- Useful OpenSSL Debugging Commands
- Common SSL errors
- Reconfigure Fails Due to Certificates
- Custom Certificates Missing or Skipped
- Custom certificates not detected
- Let’s Encrypt Certificate signed by unknown authority
- Let’s Encrypt fails on reconfigure
- Using an internal CA certificate with GitLab
- X.509 key values mismatch error
- Using GitLab Runner with a GitLab instance configured with internal CA certificate or self-signed certificate
- Mirroring a remote GitLab repository that uses a self-signed SSL certificate
- Unable to perform Git operations due to an internal or self-signed certificate
- SSL_connect wrong version number
schannel: SEC_E_UNTRUSTED_ROOT
- Upgrade to OpenSSL 3
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 documentation:
- Configure SSL for a Linux package installation.
- Self-signed certificates or custom Certification Authorities for GitLab Runner.
- Configure HTTPS manually.
Useful OpenSSL Debugging Commands
Sometimes it’s helpful to get a better picture of the SSL certificate chain by viewing it directly at the source. These commands are part of the standard OpenSSL library of tools for diagnostics and debugging.
-
Perform a test connection to the host over HTTPS. Replace
HOSTNAME
with your GitLab URL (excluding HTTPS), and replaceport
with the port that serves HTTPS connections (usually 443):echo | /opt/gitlab/embedded/bin/openssl s_client -connect HOSTNAME:port
The
echo
command sends a null request to the server, causing it to close the connection rather than wait for additional input. You can use the same command to test remote hosts (for example, a server hosting an external repository), by replacingHOSTNAME:port
with the remote host’s domain and port number.This command’s output shows you the certificate chain, any public certificates the server presents, along with validation or connection errors if they occur. This makes for a quick check for any immediate issues with your SSL settings.
-
View a certificate’s details in text form using
x509
. Be sure to replace/path/to/certificate.crt
with the certificate’s path:/opt/gitlab/embedded/bin/openssl x509 -in /path/to/certificate.crt -text -noout
For example, GitLab automatically fetches and places certificates acquired from Let’s Encrypt at
/etc/gitlab/ssl/hostname.crt
. You can use thex509
command with that path to quickly display the certificate’s information (for example, the hostname, issuer, validity period, and more).If there’s a problem with the certificate, an error occurs.
-
Fetch a certificate from a server and decode it. This combines both of the above commands to fetch the server’s SSL certificate and decode it to text:
echo | /opt/gitlab/embedded/bin/openssl s_client -connect HOSTNAME:port | /opt/gitlab/embedded/bin/openssl x509 -text -noout
Common SSL errors
-
SSL certificate problem: unable to get local issuer certificate
This error indicates the client cannot get the root CA. To fix this, you can either trust the root CA of the server you are trying to connect to on the client or modify the certificate to present the full chained certificate on the server you are trying to connect to.
It is recommended to use the full certificate chain in order to prevent SSL errors when clients connect. The full certificate chain order should consist of the server certificate first, followed by all intermediate certificates, with the root CA last. -
unable to verify the first certificate
This error indicates that an incomplete certificate chain is being presented by the server. To fix this error, you will need to replace server’s certificate with the full chained certificate. The full certificate chain order should consist of the server certificate first, followed by all intermediate certificates, with the root CA last.
If you get this error while running the system OpenSSL utility instead of the/opt/gitlab/embedded/bin/openssl
utility, make sure you update your CA certificates at the OS level to fix it. -
certificate signed by unknown authority
This error indicates that the client does not trust the certificate or CA. To fix this error, the client connecting to server will need to trust the certificate or CA.
-
SSL certificate problem: self signed certificate in certificate chain
This error indicates that the client does not trust the certificate or CA. To fix this error, the client connecting to server will need to trust the certificate or CA.
-
x509: certificate relies on legacy Common Name field, use SANs instead
This error indicates that SANs (subjectAltName) must be configured in the certificate. For more information, see this issue.
