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-rw-r--r--synapse/config/tls.py252
1 files changed, 164 insertions, 88 deletions
diff --git a/synapse/config/tls.py b/synapse/config/tls.py
index a75e233aa0..5fb3486db1 100644
--- a/synapse/config/tls.py
+++ b/synapse/config/tls.py
@@ -15,6 +15,7 @@
 
 import logging
 import os
+import warnings
 from datetime import datetime
 from hashlib import sha256
 
@@ -22,28 +23,47 @@ from unpaddedbase64 import encode_base64
 
 from OpenSSL import crypto
 
-from synapse.config._base import Config
+from synapse.config._base import Config, ConfigError
 
-logger = logging.getLogger()
+logger = logging.getLogger(__name__)
 
 
 class TlsConfig(Config):
     def read_config(self, config):
 
-        acme_config = config.get("acme", {})
+        acme_config = config.get("acme", None)
+        if acme_config is None:
+            acme_config = {}
+
         self.acme_enabled = acme_config.get("enabled", False)
         self.acme_url = acme_config.get(
-            "url", "https://acme-v01.api.letsencrypt.org/directory"
+            "url", u"https://acme-v01.api.letsencrypt.org/directory"
         )
-        self.acme_port = acme_config.get("port", 8449)
-        self.acme_bind_addresses = acme_config.get("bind_addresses", ["127.0.0.1"])
+        self.acme_port = acme_config.get("port", 80)
+        self.acme_bind_addresses = acme_config.get("bind_addresses", ['::', '0.0.0.0'])
         self.acme_reprovision_threshold = acme_config.get("reprovision_threshold", 30)
 
-        self.tls_certificate_file = os.path.abspath(config.get("tls_certificate_path"))
-        self.tls_private_key_file = os.path.abspath(config.get("tls_private_key_path"))
-        self._original_tls_fingerprints = config["tls_fingerprints"]
+        self.tls_certificate_file = self.abspath(config.get("tls_certificate_path"))
+        self.tls_private_key_file = self.abspath(config.get("tls_private_key_path"))
+
+        if self.has_tls_listener():
+            if not self.tls_certificate_file:
+                raise ConfigError(
+                    "tls_certificate_path must be specified if TLS-enabled listeners are "
+                    "configured."
+                )
+            if not self.tls_private_key_file:
+                raise ConfigError(
+                    "tls_certificate_path must be specified if TLS-enabled listeners are "
+                    "configured."
+                )
+
+        self._original_tls_fingerprints = config.get("tls_fingerprints", [])
+
+        if self._original_tls_fingerprints is None:
+            self._original_tls_fingerprints = []
+
         self.tls_fingerprints = list(self._original_tls_fingerprints)
-        self.no_tls = config.get("no_tls", False)
 
         # This config option applies to non-federation HTTP clients
         # (e.g. for talking to recaptcha, identity servers, and such)
@@ -56,10 +76,14 @@ class TlsConfig(Config):
         self.tls_certificate = None
         self.tls_private_key = None
 
-    def is_disk_cert_valid(self):
+    def is_disk_cert_valid(self, allow_self_signed=True):
         """
         Is the certificate we have on disk valid, and if so, for how long?
 
+        Args:
+            allow_self_signed (bool): Should we allow the certificate we
+                read to be self signed?
+
         Returns:
             int: Days remaining of certificate validity.
             None: No certificate exists.
@@ -80,6 +104,12 @@ class TlsConfig(Config):
             logger.exception("Failed to parse existing certificate off disk!")
             raise
 
+        if not allow_self_signed:
+            if tls_certificate.get_subject() == tls_certificate.get_issuer():
+                raise ValueError(
+                    "TLS Certificate is self signed, and this is not permitted"
+                )
+
         # YYYYMMDDhhmmssZ -- in UTC
         expires_on = datetime.strptime(
             tls_certificate.get_notAfter().decode('ascii'), "%Y%m%d%H%M%SZ"
@@ -88,26 +118,40 @@ class TlsConfig(Config):
         days_remaining = (expires_on - now).days
         return days_remaining
 
-    def read_certificate_from_disk(self):
-        """
-        Read the certificates from disk.
+    def read_certificate_from_disk(self, require_cert_and_key):
         """
-        self.tls_certificate = self.read_tls_certificate(self.tls_certificate_file)
+        Read the certificates and private key from disk.
 
