root / lib / utils / hash.py @ 2dbc6857
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# Copyright (C) 2006, 2007, 2010, 2011 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""Utility functions for hashing.
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"""
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import os |
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import hmac |
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from ganeti import compat |
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def Sha1Hmac(key, text, salt=None): |
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"""Calculates the HMAC-SHA1 digest of a text.
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HMAC is defined in RFC2104.
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@type key: string
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@param key: Secret key
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@type text: string
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"""
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if salt:
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salted_text = salt + text |
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else:
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salted_text = text |
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return hmac.new(key, salted_text, compat.sha1).hexdigest()
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def VerifySha1Hmac(key, text, digest, salt=None): |
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"""Verifies the HMAC-SHA1 digest of a text.
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HMAC is defined in RFC2104.
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@type key: string
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@param key: Secret key
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@type text: string
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@type digest: string
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@param digest: Expected digest
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@rtype: bool
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@return: Whether HMAC-SHA1 digest matches
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"""
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return digest.lower() == Sha1Hmac(key, text, salt=salt).lower()
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def _FingerprintFile(filename): |
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"""Compute the fingerprint of a file.
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If the file does not exist, a None will be returned
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instead.
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@type filename: str
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@param filename: the filename to checksum
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@rtype: str
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@return: the hex digest of the sha checksum of the contents
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of the file
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"""
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if not (os.path.exists(filename) and os.path.isfile(filename)): |
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return None |
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f = open(filename)
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fp = compat.sha1_hash() |
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while True: |
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data = f.read(4096)
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if not data: |
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break
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fp.update(data) |
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return fp.hexdigest()
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def FingerprintFiles(files): |
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"""Compute fingerprints for a list of files.
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@type files: list
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@param files: the list of filename to fingerprint
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@rtype: dict
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@return: a dictionary filename: fingerprint, holding only
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existing files
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"""
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ret = {} |
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for filename in files: |
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cksum = _FingerprintFile(filename) |
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if cksum:
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ret[filename] = cksum |
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return ret
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