mailinabox/management/dns_update.py

888 lines
34 KiB
Python
Executable File

#!/usr/bin/python3
# Creates DNS zone files for all of the domains of all of the mail users
# and mail aliases and restarts nsd.
########################################################################
import sys, os, os.path, urllib.parse, datetime, re, hashlib, base64
import ipaddress
import rtyaml
import dns.resolver
from mailconfig import get_mail_domains
from utils import shell, load_env_vars_from_file, safe_domain_name, sort_domains
def get_dns_domains(env):
# Add all domain names in use by email users and mail aliases and ensure
# PRIMARY_HOSTNAME is in the list.
domains = set()
domains |= get_mail_domains(env)
domains.add(env['PRIMARY_HOSTNAME'])
return domains
def get_dns_zones(env):
# What domains should we create DNS zones for? Never create a zone for
# a domain & a subdomain of that domain.
domains = get_dns_domains(env)
# Exclude domains that are subdomains of other domains we know. Proceed
# by looking at shorter domains first.
zone_domains = set()
for domain in sorted(domains, key=lambda d : len(d)):
for d in zone_domains:
if domain.endswith("." + d):
# We found a parent domain already in the list.
break
else:
# 'break' did not occur: there is no parent domain.
zone_domains.add(domain)
# Make a nice and safe filename for each domain.
zonefiles = []
for domain in zone_domains:
zonefiles.append([domain, safe_domain_name(domain) + ".txt"])
# Sort the list so that the order is nice and so that nsd.conf has a
# stable order so we don't rewrite the file & restart the service
# meaninglessly.
zone_order = sort_domains([ zone[0] for zone in zonefiles ], env)
zonefiles.sort(key = lambda zone : zone_order.index(zone[0]) )
return zonefiles
def do_dns_update(env, force=False):
# What domains (and their zone filenames) should we build?
domains = get_dns_domains(env)
zonefiles = get_dns_zones(env)
# Custom records to add to zones.
additional_records = list(get_custom_dns_config(env))
# Write zone files.
os.makedirs('/etc/nsd/zones', exist_ok=True)
updated_domains = []
for i, (domain, zonefile) in enumerate(zonefiles):
# Build the records to put in the zone.
records = build_zone(domain, domains, additional_records, env)
# See if the zone has changed, and if so update the serial number
# and write the zone file.
if not write_nsd_zone(domain, "/etc/nsd/zones/" + zonefile, records, env, force):
# Zone was not updated. There were no changes.
continue
# If this is a .justtesting.email domain, then post the update.
try:
justtestingdotemail(domain, records)
except:
# Hmm. Might be a network issue. If we stop now, will we end
# up in an inconsistent state? Let's just continue.
pass
# Mark that we just updated this domain.
updated_domains.append(domain)
# Sign the zone.
#
# Every time we sign the zone we get a new result, which means
# we can't sign a zone without bumping the zone's serial number.
# Thus we only sign a zone if write_nsd_zone returned True
# indicating the zone changed, and thus it got a new serial number.
# write_nsd_zone is smart enough to check if a zone's signature
# is nearing expiration and if so it'll bump the serial number
# and return True so we get a chance to re-sign it.
sign_zone(domain, zonefile, env)
# Now that all zones are signed (some might not have changed and so didn't
# just get signed now, but were before) update the zone filename so nsd.conf
# uses the signed file.
for i in range(len(zonefiles)):
zonefiles[i][1] += ".signed"
# Write the main nsd.conf file.
if write_nsd_conf(zonefiles, additional_records, env):
# Make sure updated_domains contains *something* if we wrote an updated
# nsd.conf so that we know to restart nsd.
if len(updated_domains) == 0:
updated_domains.append("DNS configuration")
# Kick nsd if anything changed.
if len(updated_domains) > 0:
shell('check_call', ["/usr/sbin/service", "nsd", "restart"])
# Write the OpenDKIM configuration tables.
if write_opendkim_tables(domains, env):
# Settings changed. Kick opendkim.
shell('check_call', ["/usr/sbin/service", "opendkim", "restart"])
if len(updated_domains) == 0:
# If this is the only thing that changed?
updated_domains.append("OpenDKIM configuration")
if len(updated_domains) == 0:
# if nothing was updated (except maybe OpenDKIM's files), don't show any output
return ""
else:
return "updated DNS: " + ",".join(updated_domains) + "\n"
########################################################################
def build_zone(domain, all_domains, additional_records, env, is_zone=True):
records = []
