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.
```
==================
WARNING: DATA RACE
Read at 0x0000082be990 by goroutine 205:
github.com/minio/minio/cmd.setCommonHeaders()
Previous write at 0x0000082be990 by main goroutine:
github.com/minio/minio/cmd.lookupConfigs()
```
At server startup, LDAP configuration is validated against the LDAP
server. If the LDAP server is down at that point, we need to cleanly
disable LDAP configuration. Previously, LDAP would remain configured but
error out in strange ways because initialization did not complete
without errors.
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.
Existing IAM import logic for LDAP creates new mappings when the
normalized form of the mapping key differs from the existing mapping key
in storage. This change effectively replaces the existing mapping key by
first deleting it and then recreating with the normalized form of the
mapping key.
For e.g. if an older deployment had a policy mapped to a user DN -
`UID=alice1,OU=people,OU=hwengg,DC=min,DC=io`
instead of adding a mapping for the normalized form -
`uid=alice1,ou=people,ou=hwengg,dc=min,dc=io`
we should replace the existing mapping.
This ensures that duplicates mappings won't remain after the import.
Some additional cleanup cases are also covered. If there are multiple
mappings for the name normalized key such as:
`UID=alice1,OU=people,OU=hwengg,DC=min,DC=io`
`uid=alice1,ou=people,ou=hwengg,DC=min,DC=io`
`uid=alice1,ou=people,ou=hwengg,dc=min,dc=io`
we check if the list of policies mapped to all these keys are exactly
the same, and if so remove all of them and create a single mapping with
the normalized key. However, if the policies mapped to such keys differ,
the import operation returns an error as the server cannot automatically
pick the "right" list of policies to map.
When LDAP is enabled, previously we were:
- rejecting creation of users and groups via the IAM import functionality
- throwing a `not a valid DN` error when non-LDAP group mappings are present
This change allows for these cases as we need to support situations
where the MinIO server contains users, groups and policy mappings
created before LDAP was enabled.
Follow up for #19528
If there are multiple existing DN mappings for the same normalized DN,
if they all have the same policy mapping value, we pick one of them of
them instead of returning an import error.
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.
Create new code paths for multiple subsystems in the code. This will
make maintaing this easier later.
Also introduce bugLogIf() for errors that should not happen in the first
place.
This fixes a bug where STS Accounts map accumulates accounts in memory
and never removes expired accounts and the STS Policy mappings were not
being refreshed.
The STS purge routine now runs with every IAM credentials load instead
of every 4th time.
The listing of IAM files is now cached on every IAM load operation to
prevent re-listing for STS accounts purging/reload.
Additionally this change makes each server pick a time for IAM loading
that is randomly distributed from a 10 minute interval - this is to
prevent server from thundering while performing the IAM load.
On average, IAM loading will happen between every 5-15min after the
previous IAM load operation completes.
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.
This change is to decouple need for root credentials to match between
site replication deployments.
Also ensuring site replication config initialization is re-tried until
it succeeds, this deoendency is critical to STS flow in site replication
scenario.
To force limit the duration of STS accounts, the user can create a new
policy, like the following:
{
"Version": "2012-10-17",
"Statement": [{
"Effect": "Allow",
"Action": ["sts:AssumeRoleWithWebIdentity"],
"Condition": {"NumericLessThanEquals": {"sts:DurationSeconds": "300"}}
}]
}
And force binding the policy to all OpenID users, whether using a claim name or role
ARN.
Interpret `null` inline policy for access keys as inheriting parent
policy. Since MinIO Console currently sends this value, we need to honor it
for now. A larger fix in Console and in the server are required.
Fixes#18939.
With this change, only a user with `UpdateServiceAccountAdminAction`
permission is able to edit access keys.
We would like to let a user edit their own access keys, however the
feature needs to be re-designed for better security and integration with
external systems like AD/LDAP and OpenID.
This change prevents privilege escalation via service accounts.
`OpMuxConnectError` was not handled correctly.
Remove local checks for single request handlers so they can
run before being registered locally.
Bonus: Only log IAM bootstrap on startup.
Since relaxing quorum the error across pools
for ListBuckets(), GetBucketInfo() we hit a
situation where loading IAM could potentially
return an error for second pool that server
is not initialized.
We need to handle this, let the pool come online
and retry transparently - this PR fixes that.
This helps reduce disk operations as these periodic routines would not
run concurrently any more.
Also add expired STS purging periodic operation: Since we do not scan
the on-disk STS credentials (and instead only load them on-demand) a
separate routine is needed to purge expired credentials from storage.
Currently this runs about a quarter as often as IAM refresh.
Also fix a bug where with etcd, STS accounts could get loaded into the
iamUsersMap instead of the iamSTSAccountsMap.
In situations with large number of STS credentials on disk, IAM load
time is high. To mitigate this, STS accounts will now be loaded into
memory only on demand - i.e. when the credential is used.
In each IAM cache (re)load we skip loading STS credentials and STS
policy mappings into memory. Since STS accounts only expire and cannot
be deleted, there is no risk of invalid credentials being reused,
because credential validity is checked when it is used.
For policy attach/detach API to work correctly the server should hold a
lock before reading existing policy mapping and until after writing the
updated policy mapping. This is fixed in this change.
A site replication bug, where LDAP policy attach/detach were not
correctly propagated is also fixed in this change.
Bonus: Additionally, the server responds with the actual (or net)
changes performed in the attach/detach API call. For e.g. if a user
already has policy A applied, and a call to attach policies A and B is
performed, the server will respond that B was attached successfully.
