Merge 1_0 into master

This commit is contained in:
Scott Kitterman
2019-03-12 22:06:42 -04:00
19 changed files with 572 additions and 117 deletions
+1
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@@ -1,3 +1,4 @@
dist
dkimpy_milter.egg-info
*.pyc
*~
+17
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@@ -1,3 +1,20 @@
1.1.0 UNRELEASED
- Port to python3
- Add test suite using opendkim miltertest
- When Socket is absolute path, do not strip leading /
- Handle unix: socket prefix the same as local:
- Set up correct AuthservID defaults
- config: Reassemble strings sensibly
1.0.1 2019-02-11
- Reorder milter start and dropping privileges so permissions on Unix socket
are correct (LP: 1797720)
- Make domain checks case insensitive for determining if signing should be
done (LP: #1815311)
- Add additional Sendmail configuration information to README from OpenDKIM
update based on input from Дилян Палаузов (LP: #1801619)
- Add information on Ed25519 key creation to README (LP: #1815313)
1.0.0 2018-05-11
- Minor documentation updates
- Deleted reference to obsolete syslog target in unit file
+115 -12
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@@ -1,16 +1,23 @@
This is a DKIM signing and verification milter. In theory it has been tested
with both Postfix and Sendmail.
OVERVIEW
========
This is a DKIM signing and verification milter. It has been tested with both
Postfix and Sendmail.
The configuration file is designed to be compatible with OpenDKIM, but only
a subset of OpenDKIM options are supported. If an unsupported option is
specified, an error will be raised.
INSTALLATION
===========
This package includes a default configuration file and man pages. For those
to be installed when installing using setup.py, the following incantation is
required because setuptools developers decided not being able to do this by
default is a feature:
python setup.py install --single-version-externally-managed --record=/dev/null
python3 setup.py install --single-version-externally-managed --record=/dev/null
For users of Debian Stable (Debian 9, Codename Squeeze), all dependencies are
available in either the main or backports repositories:
@@ -33,6 +40,48 @@ The milter will work with either pydns (DNS) or dnspython (dns), preferring
dnspython is both are available. The dkimpy DKIM module also works with
either.
SETUP
====
SIGNING KEYS
============
In order to create DKIM signatures, a private key must be available. Signing
keys should be protected (owned by root:root with permissions 600 in a
directory that is not world readable). Different keys are required for RSA
and (if used) Ed25519.
RSA
===
Both public and private keys for RSA have standard formats and there are many
tools available to create them. Keys must (RFC 8302) have a minimum size of
1024 bits and should have a size of at least 2048 bits. The dknewkey script
that is provided with dkimpy is one such tool:
dknewkey exampleprivkey
will produce both the private key file (.key suffix) and a file with the DKIM
public key record to be published DNS (.dns suffix). RSA is the default key
type. 2048 bits is the default key size.
ED25519
=======
There is no standardized non-binary representation for Ed25519 private keys,
so in order to generate Ed25519 keys for dkimpy-milter, dkimpy specific tools
must be used to be compatible. The same dknewkey script support Ed25519:
dknewkey --ktype ed25519 anothernewkey
will provide both the private key file (.key suffix) and a file with the DKIM
public key record to be published DNS (.dns suffix). Ed25519 keys do not have
variable bit lengths.
MTA INTEGRATION
==============
Both a systemd unit file and a sysv init file are provided. Both make
assumptions about defaults being used, e.g. if a non-standard pidfile name is
used, they will need to be updated. The sysv init file is Debian specific and
@@ -61,7 +110,8 @@ the following steps:
As with all milters, dkimpy-milter needs to be integrated with your MTA of
choice (Sendmail or Postfix).
For Sendmail:
SENDMAIL
========
Configuration is very similar to opendkim, but needs some adjustment for
dkimpy-milter. Here's an example configuration line to include in your
@@ -77,7 +127,59 @@ Milter support should be present by default in most versions of sendmail
these days, but if not included in your Sendmail build, see:
http://www.elandsys.com/resources/sendmail/milter.html
For Postfix:
ISSUES USING SENDMAIL TO SIGN AND VERIFY
========================================
When using the sendmail MTA in both signing and verifying mode, there are
a few issues of which to be aware that might cause operational problems
and deserve consideration.
(a) When the MTA will be used for relaying emails, e.g. delivering to other
hosts using the aliases mechanism, it is important not to break
signatures inserted by the original sender. This is particularly sensitive
particular when the sending domain has published a "reject" DMARC policy.
By default, sendmail quotes to address header fields when there are no
quotes and the display part of the address contains a period or an
apostrophe. However, opendkim only sees the raw, unmodified form of
the header field, and so the content that gets verified and what gets
signed will not be the same, guaranteeing the attached signature is not
valid.
To direct sendmail not to modify the headers, add this to your sendmail.mc:
conf(`confMUST_QUOTE_CHARS', `')
(b) As stated in sendmail's KNOWNBUGS file, sendmail truncates header field
values longer than 256 characters, which could mean truncating the domain
of a long From: header field value and invalidating the signature.
You may wish to consider increasing MAXNAME in sendmail/conf.h to mitigate
changing the messages and invalidating their signatures. This change
requires recompiling sendmail.