# For top-level zones, define the authoritative name servers.
#
# Normally we are our own nameservers. Some TLDs require two distinct IP addresses,
# so we allow the user to override the second nameserver definition so that
# secondary DNS can be set up elsewhere.
#
# 'False' in the tuple indicates these records would not be used if the zone
# is managed outside of the box.
if is_zone:
# Obligatory definition of ns1.PRIMARY_HOSTNAME.
records.append((None, "NS", "ns1.%s." % env["PRIMARY_HOSTNAME"], False))
# Define ns2.PRIMARY_HOSTNAME or whatever the user overrides.
secondary_ns = get_secondary_dns(additional_records) or ("ns2." + env["PRIMARY_HOSTNAME"])
records.append((None, "NS", secondary_ns+'.', False))
# In PRIMARY_HOSTNAME...
if domain == env["PRIMARY_HOSTNAME"]:
# Define ns1 and ns2.
# 'False' in the tuple indicates these records would not be used if the zone
# is managed outside of the box.
records.append(("ns1", "A", env["PUBLIC_IP"], False))
records.append(("ns2", "A", env["PUBLIC_IP"], False))
if env.get('PUBLIC_IPV6'):
records.append(("ns1", "AAAA", env["PUBLIC_IPV6"], False))
records.append(("ns2", "AAAA", env["PUBLIC_IPV6"], False))
# Set the A/AAAA records. Do this early for the PRIMARY_HOSTNAME so that the user cannot override them
# and we can provide different explanatory text.
records.append((None, "A", env["PUBLIC_IP"], "Required. Sets the IP address of the box."))
if env.get("PUBLIC_IPV6"): records.append((None, "AAAA", env["PUBLIC_IPV6"], "Required. Sets the IPv6 address of the box."))
# Add a DANE TLSA record for SMTP.
records.append(("_25._tcp", "TLSA", build_tlsa_record(env), "Recommended when DNSSEC is enabled. Advertises to mail servers connecting to the box that mandatory encryption should be used."))
# Add a SSHFP records to help SSH key validation. One per available SSH key on this system.
for value in build_sshfp_records():
records.append((None, "SSHFP", value, "Optional. Provides an out-of-band method for verifying an SSH key before connecting. Use 'VerifyHostKeyDNS yes' (or 'VerifyHostKeyDNS ask') when connecting with ssh."))
# The MX record says where email for the domain should be delivered: Here!
records.append((None, "MX", "10 %s." % env["PRIMARY_HOSTNAME"], "Required. Specifies the hostname (and priority) of the machine that handles @%s mail." % domain))
# Add DNS records for any subdomains of this domain. We should not have a zone for
# both a domain and one of its subdomains.
subdomains = [d for d in all_domains if d.endswith("." + domain)]
for subdomain in subdomains:
subdomain_qname = subdomain[0:-len("." + domain)]
subzone = build_zone(subdomain, [], additional_records, env, is_zone=False)
for child_qname, child_rtype, child_value, child_explanation in subzone:
if child_qname == None:
child_qname = subdomain_qname
else:
child_qname += "." + subdomain_qname
records.append((child_qname, child_rtype, child_value, child_explanation))
has_rec_base = list(records) # clone current state
def has_rec(qname, rtype, prefix=None):
for rec in has_rec_base:
if rec[0] == qname and rec[1] == rtype and (prefix is None or rec[2].startswith(prefix)):
return True
return False
# The user may set other records that don't conflict with our settings.
# Don't put any TXT records above this line, or it'll prevent any custom TXT records.
for qname, rtype, value in filter_custom_records(domain, additional_records):
# Don't allow custom records for record types that override anything above.
# But allow multiple custom records for the same rtype --- see how has_rec_base is used.
if has_rec(qname, rtype): continue
# The "local" keyword on A/AAAA records are short-hand for our own IP.
# This also flags for web configuration that the user wants a website here.
if rtype == "A" and value == "local":
value = env["PUBLIC_IP"]
if rtype == "AAAA" and value == "local":
if "PUBLIC_IPV6" in env:
value = env["PUBLIC_IPV6"]
else:
continue
records.append((qname, rtype, value, "(Set by user.)"))
