Hi Noriko,
i've read the design document http://directory.fedoraproject.org/wiki/Upgrade_to_New_DN_Format
In order to support "Old DN format including DN in the double quotes" another cn=config switch may be necessary. It seems there was recently a new switch introduced to make the dn syntax validation a little more "relaxed" - nsslapd-dn-validate-strict. Maybe this one could be used to allow for DNs with double-quoted values?
Here is the commit comment for that parameter :
commit 0410819d48795fca4faf986cf8658c34c4d929e3 Author: Nathan Kinder nkinder@redhat.com Date: Wed May 13 11:12:11 2009 -0700
Add strict DN syntax enforcement option.
The DN syntax has become more restrictive over time, and the current rules are quite strict. Strict adherence to the rules defined in RFC 4514, section 3, would likely cause some pain to client applications. Things such as spaces between the RDN components are not allowed, yet many people use them still since they were allowed in the previous specification outlined in RFC 1779.
To deal with the special circumstances around validation of the DN syntax, a configuration attribute is provided named nsslapd-dn-validate-strict. This configuration attribute will ensure that the value strictly adheres to the rules defined in RFC 4514, section 3 if it is set to on. If it is set to off, the server will normalize the value before checking it for syntax violations. Our current normalization function was designed to handle DN values adhering to RFC 1779 or RFC 2253
Concerning the logic of escaping/unescaping/normalisation we could test how openldap behaves in each case (as you've made it in "DN HEX HEX" bug).
For upgrades/migrations and double quotes in DNs: the two values may be left during the upgrade (just in case someone uses them as-is) and then an optional validation/cleaning script could be provided separately? The sensitive part here is the whole o-NetscapeRoot tree: console using and writing this type of values, replication agreement/management etc
As for the "related bugs" section i think another bug should be added ( https://bugzilla.redhat.com/show_bug.cgi?id=199923), it concernes the same RFC4514 compliance.
Thanks for your comments, Andrey!
On 03/17/2010 08:02 AM, Andrey Ivanov wrote:
Hi Noriko,
i've read the design document http://directory.fedoraproject.org/wiki/Upgrade_to_New_DN_Format
In order to support "Old DN format including DN in the double quotes" another cn=config switch may be necessary. It seems there was recently a new switch introduced to make the dn syntax validation a little more "relaxed" - nsslapd-dn-validate-strict. Maybe this one could be used to allow for DNs with double-quoted values?
Actually, the way how we are going to handle the old style 'dn: <type>="<nested dn>",<the rest>' is converting the old style to a new style in the normalization when the server receives DNs from clients and the converted new style DN is used in the rest of the process. The nsslapd-dn-validate-strict value is examined in the DN syntax validation code for now. Unless we change it, the DN syntax validation code always receives the new DN style.
That being said, are you suggesting if nsslapd-dn-validate-strict is on, we should not convert an old style DN to a new style? That'd be really strict. I'm leaning toward to the other side accepting the both old and new style with no restriction. Do you see any disadvantages in allowing the old style?
Here is the commit comment for that parameter :
commit 0410819d48795fca4faf986cf8658c34c4d929e3 Author: Nathan Kinder <nkinder@redhat.com mailto:nkinder@redhat.com> Date: Wed May 13 11:12:11 2009 -0700
Add strict DN syntax enforcement option. The DN syntax has become more restrictive over time, and the current rules are quite strict. Strict adherence to the rules defined in RFC 4514, section 3, would likely cause some pain to client applications. Things such as spaces between the RDN components are not allowed, yet many people use them still since they were allowed in the previous specification outlined in RFC 1779. To deal with the special circumstances around validation of the DN syntax, a configuration attribute is provided named nsslapd-dn-validate-strict. This configuration attribute will ensure that the value strictly adheres to the rules defined in RFC 4514, section 3 if it is set to on. If it is set to off, the server will normalize the value before checking it for syntax violations. Our current normalization function was designed to handle DN values adhering to RFC 1779 or RFC 2253Concerning the logic of escaping/unescaping/normalisation we could test how openldap behaves in each case (as you've made it in "DN HEX HEX" bug).
Yes, I did. :) I found they are correctly handling the cases including escaped characters and non-ASCII UTF-8 characters in the seamless manner.
For upgrades/migrations and double quotes in DNs: the two values may be left during the upgrade (just in case someone uses them as-is) and then an optional validation/cleaning script could be provided separately?
All right. That should work. I'm adding the validation/cleaning script to the design memo.
The sensitive part here is the whole o-NetscapeRoot tree: console using and writing this type of values, replication agreement/management etc
Indeed.
As for the "related bugs" section i think another bug should be added (https://bugzilla.redhat.com/show_bug.cgi?id=199923), it concernes the same RFC4514 compliance.
Oops. That's right. I'm adding it, too.
Thanks so much for your comments. --noriko
In order to support "Old DN format including DN in the double quotes" another cn=config switch may be necessary. It seems there was recently a new switch introduced to make the dn syntax validation a little more "relaxed" - nsslapd-dn-validate-strict. Maybe this one could be used to allow for DNs with double-quoted values?
Actually, the way how we are going to handle the old style 'dn: <type>="<nested dn>",<the rest>' is converting the old style to a new style in the normalization when the server receives DNs from clients and the converted new style DN is used in the rest of the process. The nsslapd-dn-validate-strict value is examined in the DN syntax validation code for now. Unless we change it, the DN syntax validation code always receives the new DN style.
Ok. What i wanted to say is that we should avoid any new config parameters
in cn=config. The way you propose to handle the problem is the best one - it is completely transparent to the user, the server back-end "sees" only the normalised DNs so it does not complain and no additional configuration parameters are necessary.
That being said, are you suggesting if nsslapd-dn-validate-strict is on, we
should not convert an old style DN to a new style? That'd be really strict. I'm leaning toward to the other side accepting the both old and new style with no restriction. Do you see any disadvantages in allowing the old style?
No, absolutely not, i agree completely with your reasoning. The code should be strict but not completely rigid :) Taking care of the "legacy" presentation in a transparent manner is the ideal solution.
On 03/17/2010 01:13 PM, Andrey Ivanov wrote:
In order to support "Old DN format including DN in the double quotes" another cn=config switch may be necessary. It seems there was recently a new switch introduced to make the dn syntax validation a little more "relaxed" - nsslapd-dn-validate-strict. Maybe this one could be used to allow for DNs with double-quoted values?Actually, the way how we are going to handle the old style 'dn: <type>="<nested dn>",<the rest>' is converting the old style to a new style in the normalization when the server receives DNs from clients and the converted new style DN is used in the rest of the process. The nsslapd-dn-validate-strict value is examined in the DN syntax validation code for now. Unless we change it, the DN syntax validation code always receives the new DN style.Ok. What i wanted to say is that we should avoid any new config parameters in cn=config. The way you propose to handle the problem is the best one - it is completely transparent to the user, the server back-end "sees" only the normalised DNs so it does not complain and no additional configuration parameters are necessary.
That being said, are you suggesting if nsslapd-dn-validate-strict is on, we should not convert an old style DN to a new style? That'd be really strict. I'm leaning toward to the other side accepting the both old and new style with no restriction. Do you see any disadvantages in allowing the old style?No, absolutely not, i agree completely with your reasoning. The code should be strict but not completely rigid :) Taking care of the "legacy" presentation in a transparent manner is the ideal solution.
Thanks so much for the confirmation, Andrey. I'm working on the issue based on the design... --noriko
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Noriko Hosoi