Merge pull request #77826 from mmahut/fido2luks

FIDO2 luks support
This commit is contained in:
Marek Mahut 2020-01-27 08:27:30 +01:00 committed by GitHub
commit 61dbbe4121
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4 changed files with 120 additions and 5 deletions

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@ -37,4 +37,38 @@ Enter passphrase for /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d: ***
on an encrypted partition, it is necessary to add the following grub option: on an encrypted partition, it is necessary to add the following grub option:
<programlisting><xref linkend="opt-boot.loader.grub.enableCryptodisk"/> = true;</programlisting> <programlisting><xref linkend="opt-boot.loader.grub.enableCryptodisk"/> = true;</programlisting>
</para> </para>
<section xml:id="sec-luks-file-systems-fido2">
<title>FIDO2</title>
<para>
NixOS also supports unlocking your LUKS-Encrypted file system using a FIDO2 compatible token. In the following example, we will create a new FIDO2 credential
and add it as a new key to our existing device <filename>/dev/sda2</filename>:
<screen>
# export FIDO2_LABEL="/dev/sda2 @ $HOSTNAME"
# fido2luks credential "$FIDO2_LABEL"
f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7
# fido2luks -i add-key /dev/sda2 f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7
Password:
Password (again):
Old password:
Old password (again):
Added to key to device /dev/sda2, slot: 2
</screen>
To ensure that this file system is decrypted using the FIDO2 compatible key, add the following to <filename>configuration.nix</filename>:
<programlisting>
<link linkend="opt-boot.initrd.luks.fido2Support">boot.initrd.luks.fido2Support</link> = true;
<link linkend="opt-boot.initrd.luks.devices._name__.fido2.credential">boot.initrd.luks.devices."/dev/sda2".fido2.credential</link> = "f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7";
</programlisting>
You can also use the FIDO2 passwordless setup, but for security reasons, you might want to enable it only when your device is PIN protected, such as <link xlink:href="https://trezor.io/">Trezor</link>.
<programlisting>
<link linkend="opt-boot.initrd.luks.devices._name__.fido2.passwordLess">boot.initrd.luks.devices."/dev/sda2".fido2.passwordLess</link> = true;
</programlisting>
</para>
</section>
</section> </section>

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@ -485,6 +485,12 @@ users.users.me =
now uses the short rather than full version string. now uses the short rather than full version string.
</para> </para>
</listitem> </listitem>
<listitem>
<para>
It is now possible to unlock LUKS-Encrypted file systems using a FIDO2 token
via <option>boot.initrd.luks.fido2Support</option>.
</para>
</listitem>
</itemizedlist> </itemizedlist>
</section> </section>
</section> </section>

