Python: Switch to a more general os.urandom for randomness source

Signed-off-by: Jan Jancar <johny@neuromancer.sk>

python/olm/__main__.py

@@ -10,11 +10,13 @@ import yaml
 
 from . import *
 
+
 def read_base64_file(filename):
     """Read a base64 file, dropping any CR/LF characters"""
     with open(filename, "rb") as f:
         return f.read().translate(None, "\r\n")
 
+
 def build_arg_parser():
     parser = argparse.ArgumentParser()
     parser.add_argument("--key", help="Account encryption key", default="")
@@ -291,7 +293,6 @@ def build_arg_parser():
                                default=sys.stdout)
     group_decrypt.set_defaults(func=do_group_decrypt)
 
-
     export_inbound_group = commands.add_parser(
         "export_inbound_group",
         help="Export the keys for an inbound group session",

python/olm/_base.py

@@ -2,9 +2,6 @@ import os.path
 
 from ctypes import *
 
-def read_random(n):
-    with open("/dev/urandom", "rb") as f:
-        return f.read(n)
 
 lib = cdll.LoadLibrary(os.path.join(
     os.path.dirname(__file__), "..", "..", "build", "libolm.so.2")

python/olm/account.py

@@ -1,4 +1,5 @@
 import json
+from os import urandom
 
 from ._base import *
 
@@ -58,7 +59,7 @@ class Account(object):
 
     def create(self):
         random_length = lib.olm_create_account_random_length(self.ptr)
-        random = read_random(random_length)
+        random = urandom(random_length)
         random_buffer = create_string_buffer(random)
         lib.olm_create_account(self.ptr, random_buffer, random_length)
 
@@ -112,7 +113,7 @@ class Account(object):
         random_length = lib.olm_account_generate_one_time_keys_random_length(
             self.ptr, count
         )
-        random = read_random(random_length)
+        random = urandom(random_length)
         random_buffer = create_string_buffer(random)
         lib.olm_account_generate_one_time_keys(
             self.ptr, count, random_buffer, random_length

python/olm/outbound_group_session.py

@@ -1,4 +1,5 @@
 import json
+from os import urandom
 
 from ._base import *
 
@@ -56,7 +57,7 @@ class OutboundGroupSession(object):
         self.ptr = lib.olm_outbound_group_session(self.buf)
 
         random_length = lib.olm_init_outbound_group_session_random_length(self.ptr)
-        random = read_random(random_length)
+        random = urandom(random_length)
         random_buffer = create_string_buffer(random)
         lib.olm_init_outbound_group_session(self.ptr, random_buffer, random_length)
 

python/olm/session.py

@@ -1,3 +1,5 @@
+from os import urandom
+
 from ._base import *
 
 
@@ -103,7 +105,7 @@ class Session(object):
 
     def create_outbound(self, account, identity_key, one_time_key):
         r_length = lib.olm_create_outbound_session_random_length(self.ptr)
-        random = read_random(r_length)
+        random = urandom(r_length)
         random_buffer = create_string_buffer(random)
         identity_key_buffer = create_string_buffer(identity_key)
         one_time_key_buffer = create_string_buffer(one_time_key)
@@ -157,7 +159,7 @@ class Session(object):
 
     def encrypt(self, plaintext):
         r_length = lib.olm_encrypt_random_length(self.ptr)
-        random = read_random(r_length)
+        random = urandom(r_length)
         random_buffer = create_string_buffer(random)
 
         message_type = lib.olm_encrypt_message_type(self.ptr)