🛡️ Sentinel: [security improvement] Add strict timeouts and buffer limits to prevent DoS

.jules/sentinel.md

@@ -1,4 +1,8 @@
 ## 2026-04-27 - Path Traversal Vulnerability in File System Tools
 **Vulnerability:** The `FileTool` operations (`read`, `write`, `patch`) allowed arbitrary file system access because user-provided paths were used directly without sanitization, exposing a path traversal risk.
 **Learning:** File path inputs to SDK operations must be properly resolved and validated to prevent unauthorized access outside the intended working directory. Unrestricted access breaks the security boundaries of an agentic execution environment.
-**Prevention:** Always use `path.resolve(process.cwd(), unsafePath)` and verify that the resulting absolute path begins with `process.cwd()`. Implement secure failure paths and never expose raw internal file structures on error.
+**Prevention:** Always use `path.resolve(process.cwd(), unsafePath)` and verify that the resulting absolute path begins with `process.cwd()`. Implement secure failure paths and never expose raw internal file structures on error.
+## 2026-04-28 - Missing External I/O Boundaries (Denial of Service Risk)
+**Vulnerability:** External network requests (`AgentConnector`) and shell command executions (`ShellTool`) lacked explicit execution timeouts and buffer/content length limits. This could allow hanging external services or intentionally large payloads to exhaust system resources, leading to a Denial of Service (DoS).
+**Learning:** Agentic systems that execute arbitrary commands or connect to external APIs must operate within strict boundaries. Default tool behavior (like infinite timeouts) can be easily exploited or inadvertently cause cascading failures if an external dependency hangs.
+**Prevention:** Always configure `timeout` (e.g., 30s) and buffer size limits (e.g., 1MB) on `axios.create` instances and `child_process.exec` calls to enforce strict resource boundaries and fail securely.

dist/src/agents/connector.d.ts

@@ -7,6 +7,7 @@ export interface ToolDefinition {
 export declare class AgentConnector {
     private core;
     private config;
+    private client;
     constructor(core: CoreEngine, config?: {
         provider?: string;
         apiKey?: string;

dist/src/agents/connector.js

@@ -1,14 +1,57 @@
 "use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || (function () {
+    var ownKeys = function(o) {
+        ownKeys = Object.getOwnPropertyNames || function (o) {
+            var ar = [];
+            for (var k in o) if (Object.prototype.hasOwnProperty.call(o, k)) ar[ar.length] = k;
+            return ar;
+        };
+        return ownKeys(o);
+    };
+    return function (mod) {
+        if (mod && mod.__esModule) return mod;
+        var result = {};
+        if (mod != null) for (var k = ownKeys(mod), i = 0; i < k.length; i++) if (k[i] !== "default") __createBinding(result, mod, k[i]);
+        __setModuleDefault(result, mod);
+        return result;
+    };
+})();
 var __importDefault = (this && this.__importDefault) || function (mod) {
     return (mod && mod.__esModule) ? mod : { "default": mod };
 };
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.AgentConnector = void 0;
 const axios_1 = __importDefault(require("axios"));
+const https = __importStar(require("https"));
 class AgentConnector {
     constructor(core, config = {}) {
         this.core = core;
         this.config = config;
+        // Optimize repeated API calls by enabling keep-alive for HTTP/HTTPS connections.
+        // This avoids expensive TCP/TLS handshakes (~100-200ms per request) on consecutive LLM calls.
+        this.client = axios_1.default.create({
+            httpsAgent: new https.Agent({ keepAlive: true }),
+            // SECURITY: Prevent DoS with strict timeouts and buffer limits
+            timeout: 30000,
+            maxContentLength: 1024 * 1024,
+            maxBodyLength: 1024 * 1024
+        });
     }
     /**
      * Standard protocol to expose oneshotsx tools to any LLM
@@ -39,7 +82,7 @@ class AgentConnector {
             return "Agent running in simulation mode. No API key provided.";
         }
         try {
-            const response = await axios_1.default.post('https://openrouter.ai/api/v1/chat/completions', {
+            const response = await this.client.post('https://openrouter.ai/api/v1/chat/completions', {
                 model: 'meta-llama/llama-3.1-70b-instruct',
                 messages: [{ role: 'user', content: message }]
             }, {

