openssh: Fix key generation with systemd

106b59d9 broke SSH host key generation when systemd and a read-only root file
system are in use because there isn't a way for systemd to get the optional
weak assigment of SYSCONFDIR from /etc/default/sshd and still provide a default
value if it is not specified. Instead, move the logic for determining if keys
need to be created to a helper script that both the SysV init script and the
systemd unit file can reference.

This does mean that the systemd unit file can't check for file existence to
know if it should start the service, but it wasn't able to do that correctly
anyway anymore. This should be a problem since the serivce is only run once per
power cycle by systemd, and should exit quickly if the keys already exist

(From OE-Core rev: 7e49c5879862253ae1b6a26535d07a2740a95798)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

4 files changed, 76 insertions, 81 deletions

diff --git a/meta/recipes-connectivity/openssh/openssh/init b/meta/recipes-connectivity/openssh/openssh/init
index 386628afc8..34ba0f8460 100644
--- a/meta/recipes-connectivity/openssh/openssh/init
+++ b/meta/recipes-connectivity/openssh/openssh/init
@@ -19,25 +19,6 @@ fi
 [ -z "$SYSCONFDIR" ] && SYSCONFDIR=/etc/ssh
 mkdir -p $SYSCONFDIR
 
-parse_sshd_opts() {
-    set -- ${SSHD_OPTS} --
-    sshd_config=/etc/ssh/sshd_config
-    while true ; do
-        case "$1" in
-        -f*) if [ "$1" = "-f" ] ; then
-                 sshd_config="$2"
-                 shift
-             else
-                 sshd_config="${1#-f}"
-             fi
-             shift
-             ;;
-        --) shift; break;;
-        *) shift;;
-        esac
-    done
-}
-
 check_for_no_start() {
     # forget it if we're trying to start, and /etc/ssh/sshd_not_to_be_run exists
     if [ -e $SYSCONFDIR/sshd_not_to_be_run ]; then
@@ -58,57 +39,13 @@ check_config() {
         /usr/sbin/sshd -t $SSHD_OPTS || exit 1
 }
 
-check_keys() {
-        # parse location of keys
-        local HOST_KEY_RSA
-        local HOST_KEY_DSA
-        local HOST_KEY_ECDSA
-        local HOST_KEY_ED25519
-
-        parse_sshd_opts
-        HOST_KEY_RSA=$(grep ^HostKey "${sshd_config}" | grep _rsa_ | tail -1 | awk ' { print $2 } ')
-        [ -z "${HOST_KEY_RSA}" ] && HOST_KEY_RSA=$(grep HostKey "${sshd_config}" | grep _rsa_ | tail -1 | awk ' { print $2 } ')
-        [ -z "${HOST_KEY_RSA}" ] && HOST_KEY_RSA=$SYSCONFDIR/ssh_host_rsa_key
-        HOST_KEY_DSA=$(grep ^HostKey "${sshd_config}" | grep _dsa_ | tail -1 | awk ' { print $2 } ')
-        [ -z "${HOST_KEY_DSA}" ] && HOST_KEY_DSA=$(grep HostKey "${sshd_config}" | grep _dsa_ | tail -1 | awk ' { print $2 } ')
-        [ -z "${HOST_KEY_DSA}" ] && HOST_KEY_DSA=$SYSCONFDIR/ssh_host_dsa_key
-        HOST_KEY_ECDSA=$(grep ^HostKey "${sshd_config}" | grep _ecdsa_ | tail -1 | awk ' { print $2 } ')
-        [ -z "${HOST_KEY_ECDSA}" ] && HOST_KEY_ECDSA=$(grep HostKey "${sshd_config}" | grep _ecdsa_ | tail -1 | awk ' { print $2 } ')
-        [ -z "${HOST_KEY_ECDSA}" ] && HOST_KEY_ECDSA=$SYSCONFDIR/ssh_host_ecdsa_key
-        HOST_KEY_ED25519=$(grep ^HostKey "${sshd_config}" | grep _ed25519_ | tail -1 | awk ' { print $2 } ')
-        [ -z "${HOST_KEY_ED25519}" ] && HOST_KEY_ED25519=$(grep HostKey "${sshd_config}" | grep _ed25519_ | tail -1 | awk ' { print $2 } ')
-        [ -z "${HOST_KEY_ED25519}" ] && HOST_KEY_ED25519=$SYSCONFDIR/ssh_host_ed25519_key
-
-        # create keys if necessary
-        if [ ! -f $HOST_KEY_RSA ]; then
-                echo "  generating ssh RSA key..."
-                mkdir -p $(dirname $HOST_KEY_RSA)
-                ssh-keygen -q -f $HOST_KEY_RSA -N '' -t rsa
-        fi
-        if [ ! -f $HOST_KEY_ECDSA ]; then
-                echo "  generating ssh ECDSA key..."
-                mkdir -p $(dirname $HOST_KEY_ECDSA)
-                ssh-keygen -q -f $HOST_KEY_ECDSA -N '' -t ecdsa
-        fi
-        if [ ! -f $HOST_KEY_DSA ]; then
-                echo "  generating ssh DSA key..."
-                mkdir -p $(dirname $HOST_KEY_DSA)
-                ssh-keygen -q -f $HOST_KEY_DSA -N '' -t dsa
-        fi
-        if [ ! -f $HOST_KEY_ED25519 ]; then
-                echo "  generating ssh ED25519 key..."
-                mkdir -p $(dirname $HOST_KEY_ED25519)
-                ssh-keygen -q -f $HOST_KEY_ED25519 -N '' -t ed25519
-        fi
-}
-
 export PATH="${PATH:+$PATH:}/usr/sbin:/sbin"
 
