Disable TLS session tickets in Apache (#7771)

Fixes #7350.

This PR changes the parsed modules from a `set` to a `dict`, with the filepath argument as the value. Accordingly, after calling `enable_mod` to enable `ssl_module`, modules now need to be re-parsed, so call `reset_modules`.

* Add mechanism for selecting apache config file, based on work done in #7191.

* Check OpenSSL version

* Remove os imports

* debian override still needs os

* Reformat remaining apache tests with modules dict syntax

* Clean up more apache tests

* Switch from property to method for openssl and add tests for coverage.

* Sometimes the dict location will be None in which case we should in fact return None

* warn thoroughly and consistently in openssl_version function

* update tests for new warnings

* read file as bytes, and factor out the open for testing

* normalize ssl_module_location path to account for being relative to server root

* Use byte literals in a python 2 and 3 compatible way

* string does need to be a literal

* patch builtins open

* add debug, remove space

* Add test to check if OpenSSL detection is working on different systems

* fix relative test location for cwd

* put </IfModule> on its own line in test case

* Revert test file to status in master.

* Call augeas load before reparsing modules to pick up the changes

* fix grep, tail, and mod_ssl location on centos

* strip the trailing whitespace from fedora

* just use LooseVersion in test

* call apache2ctl on debian systems

* Use sudo for apache2ctl command

* add check to make sure we're getting a version

* Add boolean so we don't warn on debian/ubuntu before trying to enable mod_ssl

* Reduce warnings while testing by setting mock _openssl_version.

* Make sure we're not throwing away any unwritten changes to the config

* test last warning case for coverage

* text changes for clarity

certbot-apache/certbot_apache/_internal/apache_util.py

@@ -5,6 +5,8 @@ import logging
 import re
 import subprocess
 
+import pkg_resources
+
 from certbot import errors
 from certbot import util
 
@@ -241,3 +243,14 @@ def _get_runtime_cfg(command):
             "loaded because Apache is misconfigured.")
 
     return stdout
+
+def find_ssl_apache_conf(prefix):
+    """
+    Find a TLS Apache config file in the dedicated storage.
+    :param str prefix: prefix of the TLS Apache config file to find
+    :return: the path the TLS Apache config file
+    :rtype: str
+    """
+    return pkg_resources.resource_filename(
+        "certbot_apache",
+        os.path.join("_internal", "tls_configs", "{0}-options-ssl-apache.conf".format(prefix)))

certbot-apache/certbot_apache/_internal/configurator.py

@@ -1,6 +1,7 @@
 """Apache Configurator."""
 # pylint: disable=too-many-lines
 from collections import defaultdict
+from distutils.version import LooseVersion
 import copy
 import fnmatch
 import logging
@@ -8,7 +9,6 @@ import re
 import socket
 import time
 
-import pkg_resources
 import six
 import zope.component
 import zope.interface
@@ -110,14 +110,29 @@ class ApacheConfigurator(common.Installer):
         handle_modules=False,
         handle_sites=False,
         challenge_location="/etc/apache2",
-        MOD_SSL_CONF_SRC=pkg_resources.resource_filename(
-            "certbot_apache", os.path.join("_internal", "options-ssl-apache.conf"))
     )
 
     def option(self, key):
         """Get a value from options"""
         return self.options.get(key)
 
+    def pick_apache_config(self, warn_on_no_mod_ssl=True):
+        """
+        Pick the appropriate TLS Apache configuration file for current version of Apache and OS.
+
+        :param bool warn_on_no_mod_ssl: True if we should warn if mod_ssl is not found.
+
+        :return: the path to the TLS Apache configuration file to use
+        :rtype: str
+        """
+        # Disabling TLS session tickets is supported by Apache 2.4.11+ and OpenSSL 1.0.2l+.
+        # So for old versions of Apache we pick a configuration without this option.
+        openssl_version = self.openssl_version(warn_on_no_mod_ssl)
+        if self.version < (2, 4, 11) or not openssl_version or\
+            LooseVersion(openssl_version) < LooseVersion('1.0.2l'):
+            return apache_util.find_ssl_apache_conf("old")
+        return apache_util.find_ssl_apache_conf("current")
+
     def _prepare_options(self):
         """
         Set the values possibly changed by command line parameters to
@@ -184,6 +199,7 @@ class ApacheConfigurator(common.Installer):
         """
         version = kwargs.pop("version", None)
         use_parsernode = kwargs.pop("use_parsernode", False)
+        openssl_version = kwargs.pop("openssl_version", None)
         super(ApacheConfigurator, self).__init__(*args, **kwargs)
 
