forked from s434650/CatOrNot
93 lines
2.8 KiB
Python
93 lines
2.8 KiB
Python
from __future__ import absolute_import
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import hashlib
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from pip.exceptions import HashMismatch, HashMissing, InstallationError
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from pip.utils import read_chunks
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from pip._vendor.six import iteritems, iterkeys, itervalues
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# The recommended hash algo of the moment. Change this whenever the state of
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# the art changes; it won't hurt backward compatibility.
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FAVORITE_HASH = 'sha256'
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# Names of hashlib algorithms allowed by the --hash option and ``pip hash``
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# Currently, those are the ones at least as collision-resistant as sha256.
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STRONG_HASHES = ['sha256', 'sha384', 'sha512']
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class Hashes(object):
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"""A wrapper that builds multiple hashes at once and checks them against
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known-good values
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"""
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def __init__(self, hashes=None):
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"""
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:param hashes: A dict of algorithm names pointing to lists of allowed
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hex digests
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"""
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self._allowed = {} if hashes is None else hashes
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def check_against_chunks(self, chunks):
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"""Check good hashes against ones built from iterable of chunks of
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data.
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Raise HashMismatch if none match.
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"""
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gots = {}
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for hash_name in iterkeys(self._allowed):
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try:
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gots[hash_name] = hashlib.new(hash_name)
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except (ValueError, TypeError):
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raise InstallationError('Unknown hash name: %s' % hash_name)
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for chunk in chunks:
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for hash in itervalues(gots):
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hash.update(chunk)
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for hash_name, got in iteritems(gots):
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if got.hexdigest() in self._allowed[hash_name]:
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return
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self._raise(gots)
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def _raise(self, gots):
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raise HashMismatch(self._allowed, gots)
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def check_against_file(self, file):
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"""Check good hashes against a file-like object
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Raise HashMismatch if none match.
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"""
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return self.check_against_chunks(read_chunks(file))
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def check_against_path(self, path):
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with open(path, 'rb') as file:
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return self.check_against_file(file)
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def __nonzero__(self):
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"""Return whether I know any known-good hashes."""
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return bool(self._allowed)
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def __bool__(self):
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return self.__nonzero__()
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class MissingHashes(Hashes):
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"""A workalike for Hashes used when we're missing a hash for a requirement
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It computes the actual hash of the requirement and raises a HashMissing
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exception showing it to the user.
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"""
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def __init__(self):
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"""Don't offer the ``hashes`` kwarg."""
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# Pass our favorite hash in to generate a "gotten hash". With the
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# empty list, it will never match, so an error will always raise.
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super(MissingHashes, self).__init__(hashes={FAVORITE_HASH: []})
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def _raise(self, gots):
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raise HashMissing(gots[FAVORITE_HASH].hexdigest())
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