dropbear: drop support for DSA host keys in dropbear init script

Bring the dropbear init script into sync with the systemd service
file (dropbearkey.service supports RSA host keys only) and with
recent versions of openssh which deprecate DSA host keys.

  https://www.gentoo.org/support/news-items/2015-08-13-openssh-weak-keys.html

(From OE-Core rev: 6bd7341a38a8bb5387ea81dbccfed327370569f3)

Signed-off-by: Andre McCurdy <armccurdy@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 6 insertions, 30 deletions

diff --git a/meta/recipes-core/dropbear/dropbear/init b/meta/recipes-core/dropbear/dropbear/init
index 434bd6b971..f6e1c462fa 100755
--- a/meta/recipes-core/dropbear/dropbear/init
+++ b/meta/recipes-core/dropbear/dropbear/init
@@ -40,49 +40,28 @@ done
 if [ $readonly_rootfs = "1" ]; then
   mkdir -p /var/lib/dropbear
   DROPBEAR_RSAKEY_DEFAULT="/var/lib/dropbear/dropbear_rsa_host_key"
-  DROPBEAR_DSSKEY_DEFAULT="/var/lib/dropbear/dropbear_dss_host_key"
 else
   DROPBEAR_RSAKEY_DEFAULT="/etc/dropbear/dropbear_rsa_host_key"
-  DROPBEAR_DSSKEY_DEFAULT="/etc/dropbear/dropbear_dss_host_key"
 fi
 
 test -z "$DROPBEAR_BANNER" || \
   DROPBEAR_EXTRA_ARGS="$DROPBEAR_EXTRA_ARGS -b $DROPBEAR_BANNER"
 test -n "$DROPBEAR_RSAKEY" || \
   DROPBEAR_RSAKEY=$DROPBEAR_RSAKEY_DEFAULT
-test -n "$DROPBEAR_DSSKEY" || \
-  DROPBEAR_DSSKEY=$DROPBEAR_DSSKEY_DEFAULT
-test -n "$DROPBEAR_KEYTYPES" || \
-  DROPBEAR_KEYTYPES="rsa"
 
 gen_keys() {
-for t in $DROPBEAR_KEYTYPES; do
-  case $t in
-    rsa)
-        if [ -f "$DROPBEAR_RSAKEY" -a ! -s "$DROPBEAR_RSAKEY" ]; then
-                rm $DROPBEAR_RSAKEY || true
-        fi
-        test -f $DROPBEAR_RSAKEY || dropbearkey -t rsa -f $DROPBEAR_RSAKEY $DROPBEAR_RSAKEY_ARGS
-        ;;
-    dsa)
-        if [ -f "$DROPBEAR_DSSKEY" -a ! -s "$DROPBEAR_DSSKEY" ]; then
-                rm $DROPBEAR_DSSKEY || true
-        fi
-        test -f $DROPBEAR_DSSKEY || dropbearkey -t dss -f $DROPBEAR_DSSKEY $DROPBEAR_DSSKEY_ARGS
-        ;;
-  esac
-done
+    if [ -f "$DROPBEAR_RSAKEY" -a ! -s "$DROPBEAR_RSAKEY" ]; then
+        rm $DROPBEAR_RSAKEY || true
+    fi
+    test -f $DROPBEAR_RSAKEY || dropbearkey -t rsa -f $DROPBEAR_RSAKEY $DROPBEAR_RSAKEY_ARGS
 }
 
 case "$1" in
   start)
         echo -n "Starting $DESC: "
         gen_keys
-        KEY_ARGS=""
-        test -f $DROPBEAR_DSSKEY && KEY_ARGS="$KEY_ARGS -d $DROPBEAR_DSSKEY"
-        test -f $DROPBEAR_RSAKEY && KEY_ARGS="$KEY_ARGS -r $DROPBEAR_RSAKEY"
         start-stop-daemon -S -p $PIDFILE \
-          -x "$DAEMON" -- $KEY_ARGS \
+          -x "$DAEMON" -- -r $DROPBEAR_RSAKEY \
             -p "$DROPBEAR_PORT" $DROPBEAR_EXTRA_ARGS
         echo "$NAME."
         ;;
@@ -95,11 +74,8 @@ case "$1" in
         echo -n "Restarting $DESC: "
         start-stop-daemon -K -x "$DAEMON" -p $PIDFILE
         sleep 1
-        KEY_ARGS=""
-        test -f $DROPBEAR_DSSKEY && KEY_ARGS="$KEY_ARGS -d $DROPBEAR_DSSKEY"
-        test -f $DROPBEAR_RSAKEY && KEY_ARGS="$KEY_ARGS -r $DROPBEAR_RSAKEY"
         start-stop-daemon -S -p $PIDFILE \
-          -x "$DAEMON" -- $KEY_ARGS \
+          -x "$DAEMON" -- -r $DROPBEAR_RSAKEY \
             -p "$DROPBEAR_PORT" $DROPBEAR_EXTRA_ARGS
         echo "$NAME."
         ;;