gpg list key and display key details from a file (without importing the key)

Files with GPG keyspublic or private. Here is how to get more information without importing the keys.
GPG cli could give enough information for an explored key in a file:

  • public or private key
  • encrypted or unencrypted key
  • user id description (including email)
  • key id and issuer fpr v4
  • when the key was generated and when it will expire
  • the algo for the encrypted key
  • more

The key may be in binary or ascii format. No difference.
Here is the GNU GPG cli command:

gpg --list-packets < ./filewith.key

All examples below are made with gpg (GnuPG) 2.2.19.
Keep on reading!

Mirror a PPA repositories using aptly – PHP (ppa:ondrej/php)

This is a simple example of how to mirror a PPA repository to a local server. The Ubuntu PPA to mirror is ppa:ondrej/php, which offers the user different PHP version generally not available in the Ubuntu installation. Of course, the user should be very careful about adding PPA repositories, because they are exactly what the abbreviation stands for Personal Package Archives.

If you want to know how to install and a brief description of what is aptly you may want to read our previous article – Install aptly under Ubuntu 18 LTS with Nginx serving the packages and the first steps

What we are going to do – this is what you need to have a mirror of an external application repository:

  1. Install aptly in Ubuntu 18 LTS
  2. Create a mirror in aptly
  3. Create a snapshot of the mirror created before
  4. Publish the snapshot to be used in other servers.

and at the last step there is an example how to use the mirror in your local machines.

STEP 1) Install aptly in Ubuntu 18.04 LTS.

As mentioned already you may follow our article on the subject – Install aptly under Ubuntu 18 LTS with Nginx serving the packages and the first steps. The following steps are based on this installation!
The aptly home directory is in “/srv/aptly”. We use the “aptly” user and change to it to manipulate the aptly installation.
Change the user to aptly, because under this user the mirror process will happen.

root@srv ~ # su - aptly
aptly@srv:~$

STEP 2) Create a mirror in aptly.

Prepare the keys (aptly needs to have the Ubuntu keys in its trustedkeys keyring):

aptly@srv:~$ gpg --no-default-keyring --keyring trustedkeys.gpg --keyserver pool.sks-keyservers.net --recv-keys 4F4EA0AAE5267A6C
gpg: requesting key E5267A6C from hkp server pool.sks-keyservers.net
gpg: key E5267A6C: public key "Launchpad PPA for Ond\xc5\x99ej Sur�" imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)

Here we’ve used the method to obtain the key from a GPG KEY server, but the key can be downloaded directrly from the original repository as suggested in the error message below.
If you are not sure where to download the key you could always just try to create the mirror ( in fact, this is in STEP 3) ) and get the error for missing key and how to obtain the key:
Keep on reading!

Mirror the official Ubuntu repositories using aptly

This article is to show mainly how to work with aptly by mirroring an official Ubuntu mirror. If you want to know how to install and a brief description of what is aptly you may want to read our previous article – Install aptly under Ubuntu 18 LTS with Nginx serving the packages and the first steps

What we are going to do – this is what you need to have a mirror of an external application repository:

  1. Install aptly in Ubuntu 18 LTS
  2. Create a mirror in aptly
  3. Create a snapshot of the mirror created before
  4. Publish the snapshot to be used in other servers.

and at the last step there is an example how to use the mirror in your local machines.

STEP 1) Install aptly in Ubuntu 18.04 LTS.

As mentioned already you may follow our article on the subject – Install aptly under Ubuntu 18 LTS with Nginx serving the packages and the first steps. The following steps are based on this installation!
The aptly home directory is in “/srv/aptly”. We use the “aptly” user and change to it to manipulate the aptly installation.

STEP 2) Create a mirror in aptly.

Prepare the keys (aptly needs to have the Ubuntu keys in its trustedkeys keyring):

aptly@srv:~$ gpg --no-default-keyring --keyring /usr/share/keyrings/ubuntu-archive-keyring.gpg --export | gpg --no-default-keyring --keyring trustedkeys.gpg --import
gpg: key 3B4FE6ACC0B21F32: 3 signatures not checked due to missing keys
gpg: key 3B4FE6ACC0B21F32: public key "Ubuntu Archive Automatic Signing Key (2012) <ftpmaster@ubuntu.com>" imported
gpg: key D94AA3F0EFE21092: 3 signatures not checked due to missing keys
gpg: key D94AA3F0EFE21092: public key "Ubuntu CD Image Automatic Signing Key (2012) <cdimage@ubuntu.com>" imported
gpg: key 871920D1991BC93C: 1 signature not checked due to a missing key
gpg: key 871920D1991BC93C: public key "Ubuntu Archive Automatic Signing Key (2018) <ftpmaster@ubuntu.com>" imported
gpg: Total number processed: 3
gpg:               imported: 3
gpg: public key of ultimately trusted key 212A3D20E4D3351D not found
gpg: marginals needed: 3  completes needed: 1  trust model: pgp
gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u

Probably you would like to have “main” and “universe” for the three bionic, bionic updates and bionic security.
First, main and universe for bionic repository. main is ~16G and universe is ~136, these numbers will vary in future when more packages are added.
Two commands are need for the aptly mirror:

  1. create – create the mirror.
  2. update – download the repository contents locally.

