ImportError: ERROR: fail to load the dynamic library (ROP)

[bannsec]

Getting the following error when trying to instantiate a ROP object on a base ELF class with the latest pwntools (3.10.0)

In [1]: rop = ROP(elf)
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
<ipython-input-1-b73050b43606> in <module>()
----> 1 rop = ROP(elf)

/home/user/.virtualenvs/formatStringExploiter/local/lib/python2.7/site-packages/pwnlib/rop/rop.pyc in __init__(self, elfs, base, **kwargs)
    396             elfs(list): List of :class:`.ELF` objects for mining
    397         """
--> 398         import ropgadget
    399
    400         # Permit singular ROP(elf) vs ROP([elf])

/home/user/.virtualenvs/formatStringExploiter/local/lib/python2.7/site-packages/ropgadget/__init__.pyc in <module>()
     12
     13 import ropgadget.args
---> 14 import ropgadget.binary
     15 import ropgadget.core
     16 import ropgadget.gadgets

/home/user/.virtualenvs/formatStringExploiter/local/lib/python2.7/site-packages/ropgadget/binary.py in <module>()
     11 ##  (at your option) any later version.
     12
---> 13 from ropgadget.loaders.elf       import *
     14 from ropgadget.loaders.pe        import *
     15 from ropgadget.loaders.raw       import *

/home/user/.virtualenvs/formatStringExploiter/local/lib/python2.7/site-packages/ropgadget/loaders/__init__.py in <module>()
     11 ##  (at your option) any later version.
     12
---> 13 import ropgadget.loaders.elf
     14 import ropgadget.loaders.macho
     15 import ropgadget.loaders.pe

/home/user/.virtualenvs/formatStringExploiter/local/lib/python2.7/site-packages/ropgadget/loaders/elf.py in <module>()
     11 ##  (at your option) any later version.
     12
---> 13 from capstone   import *
     14 from ctypes     import *
     15 from struct     import unpack
/home/user/.virtualenvs/formatStringExploiter/local/lib/python2.7/site-packages/capstone/__init__.py in <module>()
    228             pass
    229     if _found == False:
--> 230         raise ImportError("ERROR: fail to load the dynamic library.")
    231
    232

ImportError: ERROR: fail to load the dynamic library.

Looking into the file, it appears that capstone is unable to find it's .so file. Having run into this before, I checked and found that pwntools is using capstone==3.0.4 on my install.

I resolved the issue manually on my install by doing pip install capstone==3.0.5rc2 as the 3.0.5 version appears to come with the .so file correctly.

[firmianay]

It seems that setup.py didn't specify capstone's version at installation time

[bannsec]

Appears to be related to #971

[zachriggle]

Yes, per #971, Capstone's default installation mechanism is broken.

I'd recommend installing Capstone manually. @bannsec said (on capstone-engine/capstone#916) that installing 3.0.5rc2 explicitly should fix the installation issue.

We do not require any specific version as we don't actually rely on any version's features.