 case "$1" in
   start)
         check_for_no_start
         echo "Starting OpenBSD Secure Shell server: sshd"
-        check_keys
+        @LIBEXECDIR@/sshd_check_keys
         check_privsep_dir
         start-stop-daemon -S -p $PIDFILE -x /usr/sbin/sshd -- $SSHD_OPTS
         echo "done."
@@ -121,7 +58,7 @@ case "$1" in
 
   reload|force-reload)
         check_for_no_start
-        check_keys
+        @LIBEXECDIR@/sshd_check_keys
         check_config
         echo -n "Reloading OpenBSD Secure Shell server's configuration"
         start-stop-daemon -K -p $PIDFILE -s 1 -x /usr/sbin/sshd
@@ -129,7 +66,7 @@ case "$1" in
         ;;
 
   restart)
-        check_keys
+        @LIBEXECDIR@/sshd_check_keys
         check_config
         echo -n "Restarting OpenBSD Secure Shell server: sshd"
         start-stop-daemon -K -p $PIDFILE --oknodo -x /usr/sbin/sshd
diff --git a/meta/recipes-connectivity/openssh/openssh/sshd_check_keys b/meta/recipes-connectivity/openssh/openssh/sshd_check_keys
new file mode 100644
index 0000000000..f5bba53ca3
--- /dev/null
+++ b/meta/recipes-connectivity/openssh/openssh/sshd_check_keys
@@ -0,0 +1,64 @@
+#! /bin/sh
+
+# /etc/default/ssh may set SYSCONFDIR and SSHD_OPTS
+if test -f /etc/default/ssh; then
+    . /etc/default/ssh
+fi
+
+[ -z "$SYSCONFDIR" ] && SYSCONFDIR=/etc/ssh
+mkdir -p $SYSCONFDIR
+
+# parse sshd options
+set -- ${SSHD_OPTS} --
+sshd_config=/etc/ssh/sshd_config
+while true ; do
+    case "$1" in
+    -f*) if [ "$1" = "-f" ] ; then
+            sshd_config="$2"
+            shift
+        else
+            sshd_config="${1#-f}"
+        fi
+        shift
+        ;;
+    --) shift; break;;
+    *) shift;;
+    esac
+done
+
+# parse location of keys
+HOST_KEY_RSA=$(grep ^HostKey "${sshd_config}" | grep _rsa_ | tail -1 | awk ' { print $2 } ')
+[ -z "${HOST_KEY_RSA}" ] && HOST_KEY_RSA=$(grep HostKey "${sshd_config}" | grep _rsa_ | tail -1 | awk ' { print $2 } ')
+[ -z "${HOST_KEY_RSA}" ] && HOST_KEY_RSA=$SYSCONFDIR/ssh_host_rsa_key
+HOST_KEY_DSA=$(grep ^HostKey "${sshd_config}" | grep _dsa_ | tail -1 | awk ' { print $2 } ')
+[ -z "${HOST_KEY_DSA}" ] && HOST_KEY_DSA=$(grep HostKey "${sshd_config}" | grep _dsa_ | tail -1 | awk ' { print $2 } ')
