this post was submitted on 14 Aug 2024

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why can't I connect to my ssh server UNLESS I enter eval "$(ssh-agent -s)" first? (lemmy.dbzer0.com)

submitted 3 months ago* (last edited 3 months ago) by [email protected] to c/[email protected]

72 comments fedilink hide all child comments

I have my own ssh server (on raspberry pi 5, Ubuntu Server 23) but when I try to connect from my PC using key authentication (having password disabled), I get a blank screen. A blinking cursor.

However, once I enter the command eval "$(ssh-agent -s)" and try ssh again, I successfully login after entering my passphrase. I don't want to issue this command every time. Is that possible?

This does not occur when I have password enabled on the ssh server. Also, ideally, I want to enter my passphrase EVERYTIME I connect to my server, so ideally I don't want it to be stored in cache or something. I want the passphrase to be a lil' password so that other people can't accidentally connect to my server when they use my PC.

(page 2) 22 comments

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[–] [email protected] 1 points 3 months ago (1 children)

Can you post the result of the env command as well? It sounds like your config is very minimal, but the fact that it's looking for a local Unix socket in the strace output is weird.

[–] [email protected] 1 points 3 months ago (1 children)

SYSTEMD_EXEC_PID=3980
SSH_AUTH_SOCK=/run/user/1000/gcr/ssh
SESSION_MANAGER=local/computername:@/tmp/.ICE-unix/3857,unix/computername:/tmp/.ICE-unix/3857
GNOME_TERMINAL_SCREEN=/org/gnome/Terminal/screen/668d083f_5746_4268_beac_1ab8e7e69305
GTK3_MODULES=xapp-gtk3-module
XDG_CURRENT_DESKTOP=GNOME
LANG=en_GB.UTF-8
GRADLE_HOME=/usr/share/java/gradle
LC_IDENTIFICATION=en_GB.UTF-8
DISPLAY=:1
QT_QPA_PLATFORMTHEME=qt5ct
COLORTERM=truecolor
QT_IM_MODULE=ibus
USER=username
LC_MEASUREMENT=en_GB.UTF-8
XDG_MENU_PREFIX=gnome-
HOME=/home/username
PWD=/home/username
DESKTOP_SESSION=gnome
XDG_SESSION_CLASS=user
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
LC_NUMERIC=en_GB.UTF-8
XDG_DATA_DIRS=/home/username/.local/share/flatpak/exports/share:/var/lib/flatpak/exports/share:/usr/local/share/:/usr/share/
WINDOWPATH=2
XDG_SESSION_DESKTOP=gnome
VTE_VERSION=7602
LC_TIME=en_GB.UTF-8
MAIL=/var/spool/mail/username
DEBUGINFOD_URLS=https://debuginfod.archlinux.org 
QT_AUTO_SCREEN_SCALE_FACTOR=1
LC_PAPER=en_GB.UTF-8
LOGNAME=username
MEMORY_PRESSURE_WATCH=/sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/org.gnome.SettingsDaemon.MediaKeys.service/memory.pressure
MEMORY_PRESSURE_WRITE=c29tZSAyMDAwMDAgMjAwMDAwMAA=
XMODIFIERS=@im=ibus
GNOME_TERMINAL_SERVICE=:1.870
XDG_SESSION_TYPE=x11
SHELL=/bin/zsh
XDG_RUNTIME_DIR=/run/user/1000
LC_MONETARY=en_GB.UTF-8
EDITOR=/usr/bin/nano
PATH=/home/username/.local/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:/var/lib/flatpak/exports/bin:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl
USERNAME=username
GNOME_KEYRING_CONTROL=/run/user/1000/keyring
LC_TELEPHONE=en_GB.UTF-8
GDM_LANG=en_GB.UTF-8
LC_NAME=en_GB.UTF-8
MOTD_SHOWN=pam
TERM=xterm-256color
GDMSESSION=gnome
XAUTHORITY=/run/user/1000/gdm/Xauthority
LC_ADDRESS=en_GB.UTF-8
SHLVL=1
OLDPWD=/home/username
LESS_TERMCAP_mb=
LESS_TERMCAP_md=
LESS_TERMCAP_me=
LESS_TERMCAP_se=
LESS_TERMCAP_so=
LESS_TERMCAP_ue=
LESS_TERMCAP_us=
LESS=-R
LS_OPTIONS=--color=auto
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=00:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.7z=01;31:*.ace=01;31:*.alz=01;31:*.apk=01;31:*.arc=01;31:*.arj=01;31:*.bz=01;31:*.bz2=01;31:*.cab=01;31:*.cpio=01;31:*.crate=01;31:*.deb=01;31:*.drpm=01;31:*.dwm=01;31:*.dz=01;31:*.ear=01;31:*.egg=01;31:*.esd=01;31:*.gz=01;31:*.jar=01;31:*.lha=01;31:*.lrz=01;31:*.lz=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.lzo=01;31:*.pyz=01;31:*.rar=01;31:*.rpm=01;31:*.rz=01;31:*.sar=01;31:*.swm=01;31:*.t7z=01;31:*.tar=01;31:*.taz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tgz=01;31:*.tlz=01;31:*.txz=01;31:*.tz=01;31:*.tzo=01;31:*.tzst=01;31:*.udeb=01;31:*.war=01;31:*.whl=01;31:*.wim=01;31:*.xz=01;31:*.z=01;31:*.zip=01;31:*.zoo=01;31:*.zst=01;31:*.avif=01;35:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.webp=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:*~=00;90:*#=00;90:*.bak=00;90:*.crdownload=00;90:*.dpkg-dist=00;90:*.dpkg-new=00;90:*.dpkg-old=00;90:*.dpkg-tmp=00;90:*.old=00;90:*.orig=00;90:*.part=00;90:*.rej=00;90:*.rpmnew=00;90:*.rpmorig=00;90:*.rpmsave=00;90:*.swp=00;90:*.tmp=00;90:*.ucf-dist=00;90:*.ucf-new=00;90:*.ucf-old=00;90:
P9K_SSH=0
_P9K_SSH_TTY=/dev/pts/0
P9K_TTY=old
_P9K_TTY=/dev/pts/0
_=/usr/bin/env