# Add defaults if not overridden by the user's custom settings (and not otherwise configured).
# Any "CNAME" record on the qname overrides A and AAAA.
has_rec_base = records
defaults = [
(None, "A", env["PUBLIC_IP"], "Required. May have a different value. Sets the IP address that %s resolves to for web hosting and other services besides mail. The A record must be present but its value does not affect mail delivery." % domain),
("www", "A", env["PUBLIC_IP"], "Optional. Sets the IP address that www.%s resolves to, e.g. for web hosting." % domain),
(None, "AAAA", env.get('PUBLIC_IPV6'), "Optional. Sets the IPv6 address that %s resolves to, e.g. for web hosting. (It is not necessary for receiving mail on this domain.)" % domain),
("www", "AAAA", env.get('PUBLIC_IPV6'), "Optional. Sets the IPv6 address that www.%s resolves to, e.g. for web hosting." % domain),
]
for qname, rtype, value, explanation in defaults:
if value is None or value.strip() == "": continue # skip IPV6 if not set
if not is_zone and qname == "www": continue # don't create any default 'www' subdomains on what are themselves subdomains
# Set the default record, but not if:
# (1) there is not a user-set record of the same type already
# (2) there is not a CNAME record already, since you can't set both and who knows what takes precedence
# (2) there is not an A record already (if this is an A record this is a dup of (1), and if this is an AAAA record then don't set a default AAAA record if the user sets a custom A record, since the default wouldn't make sense and it should not resolve if the user doesn't provide a new AAAA record)
if not has_rec(qname, rtype) and not has_rec(qname, "CNAME") and not has_rec(qname, "A"):
records.append((qname, rtype, value, explanation))
# SPF record: Permit the box ('mx', see above) to send mail on behalf of
# the domain, and no one else.
# Skip if the user has set a custom SPF record.
if not has_rec(None, "TXT", prefix="v=spf1 "):
records.append((None, "TXT", 'v=spf1 mx -all', "Recommended. Specifies that only the box is permitted to send @%s mail." % domain))
# Append the DKIM TXT record to the zone as generated by OpenDKIM.
# Skip if the user has set a DKIM record already.
opendkim_record_file = os.path.join(env['STORAGE_ROOT'], 'mail/dkim/mail.txt')
with open(opendkim_record_file) as orf:
m = re.match(r'(\S+)\s+IN\s+TXT\s+\( "([^"]+)"\s+"([^"]+)"\s*\)', orf.read(), re.S)
val = m.group(2) + m.group(3)
if not has_rec(m.group(1), "TXT", prefix="v=DKIM1; "):
records.append((m.group(1), "TXT", val, "Recommended. Provides a way for recipients to verify that this machine sent @%s mail." % domain))
# Append a DMARC record.
# Skip if the user has set a DMARC record already.
if not has_rec("_dmarc", "TXT", prefix="v=DMARC1; "):
records.append(("_dmarc", "TXT", 'v=DMARC1; p=quarantine', "Optional. Specifies that mail that does not originate from the box but claims to be from @%s is suspect and should be quarantined by the recipient's mail system." % domain))
# For any subdomain with an A record but no SPF or DMARC record, add strict policy records.
all_resolvable_qnames = set(r[0] for r in records if r[1] in ("A", "AAAA"))
for qname in all_resolvable_qnames:
if not has_rec(qname, "TXT", prefix="v=spf1 "):
records.append((qname, "TXT", 'v=spf1 a mx -all', "Prevents unauthorized use of this domain name for outbound mail by requiring outbound mail to originate from the indicated host(s)."))
dmarc_qname = "_dmarc" + ("" if qname is None else "." + qname)
if not has_rec(dmarc_qname, "TXT", prefix="v=DMARC1; "):
records.append((dmarc_qname, "TXT", 'v=DMARC1; p=reject', "Prevents unauthorized use of this domain name for outbound mail by requiring a valid DKIM signature."))
