Implement boot parameter "netkeys"

This allows the keys to be loaded from the boot medium even when the
root filesystem is loaded over the network.  I.e., specifying nbdroot=
no longer implies that the keys will be loaded over the network.

The ISO images generated by xorriso-usb.sh will not specify 'netkeys' so
the keys on the USB stick will be used.

The idea is that after install, the network should not be needed at
all; but that requires using a new mechanism instead of the nbdroot=
parameter, to determine dynamically whether to use a network root fs
device.

Currently, the network is still needed to boot a device that has its
root fs on the local disk and the keys on the boot medium, even though
no data is fetched from the NBD server.

You can force the machine to boot by going to the initramfs shell and
running:

  for n in $(seq 1 20); do killall ipconfig; done

Otherwise it blocks waiting for the network.

4 files changed, 62 insertions, 18 deletions

diff --git a/initramfs-tools/scripts/samizdat b/initramfs-tools/scripts/samizdat
index 0c511e8..b1752cd 100644
--- a/initramfs-tools/scripts/samizdat
+++ b/initramfs-tools/scripts/samizdat
@@ -7,28 +7,48 @@ mountroot()
   samizdat_install_udev_rules
   mkfifo "$MENUFIFO"
 
-  # Note: this blocks waiting for the network
   if [ "${nbdroot%%,*}" ]; then
-    try_nbd
+    # I guess this isn't getting called otherwise? I don't know why this should
+    # be necessary, but it is.
+    sh /scripts/local-top/nbd >/dev/null 2>&1
   fi
 
+  if keys_via_network; then
+    wait_for_gnupghome_tar "$tftp_key_server"
+  fi
+  bootwait samizdat-gpg
   bootmenu
   bootwait root-mounted
   chvt 1
 }
 
-try_nbd()
+# Sets $tftp_key_server or returns false.
+keys_via_network()
 {
-  sh /scripts/local-top/nbd >/dev/null 2>&1 & # I guess this isn't getting called otherwise?
-  wait_for_gnupghome_tar
-  (. common.sh && force_grok_block)
+    [ "${nbdroot%%,*}" ] || return
+    local arg cmdline
+    read cmdline < /proc/cmdline
+    for arg in $cmdline; do
+        case "$arg" in
+            netkeys)
+                tftp_key_server="${nbdroot%%,*}"
+                return 0
+            ;;
+            netkeys=*)
+                tftp_key_server="${arg#netkeys=}"
+                return 0
+            ;;
+        esac
+    done
+    return 1
 }
 
 wait_for_gnupghome_tar()
 {
+  local tftp_server="$1"
   [ -e /gnupghome.tar ] && return
   echo -n Waiting to receive GPG keys through the network...
-  (while ! tftp -g -r gnupghome.tar -l /gnupghome.tar.$$ ${nbdroot%%,*} 2>/dev/null; do
+  (while ! tftp -g -r gnupghome.tar -l /gnupghome.tar.$$ "$tftp_server" 2>/dev/null; do
     sleep 1;
     echo -n .
   done
diff --git a/isolinux/pxelinux.cfg/default b/isolinux/pxelinux.cfg/default
index 386012f..77796b3 100644
--- a/isolinux/pxelinux.cfg/default
+++ b/isolinux/pxelinux.cfg/default
@@ -2,4 +2,4 @@ default samizdat
 label samizdat
         linux linux/vmlinuz
         initrd linux/initrd.img
-        append boot=samizdat components quiet splash nbdroot=192.168.10.1,samizdat.btrfs nbddev=/dev/nbd0 ip=dhcp
+        append boot=samizdat components quiet splash nbdroot=192.168.10.1,samizdat.btrfs nbddev=/dev/nbd0 ip=dhcp netkeys
diff --git a/src/grub-efi.sh b/src/grub-efi.sh
index f96149d..44b9dec 100755
--- a/src/grub-efi.sh
+++ b/src/grub-efi.sh
@@ -1,11 +1,20 @@
-#!/bin/sh
+#!/bin/bash
 . samizdat-paths.sh
 
+linux_kernel_commandline='boot=samizdat components quiet splash nbdroot=192.168.10.1,samizdat.btrfs nbddev=/dev/nbd0 ip=dhcp'
+
 grub_config()
 {
     cat <<EOF
 insmod echo
 echo GRUB
+
+insmod normal
+insmod keystatus
+
+insmod linux
+insmod iso9660
+
 insmod part_acorn
 insmod part_amiga
 insmod part_apple
@@ -17,13 +26,13 @@ insmod part_plan
 insmod part_sun
 insmod part_sunpc
 
-insmod linux
-insmod iso9660
-
 echo Loading vmlinuz...
-linux /linux/vmlinuz boot=samizdat components quiet splash
+
+linux /linux/vmlinuz ${linux_kernel_commandline}
+
 echo Loading initrd.img...
 initrd /linux/initrd.img
+
 echo Booting.
 echo
 boot
diff --git a/src/qemu.sh b/src/qemu.sh
index f9982c4..b095eb8 100755
--- a/src/qemu.sh
+++ b/src/qemu.sh
@@ -21,17 +21,32 @@ NET='tap,vlan=0,ifname=tap0,script=no,downscript=no'
 
 initrd=${samizdat_isolinux_dir}/linux/initrd.img
 kernel=${samizdat_isolinux_dir}/linux/vmlinuz
-kcmdline_NET='boot=samizdat components quiet splash nbdroot=192.168.10.1,samizdat.btrfs nbddev=/dev/nbd0 ip=dhcp'
+      kcmdline_NET='boot=samizdat components quiet splash nbdroot=192.168.10.1,samizdat.btrfs nbddev=/dev/nbd0 ip=dhcp netkeys'
+kcmdline_CDROM_NET='boot=samizdat components quiet splash nbdroot=192.168.10.1,samizdat.btrfs nbddev=/dev/nbd0 ip=dhcp'
 kcmdline_CDROM='boot=samizdat components quiet splash'
 
+set --
 if [ "$USE_ISO" ]; then
-    [ "$QEMU_LOADS_LINUX" ] && set -- -initrd "$initrd" -kernel "$kernel" -append "$kcmdline_CDROM"
-    set -- -cdrom "$iso"
+    set -- "$@" -cdrom "$iso"
+    if [ "$QEMU_LOADS_LINUX" ]; then
+        set -- "$@" -initrd "$initrd" -kernel "$kernel"
+        if [ "$NO_NET" ]; then
+            set -- "$@" -append "$kcmdline_CDROM"
+        else
+            set -- "$@" -append "$kcmdline_CDROM_NET"
+        fi
+    else
+        set -- "$@" -boot d
+    fi
 else
-    [ "$QEMU_LOADS_LINUX" ] && set -- -initrd "$initrd" -kernel "$kernel" -append "$kcmdline_NET"
-    set -- -boot n
+    if [ "$QEMU_LOADS_LINUX" ]; then
+        set -- "$@" -initrd "$initrd" -kernel "$kernel" -append "$kcmdline_NET"
+    else
+        set -- "$@" -boot n
+    fi
 fi
 
+set -x
 sudo qemu-system-x86_64 -enable-kvm -smp 2 -m 640 -k en-us \
      -vga qxl \
      -net nic,vlan=0,model=virtio \