mirror of
https://github.com/suiryc/archlinux-initrd-ssh-cryptsetup.git
synced 2025-12-18 02:18:56 +03:00
7d866bdfca
Sometimes we need to change the sources, but only for minor external dependencies diff (e.g. adding/removing upstream source), in which case we wish to only bump pkgrel.
80 lines
3.8 KiB
Markdown
80 lines
3.8 KiB
Markdown
Personal ArchLinux package combining dropbear and cryptsetup in initramfs for unlocking LUKS-encrypted devices either locally (boot console) or remotely over SSH.
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The code was reworked from legacy dropbear_initrd_encrypt AUR package.
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## Installation
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After cloning the repo, installation is done as for an AUR package, e.g.:
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makepkg -sri
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## Dropbear
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SSH server key need to be generated for `dropbear`.
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Either a new key can be generated with `dropbearkey`, e.g.:
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dropbearkey -t ecdsa -f /etc/dropbear/dropbear_ecdsa_host_key
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Or an existing OpenSSH key can be converted with `dropbearconvert` (useful so that the server fingerprint is the same with both), e.g.:
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dropbearconvert openssh dropbear /etc/ssh/ssh_host_ecdsa_key /etc/dropbear/dropbear_ecdsa_host_key
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Notes:
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* `rsa` and `ed25519` types are also handled
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* OpenSSH keys must be in `PEM` format for `dropbearconvert` to properly work
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If necessary an existing key file can be converted to `PEM` format using `ssh-keygen`:
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ssh-keygen -A -p -m PEM -f /etc/ssh/ssh_host_ecdsa_key
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## Configuration
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As explained upon installation, the following things need to be done:
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* add the authorized SSH public key to `/etc/dropbear/initrd.authorized_keys`
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* add the `ip=` kernel command parameter to the bootloader configuration (see https://wiki.archlinux.org/index.php/Mkinitcpio#Using_net)
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- e.g. with `grub`: add `ip=:::::eth0:dhcp` to `GRUB_CMDLINE_LINUX_DEFAULT` in `/etc/default/grub`, and re-generate the configuration with `grub-mkconfig -o /boot/grub/grub.cfg`
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- also see https://git.kernel.org/pub/scm/libs/klibc/klibc.git/tree/usr/kinit/ipconfig/README.ipconfig
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* in the `HOOKS` section of `/etc/mkinitcpio.conf`, add `ssh-cryptsetup` before `filesystems`; then rebuild the initramfs: `mkinitcpio -p linux`
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- when using a non-standard keyboard layout, it is also useful to add the `keymap` hook before `ssh-cryptsetup`, and also move `keyboard` before `keymap`
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The LUKS-encrypted devices to unlock are derived from `/etc/crypttab`.
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Some options can be set in `/etc/initcpio/sshcs_env` (file is sourced in initramfs shell):
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* `sshcs_opt_debug`: whether to be more verbose about ongoing actions
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- default: `0`
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- any non-zero value to enable
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* `sshcs_opt_net_wol`: Wake-on-LAN option to set on network device
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- default: `g` (MagicPacket™)
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- usually WOL is disabled once in initramfs shell
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- set empty to not change network device WOL setting
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* `sshcs_opt_timeout_ipconfig`: time (in seconds) to configure IP
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- default: `10`
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* `sshcs_opt_listen`: SSH listening port
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- default: `22`
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* `sshcs_opt_timeout_poweroff`: time (in seconds) to unlock devices before automatic powering off
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- default (and minimum value): `120` (2 minutes)
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- negative value to deactivate
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* `sshcs_opt_use_shell`: whether to start a full `ash` shell
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- default: `0`
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- `1` to enable
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- when disabled (the default), a script to unlock devices is executed instead
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For example:
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sshcs_opt_timeout_ipconfig=30
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sshcs_opt_listen=2222
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sshcs_opt_timeout_poweroff=-1
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sshcs_opt_use_shell=1
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## Building notes
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1. Modify the sources (features in `src`, and/or package building files)
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2. If `src` was modified
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* bump `pkgver`, or `pkgrel`, in `PKGBUILD`
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* archive the `src` folder in `$pkgname-$pkgver-$pkgrel.tar.xz` file; e.g.: `tar -cJf initrd-ssh-cryptsetup-$(grep "^pkgver=" PKGBUILD | cut -d'=' -f2)-$(grep "^pkgrel=" PKGBUILD | cut -d'=' -f2).tar.xz src`
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* upload the archive on the online repository (pointed by `PKGBUILD`)
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3. Update ChangeLog
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4. Update `PKGBUILD`
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* bump `pkgrel` if only building files were modified
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* refresh `sha256sums` with `updpkgsums` if necessary
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- or manually, based on `sha256sum initrd-ssh-cryptsetup-*.tar.xz initrd-ssh-cryptsetup.install` output
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5. Delete generated archive file if any
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