PHP phar archive (without stub): Ruby parsing library

A phar (PHP archive) file. The phar format is a custom archive format from the PHP ecosystem that is used to package a complete PHP library or application into a single self-contained archive. All phar archives start with an executable PHP stub, which can be used to allow executing or including phar files as if they were regular PHP scripts. PHP 5.3 and later include the phar extension, which adds native support for reading and manipulating phar files.

The phar format was originally developed as part of the PEAR library PHP_Archive, first released in 2005. Later, a native PHP extension named "phar" was developed, which was first released on PECL in 2007, and is included with PHP 5.3 and later. The phar extension has effectively superseded the PHP_Archive library, which has not been updated since 2010. The phar extension is also no longer released independently on PECL; it is now developed and released as part of PHP itself.

Because of current limitations in Kaitai Struct (seekaitai-io/kaitai_struct#158 and kaitai-io/kaitai_struct#538), the executable PHP stub that precedes the rest of the archive is not handled by this spec. Before parsing a phar using this spec, the stub must be removed manually.

A phar's stub is terminated by the special token __HALT_COMPILER(); (which may be followed by at most one space, the PHP tag end ?>, and an optional line terminator). The stub termination sequence is immediately followed by the remaining parts of the phar format, as described in this spec.

The phar stub usually contains code that loads the phar and runs a contained PHP file, but this is not required. A minimal valid phar stub is <?php __HALT_COMPILER(); - such a stub makes it impossible to execute the phar directly, but still allows loading or manipulating it using the phar extension.

Note: The phar format does not specify any encoding for text fields (stub, alias name, and all file names), so these fields may contain arbitrary binary data. The actual text encoding used in a specific phar file usually depends on the application that created the phar, and on the standard encoding of the system on which the phar was created.

Application

PHP

File extension

phar

KS implementation details

License: CC0-1.0
Minimal Kaitai Struct required: 0.9

References

This page hosts a formal specification of PHP phar archive (without stub) using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for Ruby generated by Kaitai Struct depends on the Ruby runtime library. You have to install it before you can parse data.

The Ruby runtime library can be installed from RubyGems:

gem install kaitai-struct

Code

Parse a local file and get structure in memory:

data = PharWithoutStub.from_file("path/to/local/file.phar")

Or parse structure from a string of bytes:

bytes = "\x00\x01\x02..."
data = PharWithoutStub.new(Kaitai::Struct::Stream.new(bytes))

After that, one can get various attributes from the structure by invoking getter methods like:

data.manifest # => The archive's manifest, containing general metadata about the archive
and its files.

Ruby source code to parse PHP phar archive (without stub)

phar_without_stub.rb

# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

require 'kaitai/struct/struct'

unless Gem::Version.new(Kaitai::Struct::VERSION) >= Gem::Version.new('0.9')
  raise "Incompatible Kaitai Struct Ruby API: 0.9 or later is required, but you have #{Kaitai::Struct::VERSION}"
end


