Bug 562516

Created attachment 389344 [details]
Patch to enable exact match of identity in update-policy rule for subdomainms nametype

Description of problem:
The comparison used for nametype subdomainms in version 9.6.1-9.P3 does not allow an exact match to the specified identity in the update-policy statement.

Version-Release number of selected component (if applicable):
bind-9.6.1-9.P3.fc11.x86_64.rpm

How reproducible:
Always.

Steps to Reproduce:
1. Download current Samba 4 code (either the alpha 11 tarball from http://ftp.samba.org/ftp/samba/samba4/samba-4.0.0alpha11.tar.gz or current git code as as detailed in http://wiki.samba.org/index.php/Samba4/HOWTO)
2. Build, install and provision an instance of Samba 4, ensuring the bind configuration is updated to include the new Samba 4 zone - as detailed in /usr/local/samba/private/named.txt)
3. Join a Windows 2008 DC to the new Samba 4 domain using Windows dcpromo
4. Add an entry to the Samba 4 zone in /etc/named.conf to allow the Windows DC (and only the Windows DC) to make dynamic updates to ALL records in the Samba 4 zone.  As an example: "grant <W2K8DC>$@<REALM-UC> ms-subdomain <REALM-LC> ANY;", substituting the machine name of the Windows 2008 DC for <W2K8DC>, the Windows domain name in uppercase for <REALM-UC> and the Windows domain name in lowercase for <REALM-LC>.
5. Note that when the Windows DC is restarted and attempts to update its dynamic DNS records, the updates fail
6. Apply the attached patch, rebuild and update BIND
7. Notice that the exact match specified above now works as expected

Actual results:
The updates attempted by the Windows 2008 DC fail.

Expected results:
Specifying an exact signer in the identity field of the update-policy statement should match and allow the update to succeed.

Additional info:
The current code calls dst_gssapi_identitymatchesrealmms(signer, NULL, rule->identity) from the DNS_SSUMATCHTYPE_SUBDOMAINMS case of the switch statement.  The dst_gssapi_identitymatchesrealmms() function parses the supplied parameters into their component parts to perform the comparisons, however as there is no name parameter passed to the function in this case, there is no way to have a complete, exact match to the supplied identity of the update-policy statement.

The attached patch attempts an exact match of the signer of the update request to the identity specified in the update-policy rule, and then falls back to the original dst_gssapi_identitymatchesrealmms() call.  This should not create any unexpected side effects as the exact match will either succeed or fail, and if it fails it will fall back to use the existing code.