34

Adding a gpg key via apt-key systematically fails since I've switched to Ubuntu 17.04 (I doubt it's directly related though). Example with Spotify's repo key:

$ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys BBEBDCB318AD50EC6865090613B00F1FD2C19886
Executing: /tmp/apt-key-gpghome.wRE6z9GBF8/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys BBEBDCB318AD50EC6865090613B00F1FD2C19886
gpg: keyserver receive failed: No keyserver available

Same thing if I remove the hkp:// prefix.


Context: I use CNTLM to cope with the local corporate proxy. Env variables are set (in /etc/environment):

$ env | grep 3128
https_proxy=http://localhost:3128
http_proxy=http://localhost:3128
ftp_proxy=http://localhost:3128

/etc/apt/apt.conf is configured (apt commands are working fine):

$ cat /etc/apt/apt.conf
Acquire::http::Proxy "http://localhost:3128";
Acquire::https::Proxy "http://localhost:3128";
Acquire::ftp::Proxy "http://localhost:3128";

Finally, the specified keyserver seems reachable:

$ curl keyserver.ubuntu.com:80
<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <title>SKS OpenPGP Public Key Server</title>
  </head>
  <body>
  [...]

What can I do ? I'm not even sure on how to further debug it...


Things I already tried to do, without any result:

  • run sudo with -E (preserve env) option
  • run apt-key adv with --keyserver-options http-proxy=http://localhost:3128/ option (source)
  • run $ gpg --list-keys for some reason (source)
  • use another keyserver (--keyserver pgp.mit.edu)
  • remove the hkp:// part (--keyserver keyserver.ubuntu.com:80)

Weird thing is that I never see any "cntlm" entry in /var/log/syslog when running apt-key.

  • What happens when you try to access http://keyserver.ubuntu.com/ in your browser? – dirkt May 10 '17 at 6:29
  • I've got the web page (same as the one shown in curl's output above) – Anto May 10 '17 at 10:57
50

You usually have a proxy for ftp, http and https; I am seeing there hkp:// as an URL; so it should not be directed via a pure http proxy, hence failing the communication.

Use this instead:

sudo apt-key adv --keyserver keyserver.ubuntu.com --keyserver-options http-proxy=http://localhost:3128 --recv-keys BBEBDCB318AD50EC6865090613B00F1FD2C19886

As for the system updates, I would advise using an APT proxy, for instance, apt-cacher-ng.

Another way of doing it, is searching in the public web interface, with a browser, for instance on your working station for the key you want at https://keyserver.ubuntu.com

Open the site, and you got a form. In this case I used the "Search String" "Spotify"; then select "Search" ; it will list several keys.

Searching for the signature/fingerprint that you mentioned in the result page:

pub  4096R/D2C19886 2015-05-28            
     Fingerprint=BBEB DCB3 18AD 50EC 6865  0906 13B0 0F1F D2C1 9886 

uid Spotify Public Repository Signing Key <operations@spotify.com>
sig  sig3  D2C19886 2015-05-29 __________ 2017-11-22 [selfsig]
sig  sig   94558F59 2015-06-02 __________ __________ Spotify Public Repository Signing Key <operations@spotify.com>

We see this is the entry that interests us.

So we click in D2C19886 and are presented with a page with the key at https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x13B00F1FD2C19886.

Public Key Server -- Get "0x13b00f1fd2c19886 "

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: SKS 1.1.6
Comment: Hostname: keyserver.ubuntu.com
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==
=/qip
-----END PGP PUBLIC KEY BLOCK-----

You cut between the line that begins with "-----BEGIN" and the line ending with "-----END", including those lines, and paste to a file, say spotify.pgp on the intended server you want to import that key. (do not cut it from here, as I added 4 spaces before each line while formatting)

Finally to import the key into the server you do:

$sudo apt-key add spotify.pgp
OK
  • @Anto did it work? – Rui F Ribeiro May 27 '17 at 9:03
  • 1
    Hello Rui, indeed this "manual" method works and that's how I "temporarily" solved it in the meantime. Apparently this temporary solution is not gonna stay temporary :( But thanks a lot anyway. – Anto May 29 '17 at 9:26
4

Here is a solution that uses http via curl instead of trying to proxy apt-key or gpg:

curl -sSL \
'http://keyserver.ubuntu.com/pks/lookup?op=get&search=0xBBEBDCB318AD50EC6865090613B00F1FD2C19886' \
| sudo apt-key add -

This method should be used instead of apt-key command line or http_proxy or https_proxy environment variables settings (which are disabled in the newest versions of apt-key).

-1

you can specify the keyserver as a parameter to add-apt-repository by:

sudo add-apt-repository --keyserver hkps://keyserver.ubuntu.com:443 some_ppa

Outgoing port 443 would not be blocked by the corporate firewall.

  • Why? It's blocked on all my networks by default. – cprn Nov 21 '18 at 10:53
  • This answer wont work, the challenge of the question is that the access is centrally firewalled. – Rui F Ribeiro Dec 19 '18 at 11:33

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