[Freeipa-devel] [PATCH 0049] Add support for protected tokens
Jan Cholasta
jcholast at redhat.com
Thu Jun 5 06:45:48 UTC 2014
On 28.5.2014 22:44, Nathaniel McCallum wrote:
> On Mon, 2014-05-26 at 16:57 +0200, Jan Cholasta wrote:
>> On 13.5.2014 19:12, Nathaniel McCallum wrote:
>>> On Tue, 2014-05-13 at 16:33 +0200, 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.)
>>>
>>> So since this is a 1-to-many relationship we shouldn't expose it?
>>>
>>> Or should I do it like owner is currently done?
>>
>> Do it like managedby is done in the host plugin (see
>> "attribute_members", "relationships", etc.)
>>
>>>
>>>>
>>>> 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";)
>>>
>>> The first set is organized by objectClass. The second by userattr. I
>>> have no strong opinion on this matter, though performance is probably a
>>> consideration. Do any DS guys want to chime in?
>>
>> I would still like to know someone else's opinion on this, but if
>> there's none, let's keep it your way.
>>
>>>
>>>> Would it make sense to keep --protected as a flag in otptoken-add as a
>>>> shortcut for "entry_attrs['managedby'] = None"?
>>>
>>> I can't think of a use case for this. The only use case I *can* think of
>>> is an admin creating a non-protected token for a user.
>>
>> OK.
>>
>>>
>>>> Would it make sense to default managedby to the current bind DN in
>>>> otptoken-add, even if it's not a user DN? (Do we want to allow running
>>>> otptoken-add by hosts/services/other non-users?)
>>>
>>> No idea. Dmitri?
>>
>> We can add this later if necessary.
>>
>>>
>>>> Is orphaning a token when a user is deleted only if it is not managed by
>>>> any other users the intended behavior? It just seems sort of strange to
>>>> me, since it changes the token from unprotected to protected.
>>>
>>> I don't think that is the behavior. We orphan the token if the owner is
>>> not listed as a manager. If the owner is listed as a manager, we delete
>>> the token.
>>>
>>> Put another way, protected tokens are orphaned and unprotected tokens
>>> are deleted.
>>>
>>> If I didn't implement that, please point out my bug.
>>
>> Sorry, my bad, your code is right. You can make it simpler, though:
>>
>> orphan = [x for x in token.get('managedby', []) if x == dn]
>>
>> (The "len() == 0" check is not necessary and using list comprehensions
>> makes the code more readable than using filter.)
>
> The attached version fixes all the above issues. Two issues that may
> remain:
> 1. There is no option to set managedBy during otptoken-add or
> otptoken-mod. This is probably okay.
Yes. I guess this bit is not needed anymore:
# If owner was not specified, default to the person adding
this token.
- if 'ipatokenowner' not in entry_attrs:
+ # If managedby was not specified, attempt a sensible default.
+ if 'ipatokenowner' not in entry_attrs or 'managedby' not in
entry_attrs:
result = self.api.Command.user_find(whoami=True)['result']
if result:
cur_uid = result[0]['uid'][0]
- entry_attrs.setdefault('ipatokenowner', cur_uid)
+ prev_uid = entry_attrs.setdefault('ipatokenowner', cur_uid)
+ if cur_uid == prev_uid:
+ entry_attrs.setdefault('managedby', result[0]['dn'])
> 2. I can't figure out how to get the framework to actually show
> managedBy in command output (like otptoken-show). This means you can
> add/remove relationships using otptoken-add-managedby and
> otptoken-remove-managedby, but you can't actually see the list of
> managers. What am I missing?
In the hbacrule or selinuxusermap plugins it is done by adding an
"invisible" param to the object plugin, like this:
Str('managedby_user?',
label=_('Manager'),
flags=['no_create', 'no_update', 'no_search'],
),
>
> Also, it would be helpful if someone with DS expertise could answer the
> question about the performance of the ACI structure options as listed
> above.
+1
>
> Nathaniel
>
You should update the code in user_del to use managedby_user instead of
managedby, otherwise it won't really work.
--
Jan Cholasta
More information about the Freeipa-devel
mailing list