Deleting project with deploy key deletes the corresponding key only in database and not in authorized_keys

Summary

When deleting a project with deploy keys, the corresponding keys are only deleted in the database and not in the authorized_keys file of the git user. Because of the orphaned entry in authorized_keys the key does not work if you reuse this key on another project.

Steps to reproduce

  1. Create a private project.
  2. Add a deploy key.
  3. Verify that GitLab greats you with your username when logging in using "ssh -T git@your-gitbab-server".
  4. Record the database id of your deploy key. Get it with this command on your GitLab server: sudo -u gitlab-psql /opt/gitlab/embedded/bin/psql -h /var/opt/gitlab/postgresql/ gitlabhq_production -c "select id from keys where fingerprint = 'YOUR_FINGERPRINT';".
  5. Delete project.
  6. Create another private project and add the same public key as in step 2 as deploy key.
  7. Try to clone the project created in step 5 over ssh. You should get the following message:
GitLab: The project you were looking for could not be found.
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
  1. Verify that GitLab greats you as anonymous when logging in using "ssh -T git@your-gitbab-server"
  2. Get the id of your deploy key again as in step 4.
  3. Have a look into /var/opt/gitlab/.ssh/authorized_keys, search for your public key and verify that it still uses the old database id (recorded in step 4) in "command=... key-OLD_KEY" and not the new one you recorded in step 9.
  4. Delete the wrong line from authorized_keys.
  5. Delete deploy key from the project using web gui.
  6. Readd the deploy key to your project.
  7. Everything should be fine now!

What is the current bug behavior?

The key isn't refreshed in authorized_keys and still has the same (database) id as the old key and because of that GitLab can't find a corresponding key to your reused public key.

What is the expected correct behavior?

GitLab should remove the key from authorized_keys file when deleting the key in the database.

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info 
System information
System:         Ubuntu 18.04
Current User:   git
Using RVM:      no
Ruby Version:   2.5.3p105
Gem Version:    2.7.6
Bundler Version:1.16.6
Rake Version:   12.3.2
Redis Version:  3.2.12
Git Version:    2.18.1
Sidekiq Version:5.2.5
Go Version:     unknown


GitLab information
Version:        11.9.8
Revision:       48528bcd618
Directory:      /opt/gitlab/embedded/service/gitlab-rails
DB Adapter:     postgresql
URL:            https://xxxxxx
HTTP Clone URL: https://xxxxxx/some-group/some-project.git
SSH Clone URL:  git@xxxxxx:some-group/some-project.git
Using LDAP:     yes
Using Omniauth: yes
Omniauth Providers:


GitLab Shell
Version:        8.7.1
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 
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)
Removed


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? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
3/1 ... yes
3/2 ... yes
3/3 ... yes
3/4 ... yes
3/5 ... yes
3/6 ... yes
3/7 ... yes
3/8 ... yes
3/9 ... yes
3/10 ... yes
3/11 ... yes
3/15 ... yes
5/16 ... yes
5/17 ... yes
5/18 ... yes
6/19 ... yes
5/20 ... yes
5/21 ... yes
5/22 ... yes
7/25 ... yes
2/27 ... yes
7/29 ... yes
2/30 ... yes
5/31 ... yes
7/32 ... yes
2/37 ... yes
2/38 ... yes
2/39 ... yes
2/41 ... yes
4/42 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.3.5 ? ... yes (2.5.3)
Git version >= 2.18.0 ? ... yes (2.18.1)
Git user has default SSH configuration? ... yes
Active users: ... 9


Checking GitLab App ... Finished


Checking GitLab subtasks ... Finished