..." : line
@@ -99,3 +101,14 @@ function isImageFile(filePath: string): string | false {
       return false
   }
 }
+
+async function isBinaryFile(file: Bun.BunFile): Promise<boolean> {
+  const buffer = await file.arrayBuffer()
+  const bytes = new Uint8Array(buffer.slice(0, 512)) // Check first 512 bytes
+
+  for (let i = 0; i < bytes.length; i++) {
+    if (bytes[i] === 0) return true // Null byte indicates binary
+  }
+
+  return false
+}