FileNotFoundError

[naweiss]

Trying to run 32bit elf on 64bit ubuntu, gives you the following erroe:

[x] Starting program './program'
[-] Starting program './program': Failed
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "/home/naweiss2/.local/lib/python3.5/site-packages/pwnlib/tubes/process.py", line 284, in __init__
    preexec_fn=self._preexec_fn)
  File "/usr/lib/python3.5/subprocess.py", line 947, in __init__
    restore_signals, start_new_session)
  File "/usr/lib/python3.5/subprocess.py", line 1551, in _execute_child
    raise child_exception_type(errno_num, err_msg)
FileNotFoundError: [Errno 2] No such file or directory: './program'

Used multiple ways, for example:

from pwn import *
context.update(arch='i386',bits='32')
p = process('./program')
p.interactive()

Note: using qemu-i386 ./program manualy works fine

[arthaud]

Hi @naweiss,

Sorry, I cannot reproduce it. I see pwntools spawning qemu-i386 ./program.

You can try ipdb to debug this. I would put a breakpoint at pwnlib/tubes/process.py#L275

Example of debugging session:

% ipdb test.py
> /tmp/test.py(1)<module>()
----> 1 from pwn import *
      2 context.update(arch='i386', bits='32')
      3 p = process('./program')

ipdb> break pwnlib/tubes/process.py:275
Breakpoint 1 at /tmp/env/lib/python3.6/site-packages/pwnlib/tubes/process.py:275
ipdb> continue
[x] Starting program './program'
> /tmp/env/lib/python3.6/site-packages/pwnlib/tubes/process.py(275)__init__()
    274                 try:
1-> 275                     self.proc = subprocess.Popen(args=prefix + argv,
    276                                                  shell=shell,

ipdb> print(prefix + argv)
['./program']
ipdb> continue
> /tmp/env/lib/python3.6/site-packages/pwnlib/tubes/process.py(275)__init__()
    274                 try:
1-> 275                     self.proc = subprocess.Popen(args=prefix + argv,
    276                                                  shell=shell,

ipdb> print(prefix + argv)
['qemu-i386', './program']
ipdb> print(cwd)
None
ipdb>

[naweiss]

Sorry I accidentally tested qemu-i386 ./program on my other machine.
On my machine the output is /lib/ld-linux.so.2: No such file or directory.

But I don't have access to /lib, so I can't copy ld-linux.so.2 to there.
any help?

Update: used the -L flag to run qemu-i386 worked.
pwntools for python2 seems to have similar thing QEMU_LD_PREFIX
Why this version of pwntools doesn't have same thing?

[arthaud]

python3-pwntools is way behind the original pwntools in terms of commits.

This is because I have to merge manually pwntools into python3-pwntools, and this is a bit painful. I get tons on conflicts, and then I have to rewrite part of the python2 stuff in python3.

I don't plan to keep doing this indefinitely. I would like to work directly on the official repo and make it python3-compatible. I didn't find the time and motivation yet..