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| -rw-r--r-- | docs/hazmat/backends/openssl.rst | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst index 5e51c75e..99b327d9 100644 --- a/docs/hazmat/backends/openssl.rst +++ b/docs/hazmat/backends/openssl.rst @@ -21,5 +21,32 @@ These are `CFFI`_ bindings to the `OpenSSL`_ C library. and access constants. +Using your own OpenSSL on Linux +------------------------------- + +Python links to OpenSSL for its own purposes and this can sometimes cause +problems when you wish to use a different version of OpenSSL with cryptography. +If you want to use cryptography with your own build of OpenSSL you will need to +make sure that the build is configured correctly so that your version of +OpenSSL doesn't conflict with Python's. + +The options you need to add allow the linker to identify every symbol correctly +even when multiple versions of the library are linked into the same program. If +you are using your distribution's source packages these will probably be +patched in for you already, otherwise you'll need to use options something like +this when configuring OpenSSL:: + + ./config -Wl,--version-script=openssl.ld -Wl,-Bsymbolic-functions -fPIC shared + +You'll also need to generate your own ``openssl.ld`` file. For example:: + + OPENSSL_1.0.1F_CUSTOM { + global: + *; + }; + +You should replace the version string on the first line as appropriate for your +build. + .. _`CFFI`: https://cffi.readthedocs.org/ .. _`OpenSSL`: https://www.openssl.org/ |