learn and play around luks and fido2
an idea by oertel
Updated over 1 year ago. 2 hacker ♥️. 2 followers. Has no hacker: grab it!

read up on things like

https://0pointer.net/blog/authenticated-boot-and-disk-encryption-on-linux.html https://0pointer.net/blog/unlocking-luks2-volumes-with-tpm2-fido2-pkcs11-security-hardware-on-systemd-248.html https://en.opensuse.org/SDB:LUKS2,_TPM2_and_FIDO2

follow up on the idea of remote storing the luks header https://linuxconfig.org/how-to-use-luks-with-a-detached-header

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Activity

  • about 1 year ago: dsterba liked this project.
  • over 1 year ago: bchou liked this project.
  • over 1 year ago: oertel originated this project.


    • Comments

    • oertel
      about 1 year ago by oertel | Reply

      worked on the luks2.sh script from https://en.opensuse.org/SDB:LUKS2,_TPM2_and_FIDO2 to support the setup of just /boot/efi separate and / including /boot on lvm inside the crypted disk

      #!/bin/bash

LVM=""
GRUB_MOUNT=$(df /boot/grub2 | tail -n1)
GRUB_MOUNT=${GRUB_MOUNT%% *}
set -- $(lsblk -p -r | grep "^$GRUB_MOUNT")
DEV=$1
TYP=$6
MP=$7
case $TYP in
    lvm)
        LVM="lvm"
        LVM_GRUB=${GRUB_MOUNT#/dev/mapper/}
        GRUB_ROOT="($LVM/$LVM_GRUB)"
        case $MP in
                /) GRUB_PREFIX=($LVM/$LVM_GRUB)/boot/grub2 ;;
                /boot) GRUB_PREFIX=($LVM/$LVM_GRUB)/grub2 ;;
                /boot/grub2) GRUB_PREFIX=($LVM/$LVM_GRUB) ;;
        esac
    ;;
    part)
        LVM=""
        case $DEV in
                /dev/sda*) DISK=hd0 ;;
                /dev/sdb*) DISK=hd1 ;;
                /dev/sdc*) DISK=hd2 ;;
        esac
        PART=${DEV: -1}
        GRUB_PREFIX="($DISK.gpt$PART)"
        case $MP in
                /) echo "/ not encrypted, not needed here" ; exit 1 ;;
                /boot) GRUB_PREFIX="$GRUB_PREFIX/grub2" ;;
        esac
    ;;
esac

set -- $(lsblk -p -r | grep " /$")
ROOT_DEV=$1
ROOT_TYP=$6
case $ROOT_TYP in
    crypt) GRUB_ROOT=crypto0 ;;
esac
set -- $(blkid | grep crypto_LUKS)
#second param is UUID=
eval $2
#drop the - dashes
TARGET=${UUID//-/}

GRUB_MODULES="luks2 part_gpt cryptodisk gcry_rijndael pbkdf2 gcry_sha512 btrfs gcry_sha256 gcry_sha1 ext2 luks $LVM"

grub2-install --target=x86_64-efi --modules="$GRUB_MODULES"

CONFIG=$(mktemp /tmp/grub-config.XXXXX)
cat >"$CONFIG" <<EOF
cryptomount -u "$TARGET"
set root=$GRUB_ROOT
set prefix=$GRUB_PREFIX
insmod normal
normal
EOF


cat $CONFIG

grub2-mkimage \
    -p "$GRUB_PREFIX" \
    -O x86_64-efi \
    -c "$CONFIG" \
    -o /tmp/image \
    $GRUB_MODULES
rm "$CONFIG"

cp -v /tmp/image /boot/efi/EFI/opensuse/grubx64.efi

    • oertel
      about 1 year ago by oertel | Reply

      hacked up a patch for systemd to have a chance to notice the user should touch the token on bootup

      --- a/src/shared/libfido2-util.c
+++ b/src/shared/libfido2-util.c
@@ -345,6 +345,13 @@ static int fido2_use_hmac_hash_specific_token(
                                 log_notice("%s%sPlease confirm presence on security to unlock.",
                                            emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
                                            emoji_enabled() ? " " : "");
+
+                                if (!retry_with_up) {
+                                        /* notify user for a few secs on first try */
+                                        _cleanup_(strv_free_erasep) char **pin = NULL;
+                                        ask_password_auto("Please confirm presence on security token to unlock.", "drive-harddisk", NULL, "fido2-up", "fido2-up", usec_add(now(CLOCK_MONOTONIC), 5 * USEC_PER_SEC), 0, &pin);
+                                }
+
                                 retry_with_up = true;
                         }

    • oertel
      about 1 year ago by oertel | Reply

      for systemd on 15.4 this is:

      --- systemd-v249.11+suse.129.g17d488c53a/src/shared/libfido2-util.c     2022/07/01 09:41:51     1.1
+++ systemd-v249.11+suse.129.g17d488c53a/src/shared/libfido2-util.c     2022/07/01 09:42:43
@@ -292,6 +292,11 @@
                         log_notice("%s%sPlease confirm presence on security token to unlock.",
                                    emoji_enabled() ? special_glyph(SPECIAL_GLYPH_TOUCH) : "",
                                    emoji_enabled() ? " " : "");
+
+                        /* notify user for a few secs on first try */
+                        _cleanup_(strv_free_erasep) char **pin = NULL;
+                        ask_password_auto("Please confirm presence on security token to unlock.", "drive-harddisk", NULL, "fido2-up", "fido2-up", usec_add(now(CLOCK_MONOTONIC), 5 * USEC_PER_SEC), 0, &pin);
+
         }

         if (has_uv && !FLAGS_SET(required, FIDO2ENROLL_UV_OMIT)) {

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