class PolicyRequest(object):
email_address_keys = [ 'sender', 'recipient' ]
recipients = []
auth = None
sasl_domain = None
sasl_user = None
sender_domain = None
sender_user = None
sasl_user_uses_alias = False
sasl_user_is_delegate = False
def __init__(self, policy_request={}):
"""
Creates a new policy request object. Pass it a policy_request
dictionary as described in the Postfix documentation on:
http://www.postfix.org/SMTPD_POLICY_README.html
"""
for key in policy_request.keys():
# Normalize email addresses (they may contain recipient delimiters)
if key in self.email_address_keys:
policy_request[key] = normalize_address(policy_request[key])
if not key == 'recipient':
if policy_request[key] == '':
setattr(self, key, None)
else:
setattr(self, key, policy_request[key])
else:
if not policy_request['recipient'].strip() == '':
self.recipients = list(set(self.recipients + [policy_request['recipient']]))
def add_request(self, policy_request={}):
"""
Add subsequent policy requests to the existing policy request.
All data in the request should be the same as the initial policy
request, but for the recipient - with destination limits set over
1, Postfix may attempt to deliver messages to more then one
recipient during a single delivery attempt, and during submission,
the policy will receive one policy request per recipient.
"""
# Check instance. Not sure what to do if the instance is not the same.
if hasattr(self, 'instance'):
if not policy_request['instance'] == self.instance:
# TODO: We need to empty our pockets
pass
log.debug(
_("Adding policy request to instance %s") % (self.instance),
level=8
)
# Normalize email addresses (they may contain recipient delimiters)
if policy_request.has_key('recipient'):
policy_request['recipient'] = normalize_address(
policy_request['recipient']
)
if not policy_request['recipient'].strip() == '':
self.recipients = list(set(self.recipients + [policy_request['recipient']]))
def parse_ldap_dn(self, dn):
"""
See if parameter 'dn' is a basestring LDAP dn, and if so, return
the results we can obtain from said DN. Return a list of relevant
attribute values.
If not a DN, return None.
"""
values = []
try:
import ldap.dn
ldap_dn = ldap.dn.explode_dn(dn)
except ldap.DECODING_ERROR:
# This is not a DN.
return None
if len(ldap_dn) > 0:
search_attrs = conf.get_list(
'kolab_smtp_access_policy',
'address_search_attrs'
)
rule_subject = self.auth.get_user_attributes(
self.sasl_domain,
{ 'dn': dn },
search_attrs + [ 'objectclass' ]
)
for search_attr in search_attrs:
if rule_subject.has_key(search_attr):
if isinstance(rule_subject[search_attr], basestring):
values.append(rule_subject[search_attr])
else:
values.extend(rule_subject[search_attr])
return values
else:
# ldap.dn.explode_dn didn't error out, but it also didn't split
# the DN properly.
return None
def parse_ldap_uri(self, uri):
values = []
parsed_uri = utils.parse_ldap_uri(uri)
if parsed_uri == None:
return None
(_protocol, _server, _port, _base_dn, _attrs, _scope, _filter) = \
parsed_uri
if len(_attrs) == 0:
search_attrs = conf.get_list(
'kolab_smtp_access_policy',
'address_search_attrs'
)
else:
search_attrs = [ _attrs ]
users = []
self.auth._auth._bind()
_users = self.auth._auth._search(
_base_dn,
scope=LDAP_SCOPE[_scope],
filterstr=_filter,
attrlist=search_attrs + [ 'objectclass' ],
override_search="_regular_search"
)
for _user in _users:
for search_attr in search_attrs:
values.extend(_user[1][search_attr])
return values
def parse_policy(self, _subject, _object, policy):
"""
Parse policy to apply on _subject, for object _object.
The policy is a list of rules.
The _subject is a sender for kolabAllowSMTPRecipient checks, and
a recipient for kolabAllowSMTPSender checks.
The _object is a recipient for kolabAllowSMTPRecipient checks, and
a sender for kolabAllowSMTPSender checks.
