mirror of
https://github.com/suiryc/archlinux-initrd-ssh-cryptsetup.git
synced 2025-11-04 18:22:31 +03:00
130 lines
4.6 KiB
Bash
130 lines
4.6 KiB
Bash
#!/bin/bash
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sshcs_check_nonempty() {
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local filepath="$1"
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[ -e "${filepath}" ] && grep -q -v '^\s*\(#\|$\)' "${filepath}"
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}
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sshcs_check_keys() {
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local dropbear_keyfile
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local openssh_keyfile
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local fingerprint
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for keytype in "${dropbear_key_types[@]}"; do
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dropbear_keyfile=${dropbear_keyfile_prefix}${keytype}${dropbear_keyfile_suffix}
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openssh_keyfile=${openssh_keyfile_prefix}${keytype}${openssh_keyfile_suffix}
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# Prefer OpenSSH keys, or generate missing ones
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if [ -e "${openssh_keyfile}" ]; then
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#echo "Copying OpenSSH ${keytype} host key for dropbear ..."
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dropbearconvert openssh dropbear "${openssh_keyfile}" "${dropbear_keyfile}" > /dev/null 2>&1
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elif [ ! -e "${dropbear_keyfile}" ]; then
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#echo "Generating ${keytype} host key for dropbear ..."
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dropbearkey -t "${keytype}" -f "${dropbear_keyfile}" > /dev/null 2>&1
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fi
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fingerprint=$(dropbearkey -y -f "${dropbear_keyfile}" | sed -n '/^Fingerprint:/ {s/Fingerprint: *//; p}')
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echo "$(basename "${dropbear_keyfile}") : ${fingerprint}"
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done
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}
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build() {
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local etc_crypttab="/etc/crypttab"
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local dropbear_authorized_keys="/etc/dropbear/initrd.authorized_keys"
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local sshcs_env="/etc/initcpio/sshcs_env"
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local dropbear_key_types=( "rsa" "ecdsa" "ed25519" )
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local dropbear_keyfile_prefix="/etc/dropbear/dropbear_"
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local dropbear_keyfile_suffix="_host_key"
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local openssh_keyfile_prefix="/etc/ssh/ssh_host_"
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local openssh_keyfile_suffix="_key"
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# Check we are needed
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if ! sshcs_check_nonempty "${dropbear_authorized_keys}"; then
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echo "There is no root key(s) in ${dropbear_authorized_keys}. Skipping."
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return 0
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fi
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if ! sshcs_check_nonempty "${etc_crypttab}"; then
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echo "There is no device in ${etc_crypttab}. Skipping."
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return 0
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fi
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umask 0022
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sshcs_check_keys
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add_checked_modules "/drivers/net/"
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# Note: parts of this script (modules/binaries added) are the same than the
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# 'encrypt' install script (/usr/lib/initcpio/install/encrypt) which is the
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# nominal one to deal with encrypted volumes at boot time.
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add_module dm-crypt
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# Note: crypto modules are necessary
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if [ -n "${CRYPTO_MODULES}" ]; then
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local mod
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for mod in ${CRYPTO_MODULES}; do
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add_module "${mod}"
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done
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else
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add_all_modules "/crypto/"
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fi
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# Note: dmsetup is necessary for device mapper features
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add_binary "cryptsetup"
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add_binary "dmsetup"
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add_binary "dropbear"
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add_binary "ip"
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add_binary "/usr/lib/initcpio/ipconfig" "/sbin/ipconfig"
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# Our hook files
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[ -e "${sshcs_env}" ] && add_file "${sshcs_env}"
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# auth-related files
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add_file "/lib/libnss_files.so"
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# SSH-related files
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add_file "${dropbear_authorized_keys}" "/root/.ssh/authorized_keys"
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for keytype in "${dropbear_key_types[@]}"; do
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add_file "${dropbear_keyfile_prefix}${keytype}${dropbear_keyfile_suffix}"
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done
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# cryptsetup-related files
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add_file "${etc_crypttab}"
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add_file "/usr/lib/udev/rules.d/10-dm.rules"
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add_file "/usr/lib/udev/rules.d/13-dm-disk.rules"
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add_file "/usr/lib/udev/rules.d/95-dm-notify.rules"
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add_file "/usr/lib/initcpio/udev/11-dm-initramfs.rules" "/usr/lib/udev/rules.d/11-dm-initramfs.rules"
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# At least with LUKS v2 volumes, cryptsetup calls pthread_cancel(), which
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# dlopen()s libgcc_s.so.1.
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# See the nominal 'encrypt' module, and similar/related bug reports (e.g.
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# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=950254).
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add_binary "/usr/lib/libgcc_s.so.1"
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add_runscript
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}
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help() {
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cat <<EOF
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This hook allows for LUKS encrypted devices to be unlocked either locally
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(boot console) or remotely over SSH.
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Network is configured with 'ip=' kernel parameter (see 'mkinitcpio-nfs-utils').
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Authorized SSH key(s) must be present in '/etc/dropbear/initrd.authorized_keys'.
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LUKS encrypted devices to unlock are derived from '/etc/crypttab', which must
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be present.
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Some options can be set in '/etc/initcpio/sshcs_env' (file is sourced in
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initrd shell):
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* 'sshcs_opt_timeout_ipconfig': time (s) to configure IP
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- default: 10 seconds
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* 'sshcs_opt_listen': listening port (22 by default)
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* 'sshcs_opt_timeout_poweroff': time (s) to unlock devices before automatic
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powering off
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- default (and minimum value): 2 minutes
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- negative value to deactivate
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Each SSH server key ('dropbear_rsa_host_key', 'dropbear_ecdsa_host_key' and
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'dropbear_ed25519_host_key' in '/etc/dropbear' folder) is imported from OpenSSH
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if present or generated if missing. Fingerprints are displayed upon building
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the initramfs image.
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EOF
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}
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