(c) Similar to (a) above, sendmail may wrap very long single-line recipient
fields for presentation purposes; for example:
To: very long name <a@example.org>,anotherloo...ong name b <b@example.org>
...might be rewritten as:
To: very long name <a@example.org>,
anotherloo...ong name b <b@example.org>
This rewrite is also done after opendkim has seen the message, meaning
the signature opendkim attaches to the message does not match the
content it signed. There is not a known configuration change to
mitigate this mutation.
The only known mechanism for dealing with this is to have distinct
instances of opendkim do the verifying (inbound) and signing (outbound)
so that the version that arrives at the signing instance is already
in the rewritten form, guaranteeing the input and output are the same
and thus the signature matches the payload.
POSTFIX
=======
Integration of dkimpy-milter into Postfix is like any milter (See Postfix's
README_FILES/MILTER_README). Here's an example master.cf excerpt that talks
@@ -127,14 +229,15 @@ MacroListVerify daemon_name|VERIFYING
...
NOTES
=====
The python DKIM library, dkimpy, requires the entire message being signed or
verified to be in memory, so dkimpy-milter does not write messages out to a
temp file. This may impact performance on low-memory systems.
This is an initial production release to support interoperability testing with
Ed25519 signatures sufficient functionality for basic use. The documented
functionality has been implemented and at generally partially tested. It is
free of known defects, but is not fully tested in a variety of environments.
DKIM Ed25519 signatures have finished development. The specification is
complete. Version 1.0.0 and later support RFC 8463.
DKIM with Ed25519 signatures are described in RFC 8463. Version 1.0.0 and
later support Ed25519 signing and verification. RFC 8301 removed rsa-sha1
from DKIM. dkimpy-milter does not sign with rsa-sha1, but still considers
rsa-sha1 signatures as valid for verification because they are still in
common use and are not known to be cryptographically broken.
+8 -4
View File
@@ -39,16 +39,20 @@ MacroListVerify implemented verified
SyslogSuccess implemented verified
1.0.0
No additional features planned
No additional features
1.0.1
Bug fix only, improved documentation
1.1.0
Port to Python 3
Subdomain support
KeyTable
KeytableEd25519
SigningTable
SigningTableEd25519
Plannedataset type support (if needed):
db:/.db
Planned dataset type support (if needed):
mdb:
Considered for near-term feature release
@@ -56,7 +60,7 @@ Considered for near-term feature release
AlwaysAddARHeader
ChangeRootDirectory
ClockDrift (requires dkimpy change)
DNSTimeout (requires dkmpy change)
DNSTimeout (requires dkimpy change)
MilterDebug
MinimumKeyBits
OversignHeaders (may require dkimpy changes)
+62 -45
View File
@@ -1,4 +1,4 @@
#! /usr/bin/python2
#! /usr/bin/python3
# Original dkim-milter.py code:
# Author: Stuart D. Gathman <stuart@bmsi.com>
# Copyright 2007 Business Management Systems, Inc.
@@ -28,8 +28,9 @@ import dkim
import authres
import os
import tempfile
import StringIO
import io
import re
import codecs
from Milter.utils import parse_addr, parseaddr
import dkimpy_milter.config as config
from dkimpy_milter.util import drop_privileges
@@ -39,7 +40,7 @@ from dkimpy_milter.util import read_keyfile
from dkimpy_milter.util import own_socketfile
from dkimpy_milter.util import fold
__version__ = "1.0.0"
__version__ = "1.0.1"
FWS = re.compile(r'\r?\n[ \t]+')
@@ -61,7 +62,9 @@ class dkimMilter(Milter.Base):
self.external_connection = False
self.hello_name = None
# sometimes people put extra space in sendmail config, so we strip
self.receiver = self.getsymval('j').strip()
self.receiver = self.getsymval('j')
if self.receiver is not None:
self.receiver = self.receiver.strip()
try:
self.AuthservID = milterconfig['AuthservID']
except:
@@ -108,7 +111,7 @@ class dkimMilter(Milter.Base):
def envfrom(self, f, *str):
if milterconfig.get('Syslog') and milterconfig.get('debugLevel') >= 2:
syslog.syslog("mail from: {0} {1}".format(f, str))
self.fp = StringIO.StringIO()
self.fp = io.BytesIO()
self.mailfrom = f
t = parse_addr(f)
if len(t) == 2:
@@ -131,7 +134,7 @@ class dkimMilter(Milter.Base):
if lname == 'from':
fname, self.author = parseaddr(val)
