sshd-regen-keys: Improve service, make more robust

Switch to using "/usr/bin/ssh-keygen -A" instead of dpkg-reconfigure.
With this we would generate new host keys every time the service starts
and no keys exist. Removing the keys from openssh-server in a postinst
makes it complete so that we really only generate on the first boot.

This is easier to handle that reusing the debian package hooks for key
generation.

Signed-off-by: Henning Schild <henning.schild@siemens.com>

meta/recipes-support/sshd-regen-keys/files/postinst

@@ -1,4 +1,6 @@
 #!/bin/sh
 set -e
 
+rm /etc/ssh/ssh_host_*_key*
+
 systemctl enable sshd-regen-keys.service

meta/recipes-support/sshd-regen-keys/files/sshd-regen-keys.service

@@ -9,9 +9,7 @@ ConditionPathIsReadWrite=/etc
 [Service]
 Type=oneshot
 RemainAfterExit=yes
-Environment=DEBIAN_FRONTEND=noninteractive
-ExecStart=/usr/sbin/sshd-regen-keys.sh
-ExecStartPost=-/bin/systemctl disable sshd-regen-keys.service
+ExecStart=/usr/bin/ssh-keygen -A
 StandardOutput=syslog
 StandardError=syslog
 

meta/recipes-support/sshd-regen-keys/files/sshd-regen-keys.sh

@@ -1,20 +0,0 @@
-#!/usr/bin/env sh
-
-echo -n "SSH server is "
-if systemctl is-enabled ssh; then
-    SSHD_ENABLED="true"
-    systemctl disable --no-reload ssh
-fi
-
-echo "Removing keys ..."
-rm -v /etc/ssh/ssh_host_*_key*
-
-echo "Regenerating keys ..."
-dpkg-reconfigure openssh-server
-
-if test -n $SSHD_ENABLED; then
-    echo "Reenabling ssh server ..."
-    systemctl enable --no-reload ssh
-fi
-
-sync

meta/recipes-support/sshd-regen-keys/sshd-regen-keys_0.3.bb

@@ -1,17 +0,0 @@
-# This software is a part of ISAR.
-inherit dpkg-raw
-
-DESCRIPTION = "Systemd service to regenerate sshd keys"
-MAINTAINER = "isar-users <isar-users@googlegroups.com>"
-DEBIAN_DEPENDS = "openssh-server, systemd"
-
-SRC_URI = "file://postinst \
-           file://sshd-regen-keys.service \
-           file://sshd-regen-keys.sh"
-
-do_install[cleandirs] = "${D}/lib/systemd/system \
-                         ${D}/usr/sbin"
-do_install() {
-    install -v -m 644 "${WORKDIR}/sshd-regen-keys.service" "${D}/lib/systemd/system/sshd-regen-keys.service"
-    install -v -m 755 "${WORKDIR}/sshd-regen-keys.sh" "${D}/usr/sbin/sshd-regen-keys.sh"
-}

meta/recipes-support/sshd-regen-keys/sshd-regen-keys_0.4.bb

@@ -0,0 +1,14 @@
+# This software is a part of ISAR.
+inherit dpkg-raw
+
+DESCRIPTION = "Systemd service to regenerate sshd keys"
+MAINTAINER = "isar-users <isar-users@googlegroups.com>"
+DEBIAN_DEPENDS = "openssh-server, systemd"
+
+SRC_URI = "file://postinst \
+           file://sshd-regen-keys.service"
+
+do_install() {
+    install -d -m 0755 "${D}/lib/systemd/system"
+    install -m 0644 "${WORKDIR}/sshd-regen-keys.service" "${D}/lib/systemd/system/sshd-regen-keys.service"
+}