alt Hacker NewsI'd be interested to know under what circumstances pip executes arbitrary code while resolving dependencies ... how does that work ?
And while I'm here ... how does uv go about mitigating typosquatting risks ? I could imagine how it might issue warnings if you perhaps it notices you requesting "dlango", which would work OK for the top 10% but are you suggesting there's some more general solution built into uv ?
I did a quick search but 'typosquatting' is not an easy string to cut through.
Replies
a)"Thanks to backwards compatibility, a package offered only as a source distribution and with the legacy setup.py file for configuration and metadata specification will run the code in setup.py as part of the installation." https://blog.phylum.io/python-package-installation-attacks/
b) pip now has an option _not_ to run arbitrary code by disallowing source distributions, by passing --only-binary :all:
"By default, pip does not perform any checks to protect against remote tampering and involves running arbitrary code from distributions. It is, however, possible to use pip in a manner that changes these behaviours, to provide a more secure installation mechanism." https://pip.pypa.io/en/stable/topics/secure-installs/
For a source package based on setup tools, setup.py is executed with a minimal environment and can run arbitrary code.
To install a package and its dependencies, you need the list of dependencies. This metadata is not always statically available!
Python packages are often just a zip file full of py files, with one of them called 'setup.py'. Running this file installs the package (originally using [distutils](https://docs.python.org/3.9/install/index.html#install-index)). This installation may fail if dependencies are not present, but there’s no method provided for installing those dependencies. You’re supposed to read the error message, go download the source for the missing dependencies, then run their setup.py scripts to install them.