GHSA-j44v-mmf2-xvm9 PDM Trojan Lockfile

• PyPI pdm: <= 2.9.3 (no fix yet)

Summary It's possible to craft a malicious `pdm.lock` file that could allow e.g. an insider or a malicious open source project to appear to depend on a trusted PyPI project, but actually install another project. Details Project `foo` can be targeted by creating the project `foo-2` and uploading the file `foo-2-2.tar.gz` to pypi.org. PyPI will see this as project `foo-2` version `2`, while PDM will see this as project `foo` version `2-2`. The version must only be parseable as a version (and the filename must be a prefix of the project name), but it's not verified to match the version being installed. (Version `2-2` is also not a valid normalized version per PEP 440.) Matching the project name exactly (not just prefix) would fix the issue. The version should also be verified to avoid version downgrade attacks. PoC Example `pdm.lock` snippet to appear to depend on `foo` but actually install `foo-2` ``` "foo 2.2.0" = [ url = "https://files.pythonhosted.org/.../foo-2-2.tar.gz ] ``` Impact When installing dependencies with PDM, what's actually installed could differ from what's listed in `pyproject.toml` (including arbitrary code execution on install). It could also be used for downgrade attacks by only changing the version.