title: Installing Python Cryptography error
body: <p>When running the <code>pip install cryptography</code> I get the following result</p>
  
  <pre><code>pip install cryptography
  Downloading/unpacking cryptography
  Running setup.py egg_info for package cryptography
  Traceback (most recent call last):
    File "&lt;string&gt;", line 16, in &lt;module&gt;
    File "/tmp/pip-build-root/cryptography/setup.py", line 174, in &lt;module&gt;
      "test": PyTest,
    File "/usr/lib64/python2.6/distutils/core.py", line 152, in setup
      dist.run_commands()
    File "/usr/lib64/python2.6/distutils/dist.py", line 975, in run_commands
      self.run_command(cmd)
    File "/usr/lib64/python2.6/distutils/dist.py", line 995, in run_command
      cmd_obj.run()
    File "&lt;string&gt;", line 14, in replacement_run
    File "/usr/lib/python2.6/site-packages/setuptools/command/egg_info.py", line 254, in find_sources
      mm.run()
    File "/usr/lib/python2.6/site-packages/setuptools/command/egg_info.py", line 308, in run
      self.add_defaults()
    File "/usr/lib/python2.6/site-packages/setuptools/command/egg_info.py", line 332, in add_defaults
      sdist.add_defaults(self)
    File "/usr/lib/python2.6/site-packages/setuptools/command/sdist.py", line 187, in add_defaults
      build_py = self.get_finalized_command('build_py')
    File "/usr/lib64/python2.6/distutils/cmd.py", line 319, in get_finalized_command
      cmd_obj.ensure_finalized()
    File "/usr/lib64/python2.6/distutils/cmd.py", line 117, in ensure_finalized
      self.finalize_options()
    File "/usr/lib/python2.6/site-packages/setuptools/command/build_py.py", line 61, in finalize_options
      _build_py.finalize_options(self)
    File "/usr/lib64/python2.6/distutils/command/build_py.py", line 50, in finalize_options
      ('force', 'force'))
    File "/usr/lib64/python2.6/distutils/cmd.py", line 305, in set_undefined_options
      src_cmd_obj.ensure_finalized()
    File "/usr/lib64/python2.6/distutils/cmd.py", line 117, in ensure_finalized
      self.finalize_options()
    File "/tmp/pip-build-root/cryptography/setup.py", line 88, in finalize_options
      self.distribution.ext_modules = get_ext_modules()
    File "/tmp/pip-build-root/cryptography/setup.py", line 65, in get_ext_modules
      from cryptography.hazmat.primitives import constant_time, padding
    File "cryptography/hazmat/primitives/constant_time.py", line 49, in &lt;module&gt;
      _ffi = cffi.FFI()
    File "/tmp/pip-build-root/cryptography/cffi-0.8.6-py2.6-linux-x86_64.egg/cffi/api.py", line 56, in __init__
      import _cffi_backend as backend
  ImportError: /tmp/pip-build-root/cryptography/cffi-0.8.6-py2.6-linux-x86_64.egg/_cffi_backend.so: failed to map segment from shared object: Operation not permitted
  Complete output from command python setup.py egg_info:
  running egg_info
  
  writing requirements to pip-egg-info/cryptography.egg-info/requires.txt
  
  writing pip-egg-info/cryptography.egg-info/PKG-INFO
  
  writing top-level names to pip-egg-info/cryptography.egg-info/top_level.txt
  
  writing dependency_links to pip-egg-info/cryptography.egg-info/dependency_links.txt
  
  warning: manifest_maker: standard file '-c' not found
  
  Traceback (most recent call last):
  
    File "&lt;string&gt;", line 16, in &lt;module&gt;
  
    File "/tmp/pip-build-root/cryptography/setup.py", line 174, in &lt;module&gt;
  
      "test": PyTest,
  
    File "/usr/lib64/python2.6/distutils/core.py", line 152, in setup
  
      dist.run_commands()
  
