[Samba] SPN and case sensitivity on LMDB backend

Denis Cardon dcardon at tranquil.it
Wed Mar 13 21:34:00 UTC 2019

Hi everyone,

samba-tool dbcheck  --reindex
../ldb_tdb/ldb_index.c:2352: duplicate attribute value in 
CN=WSTEST,OU=vm,OU=computers,OU=test,DC=ad,DC=test,DC=it for index on 
servicePrincipalName, duplicate of objectGUID 
4c723426-73f8-4991-bf95-88eb57840c2c in 

Looking at the computer entry, I indeed have thoses two SPN (notice the 
case of hostname).

servicePrincipalName: TERMSRV/WSTEST.ad.test.it
servicePrincipalName: TERMSRV/wstest.ad.test.it

Looking at documentation from Microsoft: "Service Principal Names (SPNs) 
are not case sensitive when used by Microsoft Windows-based computers. 
However, an SPN can be used by any type of computer system. Many of 
these computer systems, especially UNIX-based systems, are 
case-sensitive and require the proper case to function properly. Care 
should be taken to use the proper case particularly when an SPN can be 
used by a non-Windows-based computer."

So I don't know if it is the dbcheck or the SPN which is wrong. Those 
two SPN have been produced automatically by a Windows workstation. I 
don't know if it is the OS upgrade from the client (win7 to win10) or if 
it is the upgrade of Samba (4.8 TDB to 4.9 LMDB) that created this 
discrepancy, but it is there...

Cleaning up the SPN remove the dbcheck error. Should I fill a bugzilla 
entry for this?



Denis Cardon
Tranquil IT
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