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Diffstat (limited to 'certbot-postfix/certbot_postfix/util.py')
| -rw-r--r-- | certbot-postfix/certbot_postfix/util.py | 292 |
1 files changed, 0 insertions, 292 deletions
diff --git a/certbot-postfix/certbot_postfix/util.py b/certbot-postfix/certbot_postfix/util.py deleted file mode 100644 index f06989903..000000000 --- a/certbot-postfix/certbot_postfix/util.py +++ /dev/null @@ -1,292 +0,0 @@ -"""Utility functions for use in the Postfix installer.""" -import logging -import re -import subprocess - -from certbot import errors -from certbot import util as certbot_util -from certbot.plugins import util as plugins_util -from certbot_postfix import constants - -logger = logging.getLogger(__name__) - -COMMAND = "postfix" - -class PostfixUtilBase(object): - """A base class for wrapping Postfix command line utilities.""" - - def __init__(self, executable, config_dir=None): - """Sets up the Postfix utility class. - - :param str executable: name or path of the Postfix utility - :param str config_dir: path to an alternative Postfix config - - :raises .NoInstallationError: when the executable isn't found - - """ - self.executable = executable - verify_exe_exists(executable) - self._set_base_command(config_dir) - self.config_dir = None - - def _set_base_command(self, config_dir): - self._base_command = [self.executable] - if config_dir is not None: - self._base_command.extend(('-c', config_dir,)) - - def _call(self, extra_args=None): - """Runs the Postfix utility and returns the result. - - :param list extra_args: additional arguments for the command - - :returns: data written to stdout and stderr - :rtype: `tuple` of `str` - - :raises subprocess.CalledProcessError: if the command fails - - """ - args = list(self._base_command) - if extra_args is not None: - args.extend(extra_args) - return check_all_output(args) - - def _get_output(self, extra_args=None): - """Runs the Postfix utility and returns only stdout output. - - This function relies on self._call for running the utility. - - :param list extra_args: additional arguments for the command - - :returns: data written to stdout - :rtype: str - - :raises subprocess.CalledProcessError: if the command fails - - """ - return self._call(extra_args)[0] - -class PostfixUtil(PostfixUtilBase): - """Wrapper around Postfix CLI tool. - """ - - def __init__(self, config_dir=None): - super(PostfixUtil, self).__init__(COMMAND, config_dir) - - def test(self): - """Make sure the configuration is valid. - - :raises .MisconfigurationError: if the config is invalid - """ - try: - self._call(["check"]) - except subprocess.CalledProcessError as e: - logger.debug("Could not check postfix configuration:\n%s", e) - raise errors.MisconfigurationError( - "Postfix failed internal configuration check.") - - def restart(self): - """Restart or refresh the server content. - - :raises .PluginError: when server cannot be restarted - - """ - logger.info("Reloading Postfix configuration...") - if self._is_running(): - self._reload() - else: - self._start() - - - def _is_running(self): - """Is Postfix currently running? - - Uses the 'postfix status' command to determine if Postfix is - currently running using the specified configuration files. - - :returns: True if Postfix is running, otherwise, False - :rtype: bool - - """ - try: - self._call(["status"]) - except subprocess.CalledProcessError: - return False - return True - - def _start(self): - """Instructions Postfix to start running. - - :raises .PluginError: when Postfix cannot start - - """ - try: - self._call(["start"]) - except subprocess.CalledProcessError: - raise errors.PluginError("Postfix failed to start") - - def _reload(self): - """Instructs Postfix to reload its configuration. - - If Postfix isn't currently running, this method will fail. - - :raises .PluginError: when Postfix cannot reload - """ - try: - self._call(["reload"]) - except subprocess.CalledProcessError: - raise errors.PluginError( - "Postfix failed to reload its configuration") - -def check_all_output(*args, **kwargs): - """A version of subprocess.check_output that also captures stderr. - - This is the same as :func:`subprocess.check_output` except output - written to stderr is also captured and returned to the caller. The - return value is a tuple of two strings (rather than byte strings). - To accomplish this, the caller cannot set the stdout, stderr, or - universal_newlines parameters to :class:`subprocess.Popen`. - - Additionally, if the command exits with a nonzero status, output is - not included in the raised :class:`subprocess.CalledProcessError` - because Python 2.6 does not support this. Instead, the failure - including the output is logged. - - :param tuple args: positional arguments for Popen - :param dict kwargs: keyword arguments for Popen - - :returns: data written to stdout and stderr - :rtype: `tuple` of `str` - - :raises ValueError: if arguments are invalid - :raises subprocess.CalledProcessError: if the command fails - - """ - for keyword in ('stdout', 'stderr', 'universal_newlines',): - if keyword in kwargs: - raise ValueError( - keyword + ' argument not allowed, it will be