[Freeipa-devel] [PATCH 0049] Add support for protected tokens

[Nathaniel McCallum]

On Wed, 2014-06-11 at 12:12 +0200, Ludwig Krispenz wrote:
> On 05/13/2014 04:33 PM, Jan Cholasta wrote:
> > On 12.5.2014 21:02, Nathaniel McCallum wrote:
> >> On Thu, 2014-05-08 at 13:51 -0400, Simo Sorce wrote:
> >>> On Thu, 2014-05-08 at 12:26 -0400, Nathaniel McCallum wrote:
> >>>> On Wed, 2014-05-07 at 11:17 -0400, Simo Sorce wrote:
> >>>>> On Wed, 2014-05-07 at 09:54 -0400, Dmitri Pal wrote:
> >>>>>> On 05/07/2014 09:05 AM, Nathaniel McCallum wrote:
> >>>>>>> On Wed, 2014-05-07 at 11:42 +0200, Jan Cholasta wrote:
> >>>>>>>> Hi,
> >>>>>>>>
> >>>>>>>> On 6.5.2014 17:08, Nathaniel McCallum wrote:
> >>>>>>>>> On Tue, 2014-05-06 at 09:49 -0400, Nathaniel McCallum wrote:
> >>>>>>>>>> On Mon, 2014-05-05 at 12:42 -0400, Nathaniel McCallum wrote:
> >>>>>>>>>>> This also constitutes a rethinking of the token ACIs after the
> >>>>>>>>>>> introduction of SELFDN support.
> >>>>>>>>>>>
> >>>>>>>>>>> Admins, as before, have full access to all token permissions.
> >>>>>>>>>>>
> >>>>>>>>>>> Normal users have read/search/compare access to all of the 
> >>>>>>>>>>> non-secret
> >>>>>>>>>>> data for tokens assigned to them, whether protected or 
> >>>>>>>>>>> non-protected.
> >>>>>>>>>>> Users can add or delete non-protected tokens and modify most 
> >>>>>>>>>>> of their
> >>>>>>>>>>> metadata. However they cannot create, delete or modify 
> >>>>>>>>>>> protected tokens.
> >>>>>>>>>>> Regardless of whether the token is protected or not, users 
> >>>>>>>>>>> cannot change
> >>>>>>>>>>> a token's ownership or unique identity.
> >>>>>>>>>>>
> >>>>>>>>>>> In contrast, admins can create protected tokens. This 
> >>>>>>>>>>> protects the token
> >>>>>>>>>>> from deletion or modification when assigned to users. 
> >>>>>>>>>>> Additionally, when
> >>>>>>>>>>> a user account is deleted, the assigned non-protected tokens 
> >>>>>>>>>>> are deleted
> >>>>>>>>>>> but the protected tokens are merely orphaned. This permits 
> >>>>>>>>>>> the token to
> >>>>>>>>>>> be reassigned without having to recreate it. This last point is
> >>>>>>>>>>> particularly useful in the case of hardware tokens.
> >>>>>>>>>>>
> >>>>>>>>>>> https://fedorahosted.org/freeipa/ticket/4228
> >>>>>>>>>>>
> >>>>>>>>>>> NOTE: This patch depends on my patch 0048.
> >>>>>>>>>> This new version makes ipatokenDisabled visible for token 
> >>>>>>>>>> owners. It is
> >>>>>>>>>> also writable if the token is non-protected. This 
> >>>>>>>>>> additionally fixes:
> >>>>>>>>>>
> >>>>>>>>>> https://fedorahosted.org/freeipa/ticket/4259
> >>>>>>>>> This new version changes the way the default value of 
> >>>>>>>>> protected is setup
> >>>>>>>>> in accordance with the changes made for the review of my patch 
> >>>>>>>>> 0048.2.
> >>>>>>>>>
> >>>>>>>>> Nathaniel
> >>>>>>>> Is using the ipatokenprotected attribute the final design?
> >>>>>>> No. Alternate designs are welcome. The code is easy enough to 
> >>>>>>> modify.
> >>>>>>>
> >>>>>>>> I did not dig too deep into this, but I think it might be 
> >>>>>>>> better to
> >>>>>>>> instead use the managedby attribute on a token to limit who can 
> >>>>>>>> delete
> >>>>>>>> (or administer in other way) the token. On otptoken-add, 
> >>>>>>>> managedby would
> >>>>>>>> be set to the "whoami" user DN, unless run with --protected, in 
> >>>>>>>> which
> >>>>>>>> case managedby would be left empty. Then, when deleting a user, 
> >>>>>>>> the
> >>>>>>>> token would be deleted only if the user manages the token.
> >>>>>>> It seems to me that the mechanics of this are roughly the same as
> >>>>>>> protected, just with a different syntax. The cost of this is more
> >>>>>>> complex ACIs. In particular, we'd have to use two userdn clauses 
> >>>>>>> (is
> >>>>>>> this possible?) instead of a simple filter. If there is a clear 
> >>>>>>> benefit,
> >>>>>>> we can justify the more obtuse syntax.
> >>>>>>
> >>>>>> We usually try not to create new attributes until it is fully 
> >>>>>> justified.
> >>>>>> I would like Simo to chime in on this.
> >>>>>
> >>>>> I would also prefer to reuse existing attributes and mechanism if
> >>>>> possible and if it will not preclude future work.