         # Add name_server association dict
@@ -209,6 +225,7 @@ class ApacheConfigurator(common.Installer):
         self.parser = None
         self.parser_root = None
         self.version = version
+        self._openssl_version = openssl_version
         self.vhosts = None
         self.options = copy.deepcopy(self.OS_DEFAULTS)
         self._enhance_func = {"redirect": self._enable_redirect,
@@ -225,6 +242,52 @@ class ApacheConfigurator(common.Installer):
         """Full absolute path to digest of updated SSL configuration file."""
         return os.path.join(self.config.config_dir, constants.UPDATED_MOD_SSL_CONF_DIGEST)
 
+    def _open_module_file(self, ssl_module_location):
+        """Extract the open lines of openssl_version for testing purposes"""
+        try:
+            with open(ssl_module_location, mode="rb") as f:
+                contents = f.read()
+        except IOError as error:
+            logger.debug(str(error), exc_info=True)
+            return None
+        return contents
+
+    def openssl_version(self, warn_on_no_mod_ssl=True):
+        """Lazily retrieve openssl version
+
+        :param bool warn_on_no_mod_ssl: `True` if we should warn if mod_ssl is not found. Set to
+            `False` when we know we'll try to enable mod_ssl later. This is currently debian/ubuntu,
+            when called from `prepare`.
+
+        :return: the OpenSSL version as a string, or None.
+        :rtype: str or None
+        """
+        if self._openssl_version:
+            return self._openssl_version
+        # Step 1. Check for LoadModule directive
+        try:
+            ssl_module_location = self.parser.modules['ssl_module']
+        except KeyError:
+            if warn_on_no_mod_ssl:
+                logger.warning("Could not find ssl_module; not disabling session tickets.")
+            return None
+        if not ssl_module_location:
+            logger.warning("Could not find ssl_module; not disabling session tickets.")
+            return None
+        ssl_module_location = self.parser.standard_path_from_server_root(ssl_module_location)
+        # Step 2. Grep in the .so for openssl version
+        contents = self._open_module_file(ssl_module_location)
+        if not contents:
+            logger.warning("Unable to read ssl_module file; not disabling session tickets.")
+            return None
+        # looks like: OpenSSL 1.0.2s  28 May 2019
+        matches = re.findall(br"OpenSSL ([0-9]\.[^ ]+) ", contents)
+        if not matches:
+            logger.warning("Could not find OpenSSL version; not disabling session tickets.")
+            return None
+        self._openssl_version = matches[0].decode('UTF-8')
+        return self._openssl_version
+
     def prepare(self):
         """Prepare the authenticator/installer.
 
@@ -271,8 +334,12 @@ class ApacheConfigurator(common.Installer):
         # Get all of the available vhosts
         self.vhosts = self.get_virtual_hosts()
 
+        # We may try to enable mod_ssl later. If so, we shouldn't warn if we can't find it now.
+        # This is currently only true for debian/ubuntu.
+        warn_on_no_mod_ssl = not self.option("handle_modules")
         self.install_ssl_options_conf(self.mod_ssl_conf,
-                                      self.updated_mod_ssl_conf_digest)
+                                      self.updated_mod_ssl_conf_digest,
+                                      warn_on_no_mod_ssl)
 
         # Prevent two Apache plugins from modifying a config at once
         try:
@@ -1241,6 +1308,14 @@ class ApacheConfigurator(common.Installer):
                 self.enable_mod("socache_shmcb", temp=temp)
             if "ssl_module" not in self.parser.modules:
                 self.enable_mod("ssl", temp=temp)
+                # Make sure we're not throwing away any unwritten changes to the config
+                self.parser.ensure_augeas_state()
+                self.parser.aug.load()
+                self.parser.reset_modules() # Reset to load the new ssl_module path
+                # Call again because now we can gate on openssl version
+                self.install_ssl_options_conf(self.mod_ssl_conf,
+                                              self.updated_mod_ssl_conf_digest,
+                                              warn_on_no_mod_ssl=True)
 
     def make_vhost_ssl(self, nonssl_vhost):
         """Makes an ssl_vhost version of a nonssl_vhost.
@@ -2454,14 +2529,19 @@ class ApacheConfigurator(common.Installer):
             self.restart()
             self.parser.reset_modules()
 
