# Security Audit Report

**Branch**: fix/tech-debt-quick-wins
**Base**: main
**Date**: 2025-12-13 20:01
**Files Analyzed**: 8
**Lines Changed**: +407 / -88

---

## Executive Summary

This branch introduces tech debt improvements including:
1. Type safety enhancements via Zod schema validation at data layer boundaries
2. Database CHECK constraints for defense-in-depth
3. Test isolation improvements with temp directories
4. NoOpProcessSpawner for test mode to prevent resource exhaustion
5. Path traversal validation for `AUTOBEAT_DATABASE_PATH` environment variable

**Overall Assessment**: The changes are security-positive. They ADD security controls rather than removing them. No blocking issues found.

---

## Analysis by Category

### Files Changed

| File | Lines Changed | Security Relevance |
|------|---------------|-------------------|
| `src/implementations/database.ts` | +95 | HIGH - Path validation, CHECK constraints |
| `src/implementations/task-repository.ts` | +54 | MEDIUM - Schema validation |
| `src/implementations/dependency-repository.ts` | +30 | MEDIUM - Schema validation |
| `src/bootstrap.ts` | +92 | LOW - Test mode spawner |
| `src/core/container.ts` | +10 | LOW - Shutdown sequencing |
| `tests/integration/task-dependencies.test.ts` | +85 | LOW - Test isolation |
| `tests/fixtures/test-data.ts` | +1 | NONE - Bug fix |
| `package.json` | +1 | NONE - Test script |

---

## [GREEN] Issues in Your Changes (BLOCKING)

**No blocking security issues found in changed lines.**

The changes in this branch are security-positive:

### Security Improvements Added

#### 1. Path Traversal Validation (GOOD)
**File**: `/workspace/delegate/src/implementations/database.ts:70-85`

```typescript
// AUTOBEAT_DATABASE_PATH: Full path to database file (used by tests)
if (process.env.AUTOBEAT_DATABASE_PATH) {
  const dbPath = process.env.AUTOBEAT_DATABASE_PATH;

  // Validate path is absolute and doesn't contain traversal
  if (!path.isAbsolute(dbPath)) {
    throw new Error('AUTOBEAT_DATABASE_PATH must be an absolute path');
  }

  const normalized = path.normalize(dbPath);
  if (normalized.includes('..')) {
    throw new Error('AUTOBEAT_DATABASE_PATH must not contain path traversal sequences (..)');
  }

  return normalized;
}
```

**Assessment**: POSITIVE SECURITY CHANGE
- Adds explicit path traversal validation for new environment variable
- Requires absolute paths, preventing relative path attacks
- Normalizes path and checks for `..` sequences
- This is good defense-in-depth for the new `AUTOBEAT_DATABASE_PATH` feature

#### 2. Database CHECK Constraints (GOOD)
**File**: `/workspace/delegate/src/implementations/database.ts:357-407`

```sql
-- Migration v3: Add CHECK constraints
CREATE TABLE tasks_new (
  ...
  status TEXT NOT NULL CHECK (status IN ('queued', 'running', 'completed', 'failed', 'cancelled')),
  priority TEXT NOT NULL CHECK (priority IN ('P0', 'P1', 'P2')),
  ...
);
```

**Assessment**: POSITIVE SECURITY CHANGE
- Adds database-level validation as defense-in-depth
- Prevents invalid status/priority values even if application code has bugs
- Follows principle of validate-at-every-layer

#### 3. Zod Schema Validation at Repository Boundaries (GOOD)
**File**: `/workspace/delegate/src/implementations/task-repository.ts:17-44`
**File**: `/workspace/delegate/src/implementations/dependency-repository.ts:19-27`

```typescript
const TaskRowSchema = z.object({
  id: z.string().min(1),
  status: z.enum(['queued', 'running', 'completed', 'failed', 'cancelled']),
  priority: z.enum(['P0', 'P1', 'P2']),
  // ... other fields
});

private rowToTask(row: TaskRow): Task {
  const validated = TaskRowSchema.safeParse(row);
  if (!validated.success) {
    throw new Error(`Invalid task row data for id=${row.id}: ${validated.error.message}`);
  }
  // ...
}
```

**Assessment**: POSITIVE SECURITY CHANGE
- Implements "parse, don't validate" pattern
- Catches database corruption or schema mismatches early
- Provides type safety guarantee at data layer boundary
- Error messages include task ID for debugging (not sensitive data)

---

## [YELLOW] Issues in Code You Touched (Should Fix)

### MEDIUM: Test Mode Detection Uses Environment Variable

**File**: `/workspace/delegate/src/bootstrap.ts:285-288` (lines ADDED)

```typescript
// Use NoOpProcessSpawner in test mode to prevent spawning real Claude Code instances
if (process.env.AUTOBEAT_TEST_MODE === 'true') {
  logger.info('Test mode enabled - using NoOpProcessSpawner');
  return new NoOpProcessSpawner();
}
```

**Concern**: Environment variable-based behavior switching
- In production, environment variables are controlled by operators
- However, if an attacker gains ability to set environment variables, they could enable test mode
- Test mode disables actual process spawning and resource monitoring

**Risk Level**: LOW in practice
- Attacker would need ability to modify environment variables
- If they have that access, they likely have more direct attack vectors
- Test mode doesn't expose new attack surface, it reduces functionality

**Recommendation**: OPTIONAL
- Consider documenting this behavior in security documentation
- Consider adding a startup warning if `AUTOBEAT_TEST_MODE=true` in non-test environments
- Could use a compile-time flag instead, but env var is acceptable for this use case

---

### LOW: Mock PID Counter Starts at 90000

**File**: `/workspace/delegate/src/bootstrap.ts:75`

```typescript
private mockPidCounter = 90000; // High PID to avoid collision with real processes
```

