Private repository names publicly checkable with 'git push'

It's possible to check publicly if a private repository with a certain name exists.

Steps to reproduce

• try to push to existing/non-existing repository via HTTP/HTTPS

Initialize repository

# initialize repository
git init test
cd test
touch foo
git add foo
git commit -m "Add foo"

Push to existing repository

# push via HTTPS
git push https://gitlab.com/gitlab-org/gitlab-ce.git master
Username for 'https://gitlab.com':

Repository exists. The output is the same for existing private repositories.

Push to non-existing repository

git push https://gitlab.com/gitlab-org/non-existing.git master
remote: Not Found
fatal: repository 'https://gitlab.com/gitlab-org/non-existing.git/' not found

Repository doesn't exist, user is not asked for login data.

Possible fixes

• check user authentication before checking repository status

Tested with GitLab 6.9.1 and currently installed version at GitLab.com.