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@andsens
Last active February 15, 2022 13:23
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Script taken from https://blog.nimamoh.net/yubi-key-gpg-wsl2/ and improved
#!/usr/bin/env bash
# Inspired by https://blog.nimamoh.net/yubi-key-gpg-wsl2/
# Guide:
# Install GPG on windows & Unix
# Add "enable-putty-support" to gpg-agent.conf
# Download wsl-ssh-pageant and npiperelay and place the executables in "C:\Users\[USER]\AppData\Roaming\" under wsl-ssh-pageant & npiperelay
# https://github.com/benpye/wsl-ssh-pageant/releases/tag/20190513.14
# https://github.com/NZSmartie/npiperelay/releases/tag/v0.1
# Adjust relay() below if you alter those paths
# Place this script in WSL at ~/.local/bin/gpg-agent-relay
# Start it on login by calling it from your .bashrc: "$HOME/.local/bin/gpg-agent-relay start"
GNUPGHOME="$HOME/.gnupg"
PIDFILE="$GNUPGHOME/gpg-agent-relay.pid"
die() {
# shellcheck disable=SC2059
printf "$1\n" >&2
exit 1
}
main() {
checkdeps socat start-stop-daemon lsof timeout
case $1 in
start)
if ! start-stop-daemon --pidfile "$PIDFILE" --background --notify-await --notify-timeout 5 --make-pidfile --exec "$0" --start -- foreground; then
# shellcheck disable=SC2016
die 'Failed to start. Run `gpg-agent-relay foreground` to see output.'
fi
;;
stop)
start-stop-daemon --pidfile "$PIDFILE" --remove-pidfile --stop ;;
status)
start-stop-daemon --pidfile "$PIDFILE" --status
local result=$?
case $result in
0) printf "gpg-agent-relay is running\n" ;;
1 | 3) printf "gpg-agent-relay is not running\n" ;;
4) printf "unable to determine status\n" ;;
esac
return $result
;;
foreground)
relay ;;
*)
die "Usage:\n gpg-agent-relay start\n gpg-agent-relay stop\n gpg-agent-relay status\n gpg-agent-relay foreground" ;;
esac
}
relay() {
set -e
local winhome
local wslwinhome
winhome=$(cmd.exe /c "<nul set /p=%UserProfile%" 2>/dev/null || true)
wslwinhome="$(wslpath -u "$winhome")"
local npiperelay="$wslwinhome/AppData/Roaming/npiperelay/npiperelay.exe"
local wslsshpageant="$wslwinhome/AppData/Roaming/wsl-ssh-pageant/wsl-ssh-pageant-amd64-gui.exe"
local gpgconnectagent="/mnt/c/Program Files (x86)/GnuPG/bin/gpg-connect-agent.exe"
local gpgagentsocket="$GNUPGHOME/S.gpg-agent"
local sshagentsocket="$GNUPGHOME/S.gpg-agent.ssh"
# backslash escaping in socat EXEC doesn't seem to work very well, use forward slashes instead
# windows/npiperelay handle that just fine
local wingpgagentpath="${winhome//\\/\/}/AppData/Roaming/gnupg/S.gpg-agent"
killsocket "$gpgagentsocket"
killsocket "$sshagentsocket"
"$gpgconnectagent" /bye
"$wslsshpageant" --systray --winssh ssh-pageant 2>/dev/null &
# shellcheck disable=SC2034
WSPPID=$!
socat UNIX-LISTEN:"$gpgagentsocket,unlink-close,fork,umask=177" EXEC:"$npiperelay -ep -ei -s -a '$wingpgagentpath'",nofork &
GNUPID=$!
# shellcheck disable=SC2064
trap "kill -TERM $GNUPID" EXIT
socat UNIX-LISTEN:"$sshagentsocket,unlink-close,fork,umask=177" EXEC:"$npiperelay /\/\./\pipe/\ssh-pageant" &
SSHPID=$!
set +e
# shellcheck disable=SC2064
trap "kill -TERM $GNUPID; kill -TERM $SSHPID" EXIT
systemd-notify --ready 2>/dev/null
wait $GNUPID $SSHPID
trap - EXIT
}
killsocket() {
local socketpath=$1
if [[ -e $socketpath ]]; then
local socketpid
if socketpid=$(lsof +E -taU -- "$socketpath"); then
timeout .5s tail --pid=$socketpid -f /dev/null &
local timeoutpid=$!
kill "$socketpid"
if ! wait $timeoutpid; then
die "Timed out waiting for pid $socketpid listening at $socketpath"
fi
else
rm "$socketpath"
fi
fi
}
checkdeps() {
local deps=("$@")
local dep
local out
local ret=0
for dep in "${deps[@]}"; do
if ! out=$(type "$dep" 2>&1); then
printf -- "Dependency %s not found:\n%s\n" "$dep" "$out"
ret=1
fi
done
return $ret
}
main "$@"
@alanivey
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alanivey commented Feb 8, 2021

