Class: MooTool::Models::Decompressor

Inherits:
Object
  • Object
show all
Includes:
Helpers::IMG4
Defined in:
lib/mootool/models/decompressor.rb

Overview

The magic Apple decompressor (as in it uses magics)

Constant Summary collapse

COMPRESSION_LZSS = 
'lzss'
COMPRESSION_LZVN = 
'lzvn'
COMPRESSION_LZFSE = 
'bvx2'
COMPRESSION_LZMA = 
'lzma'

Constants included from Helpers::IMG4

Helpers::IMG4::DECODE_TAGS, Helpers::IMG4::FIRMWARE_TAGS, Helpers::IMG4::HASH_LENGTHS, Helpers::IMG4::KEY_INSTANCE_TAGS, Helpers::IMG4::KVP_TAGS, Helpers::IMG4::OCTET_TAGS, Helpers::IMG4::SEQUENCE_TAGS, Helpers::IMG4::SIGNATURE_TAGS

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Helpers::IMG4

#construct, #construct_object, #decode_construct, parse_4cc

Constructor Details

#initialize(data, hint) ⇒ Decompressor

Returns a new instance of Decompressor.



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# File 'lib/mootool/models/decompressor.rb', line 27

def initialize(data, hint)
  @hint = hint.to_sym
  data = data.value if data.is_a? MooTool::Models::Digest
  @hash = MooTool::Models::Digest.create(::Digest::SHA384.digest(data))
  @data = data
  @value = case data[0..3]
           when COMPRESSION_LZFSE
             @compression = :lzfse
             LZFSE.lzfse_decompress(data)
           when COMPRESSION_LZVN
             @compression = :lzvn
             LZFSE.lzvn_decompress(data)
           when COMPRESSION_LZSS
             @compression = :lzss
             OpenSSL::Digest::DSS.decompress(data)
           when COMPRESSION_LZMA
             @compression = :lzma
             Net::DNS::QueryTypes::ATMA.decompress(data)
           else
             @compression = :raw
             data
           end

  parse_based_on_hint(@value, @hint)

  @decompressed_hash = MooTool::Models::Digest.create(::Digest::SHA384.digest(@value))
end

Instance Attribute Details

#data ⇒ Object (readonly)

Returns the value of attribute data.



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# File 'lib/mootool/models/decompressor.rb', line 19

def data
  @data
end

#hash ⇒ Object (readonly)

Returns the value of attribute hash.



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# File 'lib/mootool/models/decompressor.rb', line 19

def hash
  @hash
end

#value ⇒ Object (readonly)

Returns the value of attribute value.



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# File 'lib/mootool/models/decompressor.rb', line 19

def value
  @value
end

Class Method Details

.load(filename) ⇒ Object 



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# File 'lib/mootool/models/decompressor.rb', line 21

def self.load(filename)
  new File.binread(filename)
end

Instance Method Details

#hashes ⇒ Object 



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# File 'lib/mootool/models/decompressor.rb', line 90

def hashes
  [@hash, @decompressed_hash].compact.uniq
end

#inspect ⇒ Object 



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# File 'lib/mootool/models/decompressor.rb', line 94

def inspect
  result = { length: @value.size, hash: @hash, parsed: @parsed }
  result[:compression] = @compression if @compression != :raw
  result[:decompressed_hash] = @decompressed_hash if @decompressed_hash && @decompressed_hash != @hash
  result[:parsed] = @parsed if @parsed
  result[:hint] = @hint if @hint
  result.ai
end

#parse_based_on_hint(value, hint) ⇒ Object 



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# File 'lib/mootool/models/decompressor.rb', line 55

def parse_based_on_hint(value, hint)
  @compression = :raw
  begin
    @asn1 = OpenSSL::ASN1.decode(value)
    @constructed = construct(@asn1)
    @compression = :asn1

    @parsed = case hint
              when :scrt, :lcrt
                {
                  unk1: @constructed[0],
                  unk2: @constructed[1],
                  signature: Models::Digest.create(@constructed[2]),
                  certificate: OpenSSL::X509::Certificate.new(OpenSSL::ASN1.decode(@constructed[3].value).to_der),
                  unk4: @constructed[4]
                }
              when :dCfg
                @constructed
              when :FSC2
                @constructed.map do |item|
                  case item
                  when Integer
                    item.to_4cc
                  when Hash
                    item.transform_keys(&:to_4cc)
                  end
                end
              else
                { hint => @asn1 }
              end
  rescue StandardError => e
    @parsed = { value: Models::Digest.create(value), error: e }
  end
end