+[ -z "${HOST_KEY_DSA}" ] && HOST_KEY_DSA=$SYSCONFDIR/ssh_host_dsa_key
+HOST_KEY_ECDSA=$(grep ^HostKey "${sshd_config}" | grep _ecdsa_ | tail -1 | awk ' { print $2 } ')
+[ -z "${HOST_KEY_ECDSA}" ] && HOST_KEY_ECDSA=$(grep HostKey "${sshd_config}" | grep _ecdsa_ | tail -1 | awk ' { print $2 } ')
+[ -z "${HOST_KEY_ECDSA}" ] && HOST_KEY_ECDSA=$SYSCONFDIR/ssh_host_ecdsa_key
+HOST_KEY_ED25519=$(grep ^HostKey "${sshd_config}" | grep _ed25519_ | tail -1 | awk ' { print $2 } ')
+[ -z "${HOST_KEY_ED25519}" ] && HOST_KEY_ED25519=$(grep HostKey "${sshd_config}" | grep _ed25519_ | tail -1 | awk ' { print $2 } ')
+[ -z "${HOST_KEY_ED25519}" ] && HOST_KEY_ED25519=$SYSCONFDIR/ssh_host_ed25519_key
+
+# create keys if necessary
+if [ ! -f $HOST_KEY_RSA ]; then
+    echo "  generating ssh RSA key..."
+    mkdir -p $(dirname $HOST_KEY_RSA)
+    ssh-keygen -q -f $HOST_KEY_RSA -N '' -t rsa
+fi
+if [ ! -f $HOST_KEY_ECDSA ]; then
+    echo "  generating ssh ECDSA key..."
+    mkdir -p $(dirname $HOST_KEY_ECDSA)
+    ssh-keygen -q -f $HOST_KEY_ECDSA -N '' -t ecdsa
+fi
+if [ ! -f $HOST_KEY_DSA ]; then
+    echo "  generating ssh DSA key..."
+    mkdir -p $(dirname $HOST_KEY_DSA)
+    ssh-keygen -q -f $HOST_KEY_DSA -N '' -t dsa
+fi
+if [ ! -f $HOST_KEY_ED25519 ]; then
+    echo "  generating ssh ED25519 key..."
+    mkdir -p $(dirname $HOST_KEY_ED25519)
+    ssh-keygen -q -f $HOST_KEY_ED25519 -N '' -t ed25519
+fi
+
diff --git a/meta/recipes-connectivity/openssh/openssh/sshdgenkeys.service b/meta/recipes-connectivity/openssh/openssh/sshdgenkeys.service
index 148e6ad63a..603c33787f 100644
--- a/meta/recipes-connectivity/openssh/openssh/sshdgenkeys.service
+++ b/meta/recipes-connectivity/openssh/openssh/sshdgenkeys.service
@@ -1,22 +1,8 @@
 [Unit]
 Description=OpenSSH Key Generation
 RequiresMountsFor=/var /run
-ConditionPathExists=!/var/run/ssh/ssh_host_rsa_key
-ConditionPathExists=!/var/run/ssh/ssh_host_dsa_key
-ConditionPathExists=!/var/run/ssh/ssh_host_ecdsa_key
-ConditionPathExists=!/var/run/ssh/ssh_host_ed25519_key
-ConditionPathExists=!/etc/ssh/ssh_host_rsa_key
-ConditionPathExists=!/etc/ssh/ssh_host_dsa_key
-ConditionPathExists=!/etc/ssh/ssh_host_ecdsa_key
-ConditionPathExists=!/etc/ssh/ssh_host_ed25519_key
 
