Merge branch '2fa-check-git-http' into 'master'

2FA checks for Git over HTTP

## What does this MR do?

This MR allows the use of `PersonalAccessTokens` to access Git over HTTP and makes that the only allowed method if the user has 2FA enabled. If a user with 2FA enabled tries to access Git over HTTP using his username and password the request will be denied and the user will be presented with the following message:

```
remote: HTTP Basic: Access denied
remote: You have 2FA enabled, please use a personal access token for Git over HTTP.
remote: You can generate one at http://localhost:3000/profile/personal_access_tokens
fatal: Authentication failed for 'http://localhost:3000/documentcloud/underscore.git/'
```

## What are the relevant issue numbers?

Fixes #13568 

See merge request !5764

1 files changed, 10 insertions, 0 deletions

diff --git a/app/controllers/projects/git_http_client_controller.rb b/app/controllers/projects/git_http_client_controller.rb
index 7c21bd181dc..a5b4031c30f 100644
--- a/app/controllers/projects/git_http_client_controller.rb
+++ b/app/controllers/projects/git_http_client_controller.rb
@@ -27,6 +27,9 @@ class Projects::GitHttpClientController < Projects::ApplicationController
         @ci = true
       elsif auth_result.type == :oauth && !download_request?
         # Not allowed
+      elsif auth_result.type == :missing_personal_token
+        render_missing_personal_token
+        return # Render above denied access, nothing left to do
       else
         @user = auth_result.user
       end
@@ -91,6 +94,13 @@ class Projects::GitHttpClientController < Projects::ApplicationController
     [nil, nil]
   end
 
+  def render_missing_personal_token
+    render plain: "HTTP Basic: Access denied\n" \
+                  "You have 2FA enabled, please use a personal access token for Git over HTTP.\n" \
+                  "You can generate one at #{profile_personal_access_tokens_url}",
+           status: 401
+  end
+
   def repository
     _, suffix = project_id_with_suffix
     if suffix == '.wiki.git'