ownCloud supports code signing for the core releases, and for ownCloud applications. Code signing gives our users an additional layer of security by ensuring that nobody other than authorized individuals can push updates.
It also ensures that all upgrades have been executed properly, so that no files are left behind, and all old files are properly replaced. In the past, invalid updates were a significant source of errors when updating ownCloud.
Why Did ownCloud Add Code Signing?
By supporting Code Signing we add another layer of security which ensures that nobody, other than authorized individuals, can push updates for applications. This ensures proper upgrades.
Do We Lock Down ownCloud?
The ownCloud project is open source and always will be. We do not want
to make it more difficult for our users to run ownCloud. Any code
signing errors on upgrades will not prevent ownCloud from running, but
will display a warning on the Admin page. For applications that are not
Official the code signing process is optional.
Is ownCloud Not Open Source Anymore?
The ownCloud project is open source and always will be. The code signing process is optional, though highly recommended. The code check for the core parts of ownCloud is enabled when the ownCloud release version branch has been set to stable.
For custom distributions of ownCloud it is recommended to change the
release version branch in version.php to something else than
ownCloud uses a X.509 based approach to handle authentication of code. Each ownCloud release contains the certificate of a shipped ownCloud Code Signing Root Authority. The private key of this certificate is only accessible to the project leader, who may grant trusted project members with a copy of this private key.
This Root Authority is only used for signing certificate signing
requests (CSRs) for additional certificates. Certificates issued by the
Root Authority must always to be limited to a specific scope, usually
the application identifier. This enforcement is done using the
attribute of the certificate.
Code signing is then done by creating a
signature.json file with the
hashes: This is an array of all files in the folder with their corresponding SHA-512 hashes.
certificate: This is the certificate used for signing.
It has to be issued by the ownCloud Root Authority
Its CN needs to be permitted to perform the required action.
signature: This is a signature of the hashes which can be verified
using the certificate. Having the certificate bundled within the
signature.json file has the advantage that even if a developer loses
their certificate, future updates can still be ensured by having a new
How Code Signing Affects Apps in the ownCloud Marketplace
Unsigned apps can’t be uploaded to the marketplace. They can be installed manually, but the warning:
"Integrity check failed", will always be visible.
Apps which have been signed in a previous release MUST be code-signed in all future releases as well, otherwise the update will be refused.
How to Get Your App Signed
The following commands require that you have OpenSSL installed on your
machine. Ensure that you keep all generated files to sign your
application. The following examples will assume that you are trying to
sign an application named
Firstly, generate a private key and CSR. This can be done with the following command.
# Replace "contacts" with your application identifier. openssl req -nodes -newkey rsa:4096 -keyout contacts.key -out contacts.csr -subj "/CN=contacts"
Then, post the CSR on https://github.com/owncloud/appstore-issues, and
configure your GitHub account to show your mail address in your profile.
ownCloud might ask you for further information to verify that you’re the
legitimate owner of the application. Make sure to keep the private key
contacts.key) secret and not disclose it to any third-parties.
ownCloud will then provide you with the signed certificate.
./occ integrity:sign-app to sign your application, and
specify your private and the public key as well as the path to the
application. A valid example looks like:
./occ integrity:sign-app \ --privateKey=/home/user/contacts.key \ --certificate=/home/user/CA/contacts.crt \ --path=/home/user/Programming/contacts
The occ tool will store a
signature.json file within the
folder of your application. Then compress the application folder, naming
contacts.tar.gz, and upload it to
https://marketplace.owncloud.com/. Be aware that making any changes to
the application, after it has been signed, requires it to be signed
again. So if you do not want to have some files shipped remove them
before running the signing command.
In case you lose your certificate please submit a new CSR as described above and mention that you have lost the previous one. ownCloud will revoke the old certificate.
If you maintain an app together with multiple people it is recommended to designate a release manager responsible for the signing process as well as the uploading to marketplace. If case this is not feasible, and multiple certificates are required, ownCloud can create them on a case by case basis. We do not recommend developers to share their private key.
The following errors can be encountered when trying to verify a code signature. For information about how to get access to those results please refer to the Issues section of the ownCloud Server Administration manual.
The file has a different hash than specified within
signature.json. This usually happens when the file has been modified after writing the signature data.
The file cannot be found but has been specified within
signature.json. Either a required file has been left out, or
signature.jsonneeds to be edited.
The file does not exist in
signature.json. This usually happens when a file has been removed and
signature.jsonhas not been updated.
Another exception has prevented the code verification. There are currently these following exceptions:
Signature data not found.
The app has mandatory code signing enforced but no
signature.jsonfile has been found in its
Certificate is not valid.
The certificate has not been issued by the official ownCloud Code Signing Root Authority.
Certificate is not valid for required scope. (Requested: %s, current: %s)
The certificate is not valid for the defined application. Certificates are only valid for the defined app identifier and cannot be used for others.
Signature could not get verified.
There was a problem with verifying the signature of