On (28/07/16 12:44), thierry bordaz wrote: > > >On 07/28/2016 11:17 AM, Lukas Slebodnik wrote: >> On (28/07/16 10:24), thierry bordaz wrote: >> > >> > On 07/28/2016 09:39 AM, Jakub Hrozek wrote: >> > > On Wed, Jul 27, 2016 at 04:09:07PM +0200, thierry bordaz wrote: >> > > > On 07/27/2016 03:36 PM, Jakub Hrozek wrote: >> > > > > On Wed, Jul 27, 2016 at 02:55:37PM +0200, thierry bordaz wrote: >> > > > > > On 07/27/2016 01:56 PM, Jakub Hrozek wrote: >> > > > > > > On Wed, Jul 27, 2016 at 01:03:59PM +0200, Jakub Hrozek wrote: >> > > > > > > > On Wed, Jul 27, 2016 at 12:22:46PM +0200, Lukas Slebodnik >> > > > > > > > wrote: >> > > > > > > > > On (27/07/16 12:08), Jakub Hrozek wrote: >> > > > > > > > > > On Wed, Jul 27, 2016 at 12:02:24PM +0200, Jakub Hrozek >> > > > > > > > > > wrote: >> > > > > > > > > > > On Wed, Jul 27, 2016 at 11:54:16AM +0200, Lukas >> > > > > > > > > > > Slebodnik wrote: >> > > > > > > > > > > > ehlo, >> > > > > > > > > > > > >> > > > > > > > > > > > attached patch fixes acces denied after activating >> > > > > > > > > > > > user in 389ds. >> > > > > > > > > > > > Jakub had some comments/ideas in ticket but I think >> > > > > > > > > > > > it's better to discuss >> > > > > > > > > > > > about virtual attributes and timestamp cache on >> > > > > > > > > > > > mailing list. >> > > > > > > > > > > Yes, so the comment I have is that while this works, it >> > > > > > > > > > > might break some >> > > > > > > > > > > strange LDAP servers. >> > > > > > > > > > > >> > > > > > > > > > > We use modifyTimestamp as a 'positive' indicator that >> > > > > > > > > > > the entry has not >> > > > > > > > > > > changed -- if the modifyTimestamp didn't change, we >> > > > > > > > > > > consider the cached >> > > > > > > > > > > entry the same as what is on the server and only bump >> > > > > > > > > > > the timestamp >> > > > > > > > > > > cache. If the timestamp is different, we do a >> > > > > > > > > > > deep-comparison of cached >> > > > > > > > > > > attribute values with what is on the LDAP server and >> > > > > > > > > > > write the sysdb >> > > > > > > > > > > cache entry only if the attributes differ. >> > > > > > > > > > > >> > > > > > > > > > > I was wondering if we can use the modifyTimestamp at >> > > > > > > > > > > all, then, because >> > > > > > > > > > > even if it's the same, we might want to check the >> > > > > > > > > > > attributes to see if >> > > > > > > > > > > some of the values are different because some of the >> > > > > > > > > > > attributes might be >> > > > > > > > > > > this operational/virtual attribute.. >> > > > > > > > > > Sorry, sent too soon. >> > > > > > > > > > >> > > > > > > > > > I think the questions are -- 1) can we enumerate the >> > > > > > > > > > virtual attributes? >> > > > > > > > > That might be a question for 389-ds developers. >> > > > > > > > > But it's very likely it will be different on other LDAP >> > > > > > > > > servers. >> > > > > > > > > >> > > > > > > > > > 2) Would different LDAP servers have different virtual >> > > > > > > > > > attributes. >> > > > > > > > > > >> > > > > > > > > > For 2) maybe a possible solution might be to set a >> > > > > > > > > > non-existing >> > > > > > > > > > modifyTimestamp attribute value, but I would consider that >> > > > > > > > > > only a >> > > > > > > > > > kludge, we shouldn't break existing setups.. >> > > > > > > > > I am not satisfied with this POC solution either. >> > > > > > > > > >> > > > > > > > > So should we remove usage of modifyTimestamp for detecting >> > > > > > > > > changes? >> > > > > > > > I would prefer to ask the DS developers before removing it >> > > > > > > > completely. >> > > > > > > > >> > > > > > > > At least for large groups it might take a long time to compare >> > > > > > > > all attribute >> > > > > > > > values and IIRC we don't depend on any virtual attributes for >> > > > > > > > groups. Maybe >> > > > > > > > we could parametrize that part of the code and enable the fast >> > > > > > > > way with >> > > > > > > > modifyTimestamps for 'known' server types, that is for setups >> > > > > > > > with AD and >> > > > > > > > IPA providers. >> > > > > > > > >> > > > > > > > For