path: root/debian/functions

if [ "${0#/usr/share/initramfs-tools/hooks/}" != "$0" ] ||
        [ "${0#/etc/initramfs-tools/hooks/}" != "$0" ]; then
    # called from an initramfs-tools hook script
    TABFILE="$DESTDIR/cryptroot/crypttab"
elif [ "${0#/scripts/}" != "$0" ]; then
    # called at initramfs stage from a boot script
    TABFILE="/cryptroot/crypttab"
else
    TABFILE="${TABFILE-/etc/crypttab}"
fi
export DM_DEFAULT_NAME_MANGLING_MODE=hex # for dmsetup(8)

# Logging helpers. Send the argument list to plymouth(1), or fold it
# and print it to the standard error.
cryptsetup_message() {
    local IFS=' '
    if [ "${0#/scripts/}" != "$0" ] && [ -x /bin/plymouth ] && plymouth --ping; then
        plymouth message --text="cryptsetup: $*"
    elif [ ${#*} -lt 70 ]; then
        echo "cryptsetup: $*" >&2
    else
        # use busybox's fold(1) and sed(1) at initramfs stage
        echo "cryptsetup: $*" | fold -s | sed '1! s/^/    /' >&2
    fi
    return 0
}

# crypttab_parse_options([--export], [--quiet], [--missing-path={ignore|warn|fail}])
#   Parse $_CRYPTTAB_OPTIONS, a comma-separated option string from the
#   crypttab(5) 4th column, and sets corresponding variables
#   CRYPTTAB_OPTION_<option>=<value> (which are added to the environment
#   if --export is set).  If --path-exists isn't set to "ignore" (the
#   default), then options taking a file name, such as header=<path>,
#   need to point to an existing path, otherwise a warning is printed;
#   and an error is raised if the value is set to "fail".
#   For error and warning messages, CRYPTTAB_NAME, (resp. CRYPTTAB_KEY)
#   should be set to the (unmangled) mapped device name (resp. key
#   file).
#   Return 1 on parsing error, 0 otherwise (incl. if unknown options
#   were encountered).
crypttab_parse_options() {
    local quiet="n" export="n" missing_path="ignore"
    while [ $# -gt 0 ]; do
        case "$1" in
            --quiet) quiet="y";;
            --export) export="y";;
            --missing-path=*) missing_path="${1#--missing-path=}";;
            *) cryptsetup_message "WARNING: crypttab_parse_options(): unknown option $1"
        esac
        shift
    done

    local IFS=',' x OPTION VALUE
    unset -v CRYPTTAB_OPTION_cipher \
             CRYPTTAB_OPTION_size \
             CRYPTTAB_OPTION_sector_size \
             CRYPTTAB_OPTION_hash \
             CRYPTTAB_OPTION_offset \
             CRYPTTAB_OPTION_skip \
             CRYPTTAB_OPTION_verify \
             CRYPTTAB_OPTION_readonly \
             CRYPTTAB_OPTION_discard \
             CRYPTTAB_OPTION_plain \
             CRYPTTAB_OPTION_luks \
             CRYPTTAB_OPTION_tcrypt \
             CRYPTTAB_OPTION_veracrypt \
             CRYPTTAB_OPTION_swap \
             CRYPTTAB_OPTION_tmp \
             CRYPTTAB_OPTION_check \
             CRYPTTAB_OPTION_checkargs \
             CRYPTTAB_OPTION_tries \
             CRYPTTAB_OPTION_initramfs \
             CRYPTTAB_OPTION_noearly \
             CRYPTTAB_OPTION_noauto \
             CRYPTTAB_OPTION_loud \
             CRYPTTAB_OPTION_quiet \
             CRYPTTAB_OPTION_keyscript \
             CRYPTTAB_OPTION_keyslot \
             CRYPTTAB_OPTION_header \
             CRYPTTAB_OPTION_tcrypthidden
    # use $_CRYPTTAB_OPTIONS not $CRYPTTAB_OPTIONS as options values may
    # contain '\054' which is decoded to ',' in the latter
    for x in $_CRYPTTAB_OPTIONS; do
        OPTION="${x%%=*}"
        VALUE="${x#*=}"
        if [ "$x" = "$OPTION" ]; then
            unset -v VALUE
        else
            VALUE="$(printf '%b' "$VALUE")"
        fi
        if ! crypttab_validate_option; then
            if [ "$quiet" = "n" ]; then
                cryptsetup_message "ERROR: $CRYPTTAB_NAME: invalid value for '${x%%=*}' option, skipping"
            fi
            return 1
        elif [ -z "${OPTION+x}" ]; then
            continue
        fi
        if [ "$export" = "y" ]; then
            export "CRYPTTAB_OPTION_$OPTION"="${VALUE-yes}"
        else
            eval "CRYPTTAB_OPTION_$OPTION"='${VALUE-yes}'
        fi
    done
    IFS=" "

    if [ "$quiet" = "n" ] &&
            [ -z "${CRYPTTAB_OPTION_luks+x}" ] && [ -n "${CRYPTTAB_OPTION_header+x}" ]; then
        cryptsetup_message "WARNING: Option 'luks' missing in crypttab for target $CRYPTTAB_NAME." \
                           "Headers are only supported for LUKS devices."
    fi
    if [ -z "${CRYPTTAB_OPTION_luks+x}" ] && [ -z "${CRYPTTAB_OPTION_tcrypt+x}" ]; then
        # the compiled-in default for these are subject to change
        options='cipher size'
        if [ -n "${CRYPTTAB_OPTION_keyscript+x}" ] || [ "$CRYPTTAB_KEY" = "none" ]; then
            options="$options hash" # --hash is being ignored in plain mode with keyfile specified
        fi
        for o in $options; do
            if [ "$quiet" = "n" ] && eval [ -z "\${CRYPTTAB_OPTION_$o+x}" ]; then
                cryptsetup_message "WARNING: Option '$o' missing in crypttab for plain dm-crypt" \
                    "mapping $CRYPTTAB_NAME. Please read /usr/share/doc/cryptsetup/README.initramfs and" \
                    "add the correct '$o' option to your crypttab(5)."
            fi
        done
    fi
}

# crypttab_validate_option()
#   Validate $OPTION=$VALUE (or flag $OPTION if VALUE is unset).  return
#   1 on error, unsets OPTION for unknown or useless options.
crypttab_validate_option() {
    # option aliases
    case "$OPTION" in
        read-only) OPTION="readonly";;
        key-slot) OPTION="keyslot";;
        tcrypt-hidden) OPTION="tcrypthidden";;
        tcrypt-veracrypt) OPTION="veracrypt";;
    esac

    # sanitize the option name so CRYPTTAB_OPTION_$OPTION is a valid variable name
    local o="$OPTION"
    case "$o" in
        keyfile-offset) OPTION="keyfile_offset";;
        keyfile-size) OPTION="keyfile_size";;
        sector-size) OPTION="sector_size";;
    esac

