hash_func.py

# Make coding more python3-ish
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

import os

PASSLIB_AVAILABLE = False
try:
    import passlib.hash
    PASSLIB_AVAILABLE = True
except:
    pass

def do_encrypt(result, encrypt, salt_size=None, salt=None):
    if PASSLIB_AVAILABLE:
        try:
            crypt = getattr(passlib.hash, encrypt)
        except:
            raise ValueError("passlib does not support '%s' algorithm" % encrypt)

        if salt_size:
            result = crypt.encrypt(result, salt_size=salt_size)
        elif salt:
            result = crypt.encrypt(result, salt=salt)
        else:
            result = crypt.encrypt(result)
    else:
        raise ValueError("passlib must be installed to encrypt vars_prompt values")

    return result


# Note, sha1 is the only hash algorithm compatible with python2.4 and with
# FIPS-140 mode (as of 11-2014)
try:
    from hashlib import sha1 as sha1
except ImportError:
    from sha import sha as sha1

# Backwards compat only
try:
    from hashlib import md5 as _md5
except ImportError:
    try:
        from md5 import md5 as _md5
    except ImportError:
        # Assume we're running in FIPS mode here
        _md5 = None


def secure_hash_s(data, hash_func=sha1):
    ''' Return a secure hash hex digest of data. '''

    digest = hash_func()
    try:
        if not isinstance(data, basestring):
            data = "%s" % data
        digest.update(data)
    except UnicodeEncodeError:
        digest.update(data.encode('utf-8'))
    return digest.hexdigest()

def secure_hash(filename, hash_func=sha1):
    ''' Return a secure hash hex digest of local file, None if file is not present or a directory. '''

    if not os.path.exists(filename) or os.path.isdir(filename):
        return None
    digest = hash_func()
    blocksize = 64 * 1024
    try:
        infile = open(filename, 'rb')
        block = infile.read(blocksize)
        while block:
            digest.update(block)
            block = infile.read(blocksize)
        infile.close()
    except IOError as e:
        raise ValueError("error while accessing the file %s, error was: %s" % (filename, e))
    return digest.hexdigest()

# The checksum algorithm must match with the algorithm in ShellModule.checksum() method
checksum = secure_hash
checksum_s = secure_hash_s

# Backwards compat functions.  Some modules include md5s in their return values
# Continue to support that for now.
# should also return "checksum" (sha1 for now)
# Do not use md5 unless it is needed for:
# 1) Optional backwards compatibility
# 2) Compliance with a third party protocol
#
# MD5 will not work on systems which are FIPS-140-2 compliant.

def md5s(data):
    if not _md5:
        raise ValueError('MD5 not available.  Possibly running in FIPS mode')
    return secure_hash_s(data, _md5)

def md5(filename):
    if not _md5:
        raise ValueError('MD5 not available.  Possibly running in FIPS mode')
    return secure_hash(filename, _md5)