-    def install_ssl_options_conf(self, options_ssl, options_ssl_digest):
-        """Copy Certbot's SSL options file into the system's config dir if required."""
+    def install_ssl_options_conf(self, options_ssl, options_ssl_digest, warn_on_no_mod_ssl=True):
+        """Copy Certbot's SSL options file into the system's config dir if required.
+
+        :param bool warn_on_no_mod_ssl: True if we should warn if mod_ssl is not found.
+        """
 
         # XXX if we ever try to enforce a local privilege boundary (eg, running
         # certbot for unprivileged users via setuid), this function will need
         # to be modified.
-        return common.install_version_controlled_file(options_ssl, options_ssl_digest,
-            self.option("MOD_SSL_CONF_SRC"), constants.ALL_SSL_OPTIONS_HASHES)
+        apache_config_path = self.pick_apache_config(warn_on_no_mod_ssl)
+
+        return common.install_version_controlled_file(
+            options_ssl, options_ssl_digest, apache_config_path, constants.ALL_SSL_OPTIONS_HASHES)
 
     def enable_autohsts(self, _unused_lineage, domains):
         """

certbot-apache/certbot_apache/_internal/constants.py

@@ -26,6 +26,7 @@ ALL_SSL_OPTIONS_HASHES = [
     '06675349e457eae856120cdebb564efe546f0b87399f2264baeb41e442c724c7',
     '5cc003edd93fb9cd03d40c7686495f8f058f485f75b5e764b789245a386e6daf',
     '007cd497a56a3bb8b6a2c1aeb4997789e7e38992f74e44cc5d13a625a738ac73',
+    '34783b9e2210f5c4a23bced2dfd7ec289834716673354ed7c7abf69fe30192a3',
 ]
 """SHA256 hashes of the contents of previous versions of all versions of MOD_SSL_CONF_SRC"""
 

certbot-apache/certbot_apache/_internal/override_arch.py

@@ -1,9 +1,7 @@
 """ Distribution specific override class for Arch Linux """
-import pkg_resources
 import zope.interface
 
 from certbot import interfaces
-from certbot.compat import os
 from certbot_apache._internal import configurator
 
 
@@ -26,6 +24,4 @@ class ArchConfigurator(configurator.ApacheConfigurator):
         handle_modules=False,
         handle_sites=False,
         challenge_location="/etc/httpd/conf",
-        MOD_SSL_CONF_SRC=pkg_resources.resource_filename(
-            "certbot_apache", os.path.join("_internal", "options-ssl-apache.conf"))
     )

certbot-apache/certbot_apache/_internal/override_centos.py

@@ -1,14 +1,12 @@
 """ Distribution specific override class for CentOS family (RHEL, Fedora) """
 import logging
 
-import pkg_resources
 import zope.interface
 
 from acme.magic_typing import List
 from certbot import errors
 from certbot import interfaces
 from certbot import util
-from certbot.compat import os
 from certbot.errors import MisconfigurationError
 from certbot_apache._internal import apache_util
 from certbot_apache._internal import configurator
@@ -37,8 +35,6 @@ class CentOSConfigurator(configurator.ApacheConfigurator):
         handle_modules=False,
         handle_sites=False,
         challenge_location="/etc/httpd/conf.d",
-        MOD_SSL_CONF_SRC=pkg_resources.resource_filename(
-            "certbot_apache", os.path.join("_internal", "options-ssl-apache.conf"))
     )
 
     def config_test(self):

certbot-apache/certbot_apache/_internal/override_darwin.py

@@ -1,9 +1,7 @@
 """ Distribution specific override class for macOS """
-import pkg_resources
 import zope.interface
 
 from certbot import interfaces
-from certbot.compat import os
 from certbot_apache._internal import configurator
 
