diff options
| -rw-r--r-- | Makefile | 2 | ||||
| -rw-r--r-- | paramiko/osrandom.py | 133 |
2 files changed, 91 insertions, 44 deletions
@@ -65,5 +65,7 @@ test: # README # transport.py # +# TRY on windows vm +# POST gpg sig on website! # POST md5sum on website! # RUN setup.py diff --git a/paramiko/osrandom.py b/paramiko/osrandom.py index ca2a0bc7..447d090e 100644 --- a/paramiko/osrandom.py +++ b/paramiko/osrandom.py @@ -20,51 +20,43 @@ import sys -# Detect an OS random number source -osrandom_source = None +## +## Find potential random number sources +## -# Try os.urandom -if osrandom_source is None: - try: - from os import urandom - osrandom_source = "os.urandom" - except ImportError: - pass +# Try to open /dev/urandom now so that paramiko will be able to access +# it even if os.chroot() is invoked later. +try: + _dev_urandom = open("/dev/urandom", "rb", 0) +except EnvironmentError: + _dev_urandom = None -# Try winrandom -if osrandom_source is None: - try: - from Crypto.Util import winrandom - osrandom_source = "winrandom" - except ImportError: - pass +# Try to import the "winrandom" module +try: + from Crypto.Util import winrandom +except ImportError: + winrandom = None -# Try /dev/urandom -if osrandom_source is None: - try: - _dev_urandom = open("/dev/urandom", "rb", 0) - def urandom(bytes): - return _dev_urandom.read(bytes) - osrandom_source = "/dev/urandom" - except (OSError, IOError): - pass -# Give up -if osrandom_source is None: - raise ImportError("Cannot find OS entropy source") +## +## Define RandomPool classes +## + +def _workaround_windows_cryptgenrandom_bug(self): + # According to "Cryptanalysis of the Random Number Generator of the + # Windows Operating System", by Leo Dorrendorf and Zvi Gutterman + # and Benny Pinkas <http://eprint.iacr.org/2007/419>, + # CryptGenRandom only updates its internal state using kernel-provided + # random data every 128KiB of output. + self.get_bytes(128*1024) # discard 128 KiB of output + class BaseOSRandomPool(object): def __init__(self, numbytes=160, cipher=None, hash=None): pass def stir(self, s=''): - # According to "Cryptanalysis of the Random Number Generator of the - # Windows Operating System", by Leo Dorrendorf and Zvi Gutterman - # and Benny Pinkas <http://eprint.iacr.org/2007/419>, - # CryptGenRandom only updates its internal state using kernel-provided - # random data every 128KiB of output. - if osrandom_source == 'winrandom' or sys.platform == 'win32': - self.get_bytes(128*1024) # discard 128 KiB of output + pass def randomize(self, N=0): self.stir() @@ -72,22 +64,75 @@ class BaseOSRandomPool(object): def add_event(self, s=None): pass -class WinrandomOSRandomPool(BaseOSRandomPool): + +class WinRandomPool(BaseOSRandomPool): + """RandomPool that uses the C{winrandom} module for input""" def __init__(self, numbytes=160, cipher=None, hash=None): self._wr = winrandom.new() self.get_bytes = self._wr.get_bytes self.randomize() -class UrandomOSRandomPool(BaseOSRandomPool): + def stir(self, s=''): + _workaround_windows_cryptgenrandom_bug(self) + + +class DevUrandomPool(BaseOSRandomPool): + """RandomPool that uses the C{/dev/urandom} special device node for input""" def __init__(self, numbytes=160, cipher=None, hash=None): - self.get_bytes = urandom self.randomize() -if osrandom_source in ("/dev/urandom", "os.urandom"): - OSRandomPool = UrandomOSRandomPool -elif osrandom_source == "winrandom": - OSRandomPool = WinrandomOSRandomPool -else: - raise AssertionError("Unrecognized osrandom_source %r" % (osrandom_source,)) + def get_bytes(self, n): + bytes = "" + while len(bytes) < n: + bytes += _dev_urandom.read(n - len(bytes)) + return bytes + + +## +## Detect default random number source +## +osrandom_source = None + +# Try /dev/urandom +if osrandom_source is None and _dev_urandom is not None: + osrandom_source = "/dev/urandom" + DefaultRandomPoolClass = DevUrandomPool + +# Try winrandom +if osrandom_source is None and winrandom is not None: + osrandom_source = "winrandom" + DefaultRandomPoolClass = WinRandomPool + +# Give up +if osrandom_source is None: + raise ImportError("Cannot find OS entropy source") + + +## +## Define wrapper class +## + +class OSRandomPool(object): + """RandomPool wrapper. + + The C{randpool} attribute of this object may be modified by users of this class at runtime. + """ + + def __init__(self, instance=None): + if instance is None: + instance = DefaultRandomPoolClass() + self.randpool = instance + + def stir(self, s=''): + self.randpool.stir(s) + + def randomize(self, N=0): + self.randpool.randomize(N) + + def add_event(self, s=None): + self.randpool.add_event(s) + + def get_bytes(self, N): + return self.randpool.get_bytes(N) # vim:set ts=4 sw=4 sts=4 expandtab: |