Gallopsled/pwntools

`context.bits` will not automatically switch when setting `context.arch` twice.

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#2,498 创建于 2024年11月10日

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 (3 评论) (0 反应) (0 负责人)Python (11,127 star) (1,684 fork)batch import
backport-requiredbuggood first issue

描述

I was using IPython to do some quick poc work that time, first I switched context.arch to 'amd64' and assembled cdqe and then I suddenly would like to try what if I assemble cdqe in 32-bit mode. So I switched context.arch back to 'i386' and wanted to assemble, only to find an error: AttributeError: Invalid arch/bits combination: i386/64

Pwntools may can not handle context.arch correctly, it could change context.bits accordingly when first setting it. However, when setting context.arch the second time, context.bits left unchanged. I guess this bug is related to self._tls?

poc:

屏幕截图_20241111_003054

one more poc:

from pwn import *
print(f"{context.arch}/{context.bits}")
context.arch = 'amd64'
print(f"{context.arch}/{context.bits}")
context.arch = 'i386'
print(f"{context.arch}/{context.bits}")

贡献者指南

技术栈
python
领域
tooling
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
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clear
前置要求
familiarity with pwntools context systemPython debugging
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
65
研究方向
Investigate how `context.arch` updates `context.bits` in the pwntools library. The bug likely resides in the context module, possibly in the ` tls` property or the arch setter. Review the code in `pwnlib/context/ init .py` or `pwnlib/context/context.py` to understand how arch changes affect bits. The fix should ensure that whenever `context.arch` changes, `context.bits` is updated accordingly, even on subsequent assignments.
`context.bits` will not automatically switch when setting `context.arch` twice. · Gallopsled/pwntools#2498 | Good First Issue