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JonathanSalwan / ROPgadget

This tool lets you search your gadgets on your binaries to facilitate your ROP exploitation. ROPgadget supports ELF, PE and Mach-O format on x86, x64, ARM, ARM64, PowerPC, SPARC, MIPS, RISC-V 64, and RISC-V Compressed architectures.
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Fix badbytes ranges python3 compatibility #170

Closed nename0 closed 3 years ago

nename0 commented 3 years ago

Is was digging around to find out, why badbytes ranges always gave my 0 gadgets. And I found this python3 compatibility bug caused by this line: https://github.com/JonathanSalwan/ROPgadget/blob/7c5d4cffc58dfa5e3ce45bdc5e6690122c70f8f3/ropgadget/options.py#L135 As chr returns a string in python3 and bbytes should be a list of single character byte-strings, we later get this exception:

"./ropgadget/options.py", line 143, in __deleteBadBytes
    if x in gadAddr:
TypeError: a bytes-like object is required, not 'str'

However this was not detected because of this raise-except goto-reimplementation you use in many places: https://github.com/JonathanSalwan/ROPgadget/blob/7c5d4cffc58dfa5e3ce45bdc5e6690122c70f8f3/ropgadget/options.py#L142-L148 As you can see by this example, this construct hides bugs and should at least be protected by using a specific Exception-Type. Therefore I refactored it to a for-else construct, which fits better in this case.

SweetVishnya commented 3 years ago

Hi!

Thank you for PR. I'll review it next week.

nename0 commented 3 years ago

Seems like Ubuntu 20 broke the python2 Github Actions.

SweetVishnya commented 3 years ago

I'll also fix CI during review. Can you check that tests run well on your PC?

nename0 commented 3 years ago

Yeah, im working on a test that shoud fail with the old version...

nename0 commented 3 years ago

I just downgraded to ubuntu 18 (obviously not a proper fix) to showcase this:

So here is the new test failing on CI using https://github.com/JonathanSalwan/ROPgadget/pull/170/commits/b6b8710bbdd9e56dfac509c0e430cdef3f7f77ec Here is the test failing with the exception not caught using https://github.com/JonathanSalwan/ROPgadget/pull/170/commits/8cd2bb7bb4fa560ca0c40f651eb6af8debe4dcf9 And the last run is successful.

SweetVishnya commented 3 years ago

Excellent! Thank you for PR) Downgrading to ubuntu 18.04 is absolutely ok.