[pkg-gnupg-maint] Bug#841909: /usr/bin/gpg: Configuration error over ssh

[Craig Small]

Package: gnupg
Version: 2.1.15-4
Severity: normal
File: /usr/bin/gpg

Since the latest upgrade, I am unable to sign anything using a ssh
shell. 

$ gpg --sign gpg.txt
File 'gpg.txt.gpg' exists. Overwrite? (y/N) y
gpg: signing failed: Configuration error
gpg: signing failed: Configuration error

There is a work-around
ssh to the remote system
killall gpg-agent
unset DBUS_SESSION_BUS_ADDRESS
gpg will now work.

I am unsure why this environment variable causes the problem. It has
something to do with the gpg-agent not gpg itself. 

I tried it with two ssh sessions, one running gpg and one running gpg
agent. If the agent had that variable unset, it worked even if the
window running gpg itself had it set. The other way around it failed
meaning gpg-agent and not gpg itself has the problem with the
environment.

This is gpg-agent with the environment vatiable set.

gpg-agent --verbose --homedir /home/csmall/.gnupg --use-standard-socket --daemon /bin/bash
gpg-agent[28745]: WARNING: "--use-standard-socket" is an obsolete option - it has no effect
gpg-agent[28745]: listening on socket '/run/user/1000/gnupg/S.gpg-agent'
gpg-agent[28745]: listening on socket '/run/user/1000/gnupg/S.gpg-agent.rstrd'
gpg-agent[28745]: listening on socket '/run/user/1000/gnupg/S.gpg-agent.brwsr'
gpg-agent[28745]: listening on socket '/run/user/1000/gnupg/S.gpg-agent.ssh'
gpg-agent[28746]: gpg-agent (GnuPG) 2.1.15 started
$ gpg-agent[28746]: handler 0x7f347273d700 for fd 8 started
gpg-agent[28746]: starting a new PIN Entry
gpg-agent[28746]: failed to unprotect the secret key: Configuration error
gpg-agent[28746]: failed to read the secret key
gpg-agent[28746]: command 'PKSIGN' failed: Configuration error <Pinentry>
gpg-agent[28746]: handler 0x7f347273d700 for fd 8 terminated
gpg-agent[28746]: handler 0x7f3471f3c700 for fd 9 started
gpg-agent[28746]: handler 0x7f3471f3c700 for fd 9 terminated



-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.7.0-1-amd64 (SMP w/6 CPU cores)
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages gnupg depends on:
ii  gnupg-agent    2.1.15-4
ii  libassuan0     2.4.3-1
ii  libbz2-1.0     1.0.6-8
ii  libc6          2.24-5
ii  libgcrypt20    1.7.3-2
ii  libgpg-error0  1.24-1
ii  libksba8       1.3.5-2
ii  libreadline7   7.0-1
ii  libsqlite3-0   3.15.0-1
ii  zlib1g         1:1.2.8.dfsg-2+b1

Versions of packages gnupg recommends:
ii  dirmngr     2.1.15-4
pn  gnupg-l10n  <none>

Versions of packages gnupg suggests:
pn  parcimonie  <none>
pn  xloadimage  <none>

-- no debconf information