Merge branch 'master' into urandom-engine

* master:
  Split OpenSSL binding
  Fixed test for earlier exceptino
  Rearrange
  Move GCM tag size/value validation farther forward -- this makes it easier by not requiring future backends to implement the same checks
  expose num_locks and {get,set}_{id,locking}_callback
  Make the PyPy tox job consistent with the main one.
  THis should be a seperate PR
  Typo fix
  This page has been subsumed by the index
  Bump the copyright year
  Document compiling OpenSSL to avoid conflicts

Conflicts:
	cryptography/hazmat/backends/openssl/backend.py

3 files changed, 73 insertions, 10 deletions

diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst
index 5e51c75e..404573a3 100644
--- a/docs/hazmat/backends/openssl.rst
+++ b/docs/hazmat/backends/openssl.rst
@@ -3,23 +3,37 @@
 OpenSSL Backend
 ===============
 
-These are `CFFI`_ bindings to the `OpenSSL`_ C library.
+The `OpenSSL`_ C library.
 
 .. data:: cryptography.hazmat.backends.openssl.backend
 
-    This is the exposed API for the OpenSSL bindings. It has two public
-    attributes:
+    This is the exposed API for the OpenSSL backend. It has no public attributes.    
 
-    .. attribute:: ffi
+Using your own OpenSSL on Linux
+-------------------------------
 
-        This is a :class:`cffi.FFI` instance. It can be used to allocate and
-        otherwise manipulate OpenSSL structures.
+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.
 
-    .. attribute:: lib
+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::
 
-        This is a ``cffi`` library. It can be used to call OpenSSL functions,
-        and access constants.
+    ./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/
diff --git a/docs/hazmat/bindings/index.rst b/docs/hazmat/bindings/index.rst
new file mode 100644
index 00000000..809eddfc
--- /dev/null
+++ b/docs/hazmat/bindings/index.rst
@@ -0,0 +1,22 @@
+.. hazmat::
+
+Bindings
+========
+
+.. currentmodule:: cryptography.hazmat.bindings
+
+``cryptography`` aims to provide low-level CFFI based bindings to multiple
+native C libraries. These provide no automatic initialisation of the library
+and may not provide complete wrappers for its API.
+
+Using these functions directly is likely to require you to be careful in
+managing memory allocation, locking and other resources.
+
+
+Individual Bindings
+-------------------
+
+.. toctree::
+    :maxdepth: 1
+
+    openssl
diff --git a/docs/hazmat/bindings/openssl.rst b/docs/hazmat/bindings/openssl.rst
new file mode 100644
index 00000000..373fe472
--- /dev/null
+++ b/docs/hazmat/bindings/openssl.rst
@@ -0,0 +1,27 @@
+.. hazmat::
+
+OpenSSL Binding
+===============
+
+.. currentmodule:: cryptography.hazmat.bindings.openssl.binding
+
+These are `CFFI`_ bindings to the `OpenSSL`_ C library.
+
+.. class:: cryptography.hazmat.bindings.openssl.binding.Binding()
+
+    This is the exposed API for the OpenSSL bindings. It has two public
+    attributes:
+
+    .. attribute:: ffi
+
+        This is a :class:`cffi.FFI` instance. It can be used to allocate and
+        otherwise manipulate OpenSSL structures.
+
+    .. attribute:: lib
+
+        This is a ``cffi`` library. It can be used to call OpenSSL functions,
+        and access constants.
+
+
+.. _`CFFI`: https://cffi.readthedocs.org/
+.. _`OpenSSL`: https://www.openssl.org/