encrypt

#!/usr/bin/ash

run_hook() {
    modprobe -a -q dm-crypt >/dev/null 2>&1
    [ "${quiet}" = "y" ] && CSQUIET=">/dev/null"

    # Get keyfile if specified
    ckeyfile="/crypto_keyfile.bin"
    if [ -n "$cryptkey" ]; then
        IFS=: read ckdev ckarg1 ckarg2 <<EOF
$cryptkey
EOF

        read_keyfile() {
            if [ "$ckdev" = "rootfs" ]; then
                ckeyfile=$ckarg1
            elif ckresolved=$(resolve_device "${ckdev}" ${rootdelay}); then
                case ${ckarg1} in
                    *[!0-9]*)
                        # Use a file on the device
                        # ckarg1 is not numeric: ckarg1=filesystem, ckarg2=path
                        mkdir -p /ckey
                        mount -r -t "$ckarg1" "$ckresolved" /ckey
                        dd if="/ckey/$ckarg2" of="$ckeyfile" >/dev/null 2>&1
                        umount /ckey
                        ;;
                    *)
                        # Read raw data from the block device
                        # ckarg1 is numeric: ckarg1=offset, ckarg2=length
                        dd if="$ckresolved" of="$ckeyfile" bs=1 skip="$ckarg1" count="$ckarg2" >/dev/null 2>&1
                        ;;
                esac
            fi
        }
    fi

    if [ -n "${cryptdevice}" ]; then
        DEPRECATED_CRYPT=0
        IFS=: read cryptdev cryptname cryptoptions <<EOF
$cryptdevice
EOF
    else
        DEPRECATED_CRYPT=1
        cryptdev="${root}"
        cryptname="root"
    fi

    warn_deprecated() {
        echo "The syntax 'root=${root}' where '${root}' is an encrypted volume is deprecated"
        echo "Use 'cryptdevice=${root}:root root=/dev/mapper/root' instead."
    }

    for cryptopt in ${cryptoptions//,/ }; do
        case ${cryptopt} in
            allow-discards)
                cryptargs="${cryptargs} --allow-discards"
                ;;
            *)
                echo "Encryption option '${cryptopt}' not known, ignoring." >&2
                ;;
        esac
    done

    if resolved=$(resolve_device "${cryptdev}" ${rootdelay}); then
        if cryptsetup isLuks ${resolved} >/dev/null 2>&1; then
            [ ${DEPRECATED_CRYPT} -eq 1 ] && warn_deprecated
            for i in `seq 1 5`; do
                read_keyfile
                # If keyfile exists, try to use that
                if [ -f ${ckeyfile} ]; then
                    if eval cryptsetup --key-file ${ckeyfile} open --type luks ${resolved} ${cryptname} ${cryptargs} ${CSQUIET}; then
                        break
                    else
                        echo "Invalid keyfile. Reverting to passphrase."
                    fi
                fi
                # Ask for a passphrase
                echo "A password is required to access the ${cryptname} volume:"

                if eval cryptsetup open --type luks --timeout 10 ${resolved} ${cryptname} ${cryptargs} ${CSQUIET}; then
                    break
                else
                    sleep 2;
                fi
            done
            if [ -e "/dev/mapper/${cryptname}" ]; then
                if [ ${DEPRECATED_CRYPT} -eq 1 ]; then
                    export root="/dev/mapper/root"
                fi
            else
                err "Password succeeded, but ${cryptname} creation failed, aborting..."
                echo "poweroff"
                /usr/bin/poweroff -f
                exit 1
            fi
        elif [ -n "${crypto}" ]; then
            [ ${DEPRECATED_CRYPT} -eq 1 ] && warn_deprecated
            msg "Non-LUKS encrypted device found..."
            if echo "$crypto" | awk -F: '{ exit(NF == 5) }'; then
                err "Verify parameter format: crypto=hash:cipher:keysize:offset:skip"
                err "Non-LUKS decryption not attempted..."
                return 1
            fi
            exe="cryptsetup open --type plain $resolved $cryptname $cryptargs"
            IFS=: read c_hash c_cipher c_keysize c_offset c_skip <<EOF
$crypto
EOF
            [ -n "$c_hash" ]    && exe="$exe --hash '$c_hash'"
            [ -n "$c_cipher" ]  && exe="$exe --cipher '$c_cipher'"
            [ -n "$c_keysize" ] && exe="$exe --key-size '$c_keysize'"
            [ -n "$c_offset" ]  && exe="$exe --offset '$c_offset'"
            [ -n "$c_skip" ]    && exe="$exe --skip '$c_skip'"
            if [ -f "$ckeyfile" ]; then
                exe="$exe --key-file $ckeyfile"
            else
                exe="$exe --verify-passphrase"
                echo ""
                echo "A password is required to access the ${cryptname} volume:"
            fi
            eval "$exe $CSQUIET"

            if [ $? -ne 0 ]; then
                err "Non-LUKS device decryption failed. verify format: "
                err "      crypto=hash:cipher:keysize:offset:skip"
                exit 1
            fi
            if [ -e "/dev/mapper/${cryptname}" ]; then
                if [ ${DEPRECATED_CRYPT} -eq 1 ]; then
                    export root="/dev/mapper/root"
                fi
            else
                err "Password succeeded, but ${cryptname} creation failed, aborting..."
                exit 1
            fi
        else
            err "Failed to open encryption mapping: The device ${cryptdev} is not a LUKS volume and the crypto= paramater was not specified."
        fi
    fi
    rm -f ${ckeyfile}
}

# vim: set ft=sh ts=4 sw=4 et: