Class: Sxn::Security::SecureFileCopier

Inherits:
Object
  • Object
show all
Defined in:
lib/sxn/security/secure_file_copier.rb

Overview

SecureFileCopier provides secure file copying operations with strict security controls. It validates source and destination paths, preserves/enforces file permissions, supports file encryption using OpenSSL AES-256, and maintains an audit trail.

Examples:

copier = SecureFileCopier.new("/path/to/project")
result = copier.copy_file("config/master.key", "session/master.key",
                         permissions: 0600, encrypt: true)

Defined Under Namespace

Classes: CopyResult

Constant Summary collapse

SENSITIVE_FILE_PATTERNS =

Patterns that identify sensitive files requiring special handling

[
  /master\.key$/,
  /credentials.*\.key$/,
  /\.env$/,
  /\.env\./,
  /secrets\.yml$/,
  /\.pem$/,
  /\.p12$/,
  /\.jks$/,
  /\.npmrc$/,
  /auth_token/i,
  /api_key/i,
  /password/i,
  /secret/i
].freeze
DEFAULT_PERMISSIONS =

Default secure permissions for different file types

{
  sensitive: 0o600,  # Owner read/write only
  config: 0o644,     # Owner read/write, group/other read
  executable: 0o755  # Owner all, group/other read/execute
}.freeze
MAX_FILE_SIZE =

Maximum file size for operations (100MB)

100 * 1024 * 1024

Instance Method Summary collapse

Constructor Details

#initialize(project_root, logger: nil) ⇒ SecureFileCopier

Returns a new instance of SecureFileCopier.

Parameters:

  • project_root (String) —

    The absolute path to the project root directory

  • logger (Logger) (defaults to: nil) —

    Optional logger for audit trail



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# File 'lib/sxn/security/secure_file_copier.rb', line 73

def initialize(project_root, logger: nil)
  @project_root = File.realpath(project_root)
  @path_validator = SecurePathValidator.new(@project_root)
  @logger = logger || Sxn.logger
  @encryption_key = nil
rescue Errno::ENOENT
  raise ArgumentError, "Project root does not exist: #{project_root}"
end

Instance Method Details

#copy_file(source, destination, permissions: nil, encrypt: false, preserve_permissions: false, create_directories: true) ⇒ CopyResult

Copies a file securely with validation and optional encryption

Parameters:

  • source (String) —

    Source file path (relative to project root)

  • destination (String) —

    Destination file path (relative to project root)

  • permissions (Integer) (defaults to: nil) —

    File permissions to set (e.g., 0600)

  • encrypt (Boolean) (defaults to: false) —

    Whether to encrypt the file

  • preserve_permissions (Boolean) (defaults to: false) —

    Whether to preserve source permissions

  • create_directories (Boolean) (defaults to: true) —

    Whether to create destination directories

Returns:

Raises:



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# File 'lib/sxn/security/secure_file_copier.rb', line 92

def copy_file(source, destination, permissions: nil, encrypt: false,
              preserve_permissions: false, create_directories: true)
  start_time = Time.now

  raw_source, raw_destination = @path_validator.validate_file_operation(
    source, destination, allow_creation: true
  )

  # Normalize paths for consistent behavior in tests and cross-platform compatibility
  validated_source = normalize_path_for_result(raw_source)
  validated_destination = normalize_path_for_result(raw_destination)

  validate_file_operation!(raw_source, raw_destination)

  # Determine appropriate permissions (use normalized path for consistent method signatures)
  target_permissions = determine_permissions(
    validated_source, permissions, preserve_permissions
  )

  # Create destination directory if needed (use raw path for actual file operations)
  create_destination_directory(raw_destination) if create_directories

  # Perform the copy operation (use normalized paths for method signatures)
  if encrypt
    copy_with_encryption(validated_source, validated_destination, target_permissions)
    encrypted = true
  else
    copy_without_encryption(validated_source, validated_destination, target_permissions)
    encrypted = false
  end

  # Generate checksum for verification (use normalized path for method signature)
  checksum = generate_checksum(validated_destination)
  duration = Time.now - start_time

  result = CopyResult.new(
    normalize_path_for_result(validated_source),
    normalize_path_for_result(validated_destination),
    :copy,
    encrypted: encrypted, checksum: checksum, duration: duration
  )

  audit_log("FILE_COPY", result)
  result
end

#create_symlink(source, destination, force: false) ⇒ CopyResult

Creates a symbolic link securely

Parameters:

  • source (String) —

    Source file path (relative to project root)

  • destination (String) —

    Link path (relative to project root)

  • force (Boolean) (defaults to: false) —

    Whether to overwrite existing links

Returns:

Raises:



