First steps into new server setup.

[config] / buster / setup_scripts / init_user_and_keybased_login.sh

diff --git a/buster/setup_scripts/init_user_and_keybased_login.sh b/buster/setup_scripts/init_user_and_keybased_login.sh
new file mode 100755 (executable)
index 0000000..73379c4
--- /dev/null
+++ b/buster/setup_scripts/init_user_and_keybased_login.sh
@@ -0,0 +1,52 @@
+#!/bin/sh
+# This script turns a fresh server with password-based root access to
+# one of only key-based access and only to new non-root account plom.
+#
+# CAUTION: This is optimized for a *fresh* setup. It will overwrite any
+# pre-existing ~/.ssh/authorized_keys of user plom with one that solely
+# contains the local ~/.ssh/id_rsa.pub, and also any old
+# /etc/ssh/sshd_config.
+#
+# Dependencies: ssh, scp, sshpass, ~/.ssh/id_rsa.pub, properly
+# configured sshd_config file in reach.
+set -e
+
+# Location auf a sshd_config with "PermitRootLogin no" and
+# "PasswordAuthentication no".
+config_tree_prefix="${HOME}/public_repos/config/buster"
+linkable_files_dir="${config_tree_prefix}/etc_files/server"
+system_path_sshd_config='/etc/ssh/sshd_config'
+local_path_sshd_config="${linkable_files_dir}${system_path_sshd_config}"
+
+# Ensure we have a server name as argument.
+if [ $# -eq 0 ]; then
+    echo "Need server as argument."
+    false
+fi
+server="$1"
+
+# Ask for root password only once, sshpass will re-use it then often.
+stty -echo
+printf "Server root password: "
+read PW_ROOT
+stty echo
+printf "\n"
+export SSHPASS="${PW_ROOT}"
+
+# Create user plom, and his ~/.ssh/authorized_keys based on the local
+# ~/.ssh/id_rsa.pub; ensure the result has proper permissions and
+# ownerships. Then disable root and pw login by copying over the
+# sshd_config and restart ssh daemon.
+#
+# This could be a line or two shorter by using ssh-copy-id, but that
+# would require setting a password for user plom otherwise not needed.
+sshpass -e scp ~/.ssh/id_rsa.pub root@"${server}":/tmp/authorized_keys
+sshpass -e ssh root@"${server}" \
+        'useradd -m plom && '\
+        'mkdir /home/plom/.ssh && '\
+        'chown plom:plom /home/plom/.ssh && '\
+        'chown plom:plom /tmp/authorized_keys && '\
+        'chmod u=rw,go= /tmp/authorized_keys && '\
+        'mv /tmp/authorized_keys /home/plom/.ssh/'
+sshpass -e scp "${local_path_sshd_config}" root@"${server}":"${system_path_sshd_config}"
+sshpass -e ssh root@"${server}" 'service ssh restart'