# Sort the records. The None records *must* go first in the nsd zone file. Otherwise it doesn't matter.
records.sort(key = lambda rec : list(reversed(rec[0].split(".")) if rec[0] is not None else ""))
return records
########################################################################
def build_tlsa_record(env):
# A DANE TLSA record in DNS specifies that connections on a port
# must use TLS and the certificate must match a particular certificate.
#
# Thanks to http://blog.huque.com/2012/10/dnssec-and-certificates.html
# for explaining all of this!
# Get the hex SHA256 of the DER-encoded server certificate:
certder = shell("check_output", [
"/usr/bin/openssl",
"x509",
"-in", os.path.join(env["STORAGE_ROOT"], "ssl", "ssl_certificate.pem"),
"-outform", "DER"
],
return_bytes=True)
certhash = hashlib.sha256(certder).hexdigest()
# Specify the TLSA parameters:
# 3: This is the certificate that the client should trust. No CA is needed.
# 0: The whole certificate is matched.
# 1: The certificate is SHA256'd here.
return "3 0 1 " + certhash
def build_sshfp_records():
# The SSHFP record is a way for us to embed this server's SSH public
# key fingerprint into the DNS so that remote hosts have an out-of-band
# method to confirm the fingerprint. See RFC 4255 and RFC 6594. This
# depends on DNSSEC.
#
# On the client side, set SSH's VerifyHostKeyDNS option to 'ask' to
# include this info in the key verification prompt or 'yes' to trust
# the SSHFP record.
#
# See https://github.com/xelerance/sshfp for inspiriation.
algorithm_number = {
"ssh-rsa": 1,
"ssh-dss": 2,
"ecdsa-sha2-nistp256": 3,
}
# Get our local fingerprints by running ssh-keyscan. The output looks
# like the known_hosts file: hostname, keytype, fingerprint. The order
# of the output is arbitrary, so sort it to prevent spurrious updates
# to the zone file (that trigger bumping the serial number).
keys = shell("check_output", ["ssh-keyscan", "localhost"])
for key in sorted(keys.split("\n")):
if key.strip() == "" or key[0] == "#": continue
try:
host, keytype, pubkey = key.split(" ")
yield "%d %d ( %s )" % (
algorithm_number[keytype],
2, # specifies we are using SHA-256 on next line
hashlib.sha256(base64.b64decode(pubkey)).hexdigest().upper(),
)
except:
# Lots of things can go wrong. Don't let it disturb the DNS
# zone.
pass
########################################################################
def write_nsd_zone(domain, zonefile, records, env, force):
# On the $ORIGIN line, there's typically a ';' comment at the end explaining
# what the $ORIGIN line does. Any further data after the domain confuses
# ldns-signzone, however. It used to say '; default zone domain'.
# The SOA contact address for all of the domains on this system is hostmaster
# @ the PRIMARY_HOSTNAME. Hopefully that's legit.
# For the refresh through TTL fields, a good reference is:
# http://www.peerwisdom.org/2013/05/15/dns-understanding-the-soa-record/
zone = """
$ORIGIN {domain}.
$TTL 1800 ; default time to live
@ IN SOA ns1.{primary_domain}. hostmaster.{primary_domain}. (
__SERIAL__ ; serial number
7200 ; Refresh (secondary nameserver update interval)
1800 ; Retry (when refresh fails, how often to try again)
1209600 ; Expire (when refresh fails, how long secondary nameserver will keep records around anyway)
1800 ; Negative TTL (how long negative responses are cached)
)
"""
# Replace replacement strings.
zone = zone.format(domain=domain, primary_domain=env["PRIMARY_HOSTNAME"])
# Add records.
for subdomain, querytype, value, explanation in records:
if subdomain:
zone += subdomain
zone += "\tIN\t" + querytype + "\t"
if querytype == "TXT":
value = value.replace('\\', '\\\\') # escape backslashes
value = value.replace('"', '\\"') # escape quotes
value = '"' + value + '"' # wrap in quotes
zone += value + "\n"
# DNSSEC requires re-signing a zone periodically. That requires
# bumping the serial number even if no other records have changed.
# We don't see the DNSSEC records yet, so we have to figure out
# if a re-signing is necessary so we can prematurely bump the
# serial number.
force_bump = False
if not os.path.exists(zonefile + ".signed"):
# No signed file yet. Shouldn't normally happen unless a box
# is going from not using DNSSEC to using DNSSEC.
force_bump = True
else:
# We've signed the domain. Check if we are close to the expiration
# time of the signature. If so, we'll force a bump of the serial
# number so we can re-sign it.
with open(zonefile + ".signed") as f:
signed_zone = f.read()
expiration_times = re.findall(r"\sRRSIG\s+SOA\s+\d+\s+\d+\s\d+\s+(\d{14})", signed_zone)
if len(expiration_times) == 0:
# weird
force_bump = True
else:
# All of the times should be the same, but if not choose the soonest.
expiration_time = min(expiration_times)
expiration_time = datetime.datetime.strptime(expiration_time, "%Y%m%d%H%M%S")
if expiration_time - datetime.datetime.now() < datetime.timedelta(days=3):
# We're within three days of the expiration, so bump serial & resign.
force_bump = True
# Set the serial number.
serial = datetime.datetime.now().strftime("%Y%m%d00")
if os.path.exists(zonefile):
# If the zone already exists, is different, and has a later serial number,
# increment the number.
with open(zonefile) as f:
existing_zone = f.read()
m = re.search(r"(\d+)\s*;\s*serial number", existing_zone)
if m:
# Clear out the serial number in the existing zone file for the
# purposes of seeing if anything *else* in the zone has changed.
existing_serial = m.group(1)
existing_zone = existing_zone.replace(m.group(0), "__SERIAL__ ; serial number")
# If the existing zone is the same as the new zone (modulo the serial number),
# there is no need to update the file. Unless we're forcing a bump.
if zone == existing_zone and not force_bump and not force:
return False
# If the existing serial is not less than a serial number
# based on the current date plus 00, increment it. Otherwise,
# the serial number is less than our desired new serial number
# so we'll use the desired new number.
if existing_serial >= serial:
serial = str(int(existing_serial) + 1)
zone = zone.replace("__SERIAL__", serial)
# Write the zone file.
with open(zonefile, "w") as f:
f.write(zone)
return True # file is updated
########################################################################
def write_nsd_conf(zonefiles, additional_records, env):
# Write the list of zones to a configuration file.
nsd_conf_file = "/etc/nsd/zones.conf"
nsdconf = ""
# Append the zones.
for domain, zonefile in zonefiles:
nsdconf += """
zone:
name: %s
zonefile: %s
""" % (domain, zonefile)
# If a custom secondary nameserver has been set, allow zone transfers
# and notifies to that nameserver.
if get_secondary_dns(additional_records):
# Get the IP address of the nameserver by resolving it.
hostname = get_secondary_dns(additional_records)
resolver = dns.resolver.get_default_resolver()
response = dns.resolver.query(hostname+'.', "A")
ipaddr = str(response[0])
nsdconf += """\tnotify: %s NOKEY
provide-xfr: %s NOKEY
""" % (ipaddr, ipaddr)
# Check if the file is changing. If it isn't changing,
# return False to flag that no change was made.
if os.path.exists(nsd_conf_file):
with open(nsd_conf_file) as f:
if f.read() == nsdconf:
return False
# Write out new contents and return True to signal that
# configuration changed.
with open(nsd_conf_file, "w") as f:
f.write(nsdconf)
return True
########################################################################
def dnssec_choose_algo(domain, env):
if '.' in domain and domain.rsplit('.')[-1] in \
("email", "guide", "fund"):
# At GoDaddy, RSASHA256 is the only algorithm supported
# for .email and .guide.
# A variety of algorithms are supported for .fund. This
# is preferred.
return "RSASHA256"
# For any domain we were able to sign before, don't change the algorithm
# on existing users. We'll probably want to migrate to SHA256 later.
return "RSASHA1-NSEC3-SHA1"
def sign_zone(domain, zonefile, env):
algo = dnssec_choose_algo(domain, env)
dnssec_keys = load_env_vars_from_file(os.path.join(env['STORAGE_ROOT'], 'dns/dnssec/%s.conf' % algo))
# In order to use the same keys for all domains, we have to generate
# a new .key file with a DNSSEC record for the specific domain. We
# can reuse the same key, but it won't validate without a DNSSEC
# record specifically for the domain.
#
# Copy the .key and .private files to /tmp to patch them up.
#
# Use os.umask and open().write() to securely create a copy that only
# we (root) can read.
files_to_kill = []
for key in ("KSK", "ZSK"):
if dnssec_keys.get(key, "").strip() == "": raise Exception("DNSSEC is not properly set up.")
