Fixing "warning: GMP or MPIR library not found; Not building Crypto.PublickKey._fastmath" error on Python 2.7 with CentOS 6.4

Question

I'm running a CentOS 6.4 server with Python 2.7 (installed via PythonBrew script)

I have gmp installed via 'yum install gmp' and python-devel installed via 'yum install python-devel' (but it's for python 2.6 series)

I'm trying to install pycrypto on my server, but it's giving me

warning: GMP or MPIR library not found; Not building Crypto.PublickKey._fastmath

Is there any way to make pip 'recognize' my gmp installation?

Thanks : D

Answer 1

I got the above error when trying to install Fabric at the system level on Centos 6.4 using pip. (Fabric uses pycrypto).

warning: GMP or MPIR library not found; Not building Crypto.PublickKey._fastmath

This is how I got it working:

yum install gmp-devel
sudo pip uninstall ecdsa pycrypto paramiko fabric 
# clear out the pip build dirs
rm -rf /tmp/pip-*
# make sure the directory containing libgmp.so.3 is on the python path
export LD_LIBRARY_PATH="/usr/lib64:$LD_LIBRARY_PATH"  
pip install fabric 

Answer 2

Here is a step-by-step I've just made up on my CentOS server (the sequence assumes you're not root):

LIBGMP INSTALL

Firstly, setup and install libgmp somewhere in your home directory, as follows:

./configure prefix=$HOME
make
make install prefix=$HOME

This will create a ~/lib, a ~/include and a ~/share directory if not existing already.

Then, add the following line to your .bashrc:

export LD_LIBRARY_PATH=$HOME/lib:/usr/local/lib:$LD_LIBRARY_PATH

Do a ". ~/.bashrc" to enforce your changes.

PYCRYPTO BUILD & INSTALL

We need to deal with the install process manually. Firstly, we may download pycrypto as follows:

• go into a directory where you store your sources:

  cd ~/src

• download pycrypto source archive:

  curl -o pycrypto.tar.gz "https://pypi.python.org/packages/source/p/pycrypto/pycrypto-2.6.tar.gz#md5=88dad0a270d1fe83a39e0467a66a22bb"

• uncompress + untar archive:

  gunzip pycrypto.tar.gz tar xvf pycrypto.tar

Then we need to cheat the configuration "a bit":

cd pycrypto-26
./configure --includedir=$HOME/include

• Edit the file cd src/config.h and amend the values for the definitions:

  #define HAVE_DECL_MPZ_POWM 0 instead of 1

  #define HAVE_DECL_MPZ_POWM_SEC 1 instead of 0

  #define HAVE_LIBGMP 1 instead of 0

• Then edit the setup.py file by searching for the keyword "_fastmath" and ensure that the Extension() declaration looks as per below:

  Extension("Crypto.PublicKey._fastmath",
            include_dirs=['/home/<yourhome>/include','src/','/usr/include/'],
            library_dirs=['/home/<yourhome>/lib'],
            libraries=['gmp'],
            sources=["src/_fastmath.c"]),
  

Finally, build pycrypto with:

python setup.py build

You should see somewhere in the trace the following line:

...
building 'Crypto.PublicKey._fastmath' extension
...

You can then do a "python setup.py install" or, if like me you prefer pip:

cd ..
pip install ./pycrypto-2.6

Then you should get no error when executing the following lines from python:

>>> from Crypto.PublicKey import _fastmath
>>> import Crypto.Random
>>> _fastmath.HAVE_DECL_MPZ_POWM_SEC
1