try:
self.fdomain = self.author.split('@')[1]
self.fdomain = self.author.split('@')[1].lower()
except IndexError as er:
self.fdomain = '' # self.author was not a proper email address
if (milterconfig.get('Syslog') and
@@ -140,13 +143,13 @@ class dkimMilter(Milter.Base):
elif lname == 'authentication-results':
self.arheaders.append(val)
if self.fp:
self.fp.write("%s: %s\n" % (name, val))
self.fp.write(b"%s: %s\n" % (codecs.encode(name, 'ascii'), codecs.encode(val, 'ascii')))
return Milter.CONTINUE
@Milter.noreply
def eoh(self):
if self.fp:
self.fp.write("\n") # terminate headers
self.fp.write(b"\n") # terminate headers
self.bodysize = 0
return Milter.CONTINUE
@@ -193,20 +196,20 @@ class dkimMilter(Milter.Base):
h = authres.AuthenticationResultsHeader(authserv_id=
self.AuthservID,
results=self.arresults)
h = fold(str(h))
h = fold(codecs.encode(str(h), 'ascii'))
if (milterconfig.get('Syslog') and
milterconfig.get('debugLevel') >= 2):
syslog.syslog(str(h))
name, val = str(h).split(': ', 1)
syslog.syslog(codecs.decode(h, 'ascii'))
name, val = codecs.decode(h, 'ascii').split(': ', 1)
self.addheader(name, val, 0)
return Milter.CONTINUE
def sign_dkim(self, txt):
canon = milterconfig.get('Canonicalization')
canon = codecs.encode(milterconfig.get('Canonicalization'), 'ascii')
canonicalize = []
if len(canon.split('/')) == 2:
canonicalize.append(canon.split('/')[0])
canonicalize.append(canon.split('/')[1])
if len(canon.split(b'/')) == 2:
canonicalize.append(canon.split(b'/')[0])
canonicalize.append(canon.split(b'/')[1])
else:
canonicalize.append(canon)
canonicalize.append(canon)
@@ -216,11 +219,12 @@ class dkimMilter(Milter.Base):
try:
if privateRSA:
d = dkim.DKIM(txt)
h = d.sign(milterconfig.get('Selector'), self.fdomain,
privateRSA, canonicalize=(canonicalize[0],
canonicalize[1]))
name, val = h.split(': ', 1)
self.addheader(name, val.strip().replace('\r\n', '\n'), 0)
h = d.sign(codecs.encode(milterconfig.get('Selector'), 'ascii'), codecs.encode(self.fdomain, 'ascii'),
codecs.encode(privateRSA, 'ascii'),
canonicalize=(canonicalize[0],
canonicalize[1]))
name, val = h.split(b': ', 1)
self.addheader(codecs.decode(name, 'ascii'), codecs.decode(val, 'ascii').strip().replace('\r\n', '\n'), 0)
if (milterconfig.get('Syslog') and
(milterconfig.get('SyslogSuccess')
or milterconfig.get('debugLevel') >= 1)):
@@ -228,15 +232,15 @@ class dkimMilter(Milter.Base):
'd={3})'.format(self.getsymval('i'),
d.signature_fields.get(b'a'),
d.signature_fields.get(b's'),
d.domain))
d.domain.lower()))
if privateEd25519:
d = dkim.DKIM(txt)
h = d.sign(milterconfig.get('SelectorEd25519'), self.fdomain,
h = d.sign(codecs.encode(milterconfig.get('SelectorEd25519'), 'ascii'), codecs.encode(self.fdomain, 'ascii'),
privateEd25519, canonicalize=(canonicalize[0],
canonicalize[1]),
signature_algorithm='ed25519-sha256')
name, val = h.split(': ', 1)
self.addheader(name, val.strip().replace('\r\n', '\n'), 0)
signature_algorithm=b'ed25519-sha256')
name, val = h.split(b': ', 1)
self.addheader(codecs.decode(name, 'ascii'), codecs.decode(val, 'ascii').strip().replace('\r\n', '\n'), 0)
if (milterconfig.get('Syslog') and
(milterconfig.get('SyslogSuccess')
or milterconfig.get('debugLevel') >= 1)):
@@ -244,7 +248,7 @@ class dkimMilter(Milter.Base):
'd={3})'.format(self.getsymval('i'),
d.signature_fields.get(b'a'),
d.signature_fields.get(b's'),
d.domain))
d.domain.lower()))
except dkim.DKIMException as x:
if milterconfig.get('Syslog'):
syslog.syslog('DKIM: {0}'.format(x))
@@ -258,21 +262,23 @@ class dkimMilter(Milter.Base):
for y in range(self.has_dkim): # Verify _ALL_ the signatures
d = dkim.DKIM(txt)
try:
res = d.verify(idx=y)
dnsoverride = milterconfig.get('DNSOverride')
if isinstance(dnsoverride, str):
syslog.syslog("DNSOverride: {0}".format(dnsoverride))
res = d.verify(idx=y, dnsfunc=lambda _x: dnsoverride)
else:
res = d.verify(idx=y)
algo = codecs.decode(d.signature_fields.get(b'a'), 'ascii')
if res:
if d.signature_fields.get(b'a') == 'ed25519-sha256':
if algo == 'ed25519-sha256':
self.dkim_comment = ('Good {0} signature'
.format(d.signature_fields
.get(b'a')))
.format(algo))
else:
self.dkim_comment = ('Good {0} bit {1} signature'
.format(d.keysize,
d.signature_fields
.get(b'a')))
.format(d.keysize, algo))
else:
self.dkim_comment = ('Bad {0} bit {1} signature.'
