meta-google: authorized-keys-comp: Add package
This adds a startup routine that compiles an authorized_keys file from
multiple locations in the filesystem, allowing for multiple providers
without clashing.
Change-Id: Ib26e04af42f29d42410154fdd809aa3a525fc9d5
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meta-google/recipes-google/ssh/authorized-keys-comp/authorized-keys-comp.sh b/meta-google/recipes-google/ssh/authorized-keys-comp/authorized-keys-comp.sh
new file mode 100644
index 0000000..caff0a7
--- /dev/null
+++ b/meta-google/recipes-google/ssh/authorized-keys-comp/authorized-keys-comp.sh
@@ -0,0 +1,51 @@
+#!/bin/bash
+shopt -s nullglob
+
+# We want to iterate over all system users, check if they are opted-in to ssh
+# authorized_keys building, and then construct their keyfile
+for user in $(cut -d':' -f1 /etc/passwd); do
+ home="$(eval echo ~$user)" || continue
+ link="$(readlink $home/.ssh/authorized_keys 2>/dev/null)" || continue
+ # Users are only opted-in if they symlink to our well-known directory where
+ # the final output of this script lives.
+ if [ "$link" != "/run/authorized_keys/$user" ]; then
+ echo "Ignoring $user $home/.ssh/authorized_keys" >&2
+ continue
+ fi
+
+ echo "Updating $link" >&2
+ declare -A basemap=()
+ declare -a dirs=(
+ "/usr/share/authorized_keys.d/$user"
+ "$home/.ssh/authorized_keys.d"
+ "/run/authorized_keys.d/$user"
+ )
+ # Build a map that can be used for sorting directories by their priority
+ # and prioritizing the last listed directories over the later ones. We
+ # append a counter to ensure that there is a stable sorting mechanism for
+ # duplicate filenames. Duplicate filenames will be overridden by higher
+ # priority directories.
+ # Ex.
+ # /usr/share/authorized_keys.d/root/10-key
+ # /usr/share/authorized_keys.d/root/15-key
+ # /run/authorized_keys.d/root/10-key
+ # /run/authorized_keys.d/root/20-key
+ # Becomes
+ # ["10-key"]="/run/authorized_keys.d/root/10-key"
+ # ["15-key"]="/usr/share/authorized_keys.d/root/15-key"
+ # ["20-key"]="/run/authorized_keys.d/root/20-key"
+ for dir in "${dirs[@]}"; do
+ for file in "$dir"/*; do
+ basemap["${file##*/}"]="$file"
+ done
+ done
+ rm -f /run/authorized_keys.tmp
+ touch /run/authorized_keys.tmp
+ for key in $(printf "%s\n" "${!basemap[@]}" | sort -r); do
+ echo " Including ${basemap[$key]}" >&2
+ cat "${basemap[$key]}" >>/run/authorized_keys.tmp
+ done
+ mkdir -p /run/authorized_keys
+ mv /run/authorized_keys.tmp /run/authorized_keys/$user
+ chown $user /run/authorized_keys/$user
+done