oldkeyfn = os.path.join(env['STORAGE_ROOT'], 'dns/dnssec/' + dnssec_keys[key])
newkeyfn = '/tmp/' + dnssec_keys[key].replace("_domain_", domain)
dnssec_keys[key] = newkeyfn
for ext in (".private", ".key"):
if not os.path.exists(oldkeyfn + ext): raise Exception("DNSSEC is not properly set up.")
with open(oldkeyfn + ext, "r") as fr:
keydata = fr.read()
keydata = keydata.replace("_domain_", domain) # trick ldns-signkey into letting our generic key be used by this zone
fn = newkeyfn + ext
prev_umask = os.umask(0o77) # ensure written file is not world-readable
try:
with open(fn, "w") as fw:
fw.write(keydata)
finally:
os.umask(prev_umask) # other files we write should be world-readable
files_to_kill.append(fn)
# Do the signing.
expiry_date = (datetime.datetime.now() + datetime.timedelta(days=30)).strftime("%Y%m%d")
shell('check_call', ["/usr/bin/ldns-signzone",
# expire the zone after 30 days
"-e", expiry_date,
# use NSEC3
"-n",
# zonefile to sign
"/etc/nsd/zones/" + zonefile,
# keys to sign with (order doesn't matter -- it'll figure it out)
dnssec_keys["KSK"],
dnssec_keys["ZSK"],
])
# Create a DS record based on the patched-up key files. The DS record is specific to the
# zone being signed, so we can't use the .ds files generated when we created the keys.
# The DS record points to the KSK only. Write this next to the zone file so we can
# get it later to give to the user with instructions on what to do with it.
#
# We want to be able to validate DS records too, but multiple forms may be valid depending
# on the digest type. So we'll write all (both) valid records. Only one DS record should
# actually be deployed. Preferebly the first.
with open("/etc/nsd/zones/" + zonefile + ".ds", "w") as f:
for digest_type in ('2', '1'):
rr_ds = shell('check_output', ["/usr/bin/ldns-key2ds",
"-n", # output to stdout
"-" + digest_type, # 1=SHA1, 2=SHA256
dnssec_keys["KSK"] + ".key"
])
f.write(rr_ds)
# Remove our temporary file.
for fn in files_to_kill:
os.unlink(fn)
########################################################################
def write_opendkim_tables(domains, env):
# Append a record to OpenDKIM's KeyTable and SigningTable for each domain
# that we send mail from (zones and all subdomains).
opendkim_key_file = os.path.join(env['STORAGE_ROOT'], 'mail/dkim/mail.private')
if not os.path.exists(opendkim_key_file):
# Looks like OpenDKIM is not installed.
return False
config = {
# The SigningTable maps email addresses to a key in the KeyTable that
# specifies signing information for matching email addresses. Here we
# map each domain to a same-named key.
#
# Elsewhere we set the DMARC policy for each domain such that mail claiming
# to be From: the domain must be signed with a DKIM key on the same domain.
# So we must have a separate KeyTable entry for each domain.
"SigningTable":
"".join(
"*@{domain} {domain}\n".format(domain=domain)