.format(d.keysize,
d.signature_fields.get(b'a')))
.format(d.keysize, algo))
except dkim.DKIMException as x:
self.dkim_comment = str(x)
if milterconfig.get('Syslog'):
@@ -281,9 +287,9 @@ class dkimMilter(Milter.Base):
self.dkim_comment = str(x)
if milterconfig.get('Syslog'):
syslog.syslog("check_dkim: {0}".format(x))
self.header_i = d.signature_fields.get(b'i')
self.header_d = d.signature_fields.get(b'd')
self.header_a = d.signature_fields.get(b'a')
self.header_i = codecs.decode(d.signature_fields.get(b'i'), 'ascii')
self.header_d = codecs.decode(d.signature_fields.get(b'd'), 'ascii')
self.header_a = codecs.decode(d.signature_fields.get(b'a'), 'ascii')
if res:
if (milterconfig.get('Syslog') and
(milterconfig.get('SyslogSuccess') or
@@ -292,8 +298,8 @@ class dkimMilter(Milter.Base):
'd={3})'.format(self.getsymval('i'),
d.signature_fields.get(b'a'),
d.signature_fields.get(b's'),
d.domain))
self.dkim_domain = d.domain
d.domain.lower()))
self.dkim_domain = d.domain.lower()
else:
if milterconfig.get('DiagnosticDirectory'):
fd, fname = tempfile.mkstemp(".dkim")
@@ -303,7 +309,7 @@ class dkimMilter(Milter.Base):
syslog.syslog('DKIM: Fail (saved as {0})'
.format(fname))
else:
syslog.syslog('DKIM: Fail ({0})'.format(d.domain))
syslog.syslog('DKIM: Fail ({0})'.format(d.domain.lower()))
if res:
result = 'pass'
else:
@@ -348,13 +354,24 @@ def main():
Milter.set_flags(Milter.CHGHDRS + Milter.ADDHDRS)
miltername = 'dkimpy-filter'
socketname = milterconfig.get('Socket')
if socketname is None:
if int(os.environ.get('LISTEN_PID', '0')) == os.getpid():
lfds = os.environ.get('LISTEN_FDS')
if lfds is not None:
if lfds != '1':
syslog.syslog('LISTEN_FDS is set to "{0}", but we only know how to deal with "1", ignoring it'.
format(lfds))
else:
socketname = 'fd:3'
if socketname is None:
socketname = 'local:/var/run/dkimpy-milter/dkimpy-milter.sock'
own_socketfile(milterconfig, socketname)
drop_privileges(milterconfig)
sys.stdout.flush()
Milter.runmilter(miltername, socketname, 240)
if milterconfig.get('Syslog'):
syslog.syslog('dkimpy-milter started:{0} user:{1}'
.format(pid, milterconfig.get('UserID')))
sys.stdout.flush()
Milter.runmilter(miltername, socketname, 240)
own_socketfile(milterconfig)
drop_privileges(milterconfig)
if __name__ == "__main__":
main()
+6
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@@ -0,0 +1,6 @@
#!/usr/bin/python3
from dkimpy_milter import main
if __name__ == "__main__":
main()
+20 -27
View File
@@ -31,16 +31,16 @@ import stat
import dkim
import socket
import ipaddress
from dnsplug import Session
from .dnsplug import Session
# default values
defaultConfigData = {
'Syslog': 'yes',
'SyslogFacility': 'mail',
'UMask': 007,
'UMask': 0o07,
'Mode': 'sv',
'Socket': 'local:/var/run/dkimpy-milter/dkimpy-milter.sock',
'PidFile': '/var/run/dkimpy-milter/dkimpy-milter.pid',
'Socket': None,
'PidFile': None,
'UserID': 'dkimpy-milter',
'Canonicalization': 'relaxed/simple',
'InternalHosts': '127.0.0.1',
@@ -48,6 +48,7 @@ defaultConfigData = {
'DiagnosticDirectory': '',
'MacroList': '',
'MacroListVerify': '',
'DNSOverride': None,
'debugLevel': 0 # Undocumented config item for developer use
}
@@ -84,14 +85,14 @@ class HostsDataset(object):
self.item = item[1:]
self.negative = True
try:
self.item = ipaddress.ip_address(unicode(self.item, "utf-8"))
self.item = ipaddress.ip_address(str(self.item, "utf-8"))
if isinstance(self.item, ipaddress.IPv4Address):
self.isipv4 = True
elif isinstance(self.item, ipaddress.IPv6Address):
self.isipv6 = True
except ValueError as e:
try:
self.item = ipaddress.ip_network(unicode
self.item = ipaddress.ip_network(str
(self.item, "utf-8"),
strict=False)
if isinstance(self.item, ipaddress.IPv4Network):
@@ -109,7 +110,7 @@ class HostsDataset(object):
def match(self, connectip):
'''Check if the connect IP is part of the dataset'''
source = ipaddress.ip_address(unicode(connectip, "utf-8"))
source = ipaddress.ip_address(str(connectip, "utf-8"))
for item in self.dataset:
if item.isdomain or item.ishostname:
result = self.matchname(source) # Match host/domains first
@@ -159,13 +160,13 @@ class HostsDataset(object):
if isinstance(source, ipaddress.IPv4Address):
ips = s.dns(name, 'A')
for ip in ips:
ip = ipaddress.IPv4Address(unicode(ip, 'UTF-8'))
ip = ipaddress.IPv4Address(str(ip, 'UTF-8'))
if ip == source:
results.append(name)
if isinstance(source, ipaddress.IPv6Address):
ips = s.dns(name, 'AAAA')
for ip in ips:
ip = ipaddress.IPv6Address(unicode(ip, 'UTF-8'))
ip = ipaddress.IPv6Address(str(ip, 'UTF-8'))
if ip == source:
results.append(name)
return results
@@ -224,13 +225,13 @@ def _processConfigFile(filename=None, configdata=None, useSyslog=1,
'''Load the specified config file, exit and log errors if it fails,
otherwise return a config dictionary.'''