-        if not self.no_tls:
-            self.tls_private_key = self.read_tls_private_key(self.tls_private_key_file)
+        Args:
+            require_cert_and_key (bool): set to True to throw an error if the certificate
+                and key file are not given
+        """
+        if require_cert_and_key:
+            self.tls_private_key = self.read_tls_private_key()
+            self.tls_certificate = self.read_tls_certificate()
+        elif self.tls_certificate_file:
+            # we only need the certificate for the tls_fingerprints. Reload it if we
+            # can, but it's not a fatal error if we can't.
+            try:
+                self.tls_certificate = self.read_tls_certificate()
+            except Exception as e:
+                logger.info(
+                    "Unable to read TLS certificate (%s). Ignoring as no "
+                    "tls listeners enabled.", e,
+                )
 
         self.tls_fingerprints = list(self._original_tls_fingerprints)
 
-        # Check that our own certificate is included in the list of fingerprints
-        # and include it if it is not.
-        x509_certificate_bytes = crypto.dump_certificate(
-            crypto.FILETYPE_ASN1, self.tls_certificate
-        )
-        sha256_fingerprint = encode_base64(sha256(x509_certificate_bytes).digest())
-        sha256_fingerprints = set(f["sha256"] for f in self.tls_fingerprints)
-        if sha256_fingerprint not in sha256_fingerprints:
-            self.tls_fingerprints.append({u"sha256": sha256_fingerprint})
+        if self.tls_certificate:
+            # Check that our own certificate is included in the list of fingerprints
+            # and include it if it is not.
+            x509_certificate_bytes = crypto.dump_certificate(
+                crypto.FILETYPE_ASN1, self.tls_certificate
+            )
+            sha256_fingerprint = encode_base64(sha256(x509_certificate_bytes).digest())
+            sha256_fingerprints = set(f["sha256"] for f in self.tls_fingerprints)
+            if sha256_fingerprint not in sha256_fingerprints:
+                self.tls_fingerprints.append({u"sha256": sha256_fingerprint})
 
     def default_config(self, config_dir_path, server_name, **kwargs):
         base_key_name = os.path.join(config_dir_path, server_name)
@@ -115,20 +159,75 @@ class TlsConfig(Config):
         tls_certificate_path = base_key_name + ".tls.crt"
         tls_private_key_path = base_key_name + ".tls.key"
 
+        # this is to avoid the max line length. Sorrynotsorry
+        proxypassline = (
+            'ProxyPass /.well-known/acme-challenge '
+            'http://localhost:8009/.well-known/acme-challenge'
+        )
+
         return (
             """\
-        # PEM encoded X509 certificate for TLS.
-        # You can replace the self-signed certificate that synapse
-        # autogenerates on launch with your own SSL certificate + key pair
-        # if you like.  Any required intermediary certificates can be
-        # appended after the primary certificate in hierarchical order.
-        tls_certificate_path: "%(tls_certificate_path)s"
+        ## TLS ##
 
-        # PEM encoded private key for TLS
-        tls_private_key_path: "%(tls_private_key_path)s"
+        # PEM-encoded X509 certificate for TLS.
+        # This certificate, as of Synapse 1.0, will need to be a valid and verifiable
+        # certificate, signed by a recognised Certificate Authority.
+        #
+        # See 'ACME support' below to enable auto-provisioning this certificate via
+        # Let's Encrypt.
+        #
+        # tls_certificate_path: "%(tls_certificate_path)s"
 
-        # Don't bind to the https port
-        no_tls: False
+        # PEM-encoded private key for TLS
+        # tls_private_key_path: "%(tls_private_key_path)s"
+
+        # ACME support: This will configure Synapse to request a valid TLS certificate
+        # for your configured `server_name` via Let's Encrypt.
+        #
+        # Note that provisioning a certificate in this way requires port 80 to be
+        # routed to Synapse so that it can complete the http-01 ACME challenge.
+        # By default, if you enable ACME support, Synapse will attempt to listen on
+        # port 80 for incoming http-01 challenges - however, this will likely fail
+        # with 'Permission denied' or a similar error.
+        #
+        # There are a couple of potential solutions to this:
+        #
+        #  * If you already have an Apache, Nginx, or similar listening on port 80,
+        #    you can configure Synapse to use an alternate port, and have your web
+        #    server forward the requests. For example, assuming you set 'port: 8009'
+        #    below, on Apache, you would write:
+        #
+        #    %(proxypassline)s
+        #
+        #  * Alternatively, you can use something like `authbind` to give Synapse
+        #    permission to listen on port 80.
+        #
+        acme:
+            # ACME support is disabled by default. Uncomment the following line
+            # (and tls_certificate_path and tls_private_key_path above) to enable it.
+            #
+            # enabled: true
+
+            # Endpoint to use to request certificates. If you only want to test,
+            # use Let's Encrypt's staging url:
+            #     https://acme-staging.api.letsencrypt.org/directory
+            #
+            # url: https://acme-v01.api.letsencrypt.org/directory
+
+            # Port number to listen on for the HTTP-01 challenge. Change this if
+            # you are forwarding connections through Apache/Nginx/etc.
+            #
+            # port: 80
+
+            # Local addresses to listen on for incoming connections.
+            # Again, you may want to change this if you are forwarding connections
+            # through Apache/Nginx/etc.
+            #
+            # bind_addresses: ['::', '0.0.0.0']
+
+            # How many days remaining on a certificate before it is renewed.
+            #
+            # reprovision_threshold: 30
 
