From 23b08135998e932d5d600941bd42389db0628a11 Mon Sep 17 00:00:00 2001 From: Amber Brown Date: Tue, 22 Jan 2019 21:58:50 +1100 Subject: [PATCH] Require ECDH key exchange & remove dh_params (#4429) * remove dh_params and set better cipher string --- README.rst | 2 +- changelog.d/4229.feature | 1 + debian/homeserver.yaml | 3 --- demo/demo.tls.dh | 9 ------- docker/conf/homeserver.yaml | 1 - synapse/config/tls.py | 40 ------------------------------- synapse/crypto/context_factory.py | 6 +++-- tests/config/test_generate.py | 1 - 8 files changed, 6 insertions(+), 57 deletions(-) create mode 100644 changelog.d/4229.feature delete mode 100644 demo/demo.tls.dh diff --git a/README.rst b/README.rst index 8bff55e78e..05a3bb3751 100644 --- a/README.rst +++ b/README.rst @@ -220,7 +220,7 @@ is configured to use TLS with a self-signed certificate. If you would like to do initial test with a client without having to setup a reverse proxy, you can temporarly use another certificate. (Note that a self-signed certificate is fine for `Federation`_). You can do so by changing -``tls_certificate_path``, ``tls_private_key_path`` and ``tls_dh_params_path`` +``tls_certificate_path`` and ``tls_private_key_path`` in ``homeserver.yaml``; alternatively, you can use a reverse-proxy, but be sure to read `Using a reverse proxy with Synapse`_ when doing so. diff --git a/changelog.d/4229.feature b/changelog.d/4229.feature new file mode 100644 index 0000000000..0d1996c7e8 --- /dev/null +++ b/changelog.d/4229.feature @@ -0,0 +1 @@ +Synapse's cipher string has been updated to require ECDH key exchange. Configuring and generating dh_params is no longer required, and they will be ignored. diff --git a/debian/homeserver.yaml b/debian/homeserver.yaml index 188a2d5483..0bb2d22a95 100644 --- a/debian/homeserver.yaml +++ b/debian/homeserver.yaml @@ -9,9 +9,6 @@ tls_certificate_path: "/etc/matrix-synapse/homeserver.tls.crt" # PEM encoded private key for TLS tls_private_key_path: "/etc/matrix-synapse/homeserver.tls.key" -# PEM dh parameters for ephemeral keys -tls_dh_params_path: "/etc/matrix-synapse/homeserver.tls.dh" - # Don't bind to the https port no_tls: False diff --git a/demo/demo.tls.dh b/demo/demo.tls.dh deleted file mode 100644 index cbc58272a0..0000000000 --- a/demo/demo.tls.dh +++ /dev/null @@ -1,9 +0,0 @@ -2048-bit DH parameters taken from rfc3526 ------BEGIN DH PARAMETERS----- -MIIBCAKCAQEA///////////JD9qiIWjCNMTGYouA3BzRKQJOCIpnzHQCC76mOxOb -IlFKCHmONATd75UZs806QxswKwpt8l8UN0/hNW1tUcJF5IW1dmJefsb0TELppjft -awv/XLb0Brft7jhr+1qJn6WunyQRfEsf5kkoZlHs5Fs9wgB8uKFjvwWY2kg2HFXT -mmkWP6j9JM9fg2VdI9yjrZYcYvNWIIVSu57VKQdwlpZtZww1Tkq8mATxdGwIyhgh -fDKQXkYuNs474553LBgOhgObJ4Oi7Aeij7XFXfBvTFLJ3ivL9pVYFxg5lUl86pVq -5RXSJhiY+gUQFXKOWoqsqmj//////////wIBAg== ------END DH PARAMETERS----- diff --git a/docker/conf/homeserver.yaml b/docker/conf/homeserver.yaml index c2b8576a32..529118d184 100644 --- a/docker/conf/homeserver.yaml +++ b/docker/conf/homeserver.yaml @@ -4,7 +4,6 @@ tls_certificate_path: "/data/{{ SYNAPSE_SERVER_NAME }}.tls.crt" tls_private_key_path: "/data/{{ SYNAPSE_SERVER_NAME }}.tls.key" -tls_dh_params_path: "/data/{{ SYNAPSE_SERVER_NAME }}.tls.dh" no_tls: {{ "True" if SYNAPSE_NO_TLS else "False" }} tls_fingerprints: [] diff --git a/synapse/config/tls.py b/synapse/config/tls.py index fef1ea99cb..bb8952c672 100644 --- a/synapse/config/tls.py +++ b/synapse/config/tls.py @@ -14,7 +14,6 @@ # limitations