    File "/usr/lib64/python2.6/distutils/dist.py", line 975, in run_commands
  
      self.run_command(cmd)
  
    File "/usr/lib64/python2.6/distutils/dist.py", line 995, in run_command
  
      cmd_obj.run()
  
    File "&lt;string&gt;", line 14, in replacement_run
  
    File "/usr/lib/python2.6/site-packages/setuptools/command/egg_info.py", line 254, in find_sources
  
      mm.run()
  
    File "/usr/lib/python2.6/site-packages/setuptools/command/egg_info.py", line 308, in run
  
      self.add_defaults()
  
    File "/usr/lib/python2.6/site-packages/setuptools/command/egg_info.py", line 332, in add_defaults
  
      sdist.add_defaults(self)
  
    File "/usr/lib/python2.6/site-packages/setuptools/command/sdist.py", line 187, in add_defaults
  
      build_py = self.get_finalized_command('build_py')
  
    File "/usr/lib64/python2.6/distutils/cmd.py", line 319, in get_finalized_command
  
      cmd_obj.ensure_finalized()
  
    File "/usr/lib64/python2.6/distutils/cmd.py", line 117, in ensure_finalized
  
      self.finalize_options()
  
    File "/usr/lib/python2.6/site-packages/setuptools/command/build_py.py", line 61, in finalize_options
  
      _build_py.finalize_options(self)
  
    File "/usr/lib64/python2.6/distutils/command/build_py.py", line 50, in finalize_options
  
      ('force', 'force'))
  
    File "/usr/lib64/python2.6/distutils/cmd.py", line 305, in set_undefined_options
  
      src_cmd_obj.ensure_finalized()
  
    File "/usr/lib64/python2.6/distutils/cmd.py", line 117, in ensure_finalized
  
      self.finalize_options()
  
    File "/tmp/pip-build-root/cryptography/setup.py", line 88, in finalize_options
  
      self.distribution.ext_modules = get_ext_modules()
  
    File "/tmp/pip-build-root/cryptography/setup.py", line 65, in get_ext_modules
  
      from cryptography.hazmat.primitives import constant_time, padding
  
    File "cryptography/hazmat/primitives/constant_time.py", line 49, in &lt;module&gt;
  
       _ffi = cffi.FFI()
  
    File "/tmp/pip-build-root/cryptography/cffi-0.8.6-py2.6-linux-x86_64.egg/cffi/api.py", line 56, in  __init__
  
      import _cffi_backend as backend
  
  ImportError: /tmp/pip-build-root/cryptography/cffi-0.8.6-py2.6-linux-x86_64.egg/_cffi_backend.so: failed to map segment from shared object: Operation not permitted
  
  ----------------------------------------
  Command python setup.py egg_info failed with error code 1 in /tmp/pip-build-root/cryptography
  Storing complete log in /root/.pip/pip.log
  </code></pre>
  
  <p>I'm guessing theirs something wrong with some dependencies I'm missing?</p>
  
  <p>When I run the <code>sudo yum install gcc libffi-devel python-devel openssl-devel</code> to install the dependencies that are required, I get the following result</p>
  
  <pre><code>sudo yum install gcc libffi-devel python-devel openssl-devel
  Loaded plugins: fastestmirror
  Loading mirror speeds from cached hostfile
   * base: mirror.econdc.com
   * epel: mirrors.coreix.net
   * extras: centos.hyve.com
   * updates: mirror.sov.uk.goscomb.net
  Setting up Install Process
  Package gcc-4.4.7-4.el6.x86_64 already installed and latest version
  Package libffi-devel-3.0.5-3.2.el6.x86_64 already installed and latest version
  Package python-devel-2.6.6-52.el6.x86_64 already installed and latest version
  Package openssl-devel-1.0.1e-16.el6_5.15.x86_64 already installed and latest version
  Nothing to do
  </code></pre>
  
  <p>Does anyone have any suggestions as to what I'm missing?</p>