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Troubleshooting SSL

This page contains a list of common SSL-related errors and scenarios that you may encounter 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 by using various CLI tools. You may see experience the following issues:

  • 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 by using 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 displayed 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 previously described issues, add your certificate to /etc/gitlab/trusted-certs, and then run sudo gitlab-ctl reconfigure.

X.509 key values mismatch error

After configuring your instance with a certificate bundle, NGINX may display the following error message:

SSL: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch

This error message means that the server certificate and key you have provided don't match. You can confirm this by running the following command and then comparing the output:

openssl rsa -noout -modulus -in path/to/your/.key | openssl md5
openssl x509 -noout -modulus -in path/to/your/.crt | openssl md5

The following is an example of an md5 output between a matching key and certificate. Note the matching md5 hashes:

$ openssl rsa -noout -modulus -in private.key | openssl md5
4f49b61b25225abeb7542b29ae20e98c
$ openssl x509 -noout -modulus -in public.crt | openssl md5
4f49b61b25225abeb7542b29ae20e98c

This is an opposing output with a non-matching key and certificate which shows different md5 hashes:

$ openssl rsa -noout -modulus -in private.key | openssl md5
d418865077299af27707b1d1fa83cd99
$ openssl x509 -noout -modulus -in public.crt | openssl md5
4f49b61b25225abeb7542b29ae20e98c

If the two outputs differ like the previous example, there's a mismatch between the certificate and key. Contact the provider of the SSL certificate for further support.

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 get stuck in Pending status. In the runner logs you may see the following error message:

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 encounter a similar problem, add your certificate to /etc/gitlab-runner/certs, and the restart the runner by running gitlab-runner restart.

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

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 message in the user interface.

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 by using 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 message 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:

  1. Validate that your self-signed certificate isn't missing a common name. If it is, regenerate a valid certificate
  2. Add the certificate to /etc/gitlab/trusted-certs.
  3. 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 if the certificate is signed by an internal certificate authority (CA), you might experience 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

SSL_connect wrong version number

A misconfiguration may result in:

  • gitlab-rails/exceptions_json.log entries containing:

    "exception.class":"Excon::Error::Socket","exception.message":"SSL_connect returned=1 errno=0 state=error: wrong version number (OpenSSL::SSL::SSLError)",
"exception.class":"Excon::Error::Socket","exception.message":"SSL_connect returned=1 errno=0 state=error: wrong version number (OpenSSL::SSL::SSLError)",

  • gitlab-workhorse/current containing:

    http: server gave HTTP response to HTTPS client
http: server gave HTTP response to HTTPS client

  • gitlab-rails/sidekiq.log or sidekiq/current containing:

    message: SSL_connect returned=1 errno=0 state=error: wrong version number (OpenSSL::SSL::SSLError)
message: SSL_connect returned=1 errno=0 state=error: wrong version number (OpenSSL::SSL::SSLError)

Some of these errors come from the Excon Ruby gem, and could be generated in circumstances where GitLab is configured to initiate an HTTPS session to a remote server that is serving only HTTP.

One scenario is that you're using object storage, which isn't served under HTTPS. GitLab is misconfigured and attempts a TLS handshake, but the object storage will respond with plain HTTP.