##
# A phar (PHP archive) file. The phar format is a custom archive format
# from the PHP ecosystem that is used to package a complete PHP library
# or application into a single self-contained archive.
# All phar archives start with an executable PHP stub, which can be used to
# allow executing or including phar files as if they were regular PHP scripts.
# PHP 5.3 and later include the phar extension, which adds native support for
# reading and manipulating phar files.
# 
# The phar format was originally developed as part of the PEAR library
# PHP_Archive, first released in 2005. Later, a native PHP extension
# named "phar" was developed, which was first released on PECL in 2007,
# and is included with PHP 5.3 and later. The phar extension has effectively
# superseded the PHP_Archive library, which has not been updated since 2010.
# The phar extension is also no longer released independently on PECL;
# it is now developed and released as part of PHP itself.
# 
# Because of current limitations in Kaitai Struct
# (seekaitai-io/kaitai_struct#158 and kaitai-io/kaitai_struct#538),
# the executable PHP stub that precedes the rest of the archive is not handled
# by this spec. Before parsing a phar using this spec, the stub must be
# removed manually.
# 
# A phar's stub is terminated by the special token `__HALT_COMPILER();`
# (which may be followed by at most one space, the PHP tag end `?>`,
# and an optional line terminator). The stub termination sequence is
# immediately followed by the remaining parts of the phar format,
# as described in this spec.
# 
# The phar stub usually contains code that loads the phar and runs
# a contained PHP file, but this is not required. A minimal valid phar stub
# is `<?php __HALT_COMPILER();` - such a stub makes it impossible to execute
# the phar directly, but still allows loading or manipulating it using the
# phar extension.
# 
# Note: The phar format does not specify any encoding for text fields
# (stub, alias name, and all file names), so these fields may contain arbitrary
# binary data. The actual text encoding used in a specific phar file usually
# depends on the application that created the phar, and on the
# standard encoding of the system on which the phar was created.
# @see https://www.php.net/manual/en/phar.fileformat.php Source
# @see https://github.com/php/php-src/tree/master/ext/phar Source
# @see https://svn.php.net/viewvc/pecl/phar/ Source
# @see https://svn.php.net/viewvc/pear/packages/PHP_Archive/ Source
class PharWithoutStub < Kaitai::Struct::Struct

  SIGNATURE_TYPE = {
    1 => :signature_type_md5,
    2 => :signature_type_sha1,
    4 => :signature_type_sha256,
    8 => :signature_type_sha512,
    16 => :signature_type_openssl,
  }
  I__SIGNATURE_TYPE = SIGNATURE_TYPE.invert
  def initialize(_io, _parent = nil, _root = self)
    super(_io, _parent, _root)
    _read
  end

  def _read
    @manifest = Manifest.new(@_io, self, @_root)
    @files = Array.new(manifest.num_files)
    (manifest.num_files).times { |i|
      @files[i] = @_io.read_bytes(manifest.file_entries[i].len_data_compressed)
    }
    if manifest.flags.has_signature
      @_raw_signature = @_io.read_bytes_full
      _io__raw_signature = Kaitai::Struct::Stream.new(@_raw_signature)
      @signature = Signature.new(_io__raw_signature, self, @_root)
    end
    self
  end
  class SerializedValue < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @raw = @_io.read_bytes_full
      self
    end

    ##
    # The serialized value, parsed as a structure.
    def parsed
      return @parsed unless @parsed.nil?
      _pos = @_io.pos
      @_io.seek(0)
      @parsed = PhpSerializedValue.new(@_io)
      @_io.seek(_pos)
      @parsed
    end

    ##
    # The serialized value, as a raw byte array.
    attr_reader :raw
  end
  class Signature < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @data = @_io.read_bytes(((_io.size - _io.pos) - 8))
      @type = Kaitai::Struct::Stream::resolve_enum(PharWithoutStub::SIGNATURE_TYPE, @_io.read_u4le)
      @magic = @_io.read_bytes(4)
      raise Kaitai::Struct::ValidationNotEqualError.new([71, 66, 77, 66].pack('C*'), magic, _io, "/types/signature/seq/2") if not magic == [71, 66, 77, 66].pack('C*')
      self
    end

    ##
    # The signature data. The size and contents depend on the
    # signature type.
    attr_reader :data

    ##
    # The signature type.
    attr_reader :type
    attr_reader :magic
  end
  class FileFlags < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @value = @_io.read_u4le
      self
    end

    ##
    # The file's permission bits.
    def permissions
      return @permissions unless @permissions.nil?
      @permissions = (value & 511)
      @permissions
    end

    ##
    # Whether this file's data is stored using zlib compression.
    def zlib_compressed
      return @zlib_compressed unless @zlib_compressed.nil?
      @zlib_compressed = (value & 4096) != 0
      @zlib_compressed
    end

