gnupg: dynamic pinentry

3 files changed, 43 insertions, 5 deletions

diff --git a/gnupg/.config/zsh/.zshrc.d/20-gnupg.zsh b/gnupg/.config/zsh/.zshrc.d/20-gnupg.zsh
index 532697e..0b3c422 100644
--- a/gnupg/.config/zsh/.zshrc.d/20-gnupg.zsh
+++ b/gnupg/.config/zsh/.zshrc.d/20-gnupg.zsh
@@ -1,9 +1,9 @@
 #!/bin/zsh
 # vim:ft=sh
 
-GPG_TTY=$(tty)
-export GPG_TTY
+if [ -t 0 ] && [ -z "$SSH_TTY" ]; then
+	export GPG_TTY="$(tty)"
+	export PINENTRY_USER_DATA=USE_TTY=1
+fi
 
 gpg-connect-agent updatestartuptty /bye >/dev/null 2>&1
-
-alias unlock='echo "" | gpg --clearsign 1>/dev/null && ssh localhost -- : 1>/dev/null'
diff --git a/gnupg/.gnupg/gpg-agent.conf b/gnupg/.gnupg/gpg-agent.conf
index 2e3f358..b15e92e 100644
--- a/gnupg/.gnupg/gpg-agent.conf
+++ b/gnupg/.gnupg/gpg-agent.conf
@@ -1,3 +1,3 @@
 enable-ssh-support
 enable-putty-support
-pinentry-program /usr/bin/pinentry-curses
+pinentry-program /home/tobyv/.local/bin/pinentry-auto
diff --git a/gnupg/.local/bin/pinentry-auto b/gnupg/.local/bin/pinentry-auto
new file mode 100755
index 0000000..b788361
--- /dev/null
+++ b/gnupg/.local/bin/pinentry-auto
@@ -0,0 +1,38 @@
+#!/bin/sh
+# Choose between pinentry-tty and pinentry-x11 based on whether
+# $PINENTRY_USER_DATA contains USE_TTY=1
+#
+# Based on:
+# https://kevinlocke.name/bits/2019/07/31/prefer-terminal-for-gpg-pinentry
+#
+# Note: Environment detection is difficult.
+# - stdin is Assuan pipe, preventing tty checking
+# - configuration info (e.g. ttyname) is passed via Assuan pipe, preventing
+#   parsing or fallback without implementing Assuan protocol.
+# - environment is sanitized by atfork_cb in call-pinentry.c (removing $GPG_TTY)
+#
+# $PINENTRY_USER_DATA is preserved since 2.08 https://dev.gnupg.org/T799
+#
+# Format of $PINENTRY_USER_DATA not specified (that I can find), pinentry-mac
+# assumes comma-separated sequence of NAME=VALUE with no escaping mechanism
+# https://github.com/GPGTools/pinentry-mac/blob/v0.9.4/Source/AppDelegate.m#L78
+# and recognizes USE_CURSES=1 for curses fallback
+# https://github.com/GPGTools/pinentry-mac/pull/2
+#
+# To the extent possible under law, Kevin Locke <kevin@kevinlocke.name> has
+# waived all copyright and related or neighboring rights to this work
+# under the terms of CC0: https://creativecommons.org/publicdomain/zero/1.0/
+
+set -Ceu
+
+# Use pinentry-tty if $PINENTRY_USER_DATA contains USE_TTY=1
+case "${PINENTRY_USER_DATA-}" in
+*USE_TTY=1*)
+	# Note: Change to pinentry-curses if a Curses UI is preferred.
+	exec pinentry-curses "$@"
+	;;
+esac
+
+# Otherwise, use any X11 UI (configured by Debian Alternatives System)
+# Note: Will fall back to curses if $DISPLAY is not available.
+exec pinentry-gtk-2 "$@"