users, there is typically not as many attributes so we >> > > > > > > > should be >> > > > > > > > fine deep-comparing all attributes. >> > > > > > > I'm adding Thierry (so please reply-to-all to keep him in the >> > > > > > > thread). >> > > > > > > >> > > > > > > Thierry, in the latest sssd version we tried to add a performance >> > > > > > > improvement related to how we store SSSD entries in the cache. >> > > > > > > The short >> > > > > > > version is that we store the modifyTimestamp attribute in the >> > > > > > > cache and >> > > > > > > when we fetch an entry, we compare the entry modifyTimestamp >> > > > > > > with what >> > > > > > > is on the server. When the two are the same, we say that the >> > > > > > > entry did >> > > > > > > not change and don't update the cache. >> > > > > > > >> > > > > > > This works fine for most attributes, but not for attributes like >> > > > > > > nsAccountLock which do not change modifyTimestamp when they are >> > > > > > > modified. So when an entry was already cached but then >> > > > > > > nsAccountLock >> > > > > > > changed, we treated the entry as the same and never read the new >> > > > > > > nsAccountLock value. >> > > > > > > >> > > > > > > To fix this, I think we have several options: >> > > > > > > 1) special-case the nsAccountLock. This seems a bit >> > > > > > > dangerous, >> > > > > > > because I'm not sure we can say that some other >> > > > > > > attribute we are >> > > > > > > interested in behaves the same as nsAccountLock. >> > > > > > > 2) drop the modifyTimestamp optimization completely. >> > > > > > > Then we fall >> > > > > > > back to comparing the attribute values, which might >> > > > > > > work, but for >> > > > > > > huge objects like groups with thousands of members, this >> > > > > > > might be >> > > > > > > too expensive. >> > > > > > > 3) only use the modifyTimestamp optimization for cases >> > > > > > > where we know >> > > > > > > we don't read any virtual attributes. >> > > > > > > >> > > > > > > And my question is -- can we, in general, know if the >> > > > > > > modifyTimestamp >> > > > > > > way of detecting changes is realiable for all LDAP servers? Or >> > > > > > > do you >> > > > > > > think it should only be used for cases where we know we are not >> > > > > > > interested in any virtual attributes (that would mostly be >> > > > > > > storing >> > > > > > > groups from servers where we know exactly what is on the server >> > > > > > > side, >> > > > > > > like IPA or AD). >> > > > > > Hello, >> > > > > > >> > > > > > Relying on modifytimestamp looks a good idea. Any MOD/MODRDN will >> > > > > > update it, >> > > > > > except I think it is unchanged when updating some password policy >> > > > > > attributes. >> > > > > > >> > > > > > Regarding virtual attribute, the only one I know in IPA is >> > > > > > nsaccountlock. >> > > > > > nsaccountlock is an operational attribute (you need to request it >> > > > > > to see it) >> > > > > > and is also a virtual attribute BUT only for 'staged' and >> > > > > > 'deleted' users. >> > > > > > It is a stored attribute for regular users and we should update >> > > > > > modifytimestamp when it is set. >> > > > > > >> > > > > > thanks >> > > > > > thierry >> > > > > OK, in that case it seems like we can special-case it. But do you >> > > > > know >> > > > > about any other attributes in any other LDAP servers? >> > > > Any LDAP server following standard should provide modifytimestamp that >> > > > reflect the last update of the entry. Now virtual attribute values may >> > > > be >> > > > "attached" to the entry and its value change without modification of >> > > > modifytimestamp. >> > > > For 389-ds and IPA it is fine as virtual value of nsaccountlock is >> > > > changed >> > > > only when the DN change. >> > > > For others LDAP servers I suppose it exists the same ability to define >> > > > service providers that return virtual attribute values. The difficulty >> > > > is >> > > > that the schema may not give any hint if the retrieved attributes >> > > > values >> > > > were stored or computed and consequently trust modifytimestamp to know >> > > > if >> > > > the values changed or