    ##
    # Whether this file's data is stored using bzip2 compression.
    def bzip2_compressed
      return @bzip2_compressed unless @bzip2_compressed.nil?
      @bzip2_compressed = (value & 8192) != 0
      @bzip2_compressed
    end

    ##
    # The unparsed flag bits.
    attr_reader :value
  end

  ##
  # A phar API version number. This version number is meant to indicate
  # which features are used in a specific phar, so that tools reading
  # the phar can easily check that they support all necessary features.
  # 
  # The following API versions exist so far:
  # 
  # * 0.5, 0.6, 0.7, 0.7.1: The first official API versions. At this point,
  #   the phar format was only used by the PHP_Archive library, and the
  #   API version numbers were identical to the PHP_Archive versions that
  #   supported them. Development of the native phar extension started around
  #   API version 0.7. These API versions could only be queried using the
  #   `PHP_Archive::APIversion()` method, but were not stored physically
  #   in archives. These API versions are not supported by this spec.
  # * 0.8.0: Used by PHP_Archive 0.8.0 (released 2006-07-18) and
  #   later development versions of the phar extension. This is the first
  #   version number to be physically stored in archives. This API version
  #   is not supported by this spec.
  # * 0.9.0: Used by later development/early beta versions of the
  #   phar extension. Also temporarily used by PHP_Archive 0.9.0
  #   (released 2006-12-15), but reverted back to API version 0.8.0 in
  #   PHP_Archive 0.9.1 (released 2007-01-05).
  # * 1.0.0: Supported since PHP_Archive 0.10.0 (released 2007-05-29)
  #   and phar extension 1.0.0 (released 2007-03-28). This is the first
  #   stable, forwards-compatible and documented version of the format.
  # * 1.1.0: Supported since PHP_Archive 0.12.0 (released 2015-07-06)
  #   and phar extension 1.1.0 (released 2007-04-12). Adds SHA-256 and
  #   SHA-512 signature types.
  # * 1.1.1: Supported since phar extension 2.0.0 (released 2009-07-29 and
  #   included with PHP 5.3 and later). (PHP_Archive 0.12.0 also supports
  #   all features from API verison 1.1.1, but it reports API version 1.1.0.)
  #   Adds the OpenSSL signature type and support for storing
  #   empty directories.
  class ApiVersion < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @release = @_io.read_bits_int_be(4)
      @major = @_io.read_bits_int_be(4)
      @minor = @_io.read_bits_int_be(4)
      @unused = @_io.read_bits_int_be(4)
      self
    end
    attr_reader :release
    attr_reader :major
    attr_reader :minor
    attr_reader :unused
  end
  class GlobalFlags < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @value = @_io.read_u4le
      self
    end

    ##
    # Whether any of the files in this phar are stored using
    # zlib compression.
    def any_zlib_compressed
      return @any_zlib_compressed unless @any_zlib_compressed.nil?
      @any_zlib_compressed = (value & 4096) != 0
      @any_zlib_compressed
    end

    ##
    # Whether any of the files in this phar are stored using
    # bzip2 compression.
    def any_bzip2_compressed
      return @any_bzip2_compressed unless @any_bzip2_compressed.nil?
      @any_bzip2_compressed = (value & 8192) != 0
      @any_bzip2_compressed
    end

    ##
    # Whether this phar contains a signature.
    def has_signature
      return @has_signature unless @has_signature.nil?
      @has_signature = (value & 65536) != 0
      @has_signature
    end

    ##
    # The unparsed flag bits.
    attr_reader :value
  end
  class Manifest < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @len_manifest = @_io.read_u4le
      @num_files = @_io.read_u4le
      @api_version = ApiVersion.new(@_io, self, @_root)
      @flags = GlobalFlags.new(@_io, self, @_root)
      @len_alias = @_io.read_u4le
      @alias = @_io.read_bytes(len_alias)
      @len_metadata = @_io.read_u4le
      if len_metadata != 0
        @_raw_metadata = @_io.read_bytes(len_metadata)
        _io__raw_metadata = Kaitai::Struct::Stream.new(@_raw_metadata)
        @metadata = SerializedValue.new(_io__raw_metadata, self, @_root)
      end
      @file_entries = Array.new(num_files)
      (num_files).times { |i|
        @file_entries[i] = FileEntry.new(@_io, self, @_root)
      }
      self
    end

