From 514c1434a016b09d93e8dfc5578b14825d14005a Mon Sep 17 00:00:00 2001
From: drebs <drebs@leap.se>
Date: Wed, 4 Feb 2015 15:04:10 -0200
Subject: [feat] refactor events to use ZMQ

Before this commit, protobuf and protobuf.socketrpc were used to serialize and
transmit messages between events clients. This change implements a simpler ZMQ
client/server events mechanism that uses ZMQ sockets for transmitting messages
from clients to server and to redistribute such messages to subscribed
clients.

Closes: #6359
---
 src/leap/common/zmq_utils.py | 105 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 src/leap/common/zmq_utils.py

(limited to 'src/leap/common/zmq_utils.py')

diff --git a/src/leap/common/zmq_utils.py b/src/leap/common/zmq_utils.py
new file mode 100644
index 0000000..19625b9
--- /dev/null
+++ b/src/leap/common/zmq_utils.py
@@ -0,0 +1,105 @@
+# -*- coding: utf-8 -*-
+# zmq.py
+# Copyright (C) 2013, 2014 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+Utilities to handle ZMQ certificates.
+"""
+import os
+import logging
+import stat
+import shutil
+
+import zmq
+
+try:
+    import zmq.auth
+except ImportError:
+    pass
+
+from leap.common.files import mkdir_p
+from leap.common.check import leap_assert
+
+logger = logging.getLogger(__name__)
+
+
+KEYS_PREFIX = "zmq_certificates"
+PUBLIC_KEYS_PREFIX = os.path.join(KEYS_PREFIX, "public_keys")
+PRIVATE_KEYS_PREFIX = os.path.join(KEYS_PREFIX, "private_keys")
+
+
+def zmq_has_curve():
+    """
+    Return whether the current ZMQ has support for auth and CurveZMQ security.
+
+    :rtype: bool
+
+     Version notes:
+       `zmq.curve_keypair()` is new in version 14.0, new in version libzmq-4.0.
+            Requires libzmq (>= 4.0) to have been linked with libsodium.
+       `zmq.auth` module is new in version 14.1
+       `zmq.has()` is new in version 14.1, new in version libzmq-4.1.
+    """
+    zmq_version = zmq.zmq_version_info()
+    pyzmq_version = zmq.pyzmq_version_info()
+
+    if pyzmq_version >= (14, 1, 0) and zmq_version >= (4, 1):
+        return zmq.has('curve')
+
+    if pyzmq_version < (14, 1, 0):
+        return False
+
+    if zmq_version < (4, 0):
+        # security is new in libzmq 4.0
+        return False
+
+    try:
+        zmq.curve_keypair()
+    except zmq.error.ZMQError:
+        # security requires libzmq to be linked against libsodium
+        return False
+
+    return True
+
+
+def assert_zmq_has_curve():
+    leap_assert(zmq_has_curve, "CurveZMQ not supported!")
+
+
+def maybe_create_and_get_certificates(basedir, name):
+    """
+    Generate the needed ZMQ certificates for backend/frontend communication if
+    needed.
+    """
+    assert_zmq_has_curve()
+    private_keys_dir = os.path.join(basedir, PRIVATE_KEYS_PREFIX)
+    private_key = os.path.join(
+        private_keys_dir, name + ".key_secret")
+    if not os.path.isfile(private_key):
+        mkdir_p(private_keys_dir)
+        zmq.auth.create_certificates(private_keys_dir, name)
+        # set permissions to: 0700 (U:rwx G:--- O:---)
+        os.chmod(private_key, stat.S_IRUSR | stat.S_IWUSR)
+        # move public key to public keys directory
+        public_keys_dir = os.path.join(basedir, PUBLIC_KEYS_PREFIX)
+        old_public_key = os.path.join(
+            private_keys_dir, name + ".key")
+        new_public_key = os.path.join(
+            public_keys_dir, name + ".key")
+        mkdir_p(public_keys_dir)
+        shutil.move(old_public_key, new_public_key)
+    return zmq.auth.load_certificate(private_key)
+
+
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