From 465c4ea4d0b4ef63a9a4410d84586832f6e11f76 Mon Sep 17 00:00:00 2001
From: Adam Bolsover <13262235+bowseruk@users.noreply.github.com>
Date: Thu, 21 Oct 2021 06:31:17 +0100
Subject: [PATCH] Add public keys from github (#254)

I've added a script that downloads keys from either a line separated file or github public keys into the authorized keys file. I've tested that it's working sucessfully on my UDM Pro while it was running, and with a reset.
---
 .../on_boot.d/15-add-github-ssh-keys.sh       | 63 +++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 on-boot-script/examples/udm-files/on_boot.d/15-add-github-ssh-keys.sh

diff --git a/on-boot-script/examples/udm-files/on_boot.d/15-add-github-ssh-keys.sh b/on-boot-script/examples/udm-files/on_boot.d/15-add-github-ssh-keys.sh
new file mode 100644
index 0000000..1eb301e
--- /dev/null
+++ b/on-boot-script/examples/udm-files/on_boot.d/15-add-github-ssh-keys.sh
@@ -0,0 +1,63 @@
+#!/bin/sh
+## Config Variables - please edit these
+# Set to true to download public keys from a github user account
+USE_GITHUB_KEYS=true
+# Enter your username on github to get the public keys for
+GITHUB_USER="<YOUR_USERNAME>"
+# File location for the output of the git download
+GITHUB_KEY_PATH="/mnt/data/podman/ssh"
+GITHUB_KEY_FILE="${GITHUB_KEY_PATH}/github.keys"
+# Set to true to use a file containing a key per line in the format ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAA...\n
+USE_KEY_FILE=true
+# IF using an input file, list it here
+INPUT_KEY_PATH="/mnt/data/podman/ssh"
+INPUT_KEY_FILE="${INPUT_KEY_PATH}/ssh.keys"
+# The target key file for the script
+OUTPUT_KEY_PATH="/root/.ssh"
+OUTPUT_KEY_FILE="${OUTPUT_KEY_PATH}/authorized_keys"
+
+## Functions
+# This function downloads the keys from the selected github user
+download_from_github(){
+	if curl --output /dev/null --silent --head --fail https://github.com/${GITHUB_USER}.keys; then
+		curl https://github.com/${GITHUB_USER}.keys -o ${GITHUB_KEY_FILE}
+		echo "Downloaded keys from Github"
+	else
+		echo "Could not download ${GITHUB_USER}'s key file from github"
+	fi
+}
+# Write line to the output line. Add the input line as an arguement.
+write_to_output(){
+		# Check the file exits
+		if ! test -f ${OUTPUT_KEY_FILE}; then
+			echo "File at ${OUTPUT_KEY_FILE} does not exist, creating it"
+			touch ${OUTPUT_KEY_FILE}
+		fi
+		echo "${1}" >> ${OUTPUT_KEY_FILE}
+}
+# This function reads keys from a file into the requested file. The arguement is the input file.
+use_key_from_file(){
+	if ! test -f $1; then
+		echo "File $1 does not exist"
+		return
+	fi
+	counter=0;
+  	while IFS= read -r line;
+	do
+		write_to_output "${line}"
+		let "counter++"
+	done < $1
+	echo "${counter} number of entries read from "
+}
+
+## Script
+# Makes paths if they don't exit
+mkdir -p ${GITHUB_KEY_PATH} ${INPUT_KEY_PATH} ${OUTPUT_KEY_PATH}
+#Check flags to see which files to use
+if [ ${USE_GITHUB_KEYS} = true ]; then
+	download_from_github
+	use_key_from_file ${GITHUB_KEY_FILE}
+fi
+if [ ${USE_KEY_FILE} = true ]; then
+	use_key_from_file ${INPUT_KEY_FILE}
+fi