    ##
    # The length of the manifest, in bytes.
    # 
    # Note: The phar extension does not allow reading manifests
    # larger than 100 MiB.
    attr_reader :len_manifest

    ##
    # The number of files in this phar.
    attr_reader :num_files

    ##
    # The API version used by this phar manifest.
    attr_reader :api_version

    ##
    # Global flags for this phar.
    attr_reader :flags

    ##
    # The length of the alias, in bytes.
    attr_reader :len_alias

    ##
    # The phar's alias, i. e. the name under which it is loaded into PHP.
    attr_reader :alias

    ##
    # The size of the metadata, in bytes, or 0 if there is none.
    attr_reader :len_metadata

    ##
    # Metadata for this phar, in the format used by PHP's
    # `serialize` function. The meaning of the serialized data is not
    # specified further, it may be used to store arbitrary custom data
    # about the archive.
    attr_reader :metadata

    ##
    # Manifest entries for the files contained in this phar.
    attr_reader :file_entries
    attr_reader :_raw_metadata
  end
  class FileEntry < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @len_filename = @_io.read_u4le
      @filename = @_io.read_bytes(len_filename)
      @len_data_uncompressed = @_io.read_u4le
      @timestamp = @_io.read_u4le
      @len_data_compressed = @_io.read_u4le
      @crc32 = @_io.read_u4le
      @flags = FileFlags.new(@_io, self, @_root)
      @len_metadata = @_io.read_u4le
      if len_metadata != 0
        @_raw_metadata = @_io.read_bytes(len_metadata)
        _io__raw_metadata = Kaitai::Struct::Stream.new(@_raw_metadata)
        @metadata = SerializedValue.new(_io__raw_metadata, self, @_root)
      end
      self
    end

    ##
    # The length of the file name, in bytes.
    attr_reader :len_filename

    ##
    # The name of this file. If the name ends with a slash, this entry
    # represents a directory, otherwise a regular file. Directory entries
    # are supported since phar API version 1.1.1.
    # (Explicit directory entries are only needed for empty directories.
    # Non-empty directories are implied by the files located inside them.)
    attr_reader :filename

    ##
    # The length of the file's data when uncompressed, in bytes.
    attr_reader :len_data_uncompressed

    ##
    # The time at which the file was added or last updated, as a
    # Unix timestamp.
    attr_reader :timestamp

    ##
    # The length of the file's data when compressed, in bytes.
    attr_reader :len_data_compressed

    ##
    # The CRC32 checksum of the file's uncompressed data.
    attr_reader :crc32

    ##
    # Flags for this file.
    attr_reader :flags

    ##
    # The length of the metadata, in bytes, or 0 if there is none.
    attr_reader :len_metadata

    ##
    # Metadata for this file, in the format used by PHP's
    # `serialize` function. The meaning of the serialized data is not
    # specified further, it may be used to store arbitrary custom data
    # about the file.
    attr_reader :metadata
    attr_reader :_raw_metadata
  end

  ##
  # The archive's manifest, containing general metadata about the archive
  # and its files.
  attr_reader :manifest

  ##
  # The contents of each file in the archive (possibly compressed,
  # as indicated by the file's flags in the manifest). The files are stored
  # in the same order as they appear in the manifest.
  attr_reader :files

  ##
  # The archive's signature - a digest of all archive data before
  # the signature itself.
  # 
  # Note: Almost all of the available "signature" types are actually hashes,
  # not signatures, and cannot be used to verify that the archive has not
  # been tampered with. Only the OpenSSL signature type is a true
  # cryptographic signature.
  attr_reader :signature
  attr_reader :_raw_signature
end