Keep on reading!

Install aptly under Ubuntu 18 LTS with nginx serving the packages and the first steps

This article is how to install aptly software, which offers easy Debian repository management.
First, few words for aptly and what tasks are really simple to do:

  • Mirror an existing (remote) repository. Make a local copy of Debian or Ubuntu repostories for all your internal infrastructure.
  • Create your own repositories
  • Create snapshots of repositories and mirrors.
  • Merge repositories
  • Make diff between repositories (in fact snapshots of repositories, but you may make a mirror of an repository and then make a snapshot and then make a diff with some other snapshot to see the changes between the different repositories or the time the snapshots are made).
  • Remove or add individual packages from official mirrored repositories.
  • Use api calls to manage the repositories. HTTP REST API is still in development, but a big part of it works.

For more information you may visit the official documentation page – https://www.aptly.info/doc/overview/

We are going to install the aptly and despite it could be used to serve the repository files we will use the Nginx web server for this work. Nginx is a more fast and reliable web server with easy installation of SSL certificates for our repositories.
The aptly is included in official Ubuntu repositories in the component universe, but at present, it is 2 to 3 versions behind the stable one from the aptly site, so we are going to use their repository to install aptly. Still, if you do not want to use
Keep on reading!

emerge – cannot sync with gpg: keyserver refresh failed: General error because of wrong date

Trying to sync one of our virtual servers we got a sync error not able to refresh the OpenPGP keys. The virtual server was just resumed and it was OK before the pause. In addition, there were no errors in dmesg or some kind of kernel panics. All seemed to be working even the server was in the distributed compiling node and no problems there. But still, the emerge syncing the portage tree wasn’t possible!
And the problem was the date of our virtual server, which was 4 months behind the real date!

Check the time and date of the server – if it is behind or in the future with a big interval this is the root of the problems with the inability to refresh the GPG keys.

Just synchronize the clock of the server and be careful when you resume pause virtual servers! When you resume them you should synchronize the clock because in multiple environments the clock might be wrong!
We have multiple articles on the time syncronization topic – openntpd – immediately sync the clock on startup, simple time synchronization of a server (laptop, desktop) using built-in systemd-timesyncd service and more.

compile-local ~ # emerge --sync
>>> Syncing repository 'gentoo' into '/usr/portage'...
 * Using keys from /usr/share/openpgp-keys/gentoo-release.asc
 * Refreshing keys from keyserver ...OpenPGP keyring refresh failed:
gpg: refreshing 4 keys from hkps://hkps.pool.sks-keyservers.net
gpg: keyserver refresh failed: General error

OpenPGP keyring refresh failed:
gpg: refreshing 4 keys from hkps://hkps.pool.sks-keyservers.net
gpg: keyserver refresh failed: General error

OpenPGP keyring refresh failed:
gpg: refreshing 4 keys from hkps://hkps.pool.sks-keyservers.net
gpg: keyserver refresh failed: General error

OpenPGP keyring refresh failed:
gpg: refreshing 4 keys from hkps://hkps.pool.sks-keyservers.net
gpg: keyserver refresh failed: General error

OpenPGP keyring refresh failed:
gpg: refreshing 4 keys from hkps://hkps.pool.sks-keyservers.net
gpg: keyserver refresh failed: General error

OpenPGP keyring refresh failed:
gpg: refreshing 4 keys from hkps://hkps.pool.sks-keyservers.net
gpg: keyserver refresh failed: General error

OpenPGP keyring refresh failed:
gpg: refreshing 4 keys from hkps://hkps.pool.sks-keyservers.net
gpg: keyserver refresh failed: General error

^C

Exiting on signal Signals.SIGINT
compile-local ~ # date
Sat 08 Apr 2019 15:11:39 PM -00
compile-local ~ # /etc/init.d/ntpd restart
 * Starting OpenNTPD ...                                                                                                                                              [ ok ]
compile-local ~ # date
Sun 01 Sep 2019 08:02:34 AM -00
compile-local ~ #

Keep on reading!

aptly mirror – gpgv: Can’t check signature: public key not found

If you want to mirror repositories from your current aptly server to a new server you must import the GPG key from your old server because you are going to encounter the following error:

gpgv: Signature made Fri 22 Apr 2019 17:35:04 AM UTC using DSA key ID FDC7A25E
gpgv: Can't check signature: public key not found

Looks like some keys are missing in your trusted keyring, you may consider importing them from keyserver:

gpg --no-default-keyring --keyring trustedkeys.gpg --keyserver pool.sks-keyservers.net --recv-keys 181482CCFDC7A25E

Sometimes keys are stored in repository root in file named Release.key, to import such key:

wget -O - https://some.repo/repository/Release.key | gpg --no-default-keyring --keyring trustedkeys.gpg --import

ERROR: unable to fetch mirror: verification of detached signature failed: exit status 2

And the mirror command fails. The problem is

you must import the GPG key from your old server in trustedkeys.gpg (even if you have already imported it in the new server with apt-key!!!)

Here is how to list, export and import it (we are going to import it in default and trustedkeys.gpg, because it is more convenient, but it is not mandatory to be in the default).
Keep on reading!