**Concern**: Magic number for PID collision avoidance
- PIDs on Linux can go up to `cat /proc/sys/kernel/pid_max` (typically 32768 or 4194304)
- 90000 might collide with real PIDs on systems with high pid_max

**Risk Level**: VERY LOW
- Only used in test mode (NoOpProcessSpawner)
- Even if collision occurs, mock process doesn't interact with real process
- No security impact, only potential test confusion

**Recommendation**: INFORMATIONAL ONLY
- No action required
- If desired, could use negative PIDs or UUID strings for mock processes

---

## [BLUE] Pre-existing Issues Found (Not Blocking)

These issues exist in files that were touched but are not introduced by this branch:

### MEDIUM: Type Coercion in Repository Mapping

**File**: `/workspace/delegate/src/implementations/task-repository.ts:283-306` (pre-existing pattern, now with validated data)

```typescript
return {
  id: data.id as TaskId,                    // Type assertion
  status: data.status as TaskStatus,         // Type assertion
  priority: data.priority as Priority,       // Type assertion
  // ...
};
```

**Context**: The new Zod validation ensures values are valid BEFORE these assertions. This is actually improved by the changes - the assertions are now safe because Zod guarantees the values.

**Pre-existing Pattern**: Using `as` for branded type conversion
- Not a security issue - branded types are compile-time only
- The Zod validation makes this pattern safe at runtime

**Recommendation**: No action required - the added Zod validation addresses this concern.

---

### LOW: Database Path Uses `os.homedir()` Without Validation

**File**: `/workspace/delegate/src/implementations/database.ts:105-114` (pre-existing)

```typescript
const homeDir = os.homedir();

if (process.platform === 'win32') {
  const appData = process.env.APPDATA || path.join(homeDir, 'AppData', 'Roaming');
  return path.join(appData, 'delegate', 'autobeat.db');
} else {
  return path.join(homeDir, '.delegate', 'autobeat.db');
}
```

**Context**: Pre-existing code for default database path. Not modified by this branch.

**Concern**: 
- `os.homedir()` returns the current user's home directory
- If running as root or with misconfigured `HOME`, could write to unexpected locations

**Risk Level**: LOW
- This is standard Node.js application data storage pattern
- User running the application controls the HOME environment
- Not an injection vector since it's concatenated with fixed strings

**Recommendation**: INFORMATIONAL - Consider for future hardening:
- Could add existence check for home directory
- Could validate resulting path is within expected boundaries

---

### LOW: Console Logging Replaced with Structured Logger

**File**: `/workspace/delegate/src/implementations/database.ts:55-57` (CHANGED - security positive)

Old code:
```typescript
console.error('WAL mode failed, falling back to DELETE mode:', error);
```

New code:
```typescript
this.logger.warn('WAL mode failed, falling back to DELETE mode', {
  error: error instanceof Error ? error.message : String(error)
});
```

**Assessment**: POSITIVE CHANGE
- Moves from console.error to structured logging
- Extracts only error message, not full error object (prevents stack trace leaks in production)
- Better log hygiene

---

## Security Controls Verified

The following security controls are present and unchanged:

1. **Foreign Key Constraints**: `PRAGMA foreign_keys = ON` in database.ts:47
2. **SQL Injection Prevention**: Uses prepared statements throughout (e.g., task-repository.ts:91-107)
3. **DoS Prevention**: `MAX_DEPENDENCIES_PER_TASK = 100` limit in dependency-repository.ts:44
4. **Transaction Atomicity**: Uses `db.transaction()` for TOCTOU protection
5. **Result Pattern**: All database operations return Result types, not throwing

---

## Summary

**Your Changes:**
- [GREEN] CRITICAL: 0
- [GREEN] HIGH: 0
- [GREEN] MEDIUM: 0
- [YELLOW] LOW: 1 (env var test mode - informational)

**Code You Touched:**
- [YELLOW] MEDIUM: 1 (test mode env var)
- [YELLOW] LOW: 1 (mock PID counter)

**Pre-existing:**
- [BLUE] MEDIUM: 0
- [BLUE] LOW: 2 (type assertions now safe, home dir path)

**Security Score**: 9/10

The changes are **security-positive**. They add:
- Path traversal validation for new environment variable
- Database CHECK constraints for defense-in-depth
- Zod schema validation at repository boundaries
- Structured logging instead of console.error

---

## Merge Recommendation

**[APPROVED]** - No blocking security issues

The changes improve the security posture by adding validation layers:
1. Input validation at data layer boundaries (Zod schemas)
2. Database-level constraints (CHECK constraints)
3. Path traversal prevention (AUTOBEAT_DATABASE_PATH validation)

---

## Remediation Priority

**No remediation required before merge.**

**Optional improvements for future:**
1. Consider adding startup warning if `AUTOBEAT_TEST_MODE=true` in production
2. Document test mode behavior in security documentation

---

## Appendix: Diff Analysis

### Changed Line Numbers by File

| File | Added Lines | Removed Lines | Security-Relevant |
|------|-------------|---------------|-------------------|
| database.ts | 66-85, 197-218, 357-407 | 51-52, 159-160 | Path validation, migrations |
| task-repository.ts | 17-44, 269-307 | 229-260 | Zod schema, validation |
| dependency-repository.ts | 19-27, 544-569 | 527-542 | Zod schema, validation |
| bootstrap.ts | 17-91, 251-254, 282-288, 310-318 | - | NoOpProcessSpawner, test mode |
| container.ts | 183-191 | - | ResourceMonitor shutdown |
| task-dependencies.test.ts | 16-57, 131-218 | 114-166 | Test isolation |
| test-data.ts | 8 | 8 | Status fix |
| package.json | 31 | 31 | Test script |

