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94 lines
3.0 KiB
Python
94 lines
3.0 KiB
Python
#!/usr/bin/python
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# Copyright 2012 Citrix Systems, Inc. Licensed under the
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# Apache License, Version 2.0 (the "License"); you may not use this
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# file except in compliance with the License. Citrix Systems, Inc.
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# reserves all rights not expressly granted by the License.
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# You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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# Automatically generated by addcopyright.py at 04/03/2012
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# -*- coding: ascii -*-
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# Copyright (C) 2008 Dwayne C. Litzenberger <dlitz@dlitz.net>
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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import os
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import stat
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class error(Exception):
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pass
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class _RNG(object):
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def __init__(self, file):
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self.file = file
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def read(self, bytes):
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return self.file.read(bytes)
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def close(self):
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return self.file.close()
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def randomize(self):
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return
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def open_rng_device(device_path=None):
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"""Open /dev/urandom and perform some sanity checks."""
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f = None
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g = None
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if device_path is None:
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device_path = "/dev/urandom"
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try:
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# Try to open /dev/urandom now so that paramiko will be able to access
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# it even if os.chroot() is invoked later.
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try:
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f = open(device_path, "rb", 0)
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except EnvironmentError:
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raise error("Unable to open /dev/urandom")
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# Open a second file descriptor for sanity checking later.
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try:
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g = open(device_path, "rb", 0)
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except EnvironmentError:
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raise error("Unable to open /dev/urandom")
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# Check that /dev/urandom is a character special device, not a regular file.
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st = os.fstat(f.fileno()) # f
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if stat.S_ISREG(st.st_mode) or not stat.S_ISCHR(st.st_mode):
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raise error("/dev/urandom is not a character special device")
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st = os.fstat(g.fileno()) # g
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if stat.S_ISREG(st.st_mode) or not stat.S_ISCHR(st.st_mode):
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raise error("/dev/urandom is not a character special device")
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# Check that /dev/urandom always returns the number of bytes requested
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x = f.read(20)
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y = g.read(20)
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if len(x) != 20 or len(y) != 20:
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raise error("Error reading from /dev/urandom: input truncated")
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# Check that different reads return different data
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if x == y:
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raise error("/dev/urandom is broken; returning identical data: %r == %r" % (x, y))
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# Close the duplicate file object
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g.close()
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# Return the first file object
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return _RNG(f)
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except error:
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if f is not None:
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f.close()
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if g is not None:
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g.close()
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raise
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# vim:set ts=4 sw=4 sts=4 expandtab:
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