> >>>>>
> >>>>> In this case, it "sounds" like managed-by has the appropriate 
> >>>>> meaning:
> >>>>> "who manages the token ?" -> myself, admin, other, none ?
> >>>>>
> >>>>> Nathaniel can you send 2 lines showing the difference in ACIs between
> >>>>> using managed-by vs a new attribute ?
> >>>>
> >>>> These are the ACIs using the protected mechanism:
> >>>>
> >>>> aci: (targetfilter = "(objectClass=ipaToken)")(targetattrs =
> >>>> "objectclass || description || ipatokenUniqueID || ipatokenDisabled ||
> >>>> ipatokenNotBefore || ipatokenNotAfter || ipatokenVendor || 
> >>>> ipatokenModel
> >>>> || ipatokenSerial || ipatokenOwner || ipatokenProtected")(version 3.0;
> >>>> acl "Users can read basic token info"; allow (read, search, compare)
> >>>> userattr = "ipatokenOwner#USERDN";)
> >>>>
> >>>> aci: (targetfilter = "(objectClass=ipatokenTOTP)")(targetattrs =
> >>>> "ipatokenOTPalgorithm || ipatokenOTPdigits ||
> >>>> ipatokenTOTPtimeStep")(version 3.0; acl "Users can see TOTP details";
> >>>> allow (read, search, compare) userattr = "ipatokenOwner#USERDN";)
> >>>>
> >>>> aci: (targetfilter = "(objectClass=ipatokenHOTP)")(targetattrs =
> >>>> "ipatokenOTPalgorithm || ipatokenOTPdigits")(version 3.0; acl 
> >>>> "Users can
> >>>> see HOTP details"; allow (read, search, compare) userattr =
> >>>> "ipatokenOwner#USERDN";)
> >>>>
> >>>> aci: (targetfilter =
> >>>> "(&(objectClass=ipaToken)(!(ipatokenProtected=TRUE)))")(targetattrs =
> >>>> "description || ipatokenDisabled || ipatokenNotBefore ||
> >>>> ipatokenNotAfter || ipatokenVendor || ipatokenModel ||
> >>>> ipatokenSerial")(version 3.0; acl "Users can write basic token info";
> >>>> allow (write) userattr = "ipatokenOwner#USERDN";)
> >>>>
> >>>> aci: (target = 
> >>>> "ldap:///ipatokenuniqueid=*,cn=otp,$SUFFIX")(targetfilter
> >>>> = "(&(objectClass=ipaToken)(!(ipatokenProtected=TRUE))))")(version 
> >>>> 3.0;
> >>>> acl "Users can create and delete tokens"; allow (add, delete) 
> >>>> userattr =
> >>>> "ipatokenOwner#SELFDN";)
> >>>>
> >>>> This is what they look like using managedBy (I have not tested this):
> >>>>
> >>>> aci: (targetfilter = "(objectClass=ipaToken)")(targetattrs =
> >>>> "objectclass || description || ipatokenUniqueID || ipatokenDisabled ||
> >>>> ipatokenNotBefore || ipatokenNotAfter || ipatokenVendor || 
> >>>> ipatokenModel
> >>>> || ipatokenSerial || ipatokenOwner || ipatokenProtected")(version 3.0;
> >>>> acl "Users can read basic token info"; allow (read, search, compare)
> >>>> userattr = "ipatokenOwner#USERDN"; allow (read, search, compare)
> >>>> userattr = "managedBy#USERDN";)
> >>>>
> >>>> aci: (targetfilter = "(objectClass=ipatokenTOTP)")(targetattrs =
> >>>> "ipatokenOTPalgorithm || ipatokenOTPdigits ||
> >>>> ipatokenTOTPtimeStep")(version 3.0; acl "Users can see TOTP details";
> >>>> allow (read, search, compare) userattr = "ipatokenOwner#USERDN"; allow
> >>>> (read, search, compare) userattr = "managedBy#USERDN";)
> >>>>
> >>>> aci: (targetfilter = "(objectClass=ipatokenHOTP)")(targetattrs =
> >>>> "ipatokenOTPalgorithm || ipatokenOTPdigits")(version 3.0; acl 
> >>>> "Users can
> >>>> see HOTP details"; allow (read, search, compare) userattr =
> >>>> "ipatokenOwner#USERDN"; allow (read, search, compare) userattr =
> >>>> "managedBy#USERDN";)
> >>>>
> >>>> aci: (targetfilter = "(objectClass=ipaToken)")(targetattrs =
> >>>> "description || ipatokenDisabled || ipatokenNotBefore ||
> >>>> ipatokenNotAfter || ipatokenVendor || ipatokenModel ||
> >>>> ipatokenSerial")(version 3.0; acl "Managers can write basic token 
> >>>> info";
> >>>> allow (write) userattr = "managedBy#USERDN";)
> >>>>
> >>>> aci: (targetfilter = "(objectClass=ipaToken)")(version 3.0; acl
> >>>> "Managers can delete tokens"; allow (delete) userattr =
> >>>> "managedBy#USERDN";)
> >>>>
> >>>> aci: (target = 
> >>>> "ldap:///ipatokenuniqueid=*,cn=otp,$SUFFIX")(targetfilter
> >>>> = "(objectClass=ipaToken)")(version 3.0; acl "Users can create
> >>>> self-managed tokens"; allow (add) userattr = "ipatokenOwner#SELFDN" 
> >>>> and
> >>>> userattr = "managedBy#SELFDN";)
> >>>>
> >>>> In short:
> >>>> 1. Owner and manager get read, search and compare.