    case "$o" in
        # value must be a non-empty string
        cipher|hash)
            [ -n "${VALUE:+x}" ] || return 1
        ;;
        # value must be a non-empty string, and an existing path if --missing-path is set
        header)
            [ -n "${VALUE:+x}" ] || return 1
            if [ "$missing_path" != "ignore" ]; then
                if [ ! -e "$VALUE" ]; then
                    cryptsetup_message "WARNING: $CRYPTTAB_NAME: $VALUE does not exist";
                    [ "$missing_path" = "warn" ] || return 1
                fi
            fi
        ;;
        # numeric options >0
        size|keyfile-size|sector-size)
            if ! printf '%s' "${VALUE-}" | grep -Exq "0*[1-9][0-9]*"; then
                return 1
            fi
        ;;
        # numeric options >=0
        offset|skip|tries|keyslot|keyfile-offset)
            if ! printf '%s' "${VALUE-}" | grep -Exq "[0-9]+"; then
                return 1
            fi
        ;;
        tmp)
            if [ -z "${VALUE+x}" ]; then
                VALUE="ext4" # 'tmp flag'
            elif [ -z "$VALUE" ]; then
                return 1
            fi
        ;;
        check)
            if [ -z "${VALUE+x}" ]; then
                if [ -n "${CRYPTDISKS_CHECK-}" ]; then
                    VALUE="$CRYPTDISKS_CHECK"
                else
                    unset -v OPTION
                    return 0
                fi
            fi
            if [ -x "/lib/cryptsetup/checks/$VALUE" ] && [ -f "/lib/cryptsetup/checks/$VALUE" ]; then
                VALUE="/lib/cryptsetup/checks/$VALUE"
            elif [ ! -x "$VALUE" ] || [ ! -f "$VALUE" ]; then
                return 1
            fi
        ;;
        checkargs)
            [ -n "${VALUE+x}" ] || return 1 # must have a value (possibly empty)
        ;;
        keyscript)
            [ -n "${VALUE:+x}" ] || return 1 # must have a value
            if [ "${VALUE#/}" = "$VALUE" ]; then
                VALUE="/lib/cryptsetup/scripts/$VALUE"
            fi
            if [ ! -x "$VALUE" ] || [ ! -f "$VALUE" ]; then
                return 1
            fi
        ;;
        # and now the flags
        verify) ;;
        loud) ;;
        quiet) ;;
        initramfs) ;;
        noearly) ;;
        noauto) ;;
        readonly) ;;
        discard) ;;
        plain) ;;
        luks) ;;
        swap) ;;
        tcrypt) ;;
        veracrypt) ;;
        tcrypthidden) ;;
        *)
            if [ "${quiet:-n}" = "n" ]; then
                cryptsetup_message "WARNING: $CRYPTTAB_NAME: ignoring unknown option '$o'";
            fi
            unset -v OPTION
        ;;
    esac
}

# crypttab_resolve_source()
#   Resolve the CRYPTTAB_SOURCE variable, containing value of the second
#   field of a crypttab(5)-like file.
#   On error (non-existing source), CRYPTTAB_SOURCE is not changed and 1
#   is returned.
crypttab_resolve_source() {
    # return immediately if source is a regular file
    [ ! -f "$CRYPTTAB_SOURCE" ] || return 0
    # otherwise resolve the block device specification
    local dev="$CRYPTTAB_SOURCE"
    dev="$(resolve_device_spec "$dev")" && CRYPTTAB_SOURCE="$dev" || return 1
}

# run_keyscript($keyscriptarg, $tried_count)
#   exec()'ute `$CRYPTTAB_OPTION_keyscript $keyscriptarg`.
#   If $CRYPTTAB_OPTION_keyscript is unset or null and $keyscriptarg is
#   "none" (meaning the passphrase is to be read interactively from the
#   console), use `/lib/cryptsetup/askpass` as keyscript with a suitable
#   prompt message.
#   Since the shell process is replaced with the $CRYPTTAB_OPTION_keyscript
#   program, run_keyscript() must be used on the left-hand side of a
#   pipe, or similar.
run_keyscript() {
    local keyscriptarg="$1" CRYPTTAB_TRIED="$2" keyscript;
    export CRYPTTAB_NAME CRYPTTAB_SOURCE CRYPTTAB_OPTIONS
    export CRYPTTAB_TRIED

    if [ -n "${CRYPTTAB_OPTION_keyscript+x}" ] && \
            [ "$CRYPTTAB_OPTION_keyscript" != "/lib/cryptsetup/askpass" ]; then
        # 'keyscript' option is present: export its argument as
        # $CRYPTTAB_KEY
        export CRYPTTAB_KEY="$keyscriptarg"
        keyscript="$CRYPTTAB_OPTION_keyscript"
    elif [ "$keyscriptarg" = none ]; then
        # don't export the prompt message as CRYPTTAB_KEY
        keyscript="/lib/cryptsetup/askpass"
        keyscriptarg="Please unlock disk $CRYPTTAB_NAME: "
    fi