         # List of allowed TLS fingerprints for this server to publish along
         # with the signing keys for this server. Other matrix servers that
@@ -158,65 +257,42 @@ class TlsConfig(Config):
         tls_fingerprints: []
         # tls_fingerprints: [{"sha256": "<base64_encoded_sha256_fingerprint>"}]
 
-        ## Support for ACME certificate auto-provisioning.
-        # acme:
-        #    enabled: false
-        ##   ACME path.
-        ##   If you only want to test, use the staging url:
-        ##   https://acme-staging.api.letsencrypt.org/directory
-        #    url: 'https://acme-v01.api.letsencrypt.org/directory'
-        ##   Port number (to listen for the HTTP-01 challenge).
-        ##   Using port 80 requires utilising something like authbind, or proxying to it.
-        #    port: 8449
-        ##   Hosts to bind to.
-        #    bind_addresses: ['127.0.0.1']
-        ##   How many days remaining on a certificate before it is renewed.
-        #    reprovision_threshold: 30
         """
             % locals()
         )
 
-    def read_tls_certificate(self, cert_path):
-        cert_pem = self.read_file(cert_path, "tls_certificate")
-        return crypto.load_certificate(crypto.FILETYPE_PEM, cert_pem)
-
-    def read_tls_private_key(self, private_key_path):
-        private_key_pem = self.read_file(private_key_path, "tls_private_key")
-        return crypto.load_privatekey(crypto.FILETYPE_PEM, private_key_pem)
+    def read_tls_certificate(self):
+        """Reads the TLS certificate from the configured file, and returns it
 
-    def generate_files(self, config):
-        tls_certificate_path = config["tls_certificate_path"]
-        tls_private_key_path = config["tls_private_key_path"]
+        Also checks if it is self-signed, and warns if so
 
-        if not self.path_exists(tls_private_key_path):
-            with open(tls_private_key_path, "wb") as private_key_file:
-                tls_private_key = crypto.PKey()
-                tls_private_key.generate_key(crypto.TYPE_RSA, 2048)
-                private_key_pem = crypto.dump_privatekey(
-                    crypto.FILETYPE_PEM, tls_private_key
-                )
-                private_key_file.write(private_key_pem)
-        else:
-            with open(tls_private_key_path) as private_key_file:
-                private_key_pem = private_key_file.read()
-                tls_private_key = crypto.load_privatekey(
-                    crypto.FILETYPE_PEM, private_key_pem
+        Returns:
+            OpenSSL.crypto.X509: the certificate
+        """
+        cert_path = self.tls_certificate_file
+        logger.info("Loading TLS certificate from %s", cert_path)
+        cert_pem = self.read_file(cert_path, "tls_certificate_path")
+        cert = crypto.load_certificate(crypto.FILETYPE_PEM, cert_pem)
+
+        # Check if it is self-signed, and issue a warning if so.
+        if cert.get_issuer() == cert.get_subject():
+            warnings.warn(
+                (
+                    "Self-signed TLS certificates will not be accepted by Synapse 1.0. "
+                    "Please either provide a valid certificate, or use Synapse's ACME "
+                    "support to provision one."
                 )
+            )
 
-        if not self.path_exists(tls_certificate_path):
-            with open(tls_certificate_path, "wb") as certificate_file:
-                cert = crypto.X509()
-                subject = cert.get_subject()
-                subject.CN = config["server_name"]
-
-                cert.set_serial_number(1000)
-                cert.gmtime_adj_notBefore(0)
-                cert.gmtime_adj_notAfter(10 * 365 * 24 * 60 * 60)
-                cert.set_issuer(cert.get_subject())
-                cert.set_pubkey(tls_private_key)
+        return cert
 
-                cert.sign(tls_private_key, 'sha256')
+    def read_tls_private_key(self):
+        """Reads the TLS private key from the configured file, and returns it
 
-                cert_pem = crypto.dump_certificate(crypto.FILETYPE_PEM, cert)
-
-                certificate_file.write(cert_pem)
+        Returns:
+            OpenSSL.crypto.PKey: the private key
+        """
+        private_key_path = self.tls_private_key_file
+        logger.info("Loading TLS key from %s", private_key_path)
+        private_key_pem = self.read_file(private_key_path, "tls_private_key_path")
+        return crypto.load_privatekey(crypto.FILETYPE_PEM, private_key_pem)