diff options
Diffstat (limited to 'debian/initramfs/hooks/cryptroot')
| -rw-r--r-- | debian/initramfs/hooks/cryptroot | 461 |
1 files changed, 461 insertions, 0 deletions
diff --git a/debian/initramfs/hooks/cryptroot b/debian/initramfs/hooks/cryptroot new file mode 100644 index 0000000..90a32dd --- /dev/null +++ b/debian/initramfs/hooks/cryptroot @@ -0,0 +1,461 @@ +#!/bin/sh + +PREREQ="" + +prereqs() +{ + echo "$PREREQ" +} + +case "$1" in + prereqs) + prereqs + exit 0 + ;; +esac + +. /usr/share/initramfs-tools/hook-functions +. /lib/cryptsetup/functions +TABFILE="/etc/crypttab" + + +# device_uuid($device) +# Print the UUID attribute of given block special $device. Return 0 +# on success, 1 on error. +device_uuid() { + local device="$1" uuid + if uuid="$(blkid -s UUID -o value -- "$device")" && [ -n "$uuid" ]; then + printf '%s\n' "$uuid" + else + return 1 + fi +} + +# resolve_device({$device | $spec}) +# Take a path to (or spec for) a block special device, and set DEV to +# the (symlink to block) device, and MAJ (resp. MIN) to its major-ID +# (resp. minor ID) decimal value. On error these variables are not +# changed and 1 is returned. +resolve_device() { + local spec="$1" dev devno maj min + if dev="$(resolve_device_spec "$spec")" && + devno="$(stat -L -c"%t:%T" -- "$dev" 2>/dev/null)" && + maj="${devno%:*}" && min="${devno#*:}" && + [ "$devno" = "$maj:$min" ] && [ -n "$maj" ] && [ -n "$min" ] && + maj=$(( 0x$maj )) && min=$(( 0x$min )) && [ $maj -gt 0 ]; then + DEV="$dev" + MAJ="$maj" + MIN="$min" + return 0 + else + cryptsetup_message "ERROR: Couldn't resolve device $spec" + fi + return 1 +} + +# get_mnt_devno($mountpoint) +# Print the major:minor device ID(s) holding the file system currently +# mounted currenty mounted on $mountpoint. +# Return 0 on success, 1 on error (if $mountpoint is not a mountpoint). +get_mnt_devno() { + local wantmount="$1" devnos="" uuid dev IFS + local spec mountpoint fstype _ DEV MAJ MIN + + while IFS=" " read -r spec mountpoint fstype _; do + # treat lines starting with '#' as comments; /proc/mounts + # doesn't seem to contain these but per procfs(5) the format of + # that file is analogous to fstab(5)'s + if [ "${spec#\#}" = "$spec" ] && [ -n "$spec" ] && + [ "$(printf '%b' "$mountpoint")" = "$wantmount" ]; then + # take the last mountpoint if used several times (shadowed) + unset -v devnos + spec="$(printf '%b' "$spec")" + resolve_device "$spec" || continue # resolve_device() already warns on error + fstype="$(printf '%b' "$fstype")" + if [ "$fstype" = "btrfs" ]; then + # btrfs can span over multiple devices + if uuid="$(device_uuid "$DEV")"; then + for dev in "/sys/fs/$fstype/$uuid/devices"/*/dev; do + devnos="${devnos:+$devnos }$(cat "$dev")" + done + else + cryptsetup_message "ERROR: $spec: Couldn't determine UUID" + fi + elif [ -n "$fstype" ]; then + devnos="$MAJ:$MIN" + fi + fi + done </proc/mounts + + if [ -z "${devnos:+x}" ]; then + return 1 # not found + else + printf '%s' "$devnos" + fi +} + +# get_dmcrypt_slaves({/sys/dev/block/$maj:$min | /sys/devices/...}) +# Recursively print the crypttab(5) entries to FD nr. 3, for each +# dm-crypt device holding $maj:$min (typically corresponding to an md, +# lv, or dm-crypt device). Slaves that aren't dm-crypt devices are +# NOT printed. +get_dmcrypt_slaves() { + local d="$1" devno maj min name slave + [ -d "$d/slaves" ] || return 0 + if [ -d "$d/dm" ] && devno="$(cat "$d/dev")" && + maj="${devno%:*}" && min="${devno#*:}" && + [ "$devno" = "$maj:$min" ] && [ -n "$maj" ] && [ -n "$min" ] && + [ "$(dmsetup info -c --noheadings -o subsystem -j "$maj" -m "$min")" = "CRYPT" ] && + name="$(dmsetup info -c --noheadings -o unmangled_name -j "$maj" -m "$min")"; then + # search for a crypttab entry with the given unmangled name + crypttab_find_and_print_entry "$name" + fi + for slave in "$d/slaves"/*; do + if [ -d "$slave" ] && slave="$(realpath -e -- "$slave")"; then + get_dmcrypt_slaves "$slave" + fi + done +} + +# crypttab_find_and_print_entry($target) +# Find the crypttab(5) entry for the given (unmangled) $target and +# print it - preserving the mangling - to FD nr. 3; but only if the +# target has not already been processed during an earlier function +# call. (Processed target names are stored in +# $DESTDIR/cryptroot/targets.) +# Return 0 on success, 1 on error. +crypttab_find_and_print_entry() { + local target="$1" + local _CRYPTTAB_NAME _CRYPTTAB_SOURCE _CRYPTTAB_KEY _CRYPTTAB_OPTIONS + if ! grep -Fxqz -e "$target" -- "$DESTDIR/cryptroot/targets"; then + printf '%s\0' "$target" >>"$DESTDIR/cryptroot/targets" + crypttab_find_entry "$target" || return 1 + crypttab_parse_options --missing-path=warn || return 1 + crypttab_print_entry + fi +} + +# crypttab_print_entry() +# Print an unmangled crypttab(5) entry to FD nr. 3, using CRYPTTAB_* +# and _CRYPTTAB_* values. +# _CRYPTTAB_SOURCE is replaced with /dev/mapper/$sourcename for mapped +# sources, otherwise by UUID=<uuid> if possible (eg, for LUKS). If +# the entry uses the 'decrypt_derived' keyscript, the other +# crypttab(5) entries it depends on are (recursively) printed before +# hand. +# Various checks are performed on the key and crypttab options, but no +# parsing is done so it's the responsibility of the caller to call +# crypttab_parse_options(). +# Return 0 on success, 1 on error. +crypttab_print_entry() { + local DEV MAJ MIN sourcename uuid keyfile + if resolve_device "$CRYPTTAB_SOURCE"; then + if [ "$(dmsetup info -c --noheadings -o devnos_used -- "$CRYPTTAB_NAME" 2>/dev/null)" != "$MAJ:$MIN" ]; then + cryptsetup_message "ERROR: $CRYPTTAB_NAME: Source mismatch" + elif sourcename="$(dmsetup info -c --noheadings -o mangled_name -j "$MAJ" -m "$MIN" 2>/dev/null)" && + [ -b "/dev/mapper/$sourcename" ]; then + # for mapped sources, use the dm name as the lvm + # local-block script doesn't work with UUIDs (#902943) + _CRYPTTAB_SOURCE="/dev/mapper/$sourcename" + elif uuid="$(device_uuid "$DEV")"; then + # otherwise, use its UUID if possible (eg. for LUKS) + _CRYPTTAB_SOURCE="UUID=$uuid" + fi + # on failure resolve_device() prints a warning and we try our + # luck with the unchanged _CRYPTTAB_SOURCE value + fi + + # if keyscript is set, the "key" is just an argument to the script + if [ -z "${CRYPTTAB_OPTION_keyscript+x}" ] && [ "$CRYPTTAB_KEY" != "none" ]; then + crypttab_key_check || return 1 + case "$CRYPTTAB_KEY" in + $KEYFILE_PATTERN) + mkdir -pm0700 -- "$DESTDIR/cryptroot/keyfiles" + # $CRYPTTAB_NAME can't contain '/' (even after unmangling) + keyfile="/cryptroot/keyfiles/$CRYPTTAB_NAME.key" + if [ ! -f "$DESTDIR$keyfile" ] && ! copy_file keyfile "$CRYPTTAB_KEY" "$keyfile"; then + cryptsetup_message "WARNING: couldn't copy keyfile $CRYPTTAB_KEY" + fi + _CRYPTTAB_KEY="/cryptroot/keyfiles/$_CRYPTTAB_NAME.key" # preserve mangled name + ;; + *) + if [ "$usage" = rootfs ]; then + cryptsetup_message "WARNING: Skipping root target $CRYPTTAB_NAME: uses a key file" + return 1 + elif [ "$usage" = resume ]; then + cryptsetup_message "WARNING: Resume target $CRYPTTAB_NAME uses a key file" + fi + if [ -L "$CRYPTTAB_KEY" ] && keyfile="$(readlink -- "$CRYPTTAB_KEY")" && + [ "${keyfile#/}" != "$keyfile" ]; then + cryptsetup_message "WARNING: Skipping target $CRYPTTAB_NAME: key file is a symlink with absolute target" + return 1 + elif [ -f "$CRYPTTAB_KEY" ] && [ "$(stat -L -c"%m" -- "$CRYPTTAB_KEY" 2>/dev/null)" != "/" ]; then + cryptsetup_message "WARNING: Skipping target $CRYPTTAB_NAME: key file is not on the root FS" + return 1 + fi + if [ ! -e "$CRYPTTAB_KEY" ]; then + cryptsetup_message "WARNING: Target $CRYPTTAB_NAME has a non-existing key file $CRYPTTAB_KEY" + else + _CRYPTTAB_KEY="/FIXME-initramfs-rootmnt$_CRYPTTAB_KEY" # preserve mangled name + fi + esac + fi + + if [ -n "${CRYPTTAB_OPTION_keyscript+x}" ]; then + copy_exec "$CRYPTTAB_OPTION_keyscript" + fi + if [ "${CRYPTTAB_OPTION_keyscript-}" = "/lib/cryptsetup/scripts/decrypt_derived" ]; then + # (recursively) list first the device to derive the key from (so + # the boot scripts unlock it first); since _CRYPTTAB_* are local + # to crypttab_find_and_print_entry() the new value won't + # override the new ones + crypttab_find_and_print_entry "$CRYPTTAB_KEY" + fi + printf '%s %s %s %s\n' \ + "$_CRYPTTAB_NAME" "$_CRYPTTAB_SOURCE" "$_CRYPTTAB_KEY" "$_CRYPTTAB_OPTIONS" >&3 +} + +# get_cryptdevs($maj:$min, [$maj:$min ..]) +# Print the list of crypttab(5) entries to FD nr. 3, for dm-crypt +# devices holding any of the given devices (which can be an md, a lv, +# a mapped device, or a regular block device). +get_cryptdevs() { + local devno base + for devno in "$@"; do + base="/sys/dev/block/$devno" + if [ ! -d "$base" ]; then + cryptsetup_message "ERROR: Couldn't find sysfs directory for $devno" + return 1 + fi + get_dmcrypt_slaves "$base" + done +} + +# get_resume_devno() +# Return the device ID(s) used for system suspend/hibernate. +get_resume_devno() { + local dev filename + + # uswsusp + for filename in /etc/uswsusp.conf /etc/suspend.conf; do + [ -e "$filename" ] || continue + dev="$(sed -nr '/^resume device\s*[:=]\s*/ {s///p;q}' "$filename")" + if [ -n "$dev" ] && [ "$dev" != "<path_to_resume_device_file>" ]; then + # trim quotes + dev="$(printf '%s' "$dev" | sed -re 's/^"(.*)"\s*$/\1/' -e "s/^'(.*)'\\s*$/\\1/")" + print_devno "$(printf '%b' "$dev")" # unmangle + fi + done + + # regular swsusp + dev="$(sed -nr 's,^(.*\s)?resume=(\S+)(\s.*)?$,\2,p' /proc/cmdline)" + dev="$(printf '%b' "$dev")" # unmangle + print_devno "$(printf '%b' "$dev")" # unmangle + + # initramfs-tools >=0.129 + dev="${RESUME:-auto}" + if [ "$dev" != none ]; then + if [ "$dev" = auto ]; then + # next line from /usr/share/initramfs-tools/hooks/resume + dev="$(grep ^/dev/ /proc/swaps | sort -rnk3 | head -n 1 | cut -d " " -f 1)" + fi + print_devno "$(printf '%b' "$dev")" # unmangle + fi +} +print_devno() { + local DEV MAJ MIN # locally scope the 3 variables resolve_device() sets + if [ -n "$1" ] && resolve_device "$1"; then + printf '%d:%d\n' "$MAJ" "$MIN" + fi +} + +# crypttab_print_initramfs_entry() +# Print a crypttab(5) entry - unless it was already processed - if it +# has the 'initramfs' option set. +crypttab_print_initramfs_entry() { + local usage= + if ! grep -Fxqz -e "$CRYPTTAB_NAME" -- "$DESTDIR/cryptroot/targets" && + crypttab_parse_options --quiet && + [ "${CRYPTTAB_OPTION_initramfs-no}" = "yes" ]; then + printf '%s\0' "$CRYPTTAB_NAME" >>"$DESTDIR/cryptroot/targets" + crypttab_print_entry + fi +} + +# generate_initrd_crypttab() +# Generate the crypttab(5) snippet that is relevant at initramfs +# stage. (Devices that aren't required at initramfs stage are +# ignored.) +generate_initrd_crypttab() { + local devnos usage IFS="$(printf '\t\n ')" + mkdir -- "$DESTDIR/cryptroot" + true >"$DESTDIR/cryptroot/targets" + + { + if devnos="$(get_mnt_devno /)"; then + usage=rootfs get_cryptdevs $devnos + else + cryptsetup_message "WARNING: Couldn't determine root device" + fi + + if devnos="$(get_resume_devno)"; then + usage=resume get_cryptdevs $devnos + fi + + if devnos="$(get_mnt_devno /usr)"; then + usage="" get_cryptdevs $devnos + fi + + # add crypttab entries with the 'initramfs' option set + crypttab_foreach_entry crypttab_print_initramfs_entry + } 3>"$DESTDIR/cryptroot/crypttab" + rm -f "$DESTDIR/cryptroot/targets" +} + +# populate_CRYPTO_MODULES() +# Find out which crypto modules are required for a crypttab(5) entry, +# and append them to the CRYPTO_MODULES variable. +populate_CRYPTO_MODULES() { + local cipher iv + + # cf. dmsetup(8) and https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt + cipher="$(dmsetup table --target crypt -- "$CRYPTTAB_NAME" | cut -d' ' -f4)" + if [ -z "$cipher" ]; then + cryptsetup_message "WARNING: Couldn't determine cipher modules to load for $CRYPTTAB_NAME" + elif [ "${cipher#capi:}" = "$cipher" ]; then + # direct specification "cipher[:keycount]-chainmode-ivmode[:ivopts]" + CRYPTO_MODULES="${CRYPTO_MODULES:+$CRYPTO_MODULES }${cipher%%[-:]*}" # cipher + cipher="${cipher#"${cipher%%-*}-"}" # chainmode-ivmode[:ivopts]" + CRYPTO_MODULES="${CRYPTO_MODULES:+$CRYPTO_MODULES }${cipher%-*}" # chainmode + iv="${cipher##*-}" # ivmode[:ivopts]" + if [ "${iv#*:}" != "$iv" ]; then + CRYPTO_MODULES="${CRYPTO_MODULES:+$CRYPTO_MODULES }${iv#*:}" # ivopts + fi + else + # kernel crypto API format "capi:cipher_api_spec-ivmode[:ivopts]", since linux 4.12 + cipher="${cipher#capi:}" + cryptsetup_message "WARNING: Couldn't determine cipher modules to load for $CRYPTTAB_NAME" \ + "(kernel crypto API format isn't supported yet)" + fi +} + +# add_modules($glob, $moduledir, [$moduledir ..]) +# Add modules matching under the given $moduledir(s), the name of +# which matching $glob. +# Return 0 if any module was found found, 1 if not. +add_modules() { + local glob="$1" found=n + shift + for mod in $(find -H "$@" -name "$glob.ko" -type f -printf '%f\n'); do + manual_add_modules "${mod%.ko}" + found=y + done + [ "$found" = y ] && return 0 || return 1 +} + +# add_crypto_modules($name, [$name ..]) +# Determine kernel module name and add to initramfs. +add_crypto_modules() { + local mod + for mod in "$@"; do + # We have several potential sources of modules (in order of preference): + # + # a) /lib/modules/$VERSION/kernel/arch/$ARCH/crypto/$mod-$specific.ko + # b) /lib/modules/$VERSION/kernel/crypto/$mod_generic.ko + # c) /lib/modules/$VERSION/kernel/crypto/$mod.ko + # + # and (currently ignored): + # + # d) /lib/modules/$VERSION/kernel/drivers/crypto/$specific-$mod.ko + add_modules "$mod-*" "$MODULESDIR"/kernel/arch/*/crypto || true + add_modules "${mod}_generic" "$MODULESDIR/kernel/crypto" \ + || add_modules "$mod" "$MODULESDIR/kernel/crypto" \ + || true + done +} + + +####################################################################### +# Begin real processing + +unset -v CRYPTSETUP KEYFILE_PATTERN +KEYFILE_PATTERN= + +# Load the hook config +if [ -f "/etc/cryptsetup-initramfs/conf-hook" ]; then + . /etc/cryptsetup-initramfs/conf-hook +fi + +if [ "${CRYPTSETUP-}" = "n" ] || [ "${CRYPTSETUP-}" = "N" ]; then + # XXX post-Buster: remove this warning and the auto-detection logic below + cryptsetup_message "WARNING: Honoring CRYPTSETUP=\"n\" will deprecated in the future." \ + "Please uninstall the 'cryptsetup-initramfs' package instead" \ + "if you don't want the cryptsetup initramfs integration." + exit 0 +fi + +if [ -n "$KEYFILE_PATTERN" ]; then + case "${UMASK:-$(umask)}" in + 0[0-7]77) ;; + *) cryptsetup_message "WARNING: Permissive UMASK (${UMASK:-$(umask)})." \ + "Private key material within the initrd might be left unprotected." + ;; + esac +fi + +CRYPTO_MODULES= +if [ -r "$TABFILE" ]; then + generate_initrd_crypttab + TABFILE="$DESTDIR/cryptroot/crypttab" + crypttab_foreach_entry populate_CRYPTO_MODULES +fi + +# per comment in