Reconfigure Fails Due to Certificates
ERROR: Not a certificate: /opt/gitlab/embedded/ssl/certs/FILE. Move it from /opt/gitlab/embedded/ssl/certs to a different location and reconfigure again.
Check /opt/gitlab/embedded/ssl/certs
and remove any files other than README.md
that aren’t valid X.509 certificates.
gitlab-ctl reconfigure
constructs symlinks named from the subject hashes
of your custom public certificates and places them in /opt/gitlab/embedded/ssl/certs/
.
Broken symlinks in /opt/gitlab/embedded/ssl/certs/
will be automatically removed.
Files other than cacert.pem
and README.md
stored in
/opt/gitlab/embedded/ssl/certs/
will be moved into the /etc/gitlab/trusted-certs/
.Custom Certificates Missing or Skipped
If no symlinks are created in /opt/gitlab/embedded/ssl/certs/
and you see
the message “Skipping cert.pem
” after running gitlab-ctl reconfigure
, that
means there may be one of four issues:
- The file in
/etc/gitlab/trusted-certs/
is a symlink - The file is not a valid PEM- or DER-encoded certificate
- Perl is not installed on the operating system which is needed for c_rehash to properly symlink certificates
- The certificate contains the string
TRUSTED
Test the certificate’s validity using the commands below:
/opt/gitlab/embedded/bin/openssl x509 -in /etc/gitlab/trusted-certs/example.pem -text -noout
/opt/gitlab/embedded/bin/openssl x509 -inform DER -in /etc/gitlab/trusted-certs/example.der -text -noout
Invalid certificate files produce the following outputs:
-
unable to load certificate 140663131141784:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:701:Expecting: TRUSTED CERTIFICATE
-
cannot load certificate PEM_read_bio_X509_AUX() failed (SSL: error:0909006C:PEM routines:get_name:no start line:Expecting: TRUSTED CERTIFICATE)
In either of those cases, and if your certificates begin and end with anything other than the following:
-----BEGIN CERTIFICATE-----
-----END CERTIFICATE-----
Then they are not compatible with GitLab. You should separate them into the certificate components (server, intermediate, root), and convert them to the compatible PEM format.
To test if c_rehash
is not symlinking the certificate due to a missing perl interpreter:
$ /opt/gitlab/embedded/bin/c_rehash /etc/gitlab/trusted-certs
bash: /opt/gitlab/embedded/bin/c_rehash: /usr/bin/perl: bad interpreter: No such file or directory
If you see this message, you will need to install perl with your distribution’s package manager.
If you inspect the certificate itself, then look for the string TRUSTED
:
-----BEGIN TRUSTED CERTIFICATE-----
...
-----END TRUSTED CERTIFICATE-----
If it does, like the example above, then try removing the string TRUSTED
and running gitlab-ctl reconfigure
again.
Custom certificates not detected
If after running gitlab-ctl reconfigure
:
- no symlinks are created in
/opt/gitlab/embedded/ssl/certs/
; - you have placed custom certificates in
/etc/gitlab/trusted-certs/
; and - you do not see any skipped or symlinked custom certificate messages
You may be encountering an issue where a Linux package installation thinks that the custom certificates have already been added.
To resolve, delete the trusted certificates directory hash:
rm /var/opt/gitlab/trusted-certs-directory-hash
Then run gitlab-ctl reconfigure
again. The reconfigure should now detect and symlink
your custom certificates.
Let’s Encrypt Certificate signed by unknown authority
The initial implementation of Let’s Encrypt integration only used the certificate, not the full certificate chain.
Starting in 10.5.4, the full certificate chain will be used. For installs which are already using a certificate, the switchover will not happen until the renewal logic indicates the certificate is near expiration. To force it sooner, run the following
rm /etc/gitlab/ssl/HOSTNAME*
gitlab-ctl reconfigure
Where HOSTNAME is the hostname of the certificate.