[–] [email protected] 1 points 3 months ago (2 children)

What happens if you do:

unset  SSH_AUTH_SOCK

And then try to connect?

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[–] [email protected] 1 points 3 months ago

The only reason ssh client would "hang" without any output is when it's waiting for external key storage to allow access. It's designed that way to give user some time to approve access to key storage.

It sometimes happen that the installed key storage is broken in a way that it fails to show user modal, for any reason (showing on wrong screen, wrong desktop, wrong activity, wrong framebuffer, ....)

One solution (that you already did) is to change the SSH agent env variable to point to different key storage.

Another would be (if possible) to uninstall the broken key storage if you don't use it. But it is sometimes needed/used by other apps.

It's overall good to notify/open bug on your distro issue tracker to notify that some packages are missconfigured (maybe have missing dependencies) or conflicts with other ones.

[–] [email protected] 1 points 3 months ago (1 children)

What happens if you run commands on that blinking cursor? E.g. it you run ls do you get an output? I've had that happen in the past, don't remember the reason though.

[–] [email protected] 1 points 3 months ago

also no output

[–] [email protected] 1 points 3 months ago* (last edited 3 months ago)

I am not sure I "solved" this but when I add this to my startup script for my terminal (~/.zshrc):

SSH_AUTH_SOCK=/tmp/ssh-agent-$USER-socket
export SSH_AUTH_SOCK

it works then. I am not sure I'm still using the ssh agent, but at least it also does not cache my passphrase (or private key in ram)

[–] [email protected] 0 points 3 months ago

Your shell for user pi may be broken. Try adding the shell command to your ssh command explicitly like

ssh pi@host /bin/sh

Or use /bin/bash

[–] [email protected] 0 points 3 months ago (3 children)

@dysprosium ssh agent manages your ssh keys and automatically passes them as an identity when connecting to a server

If you want to connect without it, you can simply pass -i \<path to private key\> flag

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