Troubleshooting SSL

This page contains a list of common SSL-related errors and scenarios that you may face while working with GitLab. It should serve as an addition to the main SSL docs available here:

Using an internal CA certificate with GitLab

After configuring a GitLab instance with an internal CA certificate, you might not be able to access it via various CLI tools. You may see the following symptoms:

  • curl fails:

    curl https://gitlab.domain.tld
    curl: (60) SSL certificate problem: unable to get local issuer certificate
    More details here: https://curl.haxx.se/docs/sslcerts.html
    
  • Testing via the rails console also fails:

    uri = URI.parse("https://gitlab.domain.tld")
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = true
    http.verify_mode = 1
    response = http.request(Net::HTTP::Get.new(uri.request_uri))
    ...
    Traceback (most recent call last):
          1: from (irb):5
    OpenSSL::SSL::SSLError (SSL_connect returned=1 errno=0 state=error: certificate verify failed (unable to get local issuer certificate))
    
  • The error SSL certificate problem: unable to get local issuer certificate is shown when setting up a mirror from this GitLab instance.
  • openssl works when specifying the path to the certificate:

    /opt/gitlab/embedded/bin/openssl s_client -CAfile /root/my-cert.crt -connect gitlab.domain.tld:443
    

If you have the problems listed above, add your certificate to /etc/gitlab/trusted-certs and run sudo gitlab-ctl reconfigure.

Using GitLab Runner with a GitLab instance configured with internal CA certificate or self-signed certificate

Besides getting the errors mentioned in Using an internal CA certificate with GitLab, your CI pipelines may stuck stuck in Pending status. In the runner logs you may see the below error:

Dec  6 02:43:17 runner-host01 gitlab-runner[15131]: #033[0;33mWARNING: Checking for jobs... failed
#033[0;m  #033[0;33mrunner#033[0;m=Bfkz1fyb #033[0;33mstatus#033[0;m=couldn't execute POST against
https://gitlab.domain.tld/api/v4/jobs/request: Post https://gitlab.domain.tld/api/v4/jobs/request:
x509: certificate signed by unknown authority

If you face similar problem, add your certificate to /etc/gitlab-runner/certs and restart the runner via gitlab-runner restart.

Mirroring a remote GitLab repository that uses a self-signed SSL certificate

Scenario: When configuring a local GitLab instance to mirror a repository from a remote GitLab instance that uses a self-signed certificate, you may see the SSL certificate problem: self signed certificate error in the UI.

The cause of the issue can be confirmed by checking if:

  • curl fails:

    $ curl https://gitlab.domain.tld
    curl: (60) SSL certificate problem: self signed certificate
    More details here: https://curl.haxx.se/docs/sslcerts.html
    
  • Testing via the Rails console also fails:

    uri = URI.parse("https://gitlab.domain.tld")
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = true
    http.verify_mode = 1
    response = http.request(Net::HTTP::Get.new(uri.request_uri))
    ...
    Traceback (most recent call last):
          1: from (irb):5
    OpenSSL::SSL::SSLError (SSL_connect returned=1 errno=0 state=error: certificate verify failed (unable to get local issuer certificate))
    

To fix this problem:

You may also get another error when trying to mirror a repository from a remote GitLab instance that uses a self-signed certificate:

2:Fetching remote upstream failed: fatal: unable to access 'https://gitlab.domain.tld/root/test-repo/':
SSL: unable to obtain common name from peer certificate

In this case, the problem can be related to the certificate itself:

  • Double check that your self-signed certificate is not missing a common name. If it is then regenerate a valid certificate
  • add it to /etc/gitlab/trusted-certs and run sudo gitlab-ctl reconfigure

Unable to perform Git operations due to an internal or self-signed certificate

If your GitLab instance is using a self-signed certificate, or the certificate is signed by an internal certificate authority (CA), you might run into the following errors when attempting to perform Git operations:

$ git clone https://gitlab.domain.tld/group/project.git
Cloning into 'project'...
fatal: unable to access 'https://gitlab.domain.tld/group/project.git/': SSL certificate problem: self signed certificate
$ git clone https://gitlab.domain.tld/group/project.git
Cloning into 'project'...
fatal: unable to access 'https://gitlab.domain.tld/group/project.git/': server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none

To fix this problem:

  • If possible, use SSH remotes for all Git operations. This is considered more secure and convenient to use.
  • If you must use HTTPS remotes, you can try the following:
    • Copy the self signed certificate or the internal root CA certificate to a local directory (for example, ~/.ssl) and configure Git to trust your certificate:

      git config --global http.sslCAInfo ~/.ssl/gitlab.domain.tld.crt
      
    • Disable SSL verification in your Git client. Note that this intended as a temporary measure as it could be considered a security risk.

      git config --global http.sslVerify false