Fix broken --e-machine and --bit-size command line options

[Cr4sh]

I noticed that in most recent version --e-machine and --bit-size options are not working as they should because of inaccurate safety check in find_elf64_rela function code.

Here's an example before proposed fix:

$ ./vmlinux-to-elf vmlinuz-4.1.0-2-amd64 output.elf
[+] Kernel successfully decompressed in-memory (the offsets that follow will be given relative to the decompressed binary)
[+] Version string: Linux version 4.1.0-2-amd64 (debian-kernel@lists.debian.org) (gcc version 4.9.3 (Debian 4.9.3-3) ) #1 SMP Debian 4.1.6-1 (2015-08-23)
[!] The architecture of your kernel could not be guessed successfully. Please specify the --e-machine and --bit-size arguments manually (use --help for their precise specification).
$ ./vmlinux-to-elf --e-machine 62 --bit-size 64 vmlinuz-4.1.0-2-amd64 output.elf
[+] Kernel successfully decompressed in-memory (the offsets that follow will be given relative to the decompressed binary)
[+] Version string: Linux version 4.1.0-2-amd64 (debian-kernel@lists.debian.org) (gcc version 4.9.3 (Debian 4.9.3-3) ) #1 SMP Debian 4.1.6-1 (2015-08-23)
Traceback (most recent call last):
  File "./vmlinux-to-elf", line 63, in <module>
    ElfSymbolizer(
  File "/vagrant_home/_encrypted/data/_PoC/lkm_kif/vmlinux-to-elf/vmlinux_to_elf/elf_symbolizer.py", line 44, in __init__
    kallsyms_finder = KallsymsFinder(file_contents, bit_size)
  File "/vagrant_home/_encrypted/data/_PoC/lkm_kif/vmlinux-to-elf/vmlinux_to_elf/kallsyms_finder.py", line 187, in __init__
    self.find_elf64_rela()
  File "/vagrant_home/_encrypted/data/_PoC/lkm_kif/vmlinux-to-elf/vmlinux_to_elf/kallsyms_finder.py", line 247, in find_elf64_rela
    if ArchitectureName.aarch64 != self.architecture:
AttributeError: 'KallsymsFinder' object has no attribute 'architecture'

... and after the fix:

$ ./vmlinux-to-elf --e-machine 62 --bit-size 64 vmlinuz-4.1.0-2-amd64 output.elf
[+] Kernel successfully decompressed in-memory (the offsets that follow will be given relative to the decompressed binary)
[+] Version string: Linux version 4.1.0-2-amd64 (debian-kernel@lists.debian.org) (gcc version 4.9.3 (Debian 4.9.3-3) ) #1 SMP Debian 4.1.6-1 (2015-08-23)
[+] Found kallsyms_token_table at file offset 0x00908648
[+] Found kallsyms_token_index at file offset 0x009089a0
[+] Found kallsyms_markers at file offset 0x009082c0
[+] Found kallsyms_names at file offset 0x008b6868
[+] Found kallsyms_num_syms at file offset 0x008b6860
[i] Null addresses overall: 0.00696306 %
[+] Found kallsyms_addresses at file offset 0x0087e6c8
[+] Successfully wrote the new ELF kernel to output.elf

PS: thank you for awesome tool!

[marin-m]

Merged, thanks!