> >>>> 2. Manager gets write (to select attributes) and delete.
> >>>> 3. Users can create self-managed tokens for themselves only.
> >>>>
> >>>> The otptoken-add command should gain the following defaults:
> >>>> 1. The owner defaults to the user adding the token.
> >>>> 2. If owner == user adding token, managedBy defaults to owner.
> >>>> 3. Otherwise, managedBy defaults to None.
> >>>>
> >>>> This means that if neither owner nor managedBy are specified, the
> >>>> default is a self-owned, self-managed token. Likewise, if a different
> >>>> owner is specified, no manager is assumed.
> >>>>
> >>>> rcrit expresses worry that ipalib's ACI parser may not handle the 
> >>>> above
> >>>> syntax. This will become clear during testing if we want this 
> >>>> approach.
> >>>>
> >>>> Does this look sane?
> >>>
> >>> I am not entirely sure your ACI syntax is always right for the second
> >>> set. and perhaps we want to duplicate ACIs in some cases (once for 
> >>> owner
> >>> once for manager).
> >>>
> >>> I think the read ACIs do not need to list managedby ? Do we plan to 
> >>> have
> >>> a manager that is another regular user but not the owner nor an admin ?
> >>>
> >>> In any case I prefer the sytnax that uses managedby, as it has more
> >>> potential.
> >>
> >> Attached is a new version of the patch which implements the feature
> >> using managedBy instead of ipatokenProtected. One important thing needs
> >> to be said about this patch. I am not exposing managedBy in either the
> >> UI, the CLI or LDAP (ACI). Do we care about this? If yes, should I
> >> expose this similar to owner or as a relationship?
> >
> > I would expose it, as a relationship. (Note that ipatokenowner should 
> > ideally be represented as a relationship too, but the framework does 
> > not support 1-to-many relationships ATM.)
> >
> >
> > Just curious, why are the ACIs divided like this:
> >
> >     aci: (targetfilter = "(objectClass=ipaToken)")(targetattrs = 
> > "objectclass || description || ipatokenUniqueID || ipatokenDisabled || 
> > ipatokenNotBefore || ipatokenNotAfter || ipatokenVendor || 
> > ipatokenModel || ipatokenSerial || ipatokenOwner")(version 3.0; acl 
> > "Users/managers can read basic token info"; allow (read, search, 
> > compare) userattr = "ipatokenOwner#USERDN" or userattr = 
> > "managedBy#USERDN";)
> >     aci: (targetfilter = "(objectClass=ipatokenTOTP)")(targetattrs = 
> > "ipatokenOTPalgorithm || ipatokenOTPdigits || 
> > ipatokenTOTPtimeStep")(version 3.0; acl "Users/managers can see TOTP 
> > details"; allow (read, search, compare) userattr = 
> > "ipatokenOwner#USERDN" or userattr = "managedBy#USERDN";)
> >     aci: (targetfilter = "(objectClass=ipatokenHOTP)")(targetattrs = 
> > "ipatokenOTPalgorithm || ipatokenOTPdigits")(version 3.0; acl 
> > "Users/managers can see HOTP details"; allow (read, search, compare) 
> > userattr = "ipatokenOwner#USERDN" or userattr = "managedBy#USERDN";)
> >
> > IMHO you could make them less complex by dividing them like this:
> >
> >     aci: (targetfilter = "(objectClass=ipaToken)")(targetattrs = 
> > "objectclass || description || ipatokenUniqueID || ipatokenDisabled || 
> > ipatokenNotBefore || ipatokenNotAfter || ipatokenVendor || 
> > ipatokenModel || ipatokenSerial || ipatokenOwner || 
> > ipatokenOTPalgorithm || ipatokenOTPdigits || 
> > ipatokenTOTPtimeStep")(version 3.0; acl "Owner can read token 
> > details"; allow (read, search, compare) userattr = 
> > "ipatokenOwner#USERDN";)
> >     aci: (targetfilter = "(objectClass=ipaToken)")(targetattrs = 
> > "objectclass || description || ipatokenUniqueID || ipatokenDisabled || 
> > ipatokenNotBefore || ipatokenNotAfter || ipatokenVendor || 
> > ipatokenModel || ipatokenSerial || ipatokenOwner || 
> > ipatokenOTPalgorithm || ipatokenOTPdigits || 
> > ipatokenTOTPtimeStep")(version 3.0; acl "Managers can read token 
> > details"; allow (read, search, compare) userattr = "managedBy#USERDN";)
> do you mean aci: (targetfilter = 
> "(|(objectClass=ipaToken)(objectClass=ipatokenTOTP)(objectClass=ipatokenHOTP))") 
> or are the attrs like ipatokenOTPdigits also in the ipatoken objectclass ?
> >