import config
from . import config
if configdata is None:
configdata = config.defaultConfigData
if filename is not None:
try:
_readConfigFile(filename, configdata)
except Exception, e:
except Exception as e:
raise
if useSyslog:
syslog.syslog(e.args[0])
@@ -294,19 +295,7 @@ def _dataset_to_list(dataset):
else:
return [dataset.strip().strip(',')]
if dataset[-3:] == '.db' or dataset[:3] == 'db:':
# This is a Sleepycat (Oracle) DB dataset
import whichdb # Will need rewriting someday for python3
if dataset[-3:] == '.db':
dbname = dataset
elif dataset[:3] == 'db:':
dbname = dataset[3:]
else:
raise dkim.ParameterError('Unimplmented dataset type: {0}'
.format(type(dataset)))
if whichdb.whichdb(dbname) != 'dbhash':
raise dkim.ParameterError('Unimplmented dataset type: {0}'
.format(type(dataset)))
#TODO replace this with code to use db maps
# This is a Sleepycat (Oracle) DB dataset, which we dont support
raise dkim.ParameterError('Unsupported dataset db datase: {0}'
.format(type(dataset)))
@@ -346,13 +335,14 @@ def _readConfigFile(path, configData=None, configGlobal={}):
'DiagnosticDirectory': 'str',
'MacroList': 'dataset',
'MacroListVerify': 'dataset',
'DNSOverride': 'str',
'debugLevel': 'int'
}
# check to see if it's a file
try:
mode = os.stat(path)[0]
except OSError, e:
except OSError as e:
syslog.syslog(syslog.LOG_ERR, 'ERROR stating "%s": %s'
% (path, e.strerror))
return(configData)
@@ -400,7 +390,10 @@ def _readConfigFile(path, configData=None, configGlobal={}):
if conversion == 'bool':
configData[name] = _find_boolean(value)
elif conversion == 'str':
configData[name] = str(value)
if isinstance(value, list):
configData[name] = line.split(None, 1)[1]
else:
configData[name] = str(value)
elif conversion == 'int':
configData[name] = int(value)
elif conversion == 'dataset':
@@ -411,7 +404,7 @@ def _readConfigFile(path, configData=None, configGlobal={}):
configData[name] = conversion(value)
fp.close()
try:
configData['AuthservID'] = _make_authserv_id(configData['AuthservID'])
configData['AuthservID'] = _make_authserv_id(configData.get('AuthservID', 'HOSTNAME'))
configData['IntHosts'] = HostsDataset(configData['InternalHosts'])
except:
pass
+8 -8
View File
@@ -84,7 +84,7 @@ class Session(object):
raise DNSError('Length of CNAME chain exceeds %d' % MAX_CNAME)
cnames[name] = cname
if cname in cnames:
raise DNSError, 'CNAME loop'
raise DNSError('CNAME loop')
result = self.dns(cname, qtype, cnames=cnames)
return result
@@ -103,16 +103,16 @@ def DNSLookup_pydns(name, qtype, tcpfallback=True, timeout=30):
#
if resp.header['tc'] == True:
if not tcpfallback:
raise DNS.DNSError, 'DNS: Truncated UDP Reply, SPF records should fit in a UDP packet'
raise DNS.DNSError('DNS: Truncated UDP Reply, SPF records should fit in a UDP packet')
try:
req = DNS.DnsRequest(name, qtype=qtype, protocol='tcp',
timeout=timeout)
resp = req.req()
except DNS.DNSError, x:
raise DNS.DNSError, 'TCP Fallback error: ' + str(x)
except DNS.DNSError as x:
raise DNS.DNSError('TCP Fallback error: ' + str(x))
return [((a['name'], a['typename']), a['data']) for a in resp.answers]
except IOError, x:
raise DNS.DNSError, 'DNS: ' + str(x)
except IOError as x:
raise DNS.DNSError('DNS: ' + str(x))
def DNSLookup_dnspython(name,qtype,tcpfallback=True,timeout=30):
retVal = []
@@ -164,5 +164,5 @@ if __name__ == '__main__':
import sys
s = Session()
for n,t in zip(*[iter(sys.argv[1:])]*2):
print n,t
print s.dns(n,t)
print(n,t)
print(s.dns(n,t))
+27 -13
View File
@@ -115,45 +115,59 @@ def write_pid(milterconfig):
"""Write PID in pidfile. Will not overwrite an existing file."""
