Algorithm roll-over, unexpected content in dsset-file

[Mark Elkins]

Hi, Running BIND 9.14.4 on Gentoo.

I've been running BIND and DNSSEC for a long time. Years ago - I changed 
from Algorithm 5 to 8 and am now changing from 8 to 13.

My ZSK's have a lifetime of 34 days and my KSK a lifetime of 370 days. 
I've chosen to create a new ZSK every 17 days and KSK every 185 days - 
so usually have two of each per domain. I've 1532 domains in my system, 
74 are NSEC and 54 are NSEC3 - the rest are unsigned. Currently - 
resigning happens randomly over the year - which keeps loads (and 
changes) scattered over the year. Some parents - I manage via EPP, 
others have various other methods of updating - so having the best part 
of six month to do a key-rollover has its advantages.

I've just started allowing the system to add Algo-13 Keys... and this is 
what I see:

1 - Created a test zone file: contains enough to be legal.

2 - Created some old keys, one ZSK and one KSK - Signed the domain and 
looked inside the "dsset-" file....
   # vi db.foo.com
   # dnssec-keygen -a RSASHA256 foo.com
   # dnssec-keygen -a RSASHA256 -f KSK foo.com
   # cat Kfoo.com.*.key >> db.foo.com
   # dnssec-signzone -a -o foo.com db.foo.com
   # cat dsset-foo.com.
foo.com.        IN DS 62014 8 1 6CFC9114C7D0954195C01B488C3B8D6E1BD0F220
foo.com.        IN DS 62014 8 2 
74112FE6AE6E9DFB5A00EB3C26397E92CAA27038FA176A9B4B67D9FE 4E0154FE
(perfect!)

3 - created one additional ZSK - Algo 13, add that to the zone and resigned.

  # dnssec-keygen -a ECDSAP256SHA256 foo.com
  # cat Kfoo.com.+013+34805.key >> db.foo.com

  # dnssec-signzone -a -o foo.com db.foo.com
Verifying the zone using the following algorithms: RSASHA256.
Missing self-signed KSK for algorithm ECDSAP256SHA256
The zone is not fully signed for the following algorithms: ECDSAP256SHA256.
DNSSEC completeness test failed.
Zone verification failed (failure)

I don't mind the failure - after all there is no complete Algo-13 chain 
- but the existing Algo-8 chain is complete. Interestingly, the signed 
zone contains no mention of the Algo-13 ZSK. No problem.

However - WTF is a ZSK doing in the dsset file??? Is this a bug?

# cat dsset-foo.com.
foo.com.        IN DS 34805 13 1 A040C7BC6C03778B20AD4A3AEE3BC0648CE8AC23
foo.com.        IN DS 34805 13 2 
340DC924A523CAD49E5C22357BBFECC07A2944D7723AD8F44DCE5332 FACD3AB2
foo.com.        IN DS 62014 8 1 6CFC9114C7D0954195C01B488C3B8D6E1BD0F220
foo.com.        IN DS 62014 8 2 
74112FE6AE6E9DFB5A00EB3C26397E92CAA27038FA176A9B4B67D9FE 4E0154FE

4 - If I then add an algo-13 KSK, add it to the Zone and run signzone - 
everything looks good again...

(New KSK) foo.com. IN DNSKEY 257 3 13 
pD6yMHdPCKmLj0hY8oiLA1F2Vdb8a1LgpzU8XiO2c6eIh16n1Dv2Vogc 
9WylTUjOLTZlhRXPDmAcIUTyBUuC2Q==
# dnssec-signzone -a -o foo.com db.foo.com
Verifying the zone using the following algorithms: RSASHA256 
ECDSAP256SHA256.
Zone fully signed:
Algorithm: RSASHA256: KSKs: 1 active, 0 stand-by, 0 revoked
                       ZSKs: 1 active, 0 stand-by, 0 revoked
Algorithm: ECDSAP256SHA256: KSKs: 1 active, 0 stand-by, 0 revoked
                             ZSKs: 1 active, 0 stand-by, 0 revoked
db.foo.com.signed
# cat dsset-foo.com.
foo.com.        IN DS 23294 13 1 AADE5856B8EB3BB946DAAD2804A735816B3B3132
foo.com.        IN DS 23294 13 2 
7FD5F02A2E52A1C6E3DEBD54C05A9A974CE88FA78548E3644B36FA2D 27E0F910
foo.com.        IN DS 62014 8 1 6CFC9114C7D0954195C01B488C3B8D6E1BD0F220
foo.com.        IN DS 62014 8 2 
74112FE6AE6E9DFB5A00EB3C26397E92CAA27038FA176A9B4B67D9FE 4E0154FE

I really don't like the bad ZSK DS record in dsset because I currently 
use that info to build CDS records in to my Database - which is used to 
verify when the DS record is seen in the parent. Anyway - I think this 
is a bug in the code of dnssec-signzone.

I'm trying to wait as long as possible before forcibly creating Algo-13 
KSK's in the hope that they will be created according to the existing 
schedule. If the Second Algo-13 ZSK is to be created in under 3 days - 
then I'll replace the oldest KSK with an Algo-13 KSK.

-- 
Mark James ELKINS  -  Posix Systems - (South) Africa
mje at posix.co.za       Tel: +27.128070590  Cell: +27.826010496
For fast, reliable, low cost Internet in ZA: https://ftth.posix.co.za