for domain in domains
),
# The KeyTable specifies the signing domain, the DKIM selector, and the
# path to the private key to use for signing some mail. Per DMARC, the
# signing domain must match the sender's From: domain.
"KeyTable":
"".join(
"{domain} {domain}:mail:{key_file}\n".format(domain=domain, key_file=opendkim_key_file)
for domain in domains
),
}
did_update = False
for filename, content in config.items():
# Don't write the file if it doesn't need an update.
if os.path.exists("/etc/opendkim/" + filename):
with open("/etc/opendkim/" + filename) as f:
if f.read() == content:
continue
# The contents needs to change.
with open("/etc/opendkim/" + filename, "w") as f:
f.write(content)
did_update = True
# Return whether the files changed. If they didn't change, there's
# no need to kick the opendkim process.
return did_update
########################################################################
def get_custom_dns_config(env):
try:
custom_dns = rtyaml.load(open(os.path.join(env['STORAGE_ROOT'], 'dns/custom.yaml')))
if not isinstance(custom_dns, dict): raise ValueError() # caught below
except:
return [ ]
for qname, value in custom_dns.items():
# Short form. Mapping a domain name to a string is short-hand
# for creating A records.
if isinstance(value, str):
values = [("A", value)]
# A mapping creates multiple records.
elif isinstance(value, dict):
values = value.items()
# No other type of data is allowed.
else:
raise ValueError()
for rtype, value2 in values:
if isinstance(value2, str):
yield (qname, rtype, value2)
elif isinstance(value2, list):
for value3 in value2:
yield (qname, rtype, value3)
# No other type of data is allowed.
else:
raise ValueError()
def filter_custom_records(domain, custom_dns_iter):
for qname, rtype, value in custom_dns_iter:
# We don't count the secondary nameserver config (if present) as a record - that would just be
# confusing to users. Instead it is accessed/manipulated directly via (get/set)_custom_dns_config.
if qname == "_secondary_nameserver": continue
# Is this record for the domain or one of its subdomains?
# If `domain` is None, return records for all domains.
if domain is not None and qname != domain and not qname.endswith("." + domain): continue
# Turn the fully qualified domain name in the YAML file into
# our short form (None => domain, or a relative QNAME) if
# domain is not None.
if domain is not None:
if qname == domain:
qname = None
else:
qname = qname[0:len(qname)-len("." + domain)]
yield (qname, rtype, value)
def write_custom_dns_config(config, env):
# We get a list of (qname, rtype, value) triples. Convert this into a
# nice dictionary format for storage on disk.
from collections import OrderedDict
config = list(config)
dns = OrderedDict()
seen_qnames = set()
# Process the qnames in the order we see them.
for qname in [rec[0] for rec in config]:
if qname in seen_qnames: continue
seen_qnames.add(qname)
records = [(rec[1], rec[2]) for rec in config if rec[0] == qname]
if len(records) == 1 and records[0][0] == "A":
dns[qname] = records[0][1]
else:
dns[qname] = OrderedDict()
seen_rtypes = set()
# Process the rtypes in the order we see them.
for rtype in [rec[0] for rec in records]:
if rtype in seen_rtypes: continue
seen_rtypes.add(rtype)
values = [rec[1] for rec in records if rec[0] == rtype]
if len(values) == 1:
values = values[0]
dns[qname][rtype] = values
# Write.
config_yaml = rtyaml.dump(dns)
with open(os.path.join(env['STORAGE_ROOT'], 'dns/custom.yaml'), "w") as f:
f.write(config_yaml)
def set_custom_dns_record(qname, rtype, value, action, env):
# validate qname
for zone, fn in get_dns_zones(env):
# It must match a zone apex or be a subdomain of a zone
# that we are otherwise hosting.
if qname == zone or qname.endswith("."+zone):
break
else:
# No match.
if qname != "_secondary_nameserver":
raise ValueError("%s is not a domain name or a subdomain of a domain name managed by this box." % qname)
# validate rtype
rtype = rtype.upper()
if value is not None and qname != "_secondary_nameserver":
if rtype in ("A", "AAAA"):
if value != "local": # "local" is a special flag for us
v = ipaddress.ip_address(value) # raises a ValueError if there's a problem
if rtype == "A" and not isinstance(v, ipaddress.IPv4Address): raise ValueError("That's an IPv6 address.")
if rtype == "AAAA" and not isinstance(v, ipaddress.IPv6Address): raise ValueError("That's an IPv4 address.")