Ludwig,

objectClasses:  (2.16.840.1.113730.3.8.16.2.1  NAME 'ipaToken' SUP top
ABSTRACT DESC 'Abstract token class for tokens' MUST (ipatokenUniqueID)
MAY (description $ ipatokenOwner $ ipatokenDisabled $ ipatokenNotBefore
$ ipatokenNotAfter $ ipatokenVendor $ ipatokenModel $ ipatokenSerial)
X-ORIGIN 'IPA OTP')

objectClasses:  (2.16.840.1.113730.3.8.16.2.2  NAME 'ipatokenTOTP' SUP
ipaToken STRUCTURAL DESC 'TOTP Token Type' MUST (ipatokenOTPkey $
ipatokenOTPalgorithm $ ipatokenOTPdigits $ ipatokenTOTPclockOffset $
ipatokenTOTPtimeStep) X-ORIGIN 'IPA OTP')

objectClasses:  (2.16.840.1.113730.3.8.16.2.5  NAME 'ipatokenHOTP' SUP
ipaToken STRUCTURAL DESC 'HOTP Token Type' MUST (ipatokenOTPkey $
ipatokenOTPalgorithm $ ipatokenOTPdigits $ ipatokenHOTPcounter) X-ORIGIN
'IPA OTP')

Nathaniel