fix: authenticate LDAP via actual DN instead of normalized DN
Normalized DN is only for internal representation, not for
external communication, any communication to LDAP must be
based on actual user DN. LDAP servers do not understand
normalized DN.
fixes#19757
This change uses the updated ldap library in minio/pkg (bumped
up to v3). A new config parameter is added for LDAP configuration to
specify extra user attributes to load from the LDAP server and to store
them as additional claims for the user.
A test is added in sts_handlers.go that shows how to access the LDAP
attributes as a claim.
This is in preparation for adding SSH pubkey authentication to MinIO's SFTP
integration.
When importing access keys (i.e. service accounts) for LDAP accounts,
we are requiring groups to exist under one of the configured group base
DNs. This is not correct. This change fixes this by only checking for
existence and storing the normalized form of the group DN - we do not
return an error if the group is not under a base DN.
Test is updated to illustrate an import failure that would happen
without this change.
This is a change to IAM export/import functionality. For LDAP enabled
setups, it performs additional validations:
- for policy mappings on LDAP users and groups, it ensures that the
corresponding user or group DN exists and if so uses a normalized form
of these DNs for storage
- for access keys (service accounts), it updates (i.e. validates
existence and normalizes) the internally stored parent user DN and group
DNs.
This allows for a migration path for setups in which LDAP mappings have
been stored in previous versions of the server, where the name of the
mapping file stored on drives is not in a normalized form.
An administrator needs to execute:
`mc admin iam export ALIAS`
followed by
`mc admin iam import ALIAS /path/to/export/file`
The validations are more strict and returns errors when multiple
mappings are found for the same user/group DN. This is to ensure the
mappings stored by the server are unambiguous and to reduce the
potential for confusion.
Bonus **bug fix**: IAM export of access keys (service accounts) did not
export key name, description and expiration. This is fixed in this
change too.
This fixes a regression from #19358 which prevents policy mappings
created in the latest release from being displayed in policy entity
listing APIs.
This is due to the possibility that the base DNs in the LDAP config are
not in a normalized form and #19358 introduced normalized of mapping
keys (user DNs and group DNs). When listing, we check if the policy
mappings are on entities that parse as valid DNs that are descendants of
the base DNs in the config.
Test added that demonstrates a failure without this fix.
Instead of relying on user input values, we use the DN value returned by
the LDAP server.
This handles cases like when a mapping is set on a DN value
`uid=svc.algorithm,OU=swengg,DC=min,DC=io` with a user input value (with
unicode variation) of `uid=svc﹒algorithm,OU=swengg,DC=min,DC=io`. The
LDAP server on lookup of this DN returns the normalized value where the
unicode dot character `SMALL FULL STOP` (in the user input), gets
replaced with regular full stop.
