Thanks a lot, Jan!

Changes have been made in Git (master):

commit 3861e2252ad011f18360a31721907f0aa9473888
Author: Jan Schneider <jan@horde.org>
Date:   Tue Jan 26 22:46:00 2016 +0100

     [jan] Allow to import multiple PGP keys in a single PGP packet 
(Request #13190).

  imp/docs/CHANGES      |    2 +
  imp/lib/Basic/Pgp.php |    9 +++--
  imp/lib/Pgp.php       |   85 +++++++++++++++++++++++++++++++++---------------
  imp/package.xml       |    4 ++-
  4 files changed, 69 insertions(+), 31 deletions(-)

http://github.com/horde/horde/commit/3861e2252ad011f18360a31721907f0aa9473888

Changes have been made in Git (master):

commit 718c4a789f2f0740e0defc97b46bae14bd853fe9
Author: Jan Schneider <jan@horde.org>
Date:   Tue Jan 26 22:44:36 2016 +0100

     [jan] Add Horde_Crypt_Pgp::pgpPacketInformationMultiple() and 
Horde_Crypt_Pgp_Backend_Binary::packetInfoMultiple() (Request #13190).

  framework/Crypt/lib/Horde/Crypt/Pgp.php            |   31 ++++
  framework/Crypt/lib/Horde/Crypt/Pgp/Backend.php    |   15 ++
  .../Crypt/lib/Horde/Crypt/Pgp/Backend/Binary.php   |  191 
++++++++++++--------
  framework/Crypt/package.xml                        |   14 +-
  4 files changed, 165 insertions(+), 86 deletions(-)

http://github.com/horde/horde/commit/718c4a789f2f0740e0defc97b46bae14bd853fe9

Hi,

this is a friendly ping. Any hints or thoughs to my last commend?

I know that Horde refuses to import a binary keyfile. As I wrote above 
I exported all the keys with "-a"  - as armored data.

Maybe I wasn't clear enough: gpg -a creates a keyfile that lists all 
the keys without separator - it looks like this:

-----BEGIN PGP PUBLIC KEY BLOCK-----
$KEY_1$KEY_2$KEY_3
-----END PGP PUBLIC KEY BLOCK-----

That's how my keyfile looks like. There's no break between the keys 
and no separator. With those keyfiles the error described in this 
bugreport occurs.

It seems that Horde need a key file like this:

-----BEGIN PGP PUBLIC KEY BLOCK-----
$KEY_1
-----END PGP PUBLIC KEY BLOCK-----
-----BEGIN PGP PUBLIC KEY BLOCK-----
$KEY_2
-----END PGP PUBLIC KEY BLOCK-----
-----BEGIN PGP PUBLIC KEY BLOCK-----
$KEY_3
-----END PGP PUBLIC KEY BLOCK-----

With seahorse (a gui for key management) I created such a keyfile and 
had no problems with Horde import.
I used "-a" and the output is ASCI not binary. Tested with different 
Linux distros (Debian wheezy and Fedora 20) - same output: a keyfile 
without separators between the keys.

Hope this helps to reproduce the error.

There's your problem.  Horde/IMP only supports armored PGP data.  From 
Horde_Crypt_Pgp_Parse:

"Provides method to parse PGP armored text data."

We don't support binary data.

For what it's worth, your gpg appears to be broken.  "-a" means to 
output armored text.  And it works here:

slusarz@bigworm % gpg -a --export
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v2.0.22 (GNU/Linux)
[snip]

Ok, i'm getting closer. This is not a problem with the size of the 
keyfile (the former error I got was a problem with our setup).

But IMP can't handle keyfiles that are exported by gpg command line. I 
exported my whole public keyring with "gpg -a --output $FILE  --export".
This file contains all public keys without a separator - but IMP 
expects a separator (-----[END|BEGIN] PGP PUBLIC KEY BLOCK-----) 
between every key.

If you import such a file without single separators IMP creates new 
addressbook entries in which every single entry contains all keys - no 
matter if a key belongs to this entry or not.

Turba goes crazy if you try to open such an entry- because it runs a 
lot of gpg processes to show the keys in the addressbook entry - but 
never comes to an end. In this case it only helps to kill the webserver.

Gpg command is able to import a keyfile without the separators - so I 
assume this is an error with Horde's gpg implementation.

Sounds like #12961

Please follow the hints at 
http://wiki.horde.org/FAQ/Admin/Troubleshoot#wsod to generate and find 
a useful error message.

As far as I understand after importing the keyfile horde reads all 
mail addresses out of the keyfile and  starts a gpg process for every 
single key:
/usr/bin/gpg --no-tty --no-secmem-warning --no-options 
--no-default-keyring --yes --homedir /tmp/bto5pw3y --quiet 
--with-colons /tmp/bto5pw3y/horde-pgpeGazJY

This command runs again and again with new PIDs

For every mail address from the keyring an own adressbook entry wil be 
created.

My keyfile ha a size of 1.2 MB. Importing fails after uploading the 
file with: "An internal server error occurred. Please try again later."

After all gpg processes are finished there are some new address book 
entries, but not all. Opening an entry fails with a browser error page 
"Error code: ERR_INCOMPLETE_CHUNKED_ENCODING".

What does "fails in a gpg loop" mean?

I'm running  installation on Debian wheezy with Horde packages from 
testing and postgres as connected database.

Problem is that import of large GPG keyfiles with multiple keys inside 
fails in a gpg loop at the server.
Tested with different keyfiles, at a size of at least 1.5 MB.

Assuming that horde runs an own gpg process at the server for every 
key in that file.