New osrandom_engine in C (#3229)
* New osrandom_engine in C
Inspired by Python/random.c and the old implementation.
Signed-off-by: Christian Heimes <christian@python.org>
* osrandom_engine
* Fix naming bug caused by search 'n replace mistake
* Make it easier to override osrandom auto-detection
* Add engine ctrl and backend API to get implementation from ENGINE
Signed-off-by: Christian Heimes <christian@python.org>
* Better test coverage, documentation, LICENSE
Signed-off-by: Christian Heimes <christian@python.org>
* Coverage is hard.
Signed-off-by: Christian Heimes <christian@python.org>
* * enable win32 check
* read() returns size_t
Signed-off-by: Christian Heimes <christian@python.org>
* Add macOS to spelling list. Remove dead code from header file.
Signed-off-by: Christian Heimes <christian@python.org>
* remove CCRandomGenerateBytes path and update getentropy to work on macOS
This change allows us to test all the engines in our CI:
* getentropy (tested by macOS sierra)
* getrandom (tested on several linux builders)
* /dev/urandom (tested on FreeBSD, OS X 10.11 and below, & older linux)
* CryptGenRandom (tested on windows builders)
I also fixed bugs preventing compilation in the getentropy code
* getentropy() returns int and is restricted to 256 bytes on macOS, too.
Signed-off-by: Christian Heimes <christian@python.org>
* add versionadded
* Re-add import of os module
* Fixes related to Alex's recent review.
Signed-off-by: Christian Heimes <christian@python.org>
* Add error reporting and fail for EAGAIN
Add error reporting strings for various error cases. This gives us much
nicer and understandable error messages.
SYS_getrandom() EAGAIN is now an error. Cryptography refuses to
initialize its osrandom engine when the Kernel's CPRNG hasn't been
seeded yet.
Signed-off-by: Christian Heimes <christian@python.org>
diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst
index 791aab3..6a5ae6f 100644
--- a/docs/hazmat/backends/openssl.rst
+++ b/docs/hazmat/backends/openssl.rst
@@ -40,6 +40,12 @@
Activates the OS random engine. This will effectively disable OpenSSL's
default CSPRNG.
+ .. method:: osrandom_engine_implementation()
+
+ .. versionadded:: 1.7
+
+ Returns the implementation of OS random engine.
+
.. method:: activate_builtin_random()
This will activate the default OpenSSL CSPRNG.
@@ -81,6 +87,21 @@
Linux uses its own PRNG design. ``/dev/urandom`` is a non-blocking source
seeded from the same pool as ``/dev/random``.
++------------------------------------------+------------------------------+
+| Windows | ``CryptGenRandom()`` |
++------------------------------------------+------------------------------+
+| Linux >= 3.4.17 with working | ``getrandom(GRND_NONBLOCK)`` |
+| ``SYS_getrandom`` syscall | |
++------------------------------------------+------------------------------+
+| OpenBSD >= 5.6 | ``getentropy()`` |
++------------------------------------------+------------------------------+
+| BSD family (including macOS 10.12+) with | ``getentropy()`` |
+| ``SYS_getentropy`` in ``sys/syscall.h`` | |
++------------------------------------------+------------------------------+
+| fallback | ``/dev/urandom`` with |
+| | cached file descriptor |
++------------------------------------------+------------------------------+
+
.. _`OpenSSL`: https://www.openssl.org/
.. _`initializing the RNG`: https://en.wikipedia.org/wiki/OpenSSL#Predictable_private_keys_.28Debian-specific.29