fix(heartbeat): bound HEARTBEAT.md file read size

cxbAsDev · cxbAsDev · commit 89638b501da0 · 2026-07-13T13:01:40.000+08:00
diff --git a/src/infra/heartbeat-runner.oversized-heartbeat-file.test.ts b/src/infra/heartbeat-runner.oversized-heartbeat-file.test.ts
@@ -0,0 +1,51 @@
+// Regression test for bounded HEARTBEAT.md reads.
+import fs from "node:fs/promises";
+import path from "node:path";
+import { describe, expect, it, vi } from "vitest";
+import type { OpenClawConfig } from "../config/types.openclaw.js";
+import { runHeartbeatOnce } from "./heartbeat-runner.js";
+import { installHeartbeatRunnerTestRuntime } from "./heartbeat-runner.test-harness.js";
+import { seedMainSessionStore, withTempHeartbeatSandbox } from "./heartbeat-runner.test-utils.js";
+
+installHeartbeatRunnerTestRuntime({ includeSlack: true });
+
+describe("runHeartbeatOnce oversized HEARTBEAT.md", () => {
+  it("treats an oversized HEARTBEAT.md like a missing file and continues the run", async () => {
+    await withTempHeartbeatSandbox(async ({ tmpDir, storePath, replySpy }) => {
+      const cfg: OpenClawConfig = {
+        agents: {
+          defaults: {
+            workspace: tmpDir,
+            heartbeat: { every: "5m", target: "slack", to: "channel:C123" },
+          },
+        },
+        channels: { slack: { heartbeat: { showOk: false } } },
+        session: { store: storePath },
+      };
+      await seedMainSessionStore(storePath, cfg, {
+        lastChannel: "slack",
+        lastProvider: "slack",
+        lastTo: "channel:C123",
+      });
+      // Overwrite the default heartbeat file with content larger than the 16 MB cap.
+      const oversizedContent = Buffer.alloc(16 * 1024 * 1024 + 1, "x");
+      await fs.writeFile(path.join(tmpDir, "HEARTBEAT.md"), oversizedContent);
+
+      replySpy.mockResolvedValue({ text: "needs attention" });
+      const sendSlack = vi.fn().mockResolvedValue({ messageId: "m1", channelId: "C123" });
+
+      const res = await runHeartbeatOnce({
+        cfg,
+        deps: {
+          getReplyFromConfig: replySpy,
+          slack: sendSlack,
+          getQueueSize: () => 0,
+          nowMs: () => 0,
+        },
+      });
+
+      expect(res.status).toBe("ran");
+      expect(sendSlack).toHaveBeenCalledTimes(1);
+    });
+  });
+});
diff --git a/src/infra/heartbeat-runner.ts b/src/infra/heartbeat-runner.ts
@@ -1,6 +1,5 @@
 // Runs heartbeat checks and emits status updates for configured agents.
 import { createHash } from "node:crypto";
-import fs from "node:fs/promises";
 import path from "node:path";
 import { timestampMsToIsoString } from "@openclaw/normalization-core/number-coercion";
 import {
@@ -158,6 +157,7 @@ import {
   resolveHeartbeatDeliveryTargetWithSessionRoute,
   resolveHeartbeatSenderContext,
 } from "./outbound/targets.js";
+import { readRegularFile } from "./regular-file.js";
 import {
   consumeSelectedSystemEventEntries,
   peekSystemEventEntries,
@@ -1117,9 +1117,12 @@ async function resolveHeartbeatPreflight(params: {
 
   const workspaceDir = resolveAgentWorkspaceDir(params.cfg, params.agentId);
   const heartbeatFilePath = path.join(workspaceDir, DEFAULT_HEARTBEAT_FILENAME);
+  const MAX_HEARTBEAT_FILE_BYTES = 16 * 1024 * 1024;
   let heartbeatFileContent: string | undefined;
   try {
-    heartbeatFileContent = await fs.readFile(heartbeatFilePath, "utf-8");
+    heartbeatFileContent = (
+      await readRegularFile({ filePath: heartbeatFilePath, maxBytes: MAX_HEARTBEAT_FILE_BYTES })
+    ).buffer.toString("utf-8");
     const tasks = parseHeartbeatTasks(heartbeatFileContent);
     if (
       isHeartbeatContentEffectivelyEmpty(heartbeatFileContent) &&