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@ -4,6 +4,7 @@ with lib;
let let
luks = config.boot.initrd.luks; luks = config.boot.initrd.luks;
kernelPackages = config.boot.kernelPackages;
commonFunctions = '' commonFunctions = ''
die() { die() {
@ -139,7 +140,7 @@ let
umount /crypt-ramfs 2>/dev/null umount /crypt-ramfs 2>/dev/null
''; '';
openCommand = name': { name, device, header, keyFile, keyFileSize, keyFileOffset, allowDiscards, yubikey, gpgCard, fallbackToPassword, ... }: assert name' == name; openCommand = name': { name, device, header, keyFile, keyFileSize, keyFileOffset, allowDiscards, yubikey, gpgCard, fido2, fallbackToPassword, ... }: assert name' == name;
let let
csopen = "cryptsetup luksOpen ${device} ${name} ${optionalString allowDiscards "--allow-discards"} ${optionalString (header != null) "--header=${header}"}"; csopen = "cryptsetup luksOpen ${device} ${name} ${optionalString allowDiscards "--allow-discards"} ${optionalString (header != null) "--header=${header}"}";
cschange = "cryptsetup luksChangeKey ${device} ${optionalString (header != null) "--header=${header}"}"; cschange = "cryptsetup luksChangeKey ${device} ${optionalString (header != null) "--header=${header}"}";
@ -387,7 +388,31 @@ let
} }
''} ''}
${if (luks.yubikeySupport && (yubikey != null)) || (luks.gpgSupport && (gpgCard != null)) then '' ${optionalString (luks.fido2Support && (fido2.credential != null)) ''
open_with_hardware() {
local passsphrase
${if fido2.passwordLess then ''
export passphrase=""
'' else ''
read -rsp "FIDO2 salt for ${device}: " passphrase
echo
''}
${optionalString (lib.versionOlder kernelPackages.kernel.version "5.4") ''
echo "On systems with Linux Kernel < 5.4, it might take a while to initialize the CRNG, you might want to use linuxPackages_latest."
echo "Please move your mouse to create needed randomness."
''}
echo "Waiting for your FIDO2 device..."
fido2luks -i open ${device} ${name} ${fido2.credential} --await-dev ${toString fido2.gracePeriod} --salt string:$passphrase
if [ $? -ne 0 ]; then
echo "No FIDO2 key found, falling back to normal open procedure"
open_normally
fi
}
''}
${if (luks.yubikeySupport && (yubikey != null)) || (luks.gpgSupport && (gpgCard != null)) || (luks.fido2Support && (fido2.credential != null)) then ''
open_with_hardware open_with_hardware
'' else '' '' else ''
open_normally open_normally
@ -608,6 +633,31 @@ in
}); });
}; };
fido2 = {
credential = mkOption {
default = null;
example = "f1d00200d8dc783f7fb1e10ace8da27f8312d72692abfca2f7e4960a73f48e82e1f7571f6ebfcee9fb434f9886ccc8fcc52a6614d8d2";
type = types.str;
description = "The FIDO2 credential ID.";
};
gracePeriod = mkOption {
default = 10;
type = types.int;
description = "Time in seconds to wait for the FIDO2 key.";
};
passwordLess = mkOption {
default = false;
type = types.bool;
description = ''
Defines whatever to use an empty string as a default salt.
Enable only when your device is PIN protected, such as <link xlink:href="https://trezor.io/">Trezor</link>.
'';
};
};
yubikey = mkOption { yubikey = mkOption {
default = null; default = null;
description = '' description = ''
@ -706,6 +756,15 @@ in
and a Yubikey to work with this feature. and a Yubikey to work with this feature.
''; '';
}; };
boot.initrd.luks.fido2Support = mkOption {
default = false;
type = types.bool;
description = ''
Enables support for authenticating with FIDO2 devices.
'';
};
}; };
config = mkIf (luks.devices != {} || luks.forceLuksSupportInInitrd) { config = mkIf (luks.devices != {} || luks.forceLuksSupportInInitrd) {
@ -714,6 +773,14 @@ in
[ { assertion = !(luks.gpgSupport && luks.yubikeySupport); [ { assertion = !(luks.gpgSupport && luks.yubikeySupport);
message = "Yubikey and GPG Card may not be used at the same time."; message = "Yubikey and GPG Card may not be used at the same time.";
} }
{ assertion = !(luks.gpgSupport && luks.fido2Support);
message = "FIDO2 and GPG Card may not be used at the same time.";
}
{ assertion = !(luks.fido2Support && luks.yubikeySupport);
message = "FIDO2 and Yubikey may not be used at the same time.";
}
]; ];
# actually, sbp2 driver is the one enabling the DMA attack, but this needs to be tested # actually, sbp2 driver is the one enabling the DMA attack, but this needs to be tested
@ -753,6 +820,11 @@ in
chmod +x $out/bin/openssl-wrap chmod +x $out/bin/openssl-wrap
''} ''}
${optionalString luks.fido2Support ''
copy_bin_and_libs ${pkgs.fido2luks}/bin/fido2luks
''}
${optionalString luks.gpgSupport '' ${optionalString luks.gpgSupport ''
copy_bin_and_libs ${pkgs.gnupg}/bin/gpg copy_bin_and_libs ${pkgs.gnupg}/bin/gpg
copy_bin_and_libs ${pkgs.gnupg}/bin/gpg-agent copy_bin_and_libs ${pkgs.gnupg}/bin/gpg-agent
@ -783,6 +855,9 @@ in
$out/bin/gpg-agent --version $out/bin/gpg-agent --version
$out/bin/scdaemon --version $out/bin/scdaemon --version
''} ''}
${optionalString luks.fido2Support ''
$out/bin/fido2luks --version
''}
''; '';
boot.initrd.preFailCommands = postCommands; boot.initrd.preFailCommands = postCommands;

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@ -7,19 +7,19 @@
rustPlatform.buildRustPackage rec { rustPlatform.buildRustPackage rec {
pname = "fido2luks"; pname = "fido2luks";
version = "0.2.2"; version = "0.2.3";
src = fetchFromGitHub { src = fetchFromGitHub {
owner = "shimunn"; owner = "shimunn";
repo = pname; repo = pname;
rev = version; rev = version;
sha256 = "018qzbgmgm0f0d0c7i54nqqjbr4k5mzy1xfavi6hpifjll971wci"; sha256 = "0340xp7q6f0clb7wmqpgllllwsixmsy37k1f5kj3hwvb730rz93x";
}; };
buildInputs = [ cryptsetup ]; buildInputs = [ cryptsetup ];
nativeBuildInputs = [ pkg-config ]; nativeBuildInputs = [ pkg-config ];
cargoSha256 = "1kf757wxxk5h8dfbz588qw1pnyjbg5qzr7rz14i7x8rhmn5xwb74"; cargoSha256 = "1i37k4ih6118z3wip2qh4jqk7ja2z0v1w8dri1lwqwlciqw17zi9";
verifyCargoDeps = true; verifyCargoDeps = true;
meta = with stdenv.lib; { meta = with stdenv.lib; {