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# File 'lib/sxn/security/secure_file_copier.rb', line 145

def create_symlink(source, destination, force: false)
  start_time = Time.now

  validated_source, validated_destination = @path_validator.validate_file_operation(
    source, destination, allow_creation: true
  )

  validate_file_operation!(validated_source, validated_destination)

  # Remove existing symlink/file if force is true
  File.unlink(validated_destination) if force && (File.exist?(validated_destination) || File.symlink?(validated_destination))

  # Create the symlink
  File.symlink(validated_source, validated_destination)

  duration = Time.now - start_time
  result = CopyResult.new(
    normalize_path_for_result(validated_source),
    normalize_path_for_result(validated_destination),
    :symlink, duration: duration
  )

  audit_log("SYMLINK_CREATE", result)
  result
end

#decrypt_file(file_path, key) ⇒ Boolean

Decrypts a file in place using AES-256-GCM

Parameters:

  • file_path (String) —

    Path to file to decrypt (relative to project root)

  • key (String) —

    Base64-encoded encryption key

Returns:

  • (Boolean) —

    true if decryption successful

Raises:



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# File 'lib/sxn/security/secure_file_copier.rb', line 211

def decrypt_file(file_path, key)
  raw_path = @path_validator.validate_path(file_path)
  validated_path = normalize_path_for_result(raw_path)
  validate_file_exists!(validated_path)

  encryption_key = Base64.strict_decode64(key)

  # Read encrypted content (use real path for file operations)
  real_path = denormalize_path_for_operations(validated_path)
  encrypted_content = File.binread(real_path)

  # Decrypt content
  original_content = decrypt_content(encrypted_content, encryption_key)

  # Write decrypted content atomically (use real path for file operations)
  temp_file = "#{real_path}.tmp"
  File.binwrite(temp_file, original_content)
  File.rename(temp_file, real_path)

  audit_log("FILE_DECRYPT", { file_path: validated_path })
  true
rescue StandardError => e
  raise SecurityError, "Decryption failed: #{e.message}"
end

#encrypt_file(file_path, key: nil) ⇒ String

Encrypts a file in place using AES-256-GCM

Parameters:

  • file_path (String) —

    Path to file to encrypt (relative to project root)

  • key (String) (defaults to: nil) —

    Encryption key (if nil, generates one)

Returns:

  • (String) —

    Base64-encoded encryption key used

Raises:



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# File 'lib/sxn/security/secure_file_copier.rb', line 177

def encrypt_file(file_path, key: nil)
  raw_path = @path_validator.validate_path(file_path)
  validated_path = normalize_path_for_result(raw_path)
  validate_file_exists!(validated_path)

  encryption_key = key || generate_encryption_key

  # Read original content (use real path for file operations)
  real_path = denormalize_path_for_operations(validated_path)
  original_content = File.binread(real_path)

  # Encrypt content
  encrypted_content = encrypt_content(original_content, encryption_key)

  # Write encrypted content atomically (use real path for file operations)
  temp_file = "#{real_path}.tmp"
  File.binwrite(temp_file, encrypted_content)
  File.rename(temp_file, real_path)

  # Set secure permissions (use real path for file operations)
  File.chmod(0o600, real_path)

  audit_log("FILE_ENCRYPT", { file_path: validated_path })
  Base64.strict_encode64(encryption_key)
rescue Sxn::PathValidationError => e
  raise SecurityError, "Path validation failed: #{e.message}"
end

#secure_permissions?(file_path) ⇒ Boolean

Validates file permissions are secure

Parameters:

  • file_path (String) —

    Path to check (relative to project root)

Returns:

  • (Boolean) —

    true if permissions are secure



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# File 'lib/sxn/security/secure_file_copier.rb', line 248

def secure_permissions?(file_path)
  validated_path = @path_validator.validate_path(file_path, allow_creation: true)
  return false unless File.exist?(validated_path)

  stat = File.stat(validated_path)
  mode = stat.mode & 0o777

  if sensitive_file?(file_path)
    # Sensitive files should not be readable by group/other
    mode.nobits?(0o077)
  else
    # Non-sensitive files should not be world-writable
    mode.nobits?(0o002)
  end
rescue Sxn::PathValidationError
  false
end

#sensitive_file?(file_path) ⇒ Boolean

Checks if a file appears to be sensitive based on its path

Parameters:

  • file_path (String) —

    Path to check

Returns:

  • (Boolean) —

    true if file appears sensitive



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# File 'lib/sxn/security/secure_file_copier.rb', line 240

def sensitive_file?(file_path)
  SENSITIVE_FILE_PATTERNS.any? { |pattern| file_path.match?(pattern) }
end