not. >> > > > For example in ODSEE, memberof is a virtual attribute. >> > > Thank you, for the explanation Thierry. >> > > >> > > Then to be on the safe side I propose: >> > > 1) We add an (probably undocumented?) flag that says whether to use >> > > modifyTimestamp to detect entry changes or not >> > > 2) for the generic LDAP provider we always really compare the >> > > attribute values, in other words the option would be set to >> > > false. If there is anyone with performance issues with a generic >> > > setup, we tell them to flip the option. >> > > 3) For the IPA and AD providers, we set this option to true and use >> > > the modifyTimestamp value to detect changes >> > > 4) We special case nsAccountLock >> > I am not sure I understand why nsAccountLock is a special case ? >> > In IPA/389: >> > >> > * Stage user, it is always 'nsaccountlock: True' >> > When stage entry is created or updated, 'modifytimestamp' is also >> > updated. So you can rely on modifytimestamp to detect a change in a >> > stage user. >> > There is no way to update nsaccountlock for a stage entry >> > * Deleted user. Idem Stage user >> We haven't tested stage users yet. I ran just sssd related regression tests. >> >> > * Regular user. 'nsaccountlock' is *not* a virtual attribute, so if it >> > is enable/disable you can rely on modifytimestamp to detect a change >> > of 'nsaccountlock' for a regular user. >> > Also any change on regular user will update 'modifytimestamp' so you >> > can rely on it to detect a change. >> > >> My experience with ns-inactivate.pl and ns-activate.pl is different. >> modifytimestamp is not changed even though nsaccountlock was changed. >> >> It was a plain 389-ds with id_provider ldap in sssd >> >> LS >Hi Lukas, > > >It may have change recently because I can not reproduce. What versions are >you running ? > > # > #initial entry > # > ldapsearch -LLL -o ldif-wrap=no -D "cn=directory manager" -w xxx -b > "cn=accounts, <suffix>" 'uid=user0' nsaccountlock modifytimestamp > createtimestamp > dn: uid=user0,cn=users,cn=accounts,<suffix> > modifytimestamp: *20160728103441Z* > createtimestamp: 20160726160436Z > > # > # Inactivate: modifytimestamp changed > # > /usr/sbin/ns-inactivate.pl -Z <instance> -D "cn=directory manager" > -w xxx -I uid=user0,cn=users,cn=accounts,<suffix> > uid=user0,cn=users,cn=accounts,<suffix> inactivated. > > ldapsearch -LLL -o ldif-wrap=no -D "cn=directory manager" -w xxx -b > "cn=accounts, <suffix>" 'uid=user0' nsaccountlock modifytimestamp > createtimestamp > dn: uid=user0,cn=users,cn=accounts,<suffix> > nsaccountlock: true > modifytimestamp: *20160728103642Z* > createtimestamp: 20160726160436Z > > # > # activate: modifytimestamp changed > # > /usr/sbin/ns-activate.pl -Z <instance> -D "cn=directory manager" -w > xxx -I uid=user0,cn=users,cn=accounts,<suffix> > uid=user0,cn=users,cn=accounts,<suffix> activated. > > ldapsearch -LLL -o ldif-wrap=no -D "cn=directory manager" -w xxx -b > "cn=accounts, <suffix>" 'uid=user0' nsaccountlock modifytimestamp > createtimestamp > dn: uid=user0,cn=users,cn=accounts,<suffix> > modifytimestamp: *20160728103711Z* > createtimestamp: 20160726160436Z > rhel7.3 389-ds-base-1.3.5.10-5.el7.x86_64
But I didn't test directly with user but indirectly *Add Managed role dn: cn=managed,ou=people,dc=example,dc=com objectclass: top objectclass: LdapSubEntry objectclass: nsRoleDefinition objectclass: nsSimpleRoleDefinition objectclass: nsManagedRoleDefinition cn: Managed *Authenticate with lockuser *Add user to managed role dn: uid=lockuser,ou=people,dc=example,dc=com changetype: modify add: nsRoleDN nsRoleDN: cn=managed,ou=people,dc=example,dc=com ns-inactivate.pl -D cn=Manager,dc=example,dc=com" -E -p 389 \ -h $SERVER -I cn=managed,ou=people,dc=example,dc=com *Authenticate with lockuser ns-activate.pl -D cn=Manager,dc=example,dc=com" -E -p 389 \ -h $SERVER -I cn=managed,ou=people,dc=example,dc=com *Authenticate with lockuser Should I test with rhel7.2 or is it an expected behaviour ? LS _______________________________________________ sssd-devel mailing list sssd-devel@lists.fedorahosted.org https://lists.fedorahosted.org/admin/lists/sssd-devel@lists.fedorahosted.org