[pkg-gnupg-maint] Bug#1129944: pinentry-qt: immediate crash if X display is not available

[Vincent Lefevre]

Package: pinentry-qt
Version: 1.3.2-4
Severity: important

pinentry-qt immediately crashes if the X display is not available.
This can happen after a ssh to a remote machine (or if the value
of DISPLAY is no longer valid).

With "gpg -d file.gpg", I just get:

[...]
gpg: public key decryption failed: No pinentry
gpg: decryption failed: No pinentry

which is not informative at all. But the crash is visible when
I run pinentry-qt directly from the command line:

------------------------------------------------------------
qaa:~> pinentry-qt
qt.qpa.xcb: could not connect to display 
qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: xcb, wayland, linuxfb, offscreen, minimal, vkkhrdisplay, vnc, wayland-egl, eglfs, minimalegl.

zsh: IOT instruction (core dumped)  pinentry-qt
------------------------------------------------------------

Perhaps some "platform plugin" should be installed? But there are
no Recommends on such a plugin, and the documentation provides no
information.

pinentry-gtk-2 from the pinentry-gtk2 package (removed in this version)
did not have this issue.

A workaround might be to use a wrapper script of the form

#!/bin/sh
if xset -q > /dev/null 2> /dev/null ; then
  exec pinentry-qt "$@"
else
  exec pinentry-curses "$@"
fi

-- System Information:
Debian Release: forky/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable-debug'), (500, 'proposed-updates-debug'), (500, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 6.7.12-amd64 (SMP w/16 CPU threads; PREEMPT)
Kernel taint flags: TAINT_WARN
Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages pinentry-qt depends on:
ii  libassuan9           3.0.2-2
ii  libc6                2.42-13
ii  libgcc-s1            15.2.0-14
ii  libgpg-error0        1.59-4
ii  libkf6guiaddons6     6.23.1-1
ii  libkf6windowsystem6  6.23.0-2
ii  libncursesw6         6.6+20251231-1
ii  libqt6core6t64       6.9.2+dfsg-4+b1
ii  libqt6gui6           6.9.2+dfsg-4+b1
ii  libqt6widgets6       6.9.2+dfsg-4+b1
ii  libstdc++6           15.2.0-14
ii  libtinfo6            6.6+20251231-1

pinentry-qt recommends no packages.

Versions of packages pinentry-qt suggests:
pn  pinentry-doc  <none>

-- no debconf information

-- 
Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / Pascaline project (LIP, ENS-Lyon)