import os
import syslog
if not os.path.isfile(milterconfig.get('PidFile')):
pidfile = milterconfig.get('PidFile')
if pidfile is None:
return
if not os.path.isfile(pidfile):
pid = str(os.getpid())
try:
f = open(milterconfig.get('PidFile'), 'w')
f = open(pidfile, 'w')
except IOError as e:
if str(e)[:35] == '[Errno 2] No such file or directory':
piddir = milterconfig.get('PidFile').rsplit('/', 1)[0]
piddir = pidfile.rsplit('/', 1)[0]
os.mkdir(piddir)
user, group = user_group(milterconfig.get('UserID'))
os.chown(piddir, user, group)
f = open(milterconfig.get('PidFile'), 'w')
f = open(pidfile, 'w')
if milterconfig.get('Syslog'):
syslog.syslog('PID dir created: {0}'.format(piddir))
else:
if milterconfig.get('Syslog'):
syslog.syslog('Unable to write pidfle {0}. IOError: {1}'
.format(milterconfig.get('PidFile'), e))
.format(pidfile, e))
raise
f.write(pid)
f.close()
user, group = user_group(milterconfig.get('UserID'))
os.chown(milterconfig.get('PidFile'), user, group)
os.chown(pidfile, user, group)
else:
if milterconfig.get('Syslog'):
syslog.syslog('Unable to write pidfle {0}. File exists.'
.format(milterconfig.get('PidFile')))
.format(pidfile))
raise RuntimeError('Unable to write pidfle {0}. File exists.'
.format(milterconfig.get('PidFile')))
.format(pidfile))
return pid
def own_socketfile(milterconfig):
def own_socketfile(milterconfig, sockname=None):
"""If socket is Unix socket, chown to UserID before dropping privileges"""
import os
user, group = user_group(milterconfig.get('UserID'))
if milterconfig.get('Socket')[:1] == '/':
os.chown(milterconfig.get('Socket')[1:], user, group)
if milterconfig.get('Socket')[:6] == "local:":
os.chown(milterconfig.get('Socket')[6:], user, group)
offset = None
if sockname is None:
sockname = milterconfig.get('Socket')
if sockname is None:
return
if sockname[:1] == '/':
offset = 0
elif sockname[:6] == "local:":
offset = 6
elif sockname[:5] == "unix:":
offset = 5
if offset is not None:
if os.path.exists(sockname[offset:]):
os.chown(sockname[offset:], user, group)
def read_keyfile(milterconfig, keytype):
+8 -1
View File
@@ -324,6 +324,13 @@ be set:
(a) Domain, KeyFile, Selector, no KeyTable, no SigningTable;
(b) KeyTable, SigningTable, no Domain, no KeyFile, no Selector;
.TP
.I DNSOverride (string)
Provide a text string that a verifying milter should use instead of
consulting the DNS on each message. This is useful primarily for
testing purposes in environments where it is awkward to modify the
system DNS resolution. It should not be used in production.
.TP
.I PeerList (dataset)
Identifies a set of "peers" that identifies clients whose connections
@@ -344,7 +351,7 @@ will be checked. [PeerList NOT IMPLEMENTED - included for reference only]
.TP
.I PidFile (string)
Specifies the path to a file that should be created at process start
containing the process ID.
containing the process ID. If not specified, no such file will be created.
.TP
.I Selector (string)
+7 -7
View File
@@ -1,7 +1,7 @@
#! /usr/bin/python
#! /usr/bin/python3
# dkimpy-milter: A DKIM signing/verification Milter application
# Author: Scott Kitterman <scott@kitterman.com>
# Copyright 2018 Scott Kitterman
# Copyright 2018,2019 Scott Kitterman
""" This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
@@ -23,14 +23,14 @@ description = "Domain Keys Identified Mail (DKIM) signing/verifying milter for P
kw = {} # Work-around for lack of 'or' requires in setuptools.
try:
import DNS
kw['install_requires'] = ['dkimpy>=0.7', 'pymilter', 'authres>=1.1.0', 'PyNaCl', 'ipaddress', 'PyDNS']
import dns
kw['install_requires'] = ['dkimpy>=0.7', 'pymilter', 'authres>=1.1.0', 'PyNaCl', 'dnspython']
except ImportError: # If PyDNS is not installed, prefer dnspython
kw['install_requires'] = ['dkimpy>=0.7', 'pymilter', 'authres>=1.1.0', 'PyNaCl', 'ipaddress', 'dnspython']
kw['install_requires'] = ['dkimpy>=0.7', 'pymilter', 'authres>=1.1.0', 'PyNaCl', 'PyDNS']
setup(
name='dkimpy-milter',
version='1.0.0',
version='1.1.0',
author='Scott Kitterman',
author_email='scott@kitterman.com',
url='https://launchpad.net/dkimpy-milter',
@@ -43,7 +43,7 @@ setup(
'License :: OSI Approved :: GNU General Public License (GPL)',
'Natural Language :: English',
'Operating System :: POSIX',
'Programming Language :: Python :: 2 :: Only',
'Programming Language :: Python :: 3 :: Only',
'Topic :: Communications :: Email :: Mail Transport Agents',
'Topic :: Communications :: Email :: Filters',
'Topic :: Security',
+32
View File
@@ -0,0 +1,32 @@
This directory contains example systemd unit files for running a
supervised, socket-activated instance of dkimpy-milter.