    exec "$keyscript" "$keyscriptarg"
}

# get_crypt_type()
#    Set CRYPTTAB_TYPE to the mapping type, depending on its
#    $CRYPTTAB_OPTION_<option> values
get_crypt_type() {
    if [ "${CRYPTTAB_OPTION_tcrypt-}" = "yes" ]; then
        CRYPTTAB_TYPE="tcrypt"
    elif [ "${CRYPTTAB_OPTION_plain-}" = "yes" ]; then
        CRYPTTAB_TYPE="plain"
    elif [ "${CRYPTTAB_OPTION_luks-}" = "yes" ] ||
            /sbin/cryptsetup isLuks -- "${CRYPTTAB_OPTION_header-$CRYPTTAB_SOURCE}"; then
        CRYPTTAB_TYPE="luks"
    else
        # assume plain dm-crypt device by default
        CRYPTTAB_TYPE="plain"
    fi
}

# unlock_mapping([$keyfile])
#   Run cryptsetup(8) with suitable options and arguments to unlock
#   $CRYPTTAB_SOURCE and setup dm-crypt managed device-mapper mapping
#   $CRYPTTAB_NAME.
unlock_mapping() {
    local keyfile="${1:--}"

    if [ "$CRYPTTAB_TYPE" = "luks" ] || [ "$CRYPTTAB_TYPE" = "tcrypt" ]; then
        # ignored for LUKS and TCRYPT devices
        unset -v CRYPTTAB_OPTION_cipher \
                 CRYPTTAB_OPTION_size \
                 CRYPTTAB_OPTION_hash \
                 CRYPTTAB_OPTION_offset \
                 CRYPTTAB_OPTION_skip
    fi
    if [ "$CRYPTTAB_TYPE" = "plain" ] || [ "$CRYPTTAB_TYPE" = "tcrypt" ]; then
        unset -v CRYPTTAB_OPTION_keyfile_size
    fi
    if [ "$CRYPTTAB_TYPE" = "tcrypt" ]; then
        # ignored for TCRYPT devices
        unset -v CRYPTTAB_OPTION_keyfile_offset
    else
        # ignored for non-TCRYPT devices
        unset -v CRYPTTAB_OPTION_veracrypt CRYPTTAB_OPTION_tcrypthidden
    fi

    if [ "$CRYPTTAB_TYPE" != "luks" ]; then
        # ignored for non-LUKS devices
        unset -v CRYPTTAB_OPTION_keyslot
    fi

    /sbin/cryptsetup -T1 \
        ${CRYPTTAB_OPTION_header:+--header="$CRYPTTAB_OPTION_header"} \
        ${CRYPTTAB_OPTION_cipher:+--cipher="$CRYPTTAB_OPTION_cipher"} \
        ${CRYPTTAB_OPTION_size:+--key-size="$CRYPTTAB_OPTION_size"} \
        ${CRYPTTAB_OPTION_sector_size:+--sector-size="$CRYPTTAB_OPTION_sector_size"} \
        ${CRYPTTAB_OPTION_hash:+--hash="$CRYPTTAB_OPTION_hash"} \
        ${CRYPTTAB_OPTION_offset:+--offset="$CRYPTTAB_OPTION_offset"} \
        ${CRYPTTAB_OPTION_skip:+--skip="$CRYPTTAB_OPTION_skip"} \
        ${CRYPTTAB_OPTION_verify:+--verify-passphrase} \
        ${CRYPTTAB_OPTION_readonly:+--readonly} \
        ${CRYPTTAB_OPTION_discard:+--allow-discards} \
        ${CRYPTTAB_OPTION_veracrypt:+--veracrypt} \
        ${CRYPTTAB_OPTION_keyslot:+--key-slot="$CRYPTTAB_OPTION_keyslot"} \
        ${CRYPTTAB_OPTION_tcrypthidden:+--tcrypt-hidden} \
        ${CRYPTTAB_OPTION_keyfile_size:+--keyfile-size="$CRYPTTAB_OPTION_keyfile_size"} \
        ${CRYPTTAB_OPTION_keyfile_offset:+--keyfile-offset="$CRYPTTAB_OPTION_keyfile_offset"} \
        --type="$CRYPTTAB_TYPE" --key-file="$keyfile" \
        open -- "$CRYPTTAB_SOURCE" "$CRYPTTAB_NAME"
}

