added --allow-discards flag

Co-authored-by: cbachert <1316659-cbachert@users.noreply.gitlab.com>

.drone.yml

@@ -5,24 +5,24 @@ steps:
  - name: fmt
    image: rust:1.43.0
    commands:
-     -  rustup component add rustfmt
-     -  cargo fmt --all -- --check
+     - rustup component add rustfmt
+     - cargo fmt --all -- --check
  - name: test
-   image: rust:1.43.0
-   commands:
-    - apt update && apt install -y libkeyutils-dev libclang-dev clang pkg-config  
-    - echo 'deb http://http.us.debian.org/debian unstable main non-free contrib' >> /etc/apt/sources.list.d/unstable.list && apt update && apt install -y libcryptsetup-dev
-    - cargo test
-
- - name: publish
-   image: rust:1.43.0
+   image: ubuntu:focal
    environment:
+    DEBIAN_FRONTEND: noninteractive
+   commands:
+    - apt update && apt install -y cargo libkeyutils-dev libclang-dev clang pkg-config libcryptsetup-dev 
+    - cargo test --locked
+ - name: publish
+   image: ubuntu:focal
+   environment:
+    DEBIAN_FRONTEND: noninteractive
     CARGO_REGISTRY_TOKEN:
      from_secret: cargo_tkn
    commands:
     - grep -E 'version ?= ?"${DRONE_TAG}"' -i Cargo.toml || (printf "incorrect crate/tag version" && exit 1)
-    - apt update && apt install -y libkeyutils-dev libclang-dev clang pkg-config  
-    - echo 'deb http://http.us.debian.org/debian unstable main non-free contrib' >> /etc/apt/sources.list.d/unstable.list && apt update && apt install -y libcryptsetup-dev
+    - apt update && apt install -y cargo libkeyutils-dev libclang-dev clang pkg-config libcryptsetup-dev 
     - cargo package --all-features
     - cargo publish --all-features
    when:

.gitignore

@@ -2,3 +2,9 @@
 **/*.rs.bk
 .idea/
 *.iml
+fido2luks.bash
+fido2luks.elv
+fido2luks.fish
+fido2luks.zsh
+result
+result-*

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "fido2luks"
-version = "0.2.9"
+version = "0.2.20"
 authors = ["shimunn <shimun@shimun.net>"]
 edition = "2018"
 
@@ -11,10 +11,10 @@ repository = "https://github.com/shimunn/fido2luks"
 readme = "README.md"
 keywords = ["luks", "fido2", "u2f"]
 categories = ["command-line-utilities"]
-license-file = "LICENSE"
+license = "MPL-2.0"
 
 [dependencies]
-ctap_hmac = { version="0.4.2", features = ["request_multiple"] }
+ctap_hmac = { version="0.4.5", features = ["request_multiple"] }
 hex = "0.3.2"
 ring = "0.13.5"
 failure = "0.1.5"
@@ -25,6 +25,15 @@ serde_json = "1.0.51"
 serde_derive = "1.0.106"
 serde = "1.0.106"
 
+[build-dependencies]
+ctap_hmac = { version="0.4.5", features = ["request_multiple"] }
+hex = "0.3.2"
+ring = "0.13.5"
+failure = "0.1.5"
+rpassword = "4.0.1"
+libcryptsetup-rs = "0.4.1"
+structopt = "0.3.2"
+
 [profile.release]
 lto = true
 opt-level = 'z'
@@ -38,7 +47,10 @@ build-depends = "libclang-dev, libcryptsetup-dev"
 extended-description = "Decrypt your LUKS partition using a FIDO2 compatible authenticator"
 assets = [
     ["target/release/fido2luks", "usr/bin/", "755"],
+    ["fido2luks.bash", "usr/share/bash-completion/completions/fido2luks", "644"],
+    ["pam_mount/fido2luksmounthelper.sh", "usr/bin/", "755"],
     ["initramfs-tools/keyscript.sh", "/lib/cryptsetup/scripts/fido2luks", "755" ],
     ["initramfs-tools/hook/fido2luks.sh", "etc/initramfs-tools/hooks/", "755" ],
     ["initramfs-tools/fido2luks.conf", "etc/", "644"],
 ]
+conf-files = ["/etc/fido2luks.conf"]

PKGBUILD

@@ -0,0 +1,37 @@
+# Maintainer: shimunn <shimun@shimun.net>
+
+pkgname=fido2luks-git
+pkgver=0.2.16.7e6b33a
+pkgrel=1
+makedepends=('rust' 'cargo' 'cryptsetup' 'clang' 'git')
+depends=('cryptsetup')
+arch=('i686' 'x86_64' 'armv6h' 'armv7h')
+pkgdesc="Decrypt your LUKS partition using a FIDO2 compatible authenticator"
+url="https://github.com/shimunn/fido2luks"
+license=('MPL-2.0')
+source=('git+https://github.com/shimunn/fido2luks')
+sha512sums=('SKIP')
+
+pkgver() {
+    cd fido2luks
+
+    # Use tag version if possible otherwise concat project version and git ref
+    git describe --exact-match --tags HEAD 2>/dev/null ||
+        echo "$(cargo pkgid | cut -d'#' -f2).$(git describe --always)"
+}
+
+build() {
+    cd fido2luks
+    cargo build --release --locked --all-features --target-dir=target
+}
+
+package() {
+    cd fido2luks
+
+    install -Dm 755 target/release/fido2luks -t "${pkgdir}/usr/bin"
+    install -Dm 755 pam_mount/fido2luksmounthelper.sh -t "${pkgdir}/usr/bin"
+    install -Dm 644 initcpio/hooks/fido2luks -t "${pkgdir}/usr/lib/initcpio/hooks"
+    install -Dm 644 initcpio/install/fido2luks -t "${pkgdir}/usr/lib/initcpio/install"
+    install -Dm 644 fido2luks.bash "${pkgdir}/usr/share/bash-completion/completions/fido2luks"
+    install -Dm 644 fido2luks.fish -t "${pkgdir}/usr/share/fish/vendor_completions.d"
+}

README.md

@@ -1,8 +1,8 @@
 # fido2luks [![Crates.io Version](https://img.shields.io/crates/v/fido2luks.svg)](https://crates.io/crates/fido2luks)
 
-This will allow you to unlock your luks encrypted disk with an fido2 compatible key
+This will allow you to unlock your LUKS encrypted disk with an FIDO2 compatible key.
 
-Note: This has only been tested under Fedora 31, [Ubuntu 20.04](initramfs-tools/), [NixOS](https://nixos.org/nixos/manual/#sec-luks-file-systems-fido2) using a Solo Key, Trezor Model T
+Note: This has only been tested under Fedora 31, [Ubuntu 20.04](initramfs-tools/), [NixOS](https://nixos.org/nixos/manual/#sec-luks-file-systems-fido2) using a Solo Key, Trezor Model T, YubiKey(fw >= [5.2.3](https://support.yubico.com/hc/en-us/articles/360016649319-YubiKey-5-2-3-Enhancements-to-FIDO-2-Support))
 
 ## Setup
 
@@ -65,7 +65,7 @@ cp /usr/bin/fido2luks /boot/fido2luks/
 cp /etc/fido2luks.conf /boot/fido2luks/
 ```
 
-## Test
+## Testing
 
 Just reboot and see if it works, if that's the case you should remove your old less secure password from your LUKS header:
 
@@ -96,6 +96,13 @@ set -a
 
 Then add the new secret to each device and update dracut afterwards `dracut -f`
 
+### Multiple keys
+
+Additional/backup keys are supported, Multiple fido2luks credentials can be added to your /etc/fido2luks.conf file. Credential tokens are comma separated.
+```
+FIDO2LUKS_CREDENTIAL_ID=<CREDENTIAL1>,<CREDENTIAL2>,<CREDENTIAL3>
+```
+
 ## Removal
 
 Remove `rd.luks.2fa` from `GRUB_CMDLINE_LINUX` in /etc/default/grub
@@ -107,3 +114,47 @@ sudo -E fido2luks -i replace-key /dev/disk/by-uuid/<DISK_UUID>
 
 sudo rm -rf /usr/lib/dracut/modules.d/96luks-2fa /etc/dracut.conf.d/luks-2fa.conf /etc/fido2luks.conf
 ```
+
+## Theory of operation
+
+fido2luks builds on two basic building blocks, LUKS as an abstraction over linux disk encryption and and the FIDO2 extension [`hmac-secret`](https://fidoalliance.org/specs/fido-v2.0-rd-20180702/fido-client-to-authenticator-protocol-v2.0-rd-20180702.html#sctn-hmac-secret-extension).
+The `hmac-secret` extension allows for an secret to be dervied on the FIDO2 device from two inputs, the user supplied salt/password/keyfile and another secret contained within the FID2 device. The output of the `hmac-secret` function will then be used to decrypt the LUKS header which in turn is used to decrypt the disk.
+```
+
+        +-------------------------------------------------------------------------------+
+        |                                                                               |
+        |                       +-----------------------------------------+             |
+        |                       |               FIDO2 device              |             |
+        |                       |                                         |             |
+        |                       |                                         |             |
++-------+--------+   +------+   |                      +---------------+  |             |             +------------------------+
+| Salt/Password  +-> |sha256+------------------------> |               |  |             v             |      LUKS header       |
++----------------+   +------+   |                      |               |  |                           |                        |           +---------------+   
+                                |                      |               |  |        +--------+         +------------------------+-------->  |Disk master key| 
+                                |                      |  sha256_hmac  +---------> | sha256 +-------> | Keyslot 1              |           +---------------+ 
++----------------+              |  +----------+        |               |  |        +--------+         +------------------------+
+| FIDO credential+---------------> |Credential| +----> |               |  |                           | Keyslot 2              |
++----------------+              |  |secret    |        |               |  |                           +------------------------+
+                                |  +----------+        +---------------+  |
+                                |                                         |
+                                |                                         |
+                                +-----------------------------------------+
+
+```
+Since all these components build upon each other losing or damaging just one of them will render the disk undecryptable, it's threfore of paramount importance to backup the LUKS header and ideally set an backup password
+or utilise more than one FIDO2 device. Each additional credential and password combination will require it's own LUKS keyslot since the credential secret is randomly generated for each new credential and will thus result
+in a completly different secret.
+
+## License
+
+Licensed under
+
+ * Mozilla Public License 2.0, ([LICENSE-MPL](LICENSE-MPL) or https://www.mozilla.org/en-US/MPL/2.0/)
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally
+submitted for inclusion in the work by you, as defined in the MPL 2.0
+license, shall be licensed as above, without any additional terms or
+conditions.
+

