# Security Hardening Report

## 🛡️ **Overview**

This document outlines the security improvements implemented in the TOML configuration system following comprehensive security analysis and hardening measures.

## 🎯 **Security Issues Addressed**

### 1. Path Traversal Vulnerability (Fixed)

**Issue**: Path sanitization was preserving `..` sequences, potentially allowing path traversal attacks.

**Before**:
```bash
# Input: "/path/../../../etc/passwd"
# Output: "-path-..-..-..-etc-passwd"  # Still contains ".."!
```

**After**:
```bash
# Input: "/path/../../../etc/passwd"  
# Output: "-path-etc-passwd"  # Path traversal sequences removed
```

**Implementation**:
```bash
sanitize_path_secure() {
    local path="$1"
    local sanitized="$path"
    
    # Security-first: Remove path traversal sequences FIRST
    sanitized=$(echo "$sanitized" | sed 's|\.\./||g')        # Remove ../
    sanitized=$(echo "$sanitized" | sed 's|\.\.|dot-dot|g')  # Replace remaining ..
    sanitized=$(echo "$sanitized" | sed 's|\./||g')          # Remove ./
    
    # Then apply standard sanitization
    sanitized=$(echo "$sanitized" | sed 's|/|-|g')
    sanitized=$(echo "$sanitized" | tr -cd '[:alnum:]-_.')
    
    [[ -z "$sanitized" ]] && sanitized="unknown-path"
    echo "$sanitized"
}
```

**Risk Level**: Medium → Resolved  
**Impact**: Prevents potential security issues in path-based operations

### 2. Insecure Cache File Permissions (Fixed)

**Issue**: Cache files were created with default umask, potentially world-writable (666/777).

**Before**:
```bash
echo "$clean_version" >"$cache_file" 2>/dev/null  # No permission control
```

**After**:
```bash
create_secure_cache_file() {
    local cache_file="$1"
    local content="$2"
    
    # Create file and set explicit secure permissions
    echo "$content" > "$cache_file" 2>/dev/null
    chmod 644 "$cache_file" 2>/dev/null
    
    # Verify permissions were set correctly
    local perms=$(stat -f %A "$cache_file" 2>/dev/null || stat -c %a "$cache_file" 2>/dev/null)
    if [[ "$perms" != "644" ]]; then
        echo "Warning: Cache file has unexpected permissions: $perms (expected: 644)" >&2
    fi
}
```

**Risk Level**: Medium → Resolved  
**Impact**: Prevents accidental data exposure through overly permissive file permissions

### 3. Silent Configuration Failures (Fixed)

**Issue**: TOML parsing failures were returning empty JSON without proper error classification.

**Before**:
```bash
if [[ ! -f "$toml_file" ]]; then
    echo "ERROR: TOML configuration file not found: $toml_file" >&2
    echo "{}"
    return 0  # Always returned success!
fi
```

**After**:
```bash
# Enhanced error handling with proper exit codes
if [[ -z "$toml_file" ]]; then
    echo "ERROR: No TOML file path provided" >&2
    echo "{}"
    return 2  # Invalid arguments
fi

if [[ ! -f "$toml_file" ]]; then
    echo "ERROR: TOML configuration file not found: $toml_file" >&2
    echo "{}"
    return 1  # File not found
fi

if [[ ! -r "$toml_file" ]]; then
    echo "ERROR: TOML configuration file not readable: $toml_file" >&2
    echo "{}"
    return 3  # Permission denied
fi
```

**Exit Code Schema**:
- `0`: Success
- `1`: File not found
- `2`: Invalid arguments
- `3`: Permission denied

**Risk Level**: Low → Resolved  
**Impact**: Prevents silent failures and improves error diagnosis

## 🔒 **Security Best Practices Implemented**

### Input Validation
- **Path Length Limits**: Maximum 1000 characters to prevent buffer overflow-style attacks
- **Character Filtering**: Only alphanumeric, hyphens, underscores, and dots allowed
- **Null Input Handling**: Proper validation of empty/null inputs

### File System Security
- **Explicit Permissions**: All cache files created with 644 permissions
- **Permission Verification**: Automated checking of file permissions after creation
- **Safe File Operations**: Proper error handling for file creation failures

### Error Handling Security
- **Information Disclosure Prevention**: Error messages don't reveal sensitive system information
- **Proper Exit Codes**: Consistent error categorization for automated handling
- **Graceful Degradation**: Safe fallbacks when security checks fail

## 🧪 **Security Testing**

### Path Traversal Tests
```bash
# Test cases that should be safely handled:
test_cases=(
    "../../../etc/passwd"
    "/path/../secret"
    "file/.././../data"
    "../../.ssh/id_rsa"
)

# All should result in safe sanitized output without ".." sequences
```

### File Permission Tests
```bash
# Verify cache files have correct permissions
ls -la /tmp/.claude_version_cache
# Expected: -rw-r--r-- (644)
```

### Error Handling Tests
```bash
# Test different error scenarios
parse_toml_to_json "/nonexistent/file.toml"  # Should return exit code 1
parse_toml_to_json ""                        # Should return exit code 2
parse_toml_to_json "/etc/shadow"             # Should return exit code 3
```

## 📊 **Security Impact Assessment**

| Security Control | Before | After | Risk Reduction |
|------------------|--------|-------|----------------|
| Path Traversal Protection | None | Complete | High |
| Cache File Permissions | Umask-dependent | Explicit 644 | Medium |
| Error Information Disclosure | Potential | Controlled | Low |
| Configuration Validation | Basic | Comprehensive | Medium |

## 🔍 **Security Monitoring**

### Automated Checks
- **Performance Benchmarks**: Include security function timing
- **Permission Audits**: Verify cache file permissions in tests
- **Path Sanitization Validation**: Ensure no path traversal sequences pass through

### Manual Reviews
- **Code Reviews**: Security focus on new configuration handling code
- **Dependency Updates**: Monitor jq and other tools for security updates
- **Configuration Audits**: Periodic review of TOML parsing logic

## 📋 **Security Maintenance**

### Regular Tasks
1. **Monthly**: Review security test results
2. **Quarterly**: Audit file permissions and access patterns
3. **Annually**: Comprehensive security review of configuration system

### Update Procedures
1. **Security Patches**: Immediate application of critical security fixes
2. **Dependency Updates**: Regular updates of jq and other security-critical tools
3. **Code Changes**: Security review required for configuration handling modifications

## 🎯 **Future Security Enhancements**

### Potential Improvements
1. **Input Validation**: Enhanced TOML structure validation
2. **Sandboxing**: Consider isolating TOML parsing in restricted environment
3. **Encryption**: Evaluate encryption for sensitive configuration values
4. **Audit Logging**: Log configuration file access and modifications

### Threat Modeling
- **Attack Vectors**: Regular assessment of potential attack vectors
- **Risk Assessment**: Ongoing evaluation of security risks
- **Mitigation Strategies**: Development of additional protective measures

---

**Security Review Date**: August 2025  
**Security Framework**: Defense in Depth  
**Compliance**: Security-conscious development practices  
**Next Review**: February 2026