# crypttab_key_check()
#   Sanity checks for keyfile $CRYPTTAB_KEY.  CRYPTTAB_NAME and
#   CRYPTTAB_OPTION_<option> must be set appropriately.
crypttab_key_check() {
    if [ ! -f "$CRYPTTAB_KEY" ] && [ ! -b "$CRYPTTAB_KEY" ] && [ ! -c "$CRYPTTAB_KEY" ] ; then
        cryptsetup_message "WARNING: $CRYPTTAB_NAME: keyfile '$CRYPTTAB_KEY' not found"
        return 0
    fi

    if [ "$CRYPTTAB_KEY" = "/dev/random" ] || [ "$CRYPTTAB_KEY" = "/dev/urandom" ]; then
        if [ -n "${CRYPTTAB_OPTION_luks+x}" ] || [ -n "${CRYPTTAB_OPTION_tcrypt+x}" ]; then
            cryptsetup_message "WARNING: $CRYPTTAB_NAME: has random data as key"
            return 1
        else
            return 0
        fi
    fi

    local mode="$(stat -L -c"%04a" -- "$CRYPTTAB_KEY")"
    if [ $(stat -L -c"%u" -- "$CRYPTTAB_KEY") -ne 0 ] || [ "${mode%00}" = "$mode" ]; then
        cryptsetup_message "WARNING: $CRYPTTAB_NAME: key file $CRYPTTAB_KEY has" \
            "insecure ownership, see /usr/share/doc/cryptsetup/README.Debian."
    fi
}

# resolve_device_spec($spec)
#   Resolve LABEL=<label>, UUID=<uuid>, PARTUUID=<partuuid> and
#   PARTLABEL=<partlabel> to a block special device.  If $spec is
#   already a (link to a block special device) then it is echoed as is.
#   Return 1 if $spec doesn't correspond to a block special device.
resolve_device_spec() {
    local spec="$1"
    case "$spec" in
        UUID=*|LABEL=*|PARTUUID=*|PARTLABEL=*)
            # don't use /dev/disk/by-label/... to avoid gessing udev mangling
            spec="$(blkid -l -t "$spec" -o device)" || spec=
        ;;
    esac
    [ -b "$spec" ] && printf '%s\n' "$spec" || return 1
}

# dm_blkdevname($name)
#   Print the mapped device name, or return 1 if the the device doesn't exist.
dm_blkdevname() {
    local name="$1" dev
    # /dev/mapper/$name isn't reliable due to udev mangling
    if dev="$(dmsetup info -c --noheadings -o blkdevname -- "$name" 2>/dev/null)" &&
            [ -n "$dev" ] && [ -b "/dev/$dev" ]; then
        echo "/dev/$dev"
        return 0
    else
        return 1
    fi
}

# crypttab_find_entry([--quiet], $target)
#   Search in the crypttab(5) for the given $target, and sets the
#   variables CRYPTTAB_NAME, CRYPTTAB_SOURCE, CRYPTTAB_KEY and
#   CRYPTTAB_OPTIONS accordingly.  (In addition _CRYPTTAB_NAME,
#   _CRYPTTAB_SOURCE, _CRYPTTAB_KEY and _CRYPTTAB_OPTIONS are set to the
#   unmangled values before decoding the escape sequence.)  If there are
#   duplicates then only the first match is considered.
#   Return 0 if a match is found, and 1 otherwise.
crypttab_find_entry() {
    local target="$1" quiet="n" IFS
    if [ "$target" = "--quiet" ] && [ $# -eq 2 ]; then
        quiet="y"
        target="$2"
    fi

    if [ -f "$TABFILE" ]; then
        while IFS=" 	" read -r _CRYPTTAB_NAME _CRYPTTAB_SOURCE _CRYPTTAB_KEY _CRYPTTAB_OPTIONS; do
            if [ "${_CRYPTTAB_NAME#\#}" != "$_CRYPTTAB_NAME" ] || [ -z "$_CRYPTTAB_NAME" ]; then
                # ignore comments and empty lines
                continue
            fi