"""
special_rule_values = {
'$mydomains': expand_mydomains
}
rules = { 'allow': [], 'deny': [] }
if isinstance(policy, basestring):
policy = [policy]
for rule in policy:
# Find rules that are actually special values, simply by
# mapping the rule onto a key in "special_rule_values", a
# dictionary with the corresponding value set to a function to
# execute.
if rule in special_rule_values.keys():
special_rules = special_rule_values[rule]()
if rule.startswith("-"):
rules['deny'].extend(special_rules)
else:
rules['allow'].extend(special_rules)
continue
# Lower-case the rule
rule = rule.lower()
# Also note the '-' cannot be passed on to the functions that
# follow, so store the rule separately from the prefix that is
# prepended to deny rules.
if rule.startswith("-"):
_prefix = '-'
_rule = rule[1:]
else:
_prefix = ''
_rule = rule
# See if the value is an LDAP DN
ldap_dn = self.parse_ldap_dn(_rule)
if not ldap_dn == None and len(ldap_dn) > 0:
if _prefix == '-':
rules['deny'].extend(ldap_dn)
else:
rules['allow'].extend(ldap_dn)
else:
ldap_uri = self.parse_ldap_uri(_rule)
if not ldap_uri == None and len(ldap_uri) > 0:
if _prefix == '-':
rules['deny'].extend(ldap_uri)
else:
rules['allow'].extend(ldap_uri)
else:
if rule.startswith("-"):
rules['deny'].append(rule[1:])
else:
rules['allow'].append(rule)
allowed = False
for rule in rules['allow']:
deny_override = False
if _object.endswith(rule):
for deny_rule in rules['deny']:
if deny_rule.endswith(rule):
deny_override = True
if not deny_override:
allowed = True
denied = False
for rule in rules['deny']:
allow_override = False
if _object.endswith(rule):
if not allowed:
denied = True
continue
else:
for allow_rule in rules['allow']:
if allow_rule.endswith(rule):
allow_override = True
if not allow_override:
denied = True
if not denied:
allowed = True
return allowed
def verify_alias(self):
"""
Verify whether the user authenticated for this policy request is
using an alias of its primary authentication ID / attribute.
[email protected] (mail) for example could be sending with
envelope sender [email protected] (mailAlternateAddress, alias).
"""
search_attrs = conf.get_list(self.sasl_domain, 'mail_attributes')
if search_attrs == None or \
(isinstance(search_attrs, list) and len(search_attrs) == 0):
search_attrs = conf.get_list(
conf.get('kolab', 'auth_mechanism'),
'mail_attributes'
)
# Catch a user using one of its own alias addresses.
for search_attr in search_attrs:
if self.sasl_user.has_key(search_attr):
if isinstance(self.sasl_user[search_attr], list):
if self.sender in self.sasl_user[search_attr]:
return True
elif self.sasl_user[search_attr] == self.sender:
return True
return False
def verify_authenticity(self):
"""
Verify that the SASL username or lack thereof corresponds with
allowing or disallowing authenticated users.
If an SASL username is supplied, use it to obtain the authentication
database user object including all attributes we may find ourselves
interested in.
"""
if self.sasl_username == None:
if not conf.allow_unauthenticated:
reject(_("Unauthorized access not allowed"))
else:
# If unauthenticated is allowed, I have nothing to do here.
return True
sasl_username = self.sasl_username
# If we have an sasl_username, find the user object in the
# authentication database, along with the attributes we are
# interested in.
if self.sasl_domain == None:
if len(self.sasl_username.split('@')) > 1:
self.sasl_domain = self.sasl_username.split('@')[1]
else:
self.sasl_domain = conf.get('kolab', 'primary_domain')
sasl_username = "******" % (self.sasl_username, self.sasl_domain)
if self.auth == None:
self.auth = Auth(self.sasl_domain)
elif not self.auth.domain == self.sasl_domain:
self.auth = Auth(self.sasl_domain)
sasl_users = self.auth.find_recipient(
sasl_username,
domain=self.sasl_domain
)
if isinstance(sasl_users, list):
if len(sasl_users) == 0:
log.error(_("Could not find recipient"))
return False
else:
self.sasl_user = { 'dn': sasl_users[0] }
elif isinstance(sasl_users, basestring):
self.sasl_user = { 'dn': sasl_users }
if not self.sasl_user['dn']:
# Got a final answer here, do the caching thing.
cache_update(
function='verify_sender',
sender=self.sender,
recipients=self.recipients,
result=(int)(False),
sasl_username=self.sasl_username,
sasl_sender=self.sasl_sender
)
reject(
_("Could not find envelope sender user %s") % (
self.sasl_username
)
)
attrs = conf.get_list(self.sasl_domain, 'auth_attributes')
if attrs == None or (isinstance(attrs, list) and len(attrs) == 0):
attrs = conf.get_list(
conf.get('kolab', 'auth_mechanism'),
'auth_attributes'
)
mail_attrs = conf.get_list(self.sasl_domain, 'mail_attributes')
if mail_attrs == None or \
(isinstance(mail_attrs, list) and len(mail_attrs) == 0):
mail_attrs = conf.get_list(
conf.get('kolab', 'auth_mechanism'),
'mail_attributes'
)
if not mail_attrs == None:
attrs.extend(mail_attrs)
attrs.extend(
[
'kolabAllowSMTPRecipient',
'kolabAllowSMTPSender'
]
)
attrs = list(set(attrs))
user_attrs = self.auth.get_user_attributes(
self.sasl_domain,
self.sasl_user,
attrs
)
user_attrs['dn'] = self.sasl_user['dn']
self.sasl_user = utils.normalize(user_attrs)
log.debug(
_("Obtained authenticated user details for %r: %r") % (
self.sasl_user['dn'],
self.sasl_user.keys()
),
level=8
)
def verify_delegate(self):
"""
Verify whether the authenticated user is a delegate of the envelope
sender.
"""
if self.sender_domain == None:
if len(self.sender.split('@')) > 1:
self.sender_domain = self.sender.split('@')[1]
else:
self.sender_domain = conf.get('kolab', 'primary_domain')
if self.sender == self.sasl_username:
return True
search_attrs = conf.get_list(self.sender_domain, 'mail_attributes')
if search_attrs == None:
search_attrs = conf.get_list(
conf.get('kolab', 'auth_mechanism'),
'mail_attributes'
)
sender_users = self.auth.find_recipient(
self.sender,
domain=self.sender_domain
)
if isinstance(sender_users, list):
if len(sender_users) > 1:
# More then one sender user with this recipient address.
# TODO: check each of the sender users found.
self.sender_user = { 'dn': sender_users[0] }
elif len(sender_users) == 1:
self.sender_user = { 'dn': sender_users }
else:
self.sender_user = { 'dn': False }
elif isinstance(sender_users, basestring):
self.sender_user = { 'dn': sender_users }
if not self.sender_user['dn']:
cache_update(
function='verify_sender',
sender=self.sender,
recipients=self.recipients,
result=(int)(False),
sasl_username=self.sasl_username,
sasl_sender=self.sasl_sender
)
reject(_("Could not find envelope sender user %s") % (self.sender))
attrs = search_attrs
attrs.extend(
[
'kolabAllowSMTPRecipient',
'kolabAllowSMTPSender',
'kolabDelegate'
]
)
user_attrs = self.auth.get_user_attributes(
self.sender_domain,
self.sender_user,
attrs
)
user_attrs['dn'] = self.sender_user['dn']
self.sender_user = utils.normalize(user_attrs)
if not self.sender_user.has_key('kolabdelegate'):
reject(
_("%s is unauthorized to send on behalf of %s") % (
self.sasl_user['dn'],
self.sender_user['dn']
)
)
elif self.sender_user['kolabdelegate'] == None:
# No delegates for this sender could be found. The user is
# definitely NOT a delegate of the sender.
log.warning(
_("User %s attempted to use envelope sender address %s " + \
"without authorization") % (
policy_request["sasl_username"],
policy_request["sender"]
)
)
# Got a final answer here, do the caching thing.
if not cache == False:
record_id = cache_update(
function='verify_sender',
sender=self.sender,
recipients=self.recipients,
result=(int)(False),
sasl_username=self.sasl_username,
sasl_sender=self.sasl_sender
)
sender_is_delegate = False
else:
# See if we can match the value of the envelope sender delegates to
# the actual sender sasl_username
if self.sasl_user == None:
sasl_users = self.auth.find_recipient(
self.sasl_username,
domain=self.sasl_domain
)
if isinstance(sasl_users, list):
if len(sasl_users) == 0:
log.error(_("Could not find recipient"))
return False
else:
self.sasl_user = { 'dn': sasl_users[0] }
elif isinstance(sasl_users, basestring):
self.sasl_user = { 'dn': sasl_users }
# Possible values for the kolabDelegate attribute are:
# a 'uid', a 'dn'.
if not self.sasl_user.has_key('uid'):
self.sasl_user['uid'] = self.auth.get_user_attribute(
self.sasl_domain,
self.sasl_user,
'uid'
)
sender_delegates = self.sender_user['kolabdelegate']
if not type(sender_delegates) == list:
sender_delegates = [ sender_delegates ]
for sender_delegate in sender_delegates:
if self.sasl_user['dn'] == sender_delegate:
log.debug(
_("Found user %s to be a delegate user of %s") % (
policy_request["sasl_username"],
policy_request["sender"]
),
level=8
)
sender_is_delegate = True
elif self.sasl_user['uid'] == sender_delegate:
log.debug(
_("Found user %s to be a delegate user of %s") % (
policy_request["sasl_username"],
policy_request["sender"]
),
level=8
)
sender_is_delegate = True
# If nothing matches sender_is_delegate is still None.
if not sender_is_delegate == True:
sender_is_delegate = False
return sender_is_delegate
def verify_recipient(self, recipient):
"""
Verify whether the sender is allowed send to this recipient, using
the recipient's kolabAllowSMTPSender.