There are several advantages of using socket activation:
- dkimpy-milter never runs with elevated privileges, they are dropped
before any dkimpy-milter code is executed.
- The socket is opened before dkimpy-milter runs. This means that
clients can connect() to the socket immediately. So even if there
is a delay in dkimpy-milter startup, or in libmilter itself, the
connection will not fail.
- You can set the privileges of a listening Unix-domain socket by an
override of ListenGroup= in dkimpy-milter.socket (see
systemd.unit(5) for how to override). This lets you control who has
access to the daemon with finer granularity than is available with
dkimpy-milter on its own.
- dkimpy-milter will not consume system resources if it is not used.
- A fully-supervised dkimpy-milter needs no PIDFile, UMask, UserID, or
Socket configuation. This eliminates common race conditions and
startup failures, and simplifies the resulting configuration file.
There is one downside to using socket activation:
- it will only work on systems where libmilter can support connection
strings like "fd:3". This has been supported on Debian and derived
systems since sendmail 8.14.4-6 (before Debian Jessie, in early
2014), see for example:
https://sources.debian.org/src/sendmail/8.15.2-8/debian/patches/socket_activation.patch/
@@ -0,0 +1,11 @@
[Unit]
Description=DKIMpy Milter
Documentation=man:dkimpy-milter(8) man:dkimpy-milter.conf(5)
Requires=dkimpy-milter.socket
[Service]
ExecStart=/usr/bin/dkimpy-milter /etc/dkimpy-milter.conf
User=dkimpy-milter
[Install]
Also=dkimpy-milter.socket
@@ -0,0 +1,12 @@
[Unit]
Description=DKIMpy Milter socket
Documentation=man:dkimpy-milter(8) man:dkimpy-milter.conf(5)
[Socket]
ListenStream=/run/dkimpy-milter/dkimpy-milter.sock
SocketMode=0660
# override SocketGroup to grant access to members of another system group:
SocketGroup=dkimpy-milter
[Install]
WantedBy=sockets.target
+12
View File
@@ -0,0 +1,12 @@
-- -*- lua -*-
for _, keytype in ipairs({"ed25519", "rsa"}) do
for _, func in ipairs({"signing", "verify"}) do
mt.echo("testing "..keytype.." "..func)
conn = mt.connect("unix:"..keytype.."."..func..".sock")
if conn == nil then
error("mt.connect() failed "..keytype.." "..func)
end
mt.disconnect(conn)
mt.echo(keytype.." "..func.." complete")
end
end
+40
View File
@@ -0,0 +1,40 @@
-- -*- lua -*-
for _, keytype in ipairs({"ed25519", "rsa"}) do
for _, func in ipairs({"signing", "verify"}) do
mt.echo("testing "..keytype.." "..func)
conn = mt.connect("unix:"..keytype.."."..func..".sock")
if conn == nil then
error("mt.connect() failed "..keytype.." "..func)
end
if mt.conninfo(conn, "localhost", "127.0.0.1") ~= nil then
error("mt.conninfo() failed "..keytype.." "..func)
end
if mt.getreply(conn) ~= SMFIR_CONTINUE then
error("mt.conninfo() unexpected reply "..keytype.." "..func)
end
if mt.test_action(conn, SMFIF_ADDHDRS) then
print("could add headers "..keytype.." "..func)
else
error("mt.test_action() says could not add headers "..keytype.." "..func)
end
if mt.test_action(conn, SMFIF_CHGHDRS) then
print("could change headers "..keytype.." "..func)
else
error("mt.test_action() says could not change headers "..keytype.." "..func)
end
-- -- FIXME: this part of the test fails, as apparently the
-- -- dkimpy-milter claims the right to change the body of a message,
-- -- even though it shouldn't. How can we fix the negotiation?