build.rs

@@ -0,0 +1,24 @@
+#![allow(warnings)]
+#[macro_use]
+extern crate failure;
+extern crate ctap_hmac as ctap;
+
+#[path = "src/cli_args/mod.rs"]
+mod cli_args;
+#[path = "src/error.rs"]
+mod error;
+#[path = "src/util.rs"]
+mod util;
+
+use cli_args::Args;
+use std::env;
+use std::str::FromStr;
+use structopt::clap::Shell;
+use structopt::StructOpt;
+
+fn main() {
+    // generate completion scripts, zsh does panic for some reason
+    for shell in Shell::variants().iter().filter(|shell| **shell != "zsh") {
+        Args::clap().gen_completions(env!("CARGO_PKG_NAME"), Shell::from_str(shell).unwrap(), ".");
+    }
+}

flake.lock

@@ -0,0 +1,62 @@
+{
+  "nodes": {
+    "naersk": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1639947939,
+        "narHash": "sha256-pGsM8haJadVP80GFq4xhnSpNitYNQpaXk4cnA796Cso=",
+        "owner": "nmattia",
+        "repo": "naersk",
+        "rev": "2fc8ce9d3c025d59fee349c1f80be9785049d653",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nmattia",
+        "repo": "naersk",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1638109994,
+        "narHash": "sha256-OpA37PTiPMIqoRJbufbl5rOLII7HeeGcA0yl7FoyCIE=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "a284564b7f75ac4db73607db02076e8da9d42c9d",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "naersk": "naersk",
+        "nixpkgs": "nixpkgs",
+        "utils": "utils"
+      }
+    },
+    "utils": {
+      "locked": {
+        "lastModified": 1638122382,
+        "narHash": "sha256-sQzZzAbvKEqN9s0bzWuYmRaA03v40gaJ4+iL1LXjaeI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "74f7e4319258e287b0f9cb95426c9853b282730b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,61 @@
+{
+  description = "Decrypt your LUKS partition using a FIDO2 compatible authenticator";
+
+  inputs = {
+    utils.url = "github:numtide/flake-utils";
+    naersk = {
+      url = "github:nmattia/naersk";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, utils, naersk }:
+    let
+      root = ./.;
+      pname = (builtins.fromTOML (builtins.readFile ./Cargo.toml)).package.name;
+      forPkgs = pkgs:
+        let
+          naersk-lib = naersk.lib."${pkgs.system}";
+          buildInputs = with pkgs; [ cryptsetup ];
+          LIBCLANG_PATH = "${pkgs.clang.cc.lib}/lib";
+          nativeBuildInputs = with pkgs; [
+            pkgconfig
+            clang
+          ];
+        in
+        rec {
+          # `nix build`
+          packages.${pname} = naersk-lib.buildPackage {
+            inherit pname root buildInputs nativeBuildInputs LIBCLANG_PATH;
+          };
+          defaultPackage = packages.${pname};
+
+          # `nix run`
+          apps.${pname} = utils.lib.mkApp {
+            drv = packages.${pname};
+          };
+          defaultApp = apps.${pname};
+
+          # `nix flake check`
+          checks = {
+            fmt = with pkgs; runCommandLocal "${pname}-fmt" { buildInputs = [ cargo rustfmt nixpkgs-fmt ]; } ''
+              cd ${root}
+              cargo fmt -- --check
+              nixpkgs-fmt --check *.nix
+              touch $out
+            '';
+          };
+
+          # `nix develop`
+          devShell = pkgs.mkShell {
+            nativeBuildInputs = with pkgs; [ rustc cargo rustfmt nixpkgs-fmt ] ++ nativeBuildInputs;
+            inherit buildInputs LIBCLANG_PATH;
+          };
+        };
+      forSystem = system: forPkgs nixpkgs.legacyPackages."${system}";
+    in
+    (utils.lib.eachSystem [ "aarch64-linux" "i686-linux" "x86_64-linux" ] forSystem) // {
+      overlay = final: prev: (forPkgs final).packages;
+    };
+
+}

initcpio/Makefile

@@ -0,0 +1,18 @@
+.PHONY: install remove
+
+install:
+	install -Dm644 hooks/fido2luks -t /usr/lib/initcpio/hooks
+	install -Dm644 install/fido2luks -t /usr/lib/initcpio/install
+ifdef preset
+	mkinitcpio -p $(preset)
+else
+	mkinitcpio -P
+endif
+
+remove:
+	rm /usr/lib/initcpio/{hooks,install}/fido2luks
+ifdef preset
+	mkinitcpio -p $(preset)
+else
+	mkinitcpio -P
+endif

initcpio/README.md

@@ -0,0 +1,52 @@
+## fido2luks hook for mkinitcpio (ArchLinux and derivatives)
+
+> ⚠️ Before proceeding, it is very advised to [backup your existing LUKS2 header](https://wiki.archlinux.org/title/dm-crypt/Device_encryption#Backup_using_cryptsetup) to external storage
+
+### Setup
+
+1. Connect your FIDO2 authenticator
+2. Generate credential id
+
+```shell
+fido2luks credential
+```
+
+3. Generate salt (random string)
+
+```shell
+pwgen 48 1
+```
+
+4. Add key to your LUKS2 device
+
+```shell
+fido2luks add-key -Pt --salt <salt> <block_device> <credential_id>
+```
+
+`-P` - request PIN to unlock the authenticator  
+`-t` - add token (including credential id) to the LUKS2 header  
+`-e` - wipe all other keys  
+
+For the full list of options see `fido2luks add-key --help`
+
+5. Edit [/etc/fido2luks.conf](/initcpio/fido2luks.conf)
+
+Keyslot (`FIDO2LUKS_DEVICE_SLOT`) can be obtained from the output of
+
+```shell
+cryptsetup luksDump <block_device>
+```
+
+6. Add fido2luks hook to /etc/mkinitcpio.conf
+
+Before or instead of `encrypt` hook, for example:
+
+```shell
+HOOKS=(base udev autodetect modconf keyboard block fido2luks filesystems fsck)
+```
+
+7. Recreate initial ramdisk
+
+```shell
+mkinitcpio -p <preset>
+```

initcpio/fido2luks.conf

@@ -0,0 +1,18 @@
+# Set credential *ONLY IF* it's not embedded in the LUKS2 header
+FIDO2LUKS_CREDENTIAL_ID=
+
+# Encrypted device and its name under /dev/mapper
+# Can be overridden by `cryptdevice` kernel parameter
+FIDO2LUKS_DEVICE=
+FIDO2LUKS_MAPPER_NAME=
+
+FIDO2LUKS_SALT=string:<salt>
+
+# Use specific keyslot (ignore all other slots)
+FIDO2LUKS_DEVICE_SLOT=
+
+# Await for an authenticator to be connected (in seconds)
+FIDO2LUKS_DEVICE_AWAIT=
+
+# Set to 1 if PIN is required to unlock the authenticator
+FIDO2LUKS_ASK_PIN=