I'm also not able to get it working. When I run any gpg commands in WSL2 (Ubuntu 20.10 fwiw), it doesn't seem able to use the existing sockets. I added extra-socket /dev/null and browser-socket /dev/null to ~/.gnupg/gpg-agent.conf to keep it from creating any new sockets, and then any gpg commands return: gpg: can't connect to the agent: End of file

@mew1033
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mew1033 commented Feb 8, 2021

@alanivey Did you try the symlink method? That was the only thing that worked for me.

@alanivey
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alanivey commented Feb 9, 2021

@mew1033 yes, I symlinked the Gpg4Win exe in WSL2 Linux as $HOME/.local/bin/gpg with ln -sv /mnt/c/Program\ Files\ \(x86\)/GnuPG/bin/gpg.exe ~/.local/bin/gpg (in my WSL2 Linux environment, I have this directory at the front of $PATH). This binary does not attempt to use $HOME/.gnupg/S.gpg-agent when running gpg commands, nor does it use $HOME/.gnupg for its database, so it's not necessary to do any GPG setup in the WSL2 Linux environment. B/c I'm not looking to use the SSH agent integration, I ultimately find this easier; I maintain a single GPG database in Windows and can use it in multiple WSL2 Linux environments without replicating.

I'll caveat that I have not used this configuration for longer than a day so I might end up being wrong!

@alexdetsch
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In my Debian-WSL2, I can't access cmd.exe (and I didn't investigate in this further, as there seems to be a cleaner way), so the script isn't working. I replaced line 55 and 56 with this (you have to install wslu for this):

username="$(wslvar USERPROFILE)"
wslwinhome="$(wslpath $username)"
winhome="$(wslpath -w $wslwinhome)"

additionally, I had to add export PATH=$PATH:/sbin to my .bashrc as otherwise start-stop-daemon isn't found in path.

@matt-forster
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matt-forster commented Dec 16, 2021

@andsens I was having difficulty with this script and multiple shells (ie, a windows terminal and VSCode, which opens another terminal). It was failing because multiple PIDs were being included in the socket file, and kill was not super happy about that.

I'd end up with an error like;

gpg-agent-relay foreground
gpg-agent-relay: line 99: kill: 768
2650
8610
23065
26471
27892
30552: arguments must be process or job IDs
tail: cannot open '2650' for reading: No such file or directory
tail: cannot open '8610' for reading: No such file or directory
tail: cannot open '23065' for reading: No such file or directory
tail: cannot open '26471' for reading: No such file or directory
tail: cannot open '27892' for reading: No such file or directory
tail: cannot open '30552' for reading: No such file or directory
==> /dev/null <==

To correct it, I modified the killsocket function;

 killsocket() {
   local socketpath=$1
   if [[ -e $socketpath ]]; then
     # local socketpid
     lsof +E -taU -- "$socketpath" | awk 'length {print $1}' | xargs -rn1 kill
   fi
 }

This works and corrects my multiple-terminal issues, but the timeout is also removed. It could be added, but I am wondering if it is even necessary?

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