dist/src/tools/index.d.ts

@@ -10,9 +10,10 @@ export declare class ShellTool {
 export declare class FileTool {
     private core;
     constructor(core: CoreEngine);
-    read(path: string): Promise<ExecutionResult<string>>;
-    write(path: string, content: string): Promise<ExecutionResult<void>>;
-    patch(path: string, search: string, replace: string): Promise<ExecutionResult<void>>;
+    private resolveAndValidatePath;
+    read(unsafePath: string): Promise<ExecutionResult<string>>;
+    write(unsafePath: string, content: string): Promise<ExecutionResult<void>>;
+    patch(unsafePath: string, search: string, replace: string): Promise<ExecutionResult<void>>;
 }
 export declare class SearchTool {
     private core;

dist/src/tools/index.js

@@ -37,6 +37,7 @@ exports.SearchTool = exports.FileTool = exports.ShellTool = void 0;
 const child_process_1 = require("child_process");
 const util_1 = require("util");
 const fs = __importStar(require("fs/promises"));
+const path = __importStar(require("path"));
 const execAsync = (0, util_1.promisify)(child_process_1.exec);
 class ShellTool {
     constructor(core) {
@@ -45,7 +46,11 @@ class ShellTool {
     async run(command) {
         this.core.log(`Executing shell command: ${command}`);
         return this.core.execute(async () => {
-            const { stdout, stderr } = await execAsync(command);
+            // SECURITY: Prevent DoS by enforcing a timeout and buffer limit
+            const { stdout, stderr } = await execAsync(command, {
+                timeout: 30000,
+                maxBuffer: 1024 * 1024
+            });
             return { stdout, stderr };
         });
     }
@@ -55,23 +60,37 @@ class FileTool {
     constructor(core) {
         this.core = core;
     }
-    async read(path) {
-        this.core.log(`Reading file: ${path}`);
-        return this.core.execute(() => fs.readFile(path, 'utf-8'));
+    resolveAndValidatePath(unsafePath) {
+        const resolvedPath = path.resolve(process.cwd(), unsafePath);
+        if (!resolvedPath.startsWith(process.cwd() + path.sep) && resolvedPath !== process.cwd()) {
+            throw new Error('Access denied: Invalid path');
+        }
+        return resolvedPath;
     }
-    async write(path, content) {
-        this.core.log(`Writing file: ${path}`);
-        return this.core.execute(() => fs.writeFile(path, content));
+    async read(unsafePath) {
+        this.core.log(`Reading file: ${unsafePath}`);
+        return this.core.execute(() => {
+            const safePath = this.resolveAndValidatePath(unsafePath);
+            return fs.readFile(safePath, 'utf-8');
+        });
+    }
+    async write(unsafePath, content) {
+        this.core.log(`Writing file: ${unsafePath}`);
+        return this.core.execute(() => {
+            const safePath = this.resolveAndValidatePath(unsafePath);
+            return fs.writeFile(safePath, content);
+        });
     }
-    async patch(path, search, replace) {
-        this.core.log(`Patching file: ${path}`);
+    async patch(unsafePath, search, replace) {
+        this.core.log(`Patching file: ${unsafePath}`);
         return this.core.execute(async () => {
-            const content = await fs.readFile(path, 'utf-8');
+            const safePath = this.resolveAndValidatePath(unsafePath);
+            const content = await fs.readFile(safePath, 'utf-8');
             const newContent = content.replace(search, replace);
             if (content === newContent) {
-                throw new Error(`Search string not found in ${path}`);
+                throw new Error(`Search string not found in file`);
             }
-            await fs.writeFile(path, newContent);
+            await fs.writeFile(safePath, newContent);
         });
     }
 }

src/agents/connector.ts

@@ -15,7 +15,11 @@ export class AgentConnector {
         // Optimize repeated API calls by enabling keep-alive for HTTP/HTTPS connections.
         // This avoids expensive TCP/TLS handshakes (~100-200ms per request) on consecutive LLM calls.
         this.client = axios.create({
-            httpsAgent: new https.Agent({ keepAlive: true })
+            httpsAgent: new https.Agent({ keepAlive: true }),
+            // SECURITY: Prevent DoS with strict timeouts and buffer limits
+            timeout: 30000,
+            maxContentLength: 1024 * 1024,
+            maxBodyLength: 1024 * 1024
         });
     }
 

src/tools/index.ts

@@ -12,7 +12,11 @@ export class ShellTool {
     async run(command: string): Promise<ExecutionResult<{ stdout: string; stderr: string }>> {
         this.core.log(`Executing shell command: ${command}`);
         return this.core.execute(async () => {
-            const { stdout, stderr } = await execAsync(command);
+            // SECURITY: Prevent DoS by enforcing a timeout and buffer limit
+            const { stdout, stderr } = await execAsync(command, {
+                timeout: 30000,
+                maxBuffer: 1024 * 1024
+            });
             return { stdout, stderr };
         });
     }