"""
self.recipient = recipient
if not self.sasl_username == '' and not self.sasl_username == None:
log.debug(_("Verifying authenticated sender '%(sender)s' with " + \
"sasl_username '%(sasl_username)s' for recipient " + \
"'%(recipient)s'") % (self.__dict__)
)
else:
log.debug(_("Verifying unauthenticated sender '%(sender)s' " + \
"for recipient '%(recipient)s'") % (self.__dict__)
)
recipient_verified = False
if not cache == False:
records = cache_select(
function='verify_recipient',
sender=self.sender,
recipient=recipient,
sasl_username=self.sasl_username,
sasl_sender=self.sasl_sender,
)
if not records == None and len(records) == 1:
log.info(
_("Reproducing verify_recipient(%s, %s) from " + \
"cache, saving you queries, time and thus " + \
"money.") % (self.sender, recipient)
)
return record[0].value
# TODO: Under some conditions, the recipient may not be fully qualified.
# We'll cross that bridge when we get there, though.
if len(recipient.split('@')) > 1:
sasl_domain = recipient.split('@')[1]
else:
sasl_domain = conf.get('kolab', 'primary_domain')
if self.auth == None:
self.auth = Auth(sasl_domain)
elif not self.auth.domain == sasl_domain:
self.auth = Auth(sasl_domain)
if verify_domain(sasl_domain):
if self.auth.secondary_domains.has_key(sasl_domain):
log.debug(
_("Using authentication domain %s instead of %s") % (
self.auth.secondary_domains[sasl_domain],
sasl_domain
),
level=8
)
sasl_domain = self.auth.secondary_domains[sasl_domain]
else:
log.debug(
_("Domain %s is a primary domain") % (
sasl_domain
),
level=8
)
else:
log.warning(
_("Checking the recipient for domain %s that is not " + \
"ours. This is probably a configuration error.") % (
sasl_domain
)
)
return True
recipients = self.auth.find_recipient(
normalize_address(recipient),
domain=sasl_domain,
)
if isinstance(recipients, list):
if len(recipients) > 1:
log.info(
_("This recipient address is related to multiple " + \
"object entries and the SMTP Access Policy can " + \
"therefore not restrict message flow")
)
return True
elif len(recipients) == 1:
recipient = { 'dn': recipients[0] }
else:
log.debug(
_("Recipient address %r not found. Allowing since " + \
"the MTA was configured to accept the recipient.") % (
normalize_address(recipient)
),
level=3
)
return True
elif isinstance(recipients, basestring):
recipient = {
'dn': recipients
}
# We have gotten an invalid recipient. We need to catch this case,
# because testing can input invalid recipients, and so can faulty
# applications, or misconfigured servers.
if not recipient['dn']:
if not conf.allow_unauthenticated:
cache_update(
function='verify_recipient',
sender=self.sender,
recipient=recipient,
result=(int)(False),
sasl_username=self.sasl_username,
sasl_sender=self.sasl_sender
)
reject(_("Invalid recipient"))
else:
cache_update(
function='verify_recipient',
sender=self.sender,
recipient=recipient,
result=(int)(True),
sasl_username=self.sasl_username,
sasl_sender=self.sasl_sender
)
log.debug(_("Could not find this user, accepting"), level=8)
return True
if not recipient['dn'] == False:
recipient_policy = self.auth.get_entry_attribute(
sasl_domain,
recipient,
'kolabAllowSMTPSender'
)
# If no such attribute has been specified, allow
if recipient_policy == None:
recipient_verified = True
# Otherwise, parse the policy obtained with the subject of the policy
# being the recipient, and the object to apply the policy to being the
# sender.
else:
recipient_verified = self.parse_policy(
recipient,
self.sender,
recipient_policy
)
cache_update(
function='verify_recipient',
sender=self.sender,
recipient=recipient,
result=(int)(recipient_verified),
sasl_username=self.sasl_username,
sasl_sender=self.sasl_sender
)
return recipient_verified
def verify_recipients(self):
"""
Verify whether the sender is allowed send to the recipients in this
policy request, using each recipient's kolabAllowSMTPSender.