-- if mt.test_action(conn, SMFIF_CHGBODY) then
-- error("mt.test_action() says could change body "..keytype.." "..func)
-- else
-- print("could not change body "..keytype.." "..func)
-- end
mt.disconnect(conn)
mt.echo(keytype.." "..func.." test complete")
end
end
+100
View File
@@ -0,0 +1,100 @@
-- -*- lua -*-
msg = {
['headers'] = {
['From'] = 'Alice <alice@example.net>',
['Message-Id'] = '<dkimpy-milter-test-02@example.net>',
['To'] = 'Bob <bob@example.biz>',
['Date'] = 'Mon, 18 Feb 2019 08:32:50 -0500',
['Subject'] = 'Signing test',
['Content-Type'] = 'text/plain',
},
['body'] = "This is a test!\r\n",
}
-- returns miltertest connection object
function connect_and_send (sockname, headers, body)
conn = mt.connect(sockname)
if conn == nil then
error "mt.connect() failed"
end
if mt.conninfo(conn, "localhost", "127.0.0.1") ~= nil then
error "mt.conninfo() failed"
end
if mt.getreply(conn) ~= SMFIR_CONTINUE then
error "mt.conninfo() unexpected reply"
end
-- mt.macro(conn, SMFIC_MAIL, "i", "simple-message")
if mt.mailfrom(conn, "<alice@example.net>") ~= nil then
error "mt.mailfrom() failed"
end
if mt.getreply(conn) ~= SMFIR_CONTINUE then
error "mt.mailfrom() unexpected reply"
end
-- mt.rcptto() is called implicitly
-- send headers
for key,value in pairs(headers) do
if mt.header(conn, key, value) ~= nil then
error("mt.header(" .. key .. ") failed")
end
if mt.getreply(conn) ~= SMFIR_CONTINUE then
error("mt.header(" .. key .. ") unexpected reply")
end
end
-- send EOH
if mt.eoh(conn) ~= nil then
error "mt.eoh() failed"
end
if mt.getreply(conn) ~= SMFIR_CONTINUE then
error "mt.eoh() unexpected reply"
end
-- send body
if mt.bodystring(conn, body) ~= nil then
error "mt.bodystring() failed"
end
if mt.getreply(conn) ~= SMFIR_CONTINUE then
error "mt.bodystring() unexpected reply"
end
-- end of message; let the filter react
if mt.eom(conn) ~= nil then
error "mt.eom() failed"
end
reply = mt.getreply(conn)
if reply ~= SMFIR_CONTINUE then
error ("mt.eom() unexpected reply: " .. reply)
end
return conn
end
for _, keytype in ipairs({"ed25519", "rsa"}) do
mt.echo("testing "..keytype)
signing = connect_and_send("unix:"..keytype..".signing.sock", msg.headers, msg.body)
-- verify that a test header field got added
if not mt.eom_check(signing, MT_HDRINSERT) then
error "no header added by signer"
end
signature = mt.getheader(signing, "DKIM-Signature", 0)
mt.disconnect(signing)
mt.echo("DKIM-Signature: " .. signature)
msg.headers['DKIM-Signature'] = signature
verify = connect_and_send("unix:"..keytype..".verify.sock", msg.headers, msg.body)
if not mt.eom_check(verify, MT_HDRINSERT) then
error "no header added in verify"
end
authres = mt.getheader(verify, "Authentication-Results", 0)
mt.echo("Authentication-Results: "..authres)
mt.disconnect(verify)
mt.echo(keytype.." complete")
end
+2
View File
@@ -0,0 +1,2 @@
#!/bin/sh
python3 -m dkimpy_milter "$@"
Executable
+84
View File
@@ -0,0 +1,84 @@
#!/bin/bash
set -e
WORKDIR=$(mktemp -d)
TESTDIR=$(realpath "$(dirname "$0")")
DKIMPY_MILTER=${DKIMPY_MILTER:-"$TESTDIR/dkimpy-milter"}
KEY_TYPES=(ed25519 rsa)
cd "$WORKDIR"
printf "Testing %s from directory %s\n" "$DKIMPY_MILTER" "$WORKDIR"
for keytype in "${KEY_TYPES[@]}"; do
dknewkey --ktype "$keytype" "testkey.$keytype"
if [ "$keytype" = ed25519 ]; then
keyfile=KeyFileEd25519
selector=SelectorEd25519
else
keyfile=KeyFile
selector=Selector
fi
cat > "$keytype.signing.conf" <<EOF
Domain example.net
$keyfile testkey.$keytype.key
$selector testkey
Socket unix:$keytype.signing.sock
PidFile $keytype.signing.pid
Mode s
UserID $(id --name --user):$(id --name --group)
EOF
cat > "$keytype.verify.conf" <<EOF
Socket unix:$keytype.verify.sock
PidFile $keytype.verify.pid
Mode v
DNSOverride $(cat testkey.$keytype.dns)
UserID $(id --name --user):$(id --name --group)
EOF
done
cleanup() {
echo cleaning up jobs:
jobs
for keytype in "${KEY_TYPES[@]}"; do
for func in signing verify; do
if [ -s "$keytype.$func.pid" ] && kill -0 "$(cat "$keytype.$func.pid")"; then
kill "$(cat $keytype.$func.pid)"
fi
done
done
wait
for keytype in "${KEY_TYPES[@]}"; do
for func in signing verify; do
errdata="$keytype.$func.stderr"
if [ -s "$errdata" ]; then
printf -- "-> %s:\n" "$errdata"
cat "$errdata"
printf -- "-> end %s\n" "$errdata"
fi
done
done
rm -rf "$WORKDIR"
}
for keytype in "${KEY_TYPES[@]}"; do
for func in signing verify; do
PYTHONPATH="$(dirname "$TESTDIR")" "$DKIMPY_MILTER" "$keytype.$func.conf" 2>"$keytype.$func.stderr" &
done
done
trap cleanup EXIT
# ugly ugly (how are we supposed to know that the milters are all ready?):
sleep 2
# uses miltertest from opendkim:
for x in ${TESTS:-"$TESTDIR"/*.miltertest}; do
if ! [ -e "$x" ]; then
if [ -e "$TESTDIR/$x" ]; then
x="$TESTDIR/$x"
fi
fi
printf -- "-> running %s...\n" "$x"
miltertest -s "$x"
done