 
@@ -26,6 +24,4 @@ class DarwinConfigurator(configurator.ApacheConfigurator):
         handle_modules=False,
         handle_sites=False,
         challenge_location="/etc/apache2/other",
-        MOD_SSL_CONF_SRC=pkg_resources.resource_filename(
-            "certbot_apache", os.path.join("_internal", "options-ssl-apache.conf"))
     )

certbot-apache/certbot_apache/_internal/override_debian.py

@@ -1,7 +1,6 @@
 """ Distribution specific override class for Debian family (Ubuntu/Debian) """
 import logging
 
-import pkg_resources
 import zope.interface
 
 from certbot import errors
@@ -34,8 +33,6 @@ class DebianConfigurator(configurator.ApacheConfigurator):
         handle_modules=True,
         handle_sites=True,
         challenge_location="/etc/apache2",
-        MOD_SSL_CONF_SRC=pkg_resources.resource_filename(
-            "certbot_apache", os.path.join("_internal", "options-ssl-apache.conf"))
     )
 
     def enable_site(self, vhost):

certbot-apache/certbot_apache/_internal/override_fedora.py

@@ -1,11 +1,9 @@
 """ Distribution specific override class for Fedora 29+ """
-import pkg_resources
 import zope.interface
 
 from certbot import errors
 from certbot import interfaces
 from certbot import util
-from certbot.compat import os
 from certbot_apache._internal import apache_util
 from certbot_apache._internal import configurator
 from certbot_apache._internal import parser
@@ -31,9 +29,6 @@ class FedoraConfigurator(configurator.ApacheConfigurator):
         handle_modules=False,
         handle_sites=False,
         challenge_location="/etc/httpd/conf.d",
-        MOD_SSL_CONF_SRC=pkg_resources.resource_filename(
-            # TODO: eventually newest version of Fedora will need their own config
-            "certbot_apache", os.path.join("_internal", "options-ssl-apache.conf"))
     )
 
     def config_test(self):

certbot-apache/certbot_apache/_internal/override_gentoo.py

@@ -1,9 +1,7 @@
 """ Distribution specific override class for Gentoo Linux """
-import pkg_resources
 import zope.interface
 
 from certbot import interfaces
-from certbot.compat import os
 from certbot_apache._internal import apache_util
 from certbot_apache._internal import configurator
 from certbot_apache._internal import parser
@@ -29,8 +27,6 @@ class GentooConfigurator(configurator.ApacheConfigurator):
         handle_modules=False,
         handle_sites=False,
         challenge_location="/etc/apache2/vhosts.d",
-        MOD_SSL_CONF_SRC=pkg_resources.resource_filename(
-            "certbot_apache", os.path.join("_internal", "options-ssl-apache.conf"))
     )
 
     def _prepare_options(self):

certbot-apache/certbot_apache/_internal/override_suse.py

@@ -1,9 +1,7 @@
 """ Distribution specific override class for OpenSUSE """
-import pkg_resources
 import zope.interface
 
 from certbot import interfaces
-from certbot.compat import os
 from certbot_apache._internal import configurator
 
 
@@ -26,6 +24,4 @@ class OpenSUSEConfigurator(configurator.ApacheConfigurator):
         handle_modules=False,
         handle_sites=False,
         challenge_location="/etc/apache2/vhosts.d",
-        MOD_SSL_CONF_SRC=pkg_resources.resource_filename(
-            "certbot_apache", os.path.join("_internal", "options-ssl-apache.conf"))
     )

certbot-apache/certbot_apache/_internal/parser.py

@@ -9,7 +9,6 @@ import six
 
 from acme.magic_typing import Dict
 from acme.magic_typing import List
-from acme.magic_typing import Set
 from certbot import errors
 from certbot.compat import os
 from certbot_apache._internal import apache_util
@@ -52,7 +51,7 @@ class ApacheParser(object):
                 "version 1.2.0 or higher, please make sure you have you have "
                 "those installed.")
 