Let’s Encrypt fails on reconfigure
When you reconfigure, there are common scenarios under which Let’s Encrypt may fail:
-
Let’s Encrypt may fail if your server isn’t able to reach the Let’s Encrypt verification servers or vice versa:
letsencrypt_certificate[gitlab.domain.com] (letsencrypt::http_authorization line 3) had an error: RuntimeError: acme_certificate[staging] (/opt/gitlab/embedded/cookbooks/cache/cookbooks/letsencrypt/resources/certificate.rb line 20) had an error: RuntimeError: [gitlab.domain.com] Validation failed for domain gitlab.domain.com
If you run into issues reconfiguring GitLab due to Let’s Encrypt make sure you have ports 80 and 443 open and accessible.
-
Your domain’s Certification Authority Authorization (CAA) record does not allow Let’s Encrypt to issue a certificate for your domain. Look for the following error in the reconfigure output:
letsencrypt_certificate[gitlab.domain.net] (letsencrypt::http_authorization line 5) had an error: RuntimeError: acme_certificate[staging] (/opt/gitlab/embedded/cookbooks/cache/cookbooks/letsencrypt/resources/certificate.rb line 25) had an error: RuntimeError: ruby_block[create certificate for gitlab.domain.net] (/opt/gitlab/embedded/cookbooks/cache/cookbooks/acme/resources/certificate.rb line 108) had an error: RuntimeError: [gitlab.domain.com] Validation failed, unable to request certificate
-
If you’re using a test domain such as
gitlab.example.com
, without a certificate, you’ll see theunable to request certificate
error shown above. In that case, disable Let’s Encrypt by settingletsencrypt['enable'] = false
in/etc/gitlab/gitlab.rb
. -
Let’s Encrypt enforces rate limits, which is at the top-level domain. In case you’re using your cloud provider’s hostname as the
external_url
, for example*.cloudapp.azure.com
, Let’s Encrypt would enforce limits toazure.com
, which could make the certificate creation incomplete.In that case, you can try renewing the Let’s Encrypt certificates manually:
sudo gitlab-ctl renew-le-certs
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 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
Follow the details in Self-signed certificates or custom Certification Authorities for GitLab Runner.
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:
- Add the self-signed certificate from the remote GitLab instance to the
/etc/gitlab/trusted-certs
directory on the local GitLab instance, and then runsudo gitlab-ctl reconfigure
as per the instructions for installing custom public certificates. - If your local GitLab instance was installed using the Helm Charts, you can add your self-signed certificate to your GitLab instance.
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:
- Validate that your self-signed certificate isn’t missing a common name. If it is, regenerate a valid certificate
- Add the certificate to
/etc/gitlab/trusted-certs
. - 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. This is 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
orsidekiq/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 responds with plain HTTP.
schannel: SEC_E_UNTRUSTED_ROOT
If you’re on Windows and get the following error:
Fatal: unable to access 'https://gitlab.domain.tld/group/project.git': schannel: SEC_E_UNTRUSTED_ROOT (0x80090325) - The certificate chain was issued by an authority that is not trusted."
You must specify that Git should use OpenSSL:
git config --system http.sslbackend openssl
Alternatively, you can ignore SSL verification by running:
git config --global http.sslVerify false
Upgrade to OpenSSL 3
Starting from version 17.7, GitLab uses OpenSSL 3. Some of the older TLS protocols and cipher suites, or weaker TLS certificates for external integrations may be incompatible with OpenSSL 3 defaults.
With the upgrade to OpenSSL 3:
- TLS 1.2 or higher is required for all incoming and outgoing TLS connections.
- TLS certificates must have at least 112 bits of security. RSA, DSA, and DH keys shorter than 2048 bits, and ECC keys shorter than 224 bits are prohibited.
You can encounter one of the following error messages:
-
no protocols available
when the TLS connection uses a protocol older than TLS 1.2. -
certificate key too weak
when the TLS certificate less than 112 bits of security. -
unsupported cipher algorithm
when a legacy cipher is requested.
Use the OpenSSL 3 guide to identify and assess the compatibility of your external integrations.