Added CPUTypeMismatchException (#450)

1. New exception triggers when there is a cputype or cputype
mismatch between fat header and internal macho slice in the
FatFile#populate_machos method.

2. Added a test for it along with adding a new binary file
to the test/bin/llvm folder.

lib/macho/exceptions.rb

@@ -63,6 +63,21 @@ def initialize
  end
  end
 
+ # Raised when there is a mismatch between the fat arch
+ # and internal slice cputype or cpusubtype.
+ class CPUTypeMismatchError < NotAMachOError
+ def initialize(fat_cputype, fat_cpusubtype, macho_cputype, macho_cpusubtype)
+ # @param cputype_fat [Integer] the CPU type in the fat header
+ # @param cpusubtype_fat [Integer] the CPU subtype in the fat header
+ # @param cputype_macho [Integer] the CPU type in the macho header
+ # @param cpusubtype_macho [Integer] the CPU subtype in the macho header
+ super ("Mismatch between cputypes >> 0x%08<fat_cputype>x and 0x%08<macho_cputype>x\n" \
+ "and/or cpusubtypes >> 0x%08<fat_cpusubtype>x and 0x%08<macho_cpusubtype>x" %
+ { :fat_cputype => fat_cputype, :macho_cputype => macho_cputype,
+ :fat_cpusubtype => fat_cpusubtype, :macho_cpusubtype => macho_cpusubtype })
+ end
+ end
+
  # Raised when a fat binary is loaded with MachOFile.
  class FatBinaryError < MachOError
  def initialize

lib/macho/fat_file.rb

@@ -379,6 +379,13 @@ def populate_machos
 
  fat_archs.each do |arch|
  machos << MachOFile.new_from_bin(@raw_data[arch.offset, arch.size], **options)
+
+ # Make sure that each fat_arch and internal slice.
+ # contain matching cputypes and cpusubtypes
+ next if machos.last.header.cputype == arch.cputype &&
+ machos.last.header.cpusubtype == arch.cpusubtype
+
+ raise CPUTypeMismatchError.new(arch.cputype, arch.cpusubtype, machos.last.header.cputype, machos.last.header.cpusubtype)
  end
 
  machos

test/test_fat.rb

@@ -42,6 +42,12 @@ def test_zero_arch_file
  end
  end
 
+ def test_mismatch_cpu_arch_file
+ assert_raises MachO::CPUTypeMismatchError do
+ MachO::FatFile.new("test/bin/llvm/macho-invalid-fat_cputype")
+ end
+ end
+
  def test_fat_header
  filenames = FAT_ARCH_PAIRS.map { |a| fixture(a, "hello.bin") }