initcpio/hooks/fido2luks

@@ -0,0 +1,55 @@
+#!/usr/bin/ash
+
+run_hook() {
+    modprobe -a -q dm-crypt >/dev/null 2>&1
+    . /etc/fido2luks.conf
+
+    if [ -z "$cryptdevice" ]; then
+        device="$FIDO2LUKS_DEVICE"
+        dmname="$FIDO2LUKS_MAPPER_NAME"
+    else
+        IFS=: read cryptdev dmname _cryptoptions <<EOF
+$cryptdevice
+EOF
+        if ! device=$(resolve_device "${cryptdev}" ${rootdelay}); then
+            return 1
+        fi
+    fi
+
+    options="--salt $FIDO2LUKS_SALT"
+
+    if [ "$FIDO2LUKS_ASK_PIN" == 1 ]; then
+        options="$options --pin"
+    fi
+
+    if [ -n "$FIDO2LUKS_DEVICE_SLOT" ]; then
+        options="$options --slot $FIDO2LUKS_DEVICE_SLOT"
+    fi
+
+    if [ -n "$FIDO2LUKS_DEVICE_AWAIT" ]; then
+        options="$options --await-dev $FIDO2LUKS_DEVICE_AWAIT"
+    fi
+
+    # HACK: /dev/tty is hardcoded in rpassword, but not accessible from the ramdisk
+    # Temporary link it to /dev/tty1
+    mv /dev/tty /dev/tty.back
+    ln -s /dev/tty1 /dev/tty
+
+    printf "\nAuthentication is required to access the $dmname volume at $device\n"
+
+    if [ -z "$FIDO2LUKS_CREDENTIAL_ID" ]; then
+        fido2luks open-token $device $dmname $options
+    else
+        fido2luks open $device $dmname $FIDO2LUKS_CREDENTIAL_ID $options
+    fi
+    exit_code=$?
+
+    # Restore /dev/tty
+    mv /dev/tty.back /dev/tty
+
+    if [ $exit_code -ne 0 ]; then
+        printf '\n'
+        read -s -p 'Press Enter to continue'
+        printf '\n'
+    fi
+}

initcpio/install/fido2luks

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+build() {
+    local mod
+
+    add_module dm-crypt
+    add_module dm-integrity
+    if [[ $CRYPTO_MODULES ]]; then
+        for mod in $CRYPTO_MODULES; do
+            add_module "$mod"
+        done
+    else
+        add_all_modules /crypto/
+    fi
+
+    add_binary fido2luks
+    add_binary dmsetup
+    add_file /usr/lib/udev/rules.d/10-dm.rules
+    add_file /usr/lib/udev/rules.d/13-dm-disk.rules
+    add_file /usr/lib/udev/rules.d/95-dm-notify.rules
+    add_file /usr/lib/initcpio/udev/11-dm-initramfs.rules /usr/lib/udev/rules.d/11-dm-initramfs.rules
+    add_file /etc/fido2luks.conf /etc/fido2luks.conf
+
+    add_runscript
+}
+
+help() {
+    cat <<HELPEOF
+This hook allows to decrypt LUKS2 partition using FIDO2 compatible authenticator
+HELPEOF
+}

initramfs-tools/README.md

@@ -1,13 +1,34 @@
 ## Initramfs-tools based systems(Ubuntu and derivatives)
 
-After installation generate your credentials and add keys to your disk as described in the top-level README
-then add `initramfs,keyscript=fido2luks` to your `/etc/crypttab`
+For easiest installation [download and install the precompiled deb from releases.](https://github.com/shimunn/fido2luks/releases). However it is possible to build from source via the instructions on the main readme.
 
-Example:
 ```
-sda6_crypt UUID=9793d81a-4cfb-4712-85f3-c7a8d715112c none luks,discard,initramfs,keyscript=fido2luks
+sudo -s
+
+# Insert FIDO key.
+fido2luks credential
+# Tap FIDO key
+# Copy returned string <CREDENTIAL>
+
+nano /etc/fido2luks.conf
+# Insert <CREDENTIAL> 
+# FIDO2LUKS_CREDENTIAL_ID=<CREDENTIAL> 
+
+set -a
+. /etc/fido2luks.conf
+fido2luks -i add-key /dev/<LUKS PARTITION>
+# Current password: <Any current LUKS password>
+# Password: <Password used as FIDO challange>
+# Tap FIDO key
+
+nano /etc/crypttab
+# Append to end ",discard,initramfs,keyscript=fido2luks"
+# E.g. sda6_crypt UUID=XXXXXXXXXX none luks,discard,initramfs,keyscript=fido2luks
+
+update-initramfs -u
+
+
 ```
 
-But don't forget to run `make install` which will install all necessary scripts and regenerate your intrid.
+[Recording showing part of the setup](https://shimun.net/fido2luks/setup.svg)
 
-[Recording showing part of the setup](https://shimun.net/fido2luks/setup.svg)

initramfs-tools/fido2luks.conf

@@ -1,3 +1,5 @@
 FIDO2LUKS_SALT=Ask
-#FIDO2LUKS_PASSWORD_HELPER="/usr/bin/plymouth ask-for-password --promt 'FIDO2 password salt'"
+#FIDO2LUKS_PASSWORD_HELPER="/usr/bin/plymouth ask-for-password --prompt 'FIDO2 password salt'"
 FIDO2LUKS_CREDENTIAL_ID=
+FIDO2LUKS_USE_TOKEN=0
+FIDO2LUKS_PASSWORD_FALLBACK=1

initramfs-tools/keyscript.sh

@@ -2,8 +2,29 @@
 set -a
 . /etc/fido2luks.conf
 
+# Set Defaults
+if [ -z "$FIDO2LUKS_USE_TOKEN" ]; then
+    FIDO2LUKS_USE_TOKEN=0
+fi
+
+if [ -z "$FIDO2LUKS_PASSWORD_FALLBACK" ]; then
+    FIDO2LUKS_PASSWORD_FALLBACK=1
+fi
+
+
+
 if [ -z "$FIDO2LUKS_PASSWORD_HELPER" ]; then
-	export FIDO2LUKS_PASSWORD_HELPER="plymouth ask-for-password --promt 'FIDO2 password salt for $CRYPTTAB_NAME'"
+	MSG="FIDO2 password salt for $CRYPTTAB_NAME"
+	export FIDO2LUKS_PASSWORD_HELPER="plymouth ask-for-password --prompt '$MSG'"
+fi
+
+if [ "$FIDO2LUKS_USE_TOKEN" -eq 1 ]; then
+	export FIDO2LUKS_CREDENTIAL_ID="$FIDO2LUKS_CREDENTIAL_ID,$(fido2luks token list --csv $CRYPTTAB_SOURCE)"
 fi
 
 fido2luks print-secret --bin
+
+# Fall back to passphrase-based unlock if fido2luks fails
+if [ "$?" -gt 0 ] && [ "$FIDO2LUKS_PASSWORD_FALLBACK" -eq 1 ]; then
+  plymouth ask-for-password --prompt "Password for $CRYPTTAB_SOURCE"
+fi

pam_mount/fido2luksmounthelper.sh

@@ -0,0 +1,220 @@
+#!/bin/bash
+#
+# This is a rather minimal example Argbash potential
+# Example taken from http://argbash.readthedocs.io/en/stable/example.html
+#
+# ARG_POSITIONAL_SINGLE([operation],[Operation to perform (mount|umount)],[])
+# ARG_OPTIONAL_SINGLE([credentials-type],[c],[Type of the credentials to use (external|embedded)])
+# ARG_OPTIONAL_SINGLE([device],[d],[Name of the device to create])
+# ARG_OPTIONAL_SINGLE([mount-point],[m],[Path of the mount point to use])
+# ARG_OPTIONAL_BOOLEAN([ask-pin],[a],[Ask for a pin],[off])
+# ARG_OPTIONAL_SINGLE([salt],[s],[Salt to use],[""])
+# ARG_HELP([Unlocks/Locks a LUKS volume and mount/unmount it in the given mount point.])
+# ARGBASH_GO()
+# needed because of Argbash --> m4_ignore([
+### START OF CODE GENERATED BY Argbash v2.9.0 one line above ###
+# Argbash is a bash code generator used to get arguments parsing right.
+# Argbash is FREE SOFTWARE, see https://argbash.io for more info
+# Generated online by https://argbash.io/generate
+
+
+die()
+{
+	local _ret="${2:-1}"
+	test "${_PRINT_HELP:-no}" = yes && print_help >&2
+	echo "$1" >&2
+	exit "${_ret}"
+}
+
+
+begins_with_short_option()
+{
+	local first_option all_short_options='cdmash'
+	first_option="${1:0:1}"
+	test "$all_short_options" = "${all_short_options/$first_option/}" && return 1 || return 0
+}
+
+# THE DEFAULTS INITIALIZATION - POSITIONALS
+_positionals=()
+# THE DEFAULTS INITIALIZATION - OPTIONALS
+_arg_credentials_type=
+_arg_device=
+_arg_mount_point=
+_arg_ask_pin="off"
+_arg_salt=""
+
+
+print_help()
+{
+	printf '%s\n' "Unlocks/Locks a LUKS volume and mount/unmount it in the given mount point."
+	printf 'Usage: %s [-c|--credentials-type <arg>] [-d|--device <arg>] [-m|--mount-point <arg>] [-a|--(no-)ask-pin] [-s|--salt <arg>] [-h|--help] <operation>\n' "$0"
+	printf '\t%s\n' "<operation>: Operation to perform (mount|umount)"
+	printf '\t%s\n' "-c, --credentials-type: Type of the credentials to use (external|embedded) (no default)"
+	printf '\t%s\n' "-d, --device: Name of the device to create (no default)"
+	printf '\t%s\n' "-m, --mount-point: Path of the mount point to use (no default)"
+	printf '\t%s\n' "-a, --ask-pin, --no-ask-pin: Ask for a pin (off by default)"
+	printf '\t%s\n' "-s, --salt: Salt to use (default: '""')"
+	printf '\t%s\n' "-h, --help: Prints help"
+}
+
+
+parse_commandline()
+{
+	_positionals_count=0
+	while test $# -gt 0
+	do
+		_key="$1"
+		case "$_key" in
+			-c|--credentials-type)
+				test $# -lt 2 && die "Missing value for the optional argument '$_key'." 1
+				_arg_credentials_type="$2"
+				shift
+				;;
+			--credentials-type=*)
+				_arg_credentials_type="${_key##--credentials-type=}"
+				;;
+			-c*)
+				_arg_credentials_type="${_key##-c}"
+				;;
+			-d|--device)
+				test $# -lt 2 && die "Missing value for the optional argument '$_key'." 1
+				_arg_device="$2"
+				shift
+				;;
+			--device=*)
+				_arg_device="${_key##--device=}"
+				;;
+			-d*)
+				_arg_device="${_key##-d}"
+				;;
+			-m|--mount-point)
+				test $# -lt 2 && die "Missing value for the optional argument '$_key'." 1
+				_arg_mount_point="$2"
+				shift
+				;;
+			--mount-point=*)
+				_arg_mount_point="${_key##--mount-point=}"
+				;;
+			-m*)
+				_arg_mount_point="${_key##-m}"
+				;;
+			-a|--no-ask-pin|--ask-pin)
+				_arg_ask_pin="on"
+				test "${1:0:5}" = "--no-" && _arg_ask_pin="off"
+				;;
+			-a*)
+				_arg_ask_pin="on"
+				_next="${_key##-a}"
+				if test -n "$_next" -a "$_next" != "$_key"
+				then
+					{ begins_with_short_option "$_next" && shift && set -- "-a" "-${_next}" "$@"; } || die "The short option '$_key' can't be decomposed to ${_key:0:2} and -${_key:2}, because ${_key:0:2} doesn't accept value and '-${_key:2:1}' doesn't correspond to a short option."
+				fi
+				;;
+			-s|--salt)
+				test $# -lt 2 && die "Missing value for the optional argument '$_key'." 1
+				_arg_salt="$2"
+				shift
+				;;
+			--salt=*)
+				_arg_salt="${_key##--salt=}"
+				;;
+			-s*)
+				_arg_salt="${_key##-s}"
+				;;
+			-h|--help)
+				print_help
+				exit 0
+				;;
+			-h*)
+				print_help
+				exit 0
+				;;
+			*)
+				_last_positional="$1"
+				_positionals+=("$_last_positional")
+				_positionals_count=$((_positionals_count + 1))
+				;;
+		esac
+		shift
+	done
+}
+
+
+handle_passed_args_count()
+{
+	local _required_args_string="'operation'"
+	test "${_positionals_count}" -ge 1 || _PRINT_HELP=yes die "FATAL ERROR: Not enough positional arguments - we require exactly 1 (namely: $_required_args_string), but got only ${_positionals_count}." 1
+	test "${_positionals_count}" -le 1 || _PRINT_HELP=yes die "FATAL ERROR: There were spurious positional arguments --- we expect exactly 1 (namely: $_required_args_string), but got ${_positionals_count} (the last one was: '${_last_positional}')." 1
+}
+
+
+assign_positional_args()
+{
+	local _positional_name _shift_for=$1
+	_positional_names="_arg_operation "
+
+	shift "$_shift_for"
+	for _positional_name in ${_positional_names}
+	do
+		test $# -gt 0 || break
+		eval "$_positional_name=\${1}" || die "Error during argument parsing, possibly an Argbash bug." 1
+		shift
+	done
+}
+
+parse_commandline "$@"
+handle_passed_args_count
+assign_positional_args 1 "${_positionals[@]}"
+
+# OTHER STUFF GENERATED BY Argbash
+
+### END OF CODE GENERATED BY Argbash (sortof) ### ])
+# [ <-- needed because of Argbash
+
+if [ -z ${_arg_mount_point} ]; then
+  die "Missing '--mount-point' argument"
+fi
+
+if [ -z ${_arg_device} ]; then
+  die "Missing '--device' argument"
+fi
+
+ASK_PIN=${_arg_ask_pin}
+OPERATION=${_arg_operation}
+DEVICE=${_arg_device}
+DEVICE_NAME=$(sed "s|/|_|g" <<< ${DEVICE})
+MOUNT_POINT=${_arg_mount_point}
+CREDENTIALS_TYPE=${_arg_credentials_type}
+SALT=${_arg_salt}
+CONF_FILE_PATH="/etc/fido2luksmounthelper.conf"
+
+if [ "${OPERATION}" == "mount" ]; then
+	if [ "${CREDENTIALS_TYPE}" == "external" ]; then
+    if  [ -f ${CONF_FILE_PATH} ]; then
+			if [ "${ASK_PIN}" == "on" ]; then
+				read PASSWORD
+			fi
+			CREDENTIALS=$(<${CONF_FILE_PATH})
+		else
+			die "The configuration file '${CONF_FILE_PATH}' is missing. Please create it or use embedded credentials."
+		fi
+		printf ${PASSWORD} | fido2luks open --salt string:${SALT} --pin --pin-source /dev/stdin ${DEVICE} ${DEVICE_NAME} ${CREDENTIALS}
+	elif [ "${CREDENTIALS_TYPE}" == "embedded" ]; then
+		if [ "${ASK_PIN}" == "on" ]; then
+			read PASSWORD
+		fi
+		printf ${PASSWORD} | fido2luks open-token --salt string:${SALT} --pin --pin-source /dev/stdin ${DEVICE} ${DEVICE_NAME}
+	else
+		die "Given credential-type '${CREDENTIALS_TYPE}' is invalid. It must be 'external' or 'embedded'"
+	fi 
+	mount /dev/mapper/${DEVICE_NAME} ${MOUNT_POINT}
+elif [ "${OPERATION}" == "umount" ]; then
+  umount ${MOUNT_POINT}
+  cryptsetup luksClose ${DEVICE_NAME}
+else
+  die "Given operation '${OPERATION}' is invalid. It must be 'mount' or 'unmount'"
+fi
+
+exit 0
+
+# ] <-- needed because of Argbash

src/cli.rs

@@ -1,134 +1,36 @@
 use crate::error::*;
+use crate::luks::{Fido2LuksToken, LuksDevice};
+use crate::util::sha256;
 use crate::*;
+use cli_args::*;
 
+use structopt::clap::Shell;
 use structopt::StructOpt;
 
 use ctap::{FidoCredential, FidoErrorKind};
-use failure::_core::fmt::{Display, Error, Formatter};
-use failure::_core::str::FromStr;
-use failure::_core::time::Duration;
-use std::io::Write;
-use std::process::exit;
-use std::thread;
 
-use crate::luks::{Fido2LuksToken, LuksDevice};
-use crate::util::sha256;
+use std::io::{Read, Write};
+use std::str::FromStr;
+use std::thread;
+use std::time::Duration;
+
 use std::borrow::Cow;
 use std::collections::HashSet;
+use std::fs::File;
 use std::time::SystemTime;
 
-#[derive(Debug, Eq, PartialEq, Clone)]
-pub struct HexEncoded(pub Vec<u8>);
+pub use cli_args::Args;
 
-impl Display for HexEncoded {
-    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
-        f.write_str(&hex::encode(&self.0))
+fn read_pin(ap: &AuthenticatorParameters) -> Fido2LuksResult<String> {
+    if let Some(src) = ap.pin_source.as_ref() {
+        let mut pin = String::new();
+        File::open(src)?.read_to_string(&mut pin)?;
+        Ok(pin.trim_end_matches("\n").to_string()) //remove trailing newline
+    } else {
+        util::read_password("Authenticator PIN", false)
     }
 }
 
-impl AsRef<[u8]> for HexEncoded {
-    fn as_ref(&self) -> &[u8] {
-        &self.0[..]
-    }
-}
-
-impl FromStr for HexEncoded {
-    type Err = hex::FromHexError;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        Ok(HexEncoded(hex::decode(s)?))
-    }
-}
-
-#[derive(Debug, Eq, PartialEq, Clone)]
-pub struct CommaSeparated<T: FromStr + Display>(pub Vec<T>);
-
-impl<T: Display + FromStr> Display for CommaSeparated<T> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
-        for i in &self.0 {
-            f.write_str(&i.to_string())?;
-            f.write_str(",")?;
-        }
-        Ok(())
-    }
-}
-
-impl<T: Display + FromStr> FromStr for CommaSeparated<T> {
-    type Err = <T as FromStr>::Err;
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        Ok(CommaSeparated(
-            s.split(',')
-                .map(|part| <T as FromStr>::from_str(part))
-                .collect::<Result<Vec<_>, _>>()?,
-        ))
-    }
-}
-
-#[derive(Debug, StructOpt)]
-pub struct Credentials {
-    /// FIDO credential ids, separated by ',' generate using fido2luks credential
-    #[structopt(name = "credential-id", env = "FIDO2LUKS_CREDENTIAL_ID")]
-    pub ids: CommaSeparated<HexEncoded>,
-}
-
-#[derive(Debug, StructOpt)]
-pub struct AuthenticatorParameters {
-    /// Request a PIN to unlock the authenticator
-    #[structopt(short = "P", long = "pin")]
-    pub pin: bool,
-
-    /// Await for an authenticator to be connected, timeout after n seconds
-    #[structopt(
-        long = "await-dev",
-        name = "await-dev",
-        env = "FIDO2LUKS_DEVICE_AWAIT",
-        default_value = "15"
-    )]
-    pub await_time: u64,
-}
-
-#[derive(Debug, StructOpt)]
-pub struct LuksParameters {
-    #[structopt(env = "FIDO2LUKS_DEVICE")]
-    device: PathBuf,
-
-    /// Try to unlock the device using a specifc keyslot, ignore all other slots
-    #[structopt(long = "slot", env = "FIDO2LUKS_DEVICE_SLOT")]
-    slot: Option<u32>,
-}
-
-#[derive(Debug, StructOpt, Clone)]
-pub struct LuksModParameters {
-    /// Number of milliseconds required to derive the volume decryption key
-    /// Defaults to 10ms when using an authenticator or the default by cryptsetup when using a password
-    #[structopt(long = "kdf-time", name = "kdf-time")]
-    kdf_time: Option<u64>,
-}
-
-#[derive(Debug, StructOpt)]
-pub struct SecretParameters {
-    /// Salt for secret generation, defaults to 'ask'
-    ///
-    /// Options:{n}
-    ///  - ask              : Prompt user using password helper{n}
-    ///  - file:<PATH>      : Will read <FILE>{n}
-    ///  - string:<STRING>  : Will use <STRING>, which will be handled like a password provided to the 'ask' option{n}
-    #[structopt(
-        name = "salt",
-        long = "salt",
-        env = "FIDO2LUKS_SALT",
-        default_value = "ask"
-    )]
-    pub salt: InputSalt,
-    /// Script used to obtain passwords, overridden by --interactive flag
-    #[structopt(
-        name = "password-helper",
-        env = "FIDO2LUKS_PASSWORD_HELPER",
-        default_value = "/usr/bin/env systemd-ask-password 'Please enter second factor for LUKS disk encryption!'"
-    )]
-    pub password_helper: PasswordHelper,
-}
-
 fn derive_secret(
     credentials: &[HexEncoded],
     salt: &[u8; 32],
@@ -165,175 +67,16 @@ fn derive_secret(
     Ok((sha256(&[salt, &unsalted[..]]), cred.clone()))
 }
 
-fn read_pin() -> Fido2LuksResult<String> {
-    util::read_password("Authenticator PIN", false)
-}
-
-#[derive(Debug, StructOpt)]
-pub struct Args {
-    /// Request passwords via Stdin instead of using the password helper
-    #[structopt(short = "i", long = "interactive")]
-    pub interactive: bool,
-    #[structopt(subcommand)]
-    pub command: Command,
-}
-
-#[derive(Debug, StructOpt, Clone)]
-pub struct OtherSecret {
-    /// Use a keyfile instead of a password
-    #[structopt(short = "d", long = "keyfile", conflicts_with = "fido_device")]
-    keyfile: Option<PathBuf>,
-    /// Use another fido device instead of a password
-    /// Note: this requires for the credential fot the other device to be passed as argument as well
-    #[structopt(short = "f", long = "fido-device", conflicts_with = "keyfile")]
-    fido_device: bool,
-}
-
-#[derive(Debug, StructOpt)]
-pub enum Command {
-    #[structopt(name = "print-secret")]
-    PrintSecret {
-        /// Prints the secret as binary instead of hex encoded
-        #[structopt(short = "b", long = "bin")]
-        binary: bool,
-        #[structopt(flatten)]
-        credentials: Credentials,
-        #[structopt(flatten)]
-        authenticator: AuthenticatorParameters,
-        #[structopt(flatten)]
-        secret: SecretParameters,
-    },
-    /// Adds a generated key to the specified LUKS device
-    #[structopt(name = "add-key")]
-    AddKey {
-        #[structopt(flatten)]
-        luks: LuksParameters,
-        #[structopt(flatten)]
-        credentials: Credentials,
-        #[structopt(flatten)]
-        authenticator: AuthenticatorParameters,
-        #[structopt(flatten)]
-        secret: SecretParameters,
-        /// Will wipe all other keys
-        #[structopt(short = "e", long = "exclusive")]
-        exclusive: bool,
-        /// Will add an token to your LUKS 2 header, including the credential id
-        #[structopt(short = "t", long = "token")]
-        token: bool,
-        #[structopt(flatten)]
-        existing_secret: OtherSecret,
-        #[structopt(flatten)]
-        luks_mod: LuksModParameters,
-    },
-    /// Replace a previously added key with a password
-    #[structopt(name = "replace-key")]
-    ReplaceKey {
-        #[structopt(flatten)]
-        luks: LuksParameters,
-        #[structopt(flatten)]
-        credentials: Credentials,
-        #[structopt(flatten)]
-        authenticator: AuthenticatorParameters,
-        #[structopt(flatten)]
-        secret: SecretParameters,
-        /// Add the password and keep the key
-        #[structopt(short = "a", long = "add-password")]
-        add_password: bool,
-        /// Will add an token to your LUKS 2 header, including the credential id
-        #[structopt(short = "t", long = "token")]
-        token: bool,
-        #[structopt(flatten)]
-        replacement: OtherSecret,
-        #[structopt(flatten)]
-        luks_mod: LuksModParameters,
-    },
-    /// Open the LUKS device
-    #[structopt(name = "open")]
-    Open {
-        #[structopt(flatten)]
-        luks: LuksParameters,
-        #[structopt(env = "FIDO2LUKS_MAPPER_NAME")]
-        name: String,
-        #[structopt(flatten)]
-        credentials: Credentials,
-        #[structopt(flatten)]
-        authenticator: AuthenticatorParameters,
-        #[structopt(flatten)]
-        secret: SecretParameters,
-        #[structopt(short = "r", long = "max-retries", default_value = "0")]
-        retries: i32,
-    },
-    /// Open the LUKS device using credentials embedded in the LUKS 2 header
-    #[structopt(name = "open-token")]
-    OpenToken {
-        #[structopt(flatten)]
-        luks: LuksParameters,
-        #[structopt(env = "FIDO2LUKS_MAPPER_NAME")]
-        name: String,
-        #[structopt(flatten)]
-        authenticator: AuthenticatorParameters,
-        #[structopt(flatten)]
-        secret: SecretParameters,
-        #[structopt(short = "r", long = "max-retries", default_value = "0")]
-        retries: i32,
-    },
-    /// Generate a new FIDO credential
-    #[structopt(name = "credential")]
-    Credential {
-        #[structopt(flatten)]
-        authenticator: AuthenticatorParameters,
-        /// Name to be displayed on the authenticator if it has a display
-        #[structopt(env = "FIDO2LUKS_CREDENTIAL_NAME")]
-        name: Option<String>,
-    },
-    /// Check if an authenticator is connected
-    #[structopt(name = "connected")]
-    Connected,
-    Token(TokenCommand),
-}
-
-///LUKS2 token related operations
-#[derive(Debug, StructOpt)]
-pub enum TokenCommand {
-    /// List all tokens associated with the specified device
-    List {
-        #[structopt(env = "FIDO2LUKS_DEVICE")]
-        device: PathBuf,
-        /// Dump all credentials as CSV
-        #[structopt(long = "csv")]
-        csv: bool,
-    },
-    /// Add credential to a keyslot
-    Add {
-        #[structopt(env = "FIDO2LUKS_DEVICE")]
-        device: PathBuf,
-        #[structopt(flatten)]
-        credentials: Credentials,
-        /// Slot to which the credentials will be added
-        #[structopt(long = "slot", env = "FIDO2LUKS_DEVICE_SLOT")]
-        slot: u32,
-    },
-    /// Remove credentials from token(s)
-    Remove {
-        #[structopt(env = "FIDO2LUKS_DEVICE")]
-        device: PathBuf,
-        #[structopt(flatten)]
-        credentials: Credentials,
-        /// Token from which the credentials will be removed
-        #[structopt(long = "token")]
-        token_id: Option<u32>,
-    },
-    /// Remove all unassigned tokens
-    GC {
-        #[structopt(env = "FIDO2LUKS_DEVICE")]
-        device: PathBuf,
-    },
-}
-
 pub fn parse_cmdline() -> Args {
     Args::from_args()
 }
 
+pub fn prompt_interaction(interactive: bool) {
+    if interactive {
+        println!("Authorize using your FIDO device");
+    }
+}
+
 pub fn run_cli() -> Fido2LuksResult<()> {
     let mut stdout = io::stdout();
     let args = parse_cmdline();
@@ -345,12 +88,12 @@ pub fn run_cli() -> Fido2LuksResult<()> {
         } => {
             let pin_string;
             let pin = if authenticator.pin {
-                pin_string = read_pin()?;
+                pin_string = read_pin(authenticator)?;
                 Some(pin_string.as_ref())
             } else {
                 None
             };
-            let cred = make_credential_id(name.as_ref().map(|n| n.as_ref()), pin)?;
+            let cred = make_credential_id(Some(name.as_ref()), pin)?;
             println!("{}", hex::encode(&cred.id));
             Ok(())
         }
@@ -362,7 +105,7 @@ pub fn run_cli() -> Fido2LuksResult<()> {
         } => {
             let pin_string;
             let pin = if authenticator.pin {
-                pin_string = read_pin()?;
+                pin_string = read_pin(authenticator)?;
                 Some(pin_string.as_ref())
             } else {
                 None
@@ -370,8 +113,9 @@ pub fn run_cli() -> Fido2LuksResult<()> {
             let salt = if interactive || secret.password_helper == PasswordHelper::Stdin {
                 util::read_password_hashed("Password", false)
             } else {
-                secret.salt.obtain(&secret.password_helper)
+                secret.salt.obtain_sha256(&secret.password_helper)
             }?;
+            prompt_interaction(interactive);
             let (secret, _cred) = derive_secret(
                 credentials.ids.0.as_slice(),
                 &salt,
@@ -406,7 +150,7 @@ pub fn run_cli() -> Fido2LuksResult<()> {
             ..
         } => {
             let pin = if authenticator.pin {
-                Some(read_pin()?)
+                Some(read_pin(authenticator)?)
             } else {
                 None
             };
@@ -414,7 +158,7 @@ pub fn run_cli() -> Fido2LuksResult<()> {
                 if interactive || secret.password_helper == PasswordHelper::Stdin {
                     util::read_password_hashed(q, verify)
                 } else {
-                    secret.salt.obtain(&secret.password_helper)
+                    secret.salt.obtain_sha256(&secret.password_helper)
                 }
             };
             let other_secret = |salt_q: &str,
@@ -427,23 +171,27 @@ pub fn run_cli() -> Fido2LuksResult<()> {
                     } => Ok((util::read_keyfile(file)?, None)),
                     OtherSecret {
                         fido_device: true, ..
-                    } => Ok(derive_secret(
-                        &credentials.ids.0,
-                        &salt(salt_q, verify)?,
-                        authenticator.await_time,
-                        pin.as_deref(),
-                    )
-                    .map(|(secret, cred)| (secret[..].to_vec(), Some(cred)))?),
+                    } => {
+                        prompt_interaction(interactive);
+                        Ok(derive_secret(
+                            &credentials.ids.0,
+                            &salt(salt_q, verify)?,
+                            authenticator.await_time,
+                            pin.as_deref(),
+                        )
+                        .map(|(secret, cred)| (secret[..].to_vec(), Some(cred)))?)
+                    }
                     _ => Ok((
                         util::read_password(salt_q, verify)?.as_bytes().to_vec(),
                         None,
                     )),
                 }
             };
-            let secret = |verify: bool| -> Fido2LuksResult<([u8; 32], FidoCredential)> {
+            let secret = |q: &str, verify: bool| -> Fido2LuksResult<([u8; 32], FidoCredential)> {
+                prompt_interaction(interactive);
                 derive_secret(
                     &credentials.ids.0,
-                    &salt("Password", verify)?,
+                    &salt(q, verify)?,
                     authenticator.await_time,
                     pin.as_deref(),
                 )
@@ -453,7 +201,7 @@ pub fn run_cli() -> Fido2LuksResult<()> {
             match &args.command {
                 Command::AddKey { exclusive, .. } => {
                     let (existing_secret, _) = other_secret("Current password", false)?;
-                    let (new_secret, cred) = secret(true)?;
+                    let (new_secret, cred) = secret("Password to be added", true)?;
                     let added_slot = luks_dev.add_key(
                         &new_secret,
                         &existing_secret[..],
@@ -478,7 +226,7 @@ pub fn run_cli() -> Fido2LuksResult<()> {
                     Ok(())
                 }
                 Command::ReplaceKey { add_password, .. } => {
-                    let (existing_secret, _) = secret(false)?;
+                    let (existing_secret, _) = secret("Current password", false)?;
                     let (replacement_secret, cred) = other_secret("Replacement password", true)?;
                     let slot = if *add_password {
                         luks_dev.add_key(
@@ -511,6 +259,7 @@ pub fn run_cli() -> Fido2LuksResult<()> {
             secret,
             name,
             retries,
+            allow_discards,
             ..
         }
         | Command::OpenToken {
@@ -519,10 +268,11 @@ pub fn run_cli() -> Fido2LuksResult<()> {
             secret,
             name,
             retries,
+            allow_discards,
         } => {
             let pin_string;
             let pin = if authenticator.pin {
-                pin_string = read_pin()?;
+                pin_string = read_pin(authenticator)?;
                 Some(pin_string.as_ref())
             } else {
                 None
@@ -531,12 +281,13 @@ pub fn run_cli() -> Fido2LuksResult<()> {
                 if interactive || secret.password_helper == PasswordHelper::Stdin {
                     util::read_password_hashed(q, verify)
                 } else {
-                    secret.salt.obtain(&secret.password_helper)
+                    secret.salt.obtain_sha256(&secret.password_helper)
                 }
             };
 
             // Cow shouldn't be necessary
             let secret = |credentials: Cow<'_, Vec<HexEncoded>>| {
+                prompt_interaction(interactive);
                 derive_secret(
                     credentials.as_ref(),
                     &salt("Password", false)?,
@@ -550,7 +301,9 @@ pub fn run_cli() -> Fido2LuksResult<()> {
             loop {
                 let secret = match &args.command {
                     Command::Open { credentials, .. } => secret(Cow::Borrowed(&credentials.ids.0))
-                        .and_then(|(secret, _cred)| luks_dev.activate(&name, &secret, luks.slot)),
+                        .and_then(|(secret, _cred)| {
+                            luks_dev.activate(&name, &secret, luks.slot, *allow_discards)
+                        }),
                     Command::OpenToken { .. } => luks_dev.activate_token(
                         &name,
                         Box::new(|credentials: Vec<String>| {
@@ -562,6 +315,7 @@ pub fn run_cli() -> Fido2LuksResult<()> {
                                 .map(|(secret, cred)| (secret, hex::encode(&cred.id)))
                         }),
                         luks.slot,
+                        *allow_discards,
                     ),
                     _ => unreachable!(),
                 };
@@ -712,5 +466,17 @@ pub fn run_cli() -> Fido2LuksResult<()> {
                 Ok(())
             }
         },
+        Command::GenerateCompletions { shell, out_dir } => {
+            Args::clap().gen_completions(
+                env!("CARGO_PKG_NAME"),
+                match shell.as_ref() {
+                    "bash" => Shell::Bash,
+                    "fish" => Shell::Fish,
+                    _ => unreachable!("structopt shouldn't allow us to reach this point"),
+                },
+                &out_dir,
+            );
+            Ok(())
+        }
     }
 }

src/cli_args/config.rs

@@ -10,33 +10,33 @@ use std::process::Command;
 use std::str::FromStr;
 
 #[derive(Debug, Clone, PartialEq)]
-pub enum InputSalt {
+pub enum SecretInput {
     AskPassword,
     String(String),
     File { path: PathBuf },
 }
 
-impl Default for InputSalt {
+impl Default for SecretInput {
     fn default() -> Self {
-        InputSalt::AskPassword
+        SecretInput::AskPassword
     }
 }
 
-impl From<&str> for InputSalt {
+impl From<&str> for SecretInput {
     fn from(s: &str) -> Self {
         let mut parts = s.split(':');
         match parts.next() {
-            Some("ask") | Some("Ask") => InputSalt::AskPassword,
-            Some("file") => InputSalt::File {
+            Some("ask") | Some("Ask") => SecretInput::AskPassword,
+            Some("file") => SecretInput::File {
                 path: parts.collect::<Vec<_>>().join(":").into(),
             },
-            Some("string") => InputSalt::String(parts.collect::<Vec<_>>().join(":")),
+            Some("string") => SecretInput::String(parts.collect::<Vec<_>>().join(":")),
             _ => Self::default(),
         }
     }
 }
 
-impl FromStr for InputSalt {
+impl FromStr for SecretInput {
     type Err = Fido2LuksError;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
@@ -44,21 +44,42 @@ impl FromStr for InputSalt {
     }
 }
 
-impl fmt::Display for InputSalt {
+impl fmt::Display for SecretInput {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
         f.write_str(&match self {
-            InputSalt::AskPassword => "ask".to_string(),
-            InputSalt::String(s) => ["string", s].join(":"),
-            InputSalt::File { path } => ["file", path.display().to_string().as_str()].join(":"),
+            SecretInput::AskPassword => "ask".to_string(),
+            SecretInput::String(s) => ["string", s].join(":"),
+            SecretInput::File { path } => ["file", path.display().to_string().as_str()].join(":"),
         })
     }
 }
 
-impl InputSalt {
-    pub fn obtain(&self, password_helper: &PasswordHelper) -> Fido2LuksResult<[u8; 32]> {
+impl SecretInput {
+    pub fn obtain_string(&self, password_helper: &PasswordHelper) -> Fido2LuksResult<String> {
+        Ok(String::from_utf8(self.obtain(password_helper)?)?)
+    }
+
+    pub fn obtain(&self, password_helper: &PasswordHelper) -> Fido2LuksResult<Vec<u8>> {
+        let mut secret = Vec::new();
+        match self {
+            SecretInput::File { path } => {
+                //TODO: replace with try_blocks
+                let mut do_io = || File::open(path)?.read_to_end(&mut secret);
+                do_io().map_err(|cause| Fido2LuksError::KeyfileError { cause })?;
+            }
+            SecretInput::AskPassword => {
+                secret.extend_from_slice(password_helper.obtain()?.as_bytes())
+            }
+
+            SecretInput::String(s) => secret.extend_from_slice(s.as_bytes()),
+        }
+        Ok(secret)
+    }
+
+    pub fn obtain_sha256(&self, password_helper: &PasswordHelper) -> Fido2LuksResult<[u8; 32]> {
         let mut digest = digest::Context::new(&digest::SHA256);
         match self {
-            InputSalt::File { path } => {
+            SecretInput::File { path } => {
                 let mut do_io = || {
                     let mut reader = File::open(path)?;
                     let mut buf = [0u8; 512];
@@ -73,10 +94,7 @@ impl InputSalt {
                 };
                 do_io().map_err(|cause| Fido2LuksError::KeyfileError { cause })?;
             }
-            InputSalt::AskPassword => {
-                digest.update(password_helper.obtain()?.as_bytes());
-            }
-            InputSalt::String(s) => digest.update(s.as_bytes()),
+            _ => digest.update(self.obtain(password_helper)?.as_slice()),
         }
         let mut salt = [0u8; 32];
         salt.as_mut().copy_from_slice(digest.finish().as_ref());
@@ -135,10 +153,9 @@ impl PasswordHelper {
             Systemd => unimplemented!(),
             Stdin => Ok(util::read_password("Password", true)?),
             Script(password_helper) => {
-                let mut helper_parts = password_helper.split(' ');
-
-                let password = Command::new((&mut helper_parts).next().unwrap())
-                    .args(helper_parts)
+                let password = Command::new("sh")
+                    .arg("-c")
+                    .arg(&password_helper)
                     .output()
                     .map_err(|e| Fido2LuksError::AskPassError {
                         cause: error::AskPassError::IO(e),
@@ -158,24 +175,30 @@ mod test {
     #[test]
     fn input_salt_from_str() {
         assert_eq!(
-            "file:/tmp/abc".parse::<InputSalt>().unwrap(),
-            InputSalt::File {
+            "file:/tmp/abc".parse::<SecretInput>().unwrap(),
+            SecretInput::File {
                 path: "/tmp/abc".into()
             }
         );
         assert_eq!(
-            "string:abc".parse::<InputSalt>().unwrap(),
-            InputSalt::String("abc".into())
+            "string:abc".parse::<SecretInput>().unwrap(),
+            SecretInput::String("abc".into())
+        );
+        assert_eq!(
+            "ask".parse::<SecretInput>().unwrap(),
+            SecretInput::AskPassword
+        );
+        assert_eq!(
+            "lol".parse::<SecretInput>().unwrap(),
+            SecretInput::default()
         );
-        assert_eq!("ask".parse::<InputSalt>().unwrap(), InputSalt::AskPassword);
-        assert_eq!("lol".parse::<InputSalt>().unwrap(), InputSalt::default());
     }
 
     #[test]
     fn input_salt_obtain() {
         assert_eq!(
-            InputSalt::String("abc".into())
-                .obtain(&PasswordHelper::Stdin)
+            SecretInput::String("abc".into())
+                .obtain_sha256(&PasswordHelper::Stdin)
                 .unwrap(),
             [
                 186, 120, 22, 191, 143, 1, 207, 234, 65, 65, 64, 222, 93, 174, 34, 35, 176, 3, 97,

src/cli_args/mod.rs

@@ -0,0 +1,299 @@
+use std::fmt::{Display, Error, Formatter};
+use std::path::PathBuf;
+use std::str::FromStr;
+use structopt::clap::AppSettings;
+use structopt::StructOpt;
+
+mod config;
+
+pub use config::*;
+
+#[derive(Debug, Eq, PartialEq, Clone)]
+pub struct HexEncoded(pub Vec<u8>);
+
+impl Display for HexEncoded {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
+        f.write_str(&hex::encode(&self.0))
+    }
+}
+
+impl AsRef<[u8]> for HexEncoded {
+    fn as_ref(&self) -> &[u8] {
+        &self.0[..]
+    }
+}
+
+impl FromStr for HexEncoded {
+    type Err = hex::FromHexError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(HexEncoded(hex::decode(s)?))
+    }
+}
+
+#[derive(Debug, Eq, PartialEq, Clone)]
+pub struct CommaSeparated<T: FromStr + Display>(pub Vec<T>);
+
+impl<T: Display + FromStr> Display for CommaSeparated<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
+        for i in &self.0 {
+            f.write_str(&i.to_string())?;
+            f.write_str(",")?;
+        }
+        Ok(())
+    }
+}
+
+impl<T: Display + FromStr> FromStr for CommaSeparated<T> {
+    type Err = <T as FromStr>::Err;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(CommaSeparated(
+            s.split(',')
+                .map(|part| <T as FromStr>::from_str(part))
+                .collect::<Result<Vec<_>, _>>()?,
+        ))
+    }
+}
+
+#[derive(Debug, StructOpt)]
+pub struct Credentials {
+    /// FIDO credential ids, separated by ',' generate using fido2luks credential
+    #[structopt(name = "credential-id", env = "FIDO2LUKS_CREDENTIAL_ID")]
+    pub ids: CommaSeparated<HexEncoded>,
+}
+
+#[derive(Debug, StructOpt)]
+pub struct AuthenticatorParameters {
+    /// Request a PIN to unlock the authenticator
+    #[structopt(short = "P", long = "pin")]
+    pub pin: bool,
+
+    /// Location to read PIN from
+    #[structopt(long = "pin-source", env = "FIDO2LUKS_PIN_SOURCE")]
+    pub pin_source: Option<PathBuf>,
+
+    /// Await for an authenticator to be connected, timeout after n seconds
+    #[structopt(
+        long = "await-dev",
+        name = "await-dev",
+        env = "FIDO2LUKS_DEVICE_AWAIT",
+        default_value = "15"
+    )]
+    pub await_time: u64,
+}
+
+#[derive(Debug, StructOpt)]
+pub struct LuksParameters {
+    #[structopt(env = "FIDO2LUKS_DEVICE")]
+    pub device: PathBuf,
+
+    /// Try to unlock the device using a specifc keyslot, ignore all other slots
+    #[structopt(long = "slot", env = "FIDO2LUKS_DEVICE_SLOT")]
+    pub slot: Option<u32>,
+}
+
+#[derive(Debug, StructOpt, Clone)]
+pub struct LuksModParameters {
+    /// Number of milliseconds required to derive the volume decryption key
+    /// Defaults to 10ms when using an authenticator or the default by cryptsetup when using a password
+    #[structopt(long = "kdf-time", name = "kdf-time")]
+    pub kdf_time: Option<u64>,
+}
+
+#[derive(Debug, StructOpt)]
+pub struct SecretParameters {
+    /// Salt for secret generation, defaults to 'ask'
+    ///
+    /// Options:{n}
+    ///  - ask              : Prompt user using password helper{n}
+    ///  - file:<PATH>      : Will read <FILE>{n}
+    ///  - string:<STRING>  : Will use <STRING>, which will be handled like a password provided to the 'ask' option{n}
+    #[structopt(
+        name = "salt",
+        long = "salt",
+        env = "FIDO2LUKS_SALT",
+        default_value = "ask"
+    )]
+    pub salt: SecretInput,
+    /// Script used to obtain passwords, overridden by --interactive flag
+    #[structopt(
+        name = "password-helper",
+        env = "FIDO2LUKS_PASSWORD_HELPER",
+        default_value = "/usr/bin/env systemd-ask-password 'Please enter second factor for LUKS disk encryption!'"
+    )]
+    pub password_helper: PasswordHelper,
+}
+#[derive(Debug, StructOpt)]
+pub struct Args {
+    /// Request passwords via Stdin instead of using the password helper
+    #[structopt(short = "i", long = "interactive")]
+    pub interactive: bool,
+    #[structopt(subcommand)]
+    pub command: Command,
+}
+
+#[derive(Debug, StructOpt, Clone)]
+pub struct OtherSecret {
+    /// Use a keyfile instead of a password
+    #[structopt(short = "d", long = "keyfile", conflicts_with = "fido_device")]
+    pub keyfile: Option<PathBuf>,
+    /// Use another fido device instead of a password
+    /// Note: this requires for the credential fot the other device to be passed as argument as well
+    #[structopt(short = "f", long = "fido-device", conflicts_with = "keyfile")]
+    pub fido_device: bool,
+}
+
+#[derive(Debug, StructOpt)]
+pub enum Command {
+    #[structopt(name = "print-secret")]
+    PrintSecret {
+        /// Prints the secret as binary instead of hex encoded
+        #[structopt(short = "b", long = "bin")]
+        binary: bool,
+        #[structopt(flatten)]
+        credentials: Credentials,
+        #[structopt(flatten)]
+        authenticator: AuthenticatorParameters,
+        #[structopt(flatten)]
+        secret: SecretParameters,
+    },
+    /// Adds a generated key to the specified LUKS device
+    #[structopt(name = "add-key")]
+    AddKey {
+        #[structopt(flatten)]
+        luks: LuksParameters,
+        #[structopt(flatten)]
+        credentials: Credentials,
+        #[structopt(flatten)]
+        authenticator: AuthenticatorParameters,
+        #[structopt(flatten)]
+        secret: SecretParameters,
+        /// Will wipe all other keys
+        #[structopt(short = "e", long = "exclusive")]
+        exclusive: bool,
+        /// Will add an token to your LUKS 2 header, including the credential id
+        #[structopt(short = "t", long = "token")]
+        token: bool,
+        #[structopt(flatten)]
+        existing_secret: OtherSecret,
+        #[structopt(flatten)]
+        luks_mod: LuksModParameters,
+    },
+    /// Replace a previously added key with a password
+    #[structopt(name = "replace-key")]
+    ReplaceKey {
+        #[structopt(flatten)]
+        luks: LuksParameters,
+        #[structopt(flatten)]
+        credentials: Credentials,
+        #[structopt(flatten)]
+        authenticator: AuthenticatorParameters,
+        #[structopt(flatten)]
+        secret: SecretParameters,
+        /// Add the password and keep the key
+        #[structopt(short = "a", long = "add-password")]
+        add_password: bool,
+        /// Will add an token to your LUKS 2 header, including the credential id
+        #[structopt(short = "t", long = "token")]
+        token: bool,
+        #[structopt(flatten)]
+        replacement: OtherSecret,
+        #[structopt(flatten)]
+        luks_mod: LuksModParameters,
+    },
+    /// Open the LUKS device
+    #[structopt(name = "open")]
+    Open {
+        #[structopt(flatten)]
+        luks: LuksParameters,
+        #[structopt(env = "FIDO2LUKS_MAPPER_NAME")]
+        name: String,
+        #[structopt(flatten)]
+        credentials: Credentials,
+        #[structopt(flatten)]
+        authenticator: AuthenticatorParameters,
+        #[structopt(flatten)]
+        secret: SecretParameters,
+        #[structopt(short = "r", long = "max-retries", default_value = "0")]
+        retries: i32,
+        /// Pass SSD trim instructions to the underlying block device
+        #[structopt(long = "allow-discards")]
+        allow_discards: bool,
+    },
+    /// Open the LUKS device using credentials embedded in the LUKS 2 header
+    #[structopt(name = "open-token")]
+    OpenToken {
+        #[structopt(flatten)]
+        luks: LuksParameters,
+        #[structopt(env = "FIDO2LUKS_MAPPER_NAME")]
+        name: String,
+        #[structopt(flatten)]
+        authenticator: AuthenticatorParameters,
+        #[structopt(flatten)]
+        secret: SecretParameters,
+        #[structopt(short = "r", long = "max-retries", default_value = "0")]
+        retries: i32,
+        /// Pass SSD trim instructions to the underlying block device
+        #[structopt(long = "allow-discards")]
+        allow_discards: bool,
+    },
+    /// Generate a new FIDO credential
+    #[structopt(name = "credential")]
+    Credential {
+        #[structopt(flatten)]
+        authenticator: AuthenticatorParameters,
+        /// Name to be displayed on the authenticator display
+        #[structopt(env = "FIDO2LUKS_CREDENTIAL_NAME", default_value = "fido2luks")]
+        name: String,
+    },
+    /// Check if an authenticator is connected
+    #[structopt(name = "connected")]
+    Connected,
+    Token(TokenCommand),
+    /// Generate bash completion scripts
+    #[structopt(name = "completions", setting = AppSettings::Hidden)]
+    GenerateCompletions {
+        /// Shell to generate completions for: bash, fish
+        #[structopt(possible_values = &["bash", "fish"])]
+        shell: String,
+        out_dir: PathBuf,
+    },
+}
+
+///LUKS2 token related operations
+#[derive(Debug, StructOpt)]
+pub enum TokenCommand {
+    /// List all tokens associated with the specified device
+    List {
+        #[structopt(env = "FIDO2LUKS_DEVICE")]
+        device: PathBuf,
+        /// Dump all credentials as CSV
+        #[structopt(long = "csv")]
+        csv: bool,
+    },
+    /// Add credential to a keyslot
+    Add {
+        #[structopt(env = "FIDO2LUKS_DEVICE")]
+        device: PathBuf,
+        #[structopt(flatten)]
+        credentials: Credentials,
+        /// Slot to which the credentials will be added
+        #[structopt(long = "slot", env = "FIDO2LUKS_DEVICE_SLOT")]
+        slot: u32,
+    },
+    /// Remove credentials from token(s)
+    Remove {
+        #[structopt(env = "FIDO2LUKS_DEVICE")]
+        device: PathBuf,
+        #[structopt(flatten)]
+        credentials: Credentials,
+        /// Token from which the credentials will be removed
+        #[structopt(long = "token")]
+        token_id: Option<u32>,
+    },
+    /// Remove all unassigned tokens
+    GC {
+        #[structopt(env = "FIDO2LUKS_DEVICE")]
+        device: PathBuf,
+    },
+}

src/error.rs

@@ -1,5 +1,9 @@
 use ctap::FidoError;
+use libcryptsetup_rs::LibcryptErr;
 use std::io;
+use std::io::ErrorKind;
+use std::string::FromUtf8Error;
+use Fido2LuksError::*;
 
 pub type Fido2LuksResult<T> = Result<T, Fido2LuksError>;
 
@@ -81,11 +85,6 @@ impl From<LuksError> for Fido2LuksError {
     }
 }
 
-use libcryptsetup_rs::LibcryptErr;
-use std::io::ErrorKind;
-use std::string::FromUtf8Error;
-use Fido2LuksError::*;
-
 impl From<FidoError> for Fido2LuksError {
     fn from(e: FidoError) -> Self {
         AuthenticatorError { cause: e }

src/luks.rs

@@ -1,8 +1,8 @@
 use crate::error::*;
 
 use libcryptsetup_rs::{
-    CryptActivateFlags, CryptDevice, CryptInit, CryptTokenInfo, EncryptionFormat, KeyslotInfo,
-    TokenInput,
+    CryptActivateFlag, CryptActivateFlags, CryptDevice, CryptInit, CryptTokenInfo,
+    EncryptionFormat, KeyslotInfo, TokenInput,
 };
 use std::collections::{HashMap, HashSet};
 use std::path::Path;
@@ -221,10 +221,15 @@ impl LuksDevice {
         name: &str,
         secret: &[u8],
         slot_hint: Option<u32>,
+        allow_discard: bool,
     ) -> Fido2LuksResult<u32> {
+        let mut flags = CryptActivateFlags::empty();
+        if allow_discard {
+            flags = CryptActivateFlags::new(vec![CryptActivateFlag::AllowDiscards]);
+        }
         self.device
             .activate_handle()
-            .activate_by_passphrase(Some(name), slot_hint, secret, CryptActivateFlags::empty())
+            .activate_by_passphrase(Some(name), slot_hint, secret, flags)
             .map_err(LuksError::activate)
     }
 
@@ -233,6 +238,7 @@ impl LuksDevice {
         name: &str,
         secret: impl Fn(Vec<String>) -> Fido2LuksResult<([u8; 32], String)>,
         slot_hint: Option<u32>,
+        allow_discard: bool,
     ) -> Fido2LuksResult<u32> {
         if !self.is_luks2()? {
             return Err(LuksError::Luks2Required.into());
@@ -276,7 +282,7 @@ impl LuksDevice {
                 .chain(std::iter::once(None).take(slots.is_empty() as usize)), // Try all slots as last resort
         );
         for slot in slots {
-            match self.activate(name, &secret, slot) {
+            match self.activate(name, &secret, slot, allow_discard) {
                 Err(Fido2LuksError::WrongSecret) => (),
                 res => return res,
             }

src/main.rs

@@ -4,15 +4,13 @@ extern crate ctap_hmac as ctap;
 #[macro_use]
 extern crate serde_derive;
 use crate::cli::*;
-use crate::config::*;
 use crate::device::*;
 use crate::error::*;
 use std::io;
-use std::path::PathBuf;
 use std::process::exit;
 
 mod cli;
-mod config;
+pub mod cli_args;
 mod device;
 mod error;
 mod luks;
@@ -21,10 +19,7 @@ mod util;
 fn main() -> Fido2LuksResult<()> {
     match run_cli() {
         Err(e) => {
-            #[cfg(debug_assertions)]
             eprintln!("{:?}", e);
-            #[cfg(not(debug_assertions))]
-            eprintln!("{}", e);
             exit(e.exit_code())
         }
         _ => exit(0),