LDAP bind_dn credentials vs. personal LDAP credentials results in the same user being logged in

Summary

Logging in using different external credentials works, but upon login are tied to the same GitLab-side user.

Steps to reproduce

  1. You must have a GitLab CE instance that is connected to an external LDAP, and the credentials for at least two separate users.
  2. Log in using the first user (e.g., foo), and verify that you are correctly logged in as foo. Also note that foo in this case is what we use for the ldap_servers's main.bind_dn.
  3. Log out.
  4. Log in using the second user (e.g., bar), and find that you are incorrectly logged in as foo.
  5. Log out.

Example Project

N/A

What is the current bug behavior?

Logging in as either foo or bar unexpectedly results in the same GitLab-side user.

What is the expected correct behavior?

Logging in as either foo or bar results in two different GitLab-side users.

Relevant logs and/or screenshots

Using ldapsearch, I searched for two different usernames, they are indeed different users. And as I mentioned above, foo in this case is what we've configured as the bind_dn.

I further confirmed that the LDAP uid value in Admin Area > Users > selected user is actually changed depending on whether I used my foo or bar credentials.

Output of checks

This bug is currently reproducible on our self-hosted GitLab CE instance v12.7.6 (61654d25b20).

Results of GitLab environment info

Expand for output related to GitLab environment info 
System information
System:
Current User:   git
Using RVM:      no
Ruby Version:   2.6.5p114
Gem Version:    2.7.10
Bundler Version:1.17.3
Rake Version:   12.3.3
Redis Version:  5.0.7
Git Version:    2.24.1
Sidekiq Version:5.2.7
Go Version:     unknown


GitLab information
Version:        12.7.6
Revision:       61654d25b20
Directory:      /opt/gitlab/embedded/service/gitlab-rails
DB Adapter:     PostgreSQL
DB Version:     10.9
URL:            REDACTED
HTTP Clone URL: REDACTED
SSH Clone URL:  REDACTED
Using LDAP:     yes
Using Omniauth: yes
Omniauth Providers:


GitLab Shell
Version:        11.0.0
Repository storage paths:
  • default: /var/opt/gitlab/git-data/repositories GitLab Shell path: /opt/gitlab/embedded/service/gitlab-shell Git: /opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check 
Checking GitLab subtasks ...

Checking GitLab Shell ...


GitLab Shell: ... GitLab Shell version >= 11.0.0 ? ... OK (11.0.0)
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Internal API available: OK
Redis available via internal API: OK
gitlab-shell self-check successful


Checking GitLab Shell ... Finished


Checking Gitaly ...


Gitaly: ... default ... OK


Checking Gitaly ... Finished


Checking Sidekiq ...


Sidekiq: ... Running? ... yes
Number of Sidekiq processes ... 1


Checking Sidekiq ... Finished


Checking Incoming Email ...


Incoming Email: ... Reply by email is disabled in config/gitlab.yml


Checking Incoming Email ... Finished


Checking LDAP ...


LDAP: ... Server: ldapmain
LDAP authentication... Success
LDAP users with access to your GitLab server (only showing the first 100 results)
User output sanitized. Found 100 users of 100 limit.


Checking LDAP ... Finished


Checking GitLab App ...


Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... skipped (no tmp uploads folder yet)
Init script exists? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
3/1 ... yes
5/3 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.5.3 ? ... yes (2.6.5)
Git version >= 2.22.0 ? ... yes (2.24.1)
Git user has default SSH configuration? ... yes
Active users: ... 5
Is authorized keys file accessible? ... yes


Checking GitLab App ... Finished


Checking GitLab subtasks ... Finished

Possible fixes

N/A