Signing RPM packages

RPM signingI’m sure many Linux sysadmins around the university build RPMs to ease the deployment of software to RedHat-a-like systems. But how many people sign them? Signing is important to make sure your boxes are getting the packages you’re expecting, and allows smoother installation on the box itself. I’ve written a few notes about what we do in the ResNet NetOps team in case they are useful to anyone else. These are loosely based upon some notes hidden in the depths of the ResNet wiki.

Setting rpmbuild up to sign

Before you can sign packages, you need to set up your signing key. There is one key per repo, not per repo¬†maintainer¬†(apparently this is different from apt – I dunno, I’m an RPM guy!). There’s no point in re-inventing the wheel, so use these instructions to get set up with your signing key.

Signing your own packages

If you build your packages either from specfile and tarball, or by rebuilding a source rpm, signing is easy. At the time you build your package, just add the --sign option to sign the RPM with your key. There’s no need to specify whom to sign the package as, because your ~/.rpmmacros file specifies this.

rpmbuild -ba --sign source-1.0.spec
rpmbuild --rebuild source-1.0.srpm

Re-signing someone else’s packages

Often, you’ll need to drag someone else’s third-party RPM into your repo for easy deployment. All the RPMs in your repo should be signed with the same key, regardless of original source. You can sign existing RPMs like this:

rpm --resign package-1.0.rpm