-        self.modules = set()  # type: Set[str]
+        self.modules = {}  # type: Dict[str, str]
         self.parser_paths = {}  # type: Dict[str, List[str]]
         self.variables = {}  # type: Dict[str, str]
 
@@ -249,14 +248,14 @@ class ApacheParser(object):
     def add_mod(self, mod_name):
         """Shortcut for updating parser modules."""
         if mod_name + "_module" not in self.modules:
-            self.modules.add(mod_name + "_module")
+            self.modules[mod_name + "_module"] = None
         if "mod_" + mod_name + ".c" not in self.modules:
-            self.modules.add("mod_" + mod_name + ".c")
+            self.modules["mod_" + mod_name + ".c"] = None
 
     def reset_modules(self):
         """Reset the loaded modules list. This is called from cleanup to clear
         temporarily loaded modules."""
-        self.modules = set()
+        self.modules = {}
         self.update_modules()
         self.parse_modules()
 
@@ -267,7 +266,7 @@ class ApacheParser(object):
             the iteration issue.  Else... parse and enable mods at same time.
 
         """
-        mods = set()  # type: Set[str]
+        mods = {}  # type: Dict[str, str]
         matches = self.find_dir("LoadModule")
         iterator = iter(matches)
         # Make sure prev_size != cur_size for do: while: iteration
@@ -281,8 +280,8 @@ class ApacheParser(object):
                 mod_name = self.get_arg(match_name)
                 mod_filename = self.get_arg(match_filename)
                 if mod_name and mod_filename:
-                    mods.add(mod_name)
-                    mods.add(os.path.basename(mod_filename)[:-2] + "c")
+                    mods[mod_name] = mod_filename
+                    mods[os.path.basename(mod_filename)[:-2] + "c"] = mod_filename
                 else:
                     logger.debug("Could not read LoadModule directive from Augeas path: %s",
                                  match_name[6:])
@@ -621,7 +620,7 @@ class ApacheParser(object):
 
     def exclude_dirs(self, matches):
         """Exclude directives that are not loaded into the configuration."""
-        filters = [("ifmodule", self.modules), ("ifdefine", self.variables)]
+        filters = [("ifmodule", self.modules.keys()), ("ifdefine", self.variables)]
 
         valid_matches = []
 
@@ -662,6 +661,25 @@ class ApacheParser(object):
 
         return True
 
+    def standard_path_from_server_root(self, arg):
+        """Ensure paths are consistent and absolute
+
+        :param str arg: Argument of directive
+
+        :returns: Standardized argument path
+        :rtype: str
+        """
+        # Remove beginning and ending quotes
+        arg = arg.strip("'\"")
+
+        # Standardize the include argument based on server root
+        if not arg.startswith("/"):
+            # Normpath will condense ../
+            arg = os.path.normpath(os.path.join(self.root, arg))
+        else:
+            arg = os.path.normpath(arg)
+        return arg
+
     def _get_include_path(self, arg):
         """Converts an Apache Include directive into Augeas path.
 
@@ -682,16 +700,7 @@ class ApacheParser(object):
         # if matchObj.group() != arg:
         #     logger.error("Error: Invalid regexp characters in %s", arg)
         #     return []
-
-        # Remove beginning and ending quotes
-        arg = arg.strip("'\"")
-
-        # Standardize the include argument based on server root
-        if not arg.startswith("/"):
-            # Normpath will condense ../
-            arg = os.path.normpath(os.path.join(self.root, arg))
-        else:
-            arg = os.path.normpath(arg)
+        arg = self.standard_path_from_server_root(arg)
 
         # Attempts to add a transform to the file if one does not already exist
         if os.path.isdir(arg):

certbot-apache/certbot_apache/_internal/tls_configs/current-options-ssl-apache.conf

@@ -0,0 +1,19 @@
+# This file contains important security parameters. If you modify this file
+# manually, Certbot will be unable to automatically provide future security
+# updates. Instead, Certbot will print and log an error message with a path to
+# the up-to-date file that you will need to refer to when manually updating
+# this file.
+
+SSLEngine on
+
+# Intermediate configuration, tweak to your needs
+SSLProtocol             all -SSLv2 -SSLv3 -TLSv1 -TLSv1.1
+SSLCipherSuite          ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
+SSLHonorCipherOrder     off
+SSLSessionTickets       off
+
+SSLOptions +StrictRequire
+
+# Add vhost name to log entries:
+LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\"" vhost_combined
+LogFormat "%v %h %l %u %t \"%r\" %>s %b" vhost_common