overridden.') - - kwargs['stdout'] = subprocess.PIPE - kwargs['stderr'] = subprocess.PIPE - kwargs['universal_newlines'] = True - - process = subprocess.Popen(*args, **kwargs) - output, err = process.communicate() - retcode = process.poll() - if retcode: - cmd = kwargs.get('args') - if cmd is None: - cmd = args[0] - logger.debug( - "'%s' exited with %d. stdout output was:\n%s\nstderr output was:\n%s", - cmd, retcode, output, err) - raise subprocess.CalledProcessError(retcode, cmd) - return (output, err) - - -def verify_exe_exists(exe, message=None): - """Ensures an executable with the given name is available. - - If an executable isn't found for the given path or name, extra - directories are added to the user's PATH to help find system - utilities that may not be available in the default cron PATH. - - :param str exe: executable path or name - :param str message: Error message to print. - - :raises .NoInstallationError: when the executable isn't found - - """ - if message is None: - message = "Cannot find executable '{0}'.".format(exe) - if not (certbot_util.exe_exists(exe) or plugins_util.path_surgery(exe)): - raise errors.NoInstallationError(message) - -def report_master_overrides(name, overrides, acceptable_overrides=None): - """If the value for a parameter `name` is overridden by other services, - report a warning to notify the user. If `parameter` is a TLS version parameter - (i.e., `parameter` contains 'tls_protocols' or 'tls_mandatory_protocols'), then - `acceptable_overrides` isn't used each value in overrides is inspected for secure TLS - versions. - - :param str name: The name of the parameter that is being overridden. - :param list overrides: The values that other services are setting for `name`. - Each override is a tuple: (service name, value) - :param tuple acceptable_overrides: Override values that are acceptable. For instance, if - another service is overriding our parameter with a more secure option, we don't have - to warn. If this is set to None, errors are raised for *any* overrides of `name`! - """ - error_string = "" - for override in overrides: - service, value = override - # If this override is acceptable: - if acceptable_overrides is not None and \ - is_acceptable_value(name, value, acceptable_overrides): - continue - error_string += " {0}: {1}\n".format(service, value) - if error_string: - raise errors.PluginError("{0} is overridden with less secure options by the " - "following services in master.cf:\n".format(name) + error_string) - - -def is_acceptable_value(parameter, value, acceptable=None): - """ Returns whether the `value` for this `parameter` is acceptable, - given a tuple of `acceptable` values. If `parameter` is a TLS version parameter - (i.e., `parameter` contains 'tls_protocols' or 'tls_mandatory_protocols'), then - `acceptable` isn't used and `value` is inspected for secure TLS versions. - - :param str parameter: The name of the parameter being set. - :param str value: Proposed new value for parameter. - :param tuple acceptable: List of acceptable values for parameter. - """ - # Check if param value is a comma-separated list of protocols. - # Otherwise, just check whether the value is in the acceptable list. - if 'tls_protocols' in parameter or 'tls_mandatory_protocols' in parameter: - return _has_acceptable_tls_versions(value) - if acceptable is not None: - return value in acceptable - return False - - -def _has_acceptable_tls_versions(parameter_string): - """ - Checks to see if the list of TLS protocols is acceptable. - This requires that TLSv1.2 is supported, and neither SSLv2 nor SSLv3 are supported. - - Should be a string of protocol names delimited by commas, spaces, or colons. - - Postfix's documents suggest listing protocols to exclude, like "!SSLv2, !SSLv3". - Listing the protocols to include, like "TLSv1, TLSv1.1, TLSv1.2" is okay as well, - though not recommended - - When these two modes are interspersed, the presence of a single non-negated protocol name - (i.e. "TLSv1" rather than "!TLSv1") automatically excludes all other unnamed protocols. - - In addition, the presence of both a protocol name inclusion and exclusion isn't explicitly - documented, so this method should return False if it encounters contradicting statements - about TLSv1.2, SSLv2, or SSLv3. (for instance, "SSLv3, !SSLv3"). - """ - if not parameter_string: - return False - bad_versions = list(constants.TLS_VERSIONS) - for version in constants.ACCEPTABLE_TLS_VERSIONS: - del bad_versions[bad_versions.index(version)] - supported_version_list = re.split("[, :]+", parameter_string) - # The presence of any non-"!" protocol listing excludes the others by default. - inclusion_list = False - for version in supported_version_list: - if not version: - continue - if version in bad_versions: # short-circuit if we recognize any bad version - return False - if version[0] != "!": - inclusion_list = True - if inclusion_list: # For any inclusion list, we still require TLS 1.2. - if "TLSv1.2" not in supported_version_list or "!TLSv1.2" in supported_version_list: - return False - else: - for bad_version in bad_versions: - if "!" + bad_version not in supported_version_list: - return False - return True - |