whats_next: offer DNSSEC DS parameters rather than the full record and in validation allow for other digests than the one we suggest using

fixes #120 (hopefully), in which Gandi generates a SHA1 digest but we were only checking against a SHA256 digest

Also see http://discourse.mailinabox.email/t/how-to-set-ds-record-for-gandi-net/24/1 in which a user asks about the DS parameters that Gandi asks for.

management/dns_update.py

@@ -93,7 +93,7 @@ def do_dns_update(env, force=False):
 		# 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 experiation and if so it'll bump the serial number
+		# 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)
 
@@ -478,13 +478,18 @@ def sign_zone(domain, zonefile, env):
 	# 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.
-	rr_ds = shell('check_output', ["/usr/bin/ldns-key2ds",
-		"-n", # output to stdout
-		"-2", # SHA256
-		dnssec_keys["KSK"] + ".key"
-	])
+	#
+	# 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:
-		f.write(rr_ds)
+		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:

management/whats_next.py

@@ -14,7 +14,7 @@ from dns_update import get_dns_zones
 from web_update import get_web_domains, get_domain_ssl_files
 from mailconfig import get_mail_domains, get_mail_aliases
 
-from utils import shell, sort_domains
+from utils import shell, sort_domains, load_env_vars_from_file
 
 def run_checks(env):
 	run_system_checks(env)
@@ -125,25 +125,47 @@ def check_dns_zone(domain, env, dns_zonefiles):
 			control panel to set the nameservers to %s."""
 				% (existing_ns, correct_ns) )
 
-	# See if the domain has a DS record set.
+	# See if the domain has a DS record set at the registrar. The DS record may have
+	# several forms. We have to be prepared to check for any valid record. We've
+	# pre-generated all of the valid digests --- read them in.
+	ds_correct = open('/etc/nsd/zones/' + dns_zonefiles[domain] + '.ds').read().strip().split("\n")
+	digests = { }
+	for rr_ds in ds_correct:
+		ds_keytag, ds_alg, ds_digalg, ds_digest = rr_ds.split("\t")[4].split(" ")
+		digests[ds_digalg] = ds_digest
+
+	# Some registrars may want the public key so they can compute the digest. The DS
+	# record that we suggest using is for the KSK (and that's how the DS records were generated).
+	dnssec_keys = load_env_vars_from_file(os.path.join(env['STORAGE_ROOT'], 'dns/dnssec/keys.conf'))
+	dnsssec_pubkey = open(os.path.join(env['STORAGE_ROOT'], 'dns/dnssec/' + dnssec_keys['KSK'] + '.key')).read().split("\t")[3].split(" ")[3]
+
+	# Query public DNS for the DS record at the registrar.
 	ds = query_dns(domain, "DS", nxdomain=None)
-	ds_correct = open('/etc/nsd/zones/' + dns_zonefiles[domain] + '.ds').read().strip()
-	ds_expected = re.sub(r"\S+\.\s+3600\s+IN\s+DS\s*", "", ds_correct)
-	if ds == ds_expected:
+	ds_looks_valid = ds and len(ds.split(" ")) == 4
+	if ds_looks_valid: ds = ds.split(" ")
+	if ds_looks_valid and ds[0] == ds_keytag and ds[1] == '7' and ds[3] == digests.get(ds[2]):
 		print_ok("DNS 'DS' record is set correctly at registrar.")
-	elif ds == None:
-		print_error("""This domain's DNS DS record is not set. The DS record is optional. The DS record activates DNSSEC.
-			To set a DS record, you must follow the instructions provided by your domain name registrar and provide to them this information:""")
-		print("")
-		print("   " + ds_correct)
-		print("")
 	else:
-		print_error("""This domain's DNS DS record is incorrect. The chain of trust is broken between the public DNS system
-			and this machine's DNS server. It may take several hours for public DNS to update after a change. If you did not recently
-			make a change, you must resolve this immediately by following the instructions provided by your domain name registrar and
-			provide to them this information:""")
-		print("")
-		print("   " + ds_correct)
+		if ds == None:
+			print_error("""This domain's DNS DS record is not set. The DS record is optional. The DS record activates DNSSEC.
+				To set a DS record, you must follow the instructions provided by your domain name registrar and provide to them this information:""")
+		else:
+			print_error("""This domain's DNS DS record is incorrect. The chain of trust is broken between the public DNS system
+				and this machine's DNS server. It may take several hours for public DNS to update after a change. If you did not recently
+				make a change, you must resolve this immediately by following the instructions provided by your domain name registrar and
+				provide to them this information:""")
+		print()
+		print("\tKey Tag: " + ds_keytag + ("" if not ds_looks_valid or ds[0] == ds_keytag else " (Got '%s')" % ds[0]))
+		print("\tKey Flags: KSK")
+		print("\tAlgorithm: 7 / RSASHA1-NSEC3-SHA1" + ("" if not ds_looks_valid or ds[1] == '7' else " (Got '%s')" % ds[1]))
+		print("\tDigest Type: 2 / SHA-256")
+		print("\tDigest: " + digests['2'])
+		if ds_looks_valid and ds[3] != digests.get(ds[2]):
+			print("\t(Got digest type %s and digest %s which do not match.)" % (ds[2], ds[3]))
+		print("\tPublic Key: " + dnsssec_pubkey)
+		print()
+		print("\tBulk/Record Format:")
+		print("\t" + ds_correct[0])
 		print("")
 
 def check_mail_domain(domain, env):