under the License. import os -import subprocess from hashlib import sha256 from unpaddedbase64 import encode_base64 @@ -23,8 +22,6 @@ from OpenSSL import crypto from ._base import Config -GENERATE_DH_PARAMS = False - class TlsConfig(Config): def read_config(self, config): @@ -42,10 +39,6 @@ class TlsConfig(Config): config.get("tls_private_key_path") ) - self.tls_dh_params_path = self.check_file( - config.get("tls_dh_params_path"), "tls_dh_params" - ) - self.tls_fingerprints = config["tls_fingerprints"] # Check that our own certificate is included in the list of fingerprints @@ -72,7 +65,6 @@ class TlsConfig(Config): tls_certificate_path = base_key_name + ".tls.crt" tls_private_key_path = base_key_name + ".tls.key" - tls_dh_params_path = base_key_name + ".tls.dh" return """\ # PEM encoded X509 certificate for TLS. @@ -85,9 +77,6 @@ class TlsConfig(Config): # PEM encoded private key for TLS tls_private_key_path: "%(tls_private_key_path)s" - # PEM dh parameters for ephemeral keys - tls_dh_params_path: "%(tls_dh_params_path)s" - # Don't bind to the https port no_tls: False @@ -131,7 +120,6 @@ class TlsConfig(Config): def generate_files(self, config): tls_certificate_path = config["tls_certificate_path"] tls_private_key_path = config["tls_private_key_path"] - tls_dh_params_path = config["tls_dh_params_path"] if not self.path_exists(tls_private_key_path): with open(tls_private_key_path, "wb") as private_key_file: @@ -165,31 +153,3 @@ class TlsConfig(Config): cert_pem = crypto.dump_certificate(crypto.FILETYPE_PEM, cert) certificate_file.write(cert_pem) - - if not self.path_exists(tls_dh_params_path): - if GENERATE_DH_PARAMS: - subprocess.check_call([ - "openssl", "dhparam", - "-outform", "PEM", - "-out", tls_dh_params_path, - "2048" - ]) - else: - with open(tls_dh_params_path, "w") as dh_params_file: - dh_params_file.write( - "2048-bit DH parameters taken from rfc3526\n" - "-----BEGIN DH PARAMETERS-----\n" - "MIIBCAKCAQEA///////////JD9qiIWjC" - "NMTGYouA3BzRKQJOCIpnzHQCC76mOxOb\n" - "IlFKCHmONATd75UZs806QxswKwpt8l8U" - "N0/hNW1tUcJF5IW1dmJefsb0TELppjft\n" - "awv/XLb0Brft7jhr+1qJn6WunyQRfEsf" - "5kkoZlHs5Fs9wgB8uKFjvwWY2kg2HFXT\n" - "mmkWP6j9JM9fg2VdI9yjrZYcYvNWIIVS" - "u57VKQdwlpZtZww1Tkq8mATxdGwIyhgh\n" - "fDKQXkYuNs474553LBgOhgObJ4Oi7Aei" - "j7XFXfBvTFLJ3ivL9pVYFxg5lUl86pVq\n" - "5RXSJhiY+gUQFXKOWoqsqmj/////////" - "/wIBAg==\n" - "-----END DH PARAMETERS-----\n" - ) diff --git a/synapse/crypto/context_factory.py b/synapse/crypto/context_factory.py index 02b76dfcfb..6ba3eca7b2 100644 --- a/synapse/crypto/context_factory.py +++ b/synapse/crypto/context_factory.py @@ -46,8 +46,10 @@ class ServerContextFactory(ContextFactory): if not config.no_tls: context.use_privatekey(config.tls_private_key) - context.load_tmp_dh(config.tls_dh_params_path) - context.set_cipher_list("!ADH:HIGH+kEDH:!AECDH:HIGH+kEECDH") + # https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/ + context.set_cipher_list( + "ECDH+AESGCM:ECDH+CHACHA20:ECDH+AES256:ECDH+AES128:!aNULL:!SHA1" + ) def getContext(self): return self._context diff --git a/tests/config/test_generate.py b/tests/config/test_generate.py index 0c23068bcf..b5ad99348d 100644 --- a/tests/config/test_generate.py +++ b/tests/config/test_generate.py @@ -51,7 +51,6 @@ class ConfigGenerationTestCase(unittest.TestCase): "lemurs.win.log.config", "lemurs.win.signing.key", "lemurs.win.tls.crt", - "lemurs.win.tls.dh", "lemurs.win.tls.key", ] ),