Note there may be multiple recipients in this policy request, and
therefor self.recipients is a list - walk through that list.
"""
recipients_verified = True
if not cache == False:
records = cache_select(
function='verify_recipient',
sender=self.sender,
recipients=self.recipients,
sasl_username=self.sasl_username,
sasl_sender=self.sasl_sender,
)
if not records == None and len(records) == len(self.recipients):
for record in records:
recipient_found = False
for recipient in self.recipients:
if recipient == record['recipient']:
recipient_found = True
if not recipient_found:
reject(_("Sender %s is not allowed to send to " + \
"recipient %s") % (self.sender,recipient))
for recipient in self.recipients:
recipient_verified = self.verify_recipient(recipient)
if not recipient_verified:
recipients_verified = False
return recipients_verified
def verify_sender(self):
"""
Verify the sender's access policy.
1) Verify whether the sasl_username is allowed to send using the
envelope sender address, with the kolabDelegate attribute
associated with the LDAP object that has the envelope sender
address.
2) Verify whether the sender is allowed to send to recipient(s)
listed on the sender's object.
A third potential action could be to check the recipient object to
see if the sender is allowed to send to the recipient by the
recipient's kolabAllowSMTPSender, but this is done in
verify_recipients().
"""
sender_verified = False
if not cache == False:
records = cache_select(
sender=self.sender,
recipients=self.recipients,
sasl_username=self.sasl_username,
sasl_sender=self.sasl_sender,
function='verify_sender'
)
if not records == None and len(records) == len(self.recipients):
log.info(_("Reproducing verify_sender(%r) from cache, " + \
"saving you queries, time and thus money.") % (
self.__dict__
)
)
for record in records:
recipient_found = False
for recipient in self.recipients:
if recipient == record.recipient:
recipient_found = True
if recipient_found and not record.value:
reject(_("Sender %s is not allowed to send to " + \
"recipient %s") % (self.sender,recipient))
return True
self.verify_authenticity()
self.sasl_user_uses_alias = self.verify_alias()
if not self.sasl_user_uses_alias:
self.sasl_user_is_delegate = self.verify_delegate()
# If the authenticated user is using delegate functionality, apply the
# recipient policy attribute for the envelope sender.
if self.sasl_user_is_delegate == False and \
self.sasl_user_uses_alias == False:
reject(_("Sender uses unauthorized envelope sender address"))
elif self.sasl_user_is_delegate:
# Apply the recipient policy for the sender using the envelope
# sender user object.
recipient_policy_domain = self.sender_domain
recipient_policy_sender = self.sender
recipient_policy_user = self.sender_user
elif not self.sasl_user == None:
# Apply the recipient policy from the authenticated user.
recipient_policy_domain = self.sasl_domain
recipient_policy_sender = self.sasl_username
recipient_policy_user = self.sasl_user
else:
if not conf.allow_unauthenticated:
reject(_("Could not verify sender"))
else:
recipient_policy_domain = self.sender_domain
recipient_policy_sender = self.sender
recipient_policy_user = self.sender_user
log.debug(
_("Verifying whether sender is allowed to send to " + \
"recipient using sender policy"),
level=8
)
if recipient_policy_user.has_key('kolaballowsmtprecipient'):
recipient_policy = recipient_policy_user['kolaballowsmtprecipient']
else:
recipient_policy = self.auth.get_user_attribute(
recipient_policy_domain,
recipient_policy_user,
'kolabAllowSMTPRecipient'
)
log.debug(_("Result is %r") % (recipient_policy), level=8)
# If no such attribute has been specified, allow
if recipient_policy == None:
log.debug(
_("No recipient policy restrictions exist for this sender"),
level=8
)
sender_verified = True
# Otherwise,parse the policy obtained.
else:
log.debug(
_("Found a recipient policy to apply for this sender."),
level=8
)
recipient_allowed = None
for recipient in self.recipients:
recipient_allowed = self.parse_policy(
recipient_policy_sender,
recipient,
recipient_policy
)
if not recipient_allowed:
reject(
_("Sender %s not allowed to send to recipient " + \
"%s") % (recipient_policy_user['dn'],recipient)
)
sender_verified = True
if not cache == False:
record_id = cache_update(
function='verify_sender',
sender=self.sender,
recipients=self.recipients,
result=(int)(sender_verified),
sasl_username=self.sasl_username,
sasl_sender=self.sasl_sender
)
return sender_verified