elif rtype in ("CNAME", "TXT", "SRV", "MX"):
# anything goes
pass
else:
raise ValueError("Unknown record type '%s'." % rtype)
# load existing config
config = list(get_custom_dns_config(env))
# update
newconfig = []
made_change = False
needs_add = True
for _qname, _rtype, _value in config:
if action == "add":
if (_qname, _rtype, _value) == (qname, rtype, value):
# Record already exists. Bail.
return False
elif action == "set":
if (_qname, _rtype) == (qname, rtype):
if _value == value:
# Flag that the record already exists, don't
# need to add it.
needs_add = False
else:
# Drop any other values for this (qname, rtype).
made_change = True
continue
elif action == "remove":
if (_qname, _rtype, _value) == (qname, rtype, value):
# Drop this record.
made_change = True
continue
if value == None and (_qname, _rtype) == (qname, rtype):
# Drop all qname-rtype records.
made_change = True
continue
else:
raise ValueError("Invalid action: " + action)
# Preserve this record.
newconfig.append((_qname, _rtype, _value))
if action in ("add", "set") and needs_add and value is not None:
newconfig.append((qname, rtype, value))
made_change = True
if made_change:
# serialize & save
write_custom_dns_config(newconfig, env)
return made_change
########################################################################
def get_secondary_dns(custom_dns):
for qname, rtype, value in custom_dns:
if qname == "_secondary_nameserver":
return value
return None
def set_secondary_dns(hostname, env):
if hostname in (None, ""):
# Clear.
set_custom_dns_record("_secondary_nameserver", "A", None, "set", env)
else:
# Validate.
hostname = hostname.strip().lower()
resolver = dns.resolver.get_default_resolver()
try:
response = dns.resolver.query(hostname, "A")
except (dns.resolver.NoNameservers, dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
raise ValueError("Could not resolve the IP address of %s." % hostname)
# Set.
set_custom_dns_record("_secondary_nameserver", "A", hostname, "set", env)
# Apply.
return do_dns_update(env)
########################################################################
def justtestingdotemail(domain, records):
# If the domain is a subdomain of justtesting.email, which we own,
# automatically populate the zone where it is set up on dns4e.com.
# Ideally if dns4e.com supported NS records we would just have it
# delegate DNS to us, but instead we will populate the whole zone.
import subprocess, json, urllib.parse
if not domain.endswith(".justtesting.email"):
return
for subdomain, querytype, value, explanation in records:
if querytype in ("NS",): continue
if subdomain in ("www", "ns1", "ns2"): continue # don't do unnecessary things
if subdomain == None:
subdomain = domain
else:
subdomain = subdomain + "." + domain
if querytype == "TXT":
# nsd requires parentheses around txt records with multiple parts,
# but DNS4E requires there be no parentheses; also it goes into
# nsd with a newline and a tab, which we replace with a space here
value = re.sub("^\s*\(\s*([\w\W]*)\)", r"\1", value)
value = re.sub("\s+", " ", value)
else:
continue
print("Updating DNS for %s/%s..." % (subdomain, querytype))
resp = json.loads(subprocess.check_output([
"curl",
"-s",
"https://api.dns4e.com/v7/%s/%s" % (urllib.parse.quote(subdomain), querytype.lower()),
"--user", "2ddbd8e88ed1495fa0ec:A97TDJV26CVUJS6hqAs0CKnhj4HvjTM7MwAAg8xb",
"--data", "record=%s" % urllib.parse.quote(value),
]).decode("utf8"))
print("\t...", resp.get("message", "?"))
########################################################################
def build_recommended_dns(env):
ret = []
domains = get_dns_domains(env)
zonefiles = get_dns_zones(env)
additional_records = list(get_custom_dns_config(env))
for domain, zonefile in zonefiles:
records = build_zone(domain, domains, additional_records, env)
# remove records that we don't dislay
records = [r for r in records if r[3] is not False]
# put Required at the top, then Recommended, then everythiing else
records.sort(key = lambda r : 0 if r[3].startswith("Required.") else (1 if r[3].startswith("Recommended.") else 2))
# expand qnames
for i in range(len(records)):
if records[i][0] == None:
qname = domain
else:
qname = records[i][0] + "." + domain
records[i] = {
"qname": qname,
"rtype": records[i][1],
"value": records[i][2],
"explanation": records[i][3],
}
# return
ret.append((domain, records))
return ret
if __name__ == "__main__":
from utils import load_environment
env = load_environment()
if sys.argv[-1] == "--lint":
write_custom_dns_config(get_custom_dns_config(env), env)
else:
for zone, records in build_recommended_dns(env):
for record in records:
print("; " + record['explanation'])
print(record['qname'], record['rtype'], record['value'], sep="\t")
print()