 [Service]
-Environment="SYSCONFDIR=/etc/ssh"
-EnvironmentFile=-/etc/default/ssh
-ExecStart=@BASE_BINDIR@/mkdir -p $SYSCONFDIR
-ExecStart=@BINDIR@/ssh-keygen -q -f ${SYSCONFDIR}/ssh_host_rsa_key -N '' -t rsa
-ExecStart=@BINDIR@/ssh-keygen -q -f ${SYSCONFDIR}/ssh_host_dsa_key -N '' -t dsa
-ExecStart=@BINDIR@/ssh-keygen -q -f ${SYSCONFDIR}/ssh_host_ecdsa_key -N '' -t ecdsa
-ExecStart=@BINDIR@/ssh-keygen -q -f ${SYSCONFDIR}/ssh_host_ed25519_key -N '' -t ed25519
+ExecStart=@LIBEXECDIR@/sshd_check_keys
 Type=oneshot
 RemainAfterExit=yes
diff --git a/meta/recipes-connectivity/openssh/openssh_7.5p1.bb b/meta/recipes-connectivity/openssh/openssh_7.5p1.bb
index e46b4c86ad..86ca6ff372 100644
--- a/meta/recipes-connectivity/openssh/openssh_7.5p1.bb
+++ b/meta/recipes-connectivity/openssh/openssh_7.5p1.bb
@@ -27,6 +27,7 @@ SRC_URI = "http://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-${PV}.tar
            file://openssh-7.1p1-conditional-compile-des-in-pkcs11.patch \
            file://fix-potential-signed-overflow-in-pointer-arithmatic.patch \
            file://0001-openssh-Fix-syntax-error-on-x32.patch \
+           file://sshd_check_keys \
            "
 
 PAM_SRC_URI = "file://sshd"
@@ -120,7 +121,13 @@ do_install_append () {
         sed -i -e 's,@BASE_BINDIR@,${base_bindir},g' \
                 -e 's,@SBINDIR@,${sbindir},g' \
                 -e 's,@BINDIR@,${bindir},g' \
+                -e 's,@LIBEXECDIR@,${libexecdir}/${BPN},g' \
                 ${D}${systemd_unitdir}/system/sshd.socket ${D}${systemd_unitdir}/system/*.service
+
+        sed -i -e 's,@LIBEXECDIR@,${libexecdir}/${BPN},g' \
+                ${D}${sysconfdir}/init.d/sshd
+
+        install -D -m 0755 ${WORKDIR}/sshd_check_keys ${D}${libexecdir}/${BPN}/sshd_check_keys
 }
 
 do_install_ptest () {
@@ -135,6 +142,7 @@ FILES_${PN}-scp = "${bindir}/scp.${BPN}"
 FILES_${PN}-ssh = "${bindir}/ssh.${BPN} ${sysconfdir}/ssh/ssh_config"
 FILES_${PN}-sshd = "${sbindir}/sshd ${sysconfdir}/init.d/sshd ${systemd_unitdir}/system"
 FILES_${PN}-sshd += "${sysconfdir}/ssh/moduli ${sysconfdir}/ssh/sshd_config ${sysconfdir}/ssh/sshd_config_readonly ${sysconfdir}/default/volatiles/99_sshd ${sysconfdir}/pam.d/sshd"
+FILES_${PN}-sshd += "${libexecdir}/${BPN}/sshd_check_keys"
 FILES_${PN}-sftp = "${bindir}/sftp"
 FILES_${PN}-sftp-server = "${libexecdir}/sftp-server"
 FILES_${PN}-misc = "${bindir}/ssh* ${libexecdir}/ssh*"