            # unmangle names
            CRYPTTAB_NAME="$(printf '%b' "$_CRYPTTAB_NAME")"
            if [ -z "$_CRYPTTAB_SOURCE" ] || [ -z "$_CRYPTTAB_KEY" ] || [ -z "$_CRYPTTAB_OPTIONS" ]; then
                cryptsetup_message "WARNING: '$CRYPTTAB_NAME' is missing some arguments, see crypttab(5)"
                continue
            elif [ "$CRYPTTAB_NAME" = "$target" ]; then
                CRYPTTAB_SOURCE="$( printf '%b' "$_CRYPTTAB_SOURCE" )"
                CRYPTTAB_KEY="$(    printf '%b' "$_CRYPTTAB_KEY"    )"
                CRYPTTAB_OPTIONS="$(printf '%b' "$_CRYPTTAB_OPTIONS")"
                return 0
            fi
        done <"$TABFILE"
    fi

    if [ "$quiet" = "n" ]; then
        cryptsetup_message "WARNING: target '$target' not found in $TABFILE"
    fi
    return 1
}

# crypttab_foreach_entry($callback)
#   Iterate through the crypttab(5) and run the given $callback for each
#   entry found. Variables CRYPTTAB_NAME, CRYPTTAB_SOURCE, CRYPTTAB_KEY
#   and CRYPTTAB_OPTIONS are set accordingly and available to the
#   $callback.  (In addition _CRYPTTAB_NAME, _CRYPTTAB_SOURCE,
#   _CRYPTTAB_KEY and _CRYPTTAB_OPTIONS are set to the unmangled values
#   before decoding the escape sequence.)
#   Return 0 if a match is found, and 1 otherwise.
crypttab_foreach_entry() {
    local callback="$1" IFS
    local _CRYPTTAB_NAME _CRYPTTAB_SOURCE _CRYPTTAB_KEY _CRYPTTAB_OPTIONS \
           CRYPTTAB_NAME  CRYPTTAB_SOURCE  CRYPTTAB_KEY  CRYPTTAB_OPTIONS

    [ -f "$TABFILE" ] || return
    while IFS=" 	" read -r _CRYPTTAB_NAME _CRYPTTAB_SOURCE _CRYPTTAB_KEY _CRYPTTAB_OPTIONS <&9; do
        if [ "${_CRYPTTAB_NAME#\#}" != "$_CRYPTTAB_NAME" ] || [ -z "$_CRYPTTAB_NAME" ]; then
            # ignore comments and empty lines
            continue
        fi

        # unmangle names
        CRYPTTAB_NAME="$(   printf '%b' "$_CRYPTTAB_NAME"   )"
        CRYPTTAB_SOURCE="$( printf '%b' "$_CRYPTTAB_SOURCE" )"
        CRYPTTAB_KEY="$(    printf '%b' "$_CRYPTTAB_KEY"    )"
        CRYPTTAB_OPTIONS="$(printf '%b' "$_CRYPTTAB_OPTIONS")"

        if [ -z "$CRYPTTAB_SOURCE" ] || [ -z "$CRYPTTAB_KEY" ] || [ -z "$CRYPTTAB_OPTIONS" ]; then
            cryptsetup_message "WARNING: '$CRYPTTAB_NAME' is missing some arguments, see crypttab(5)"
            continue
        fi

        "$callback" 9<&-
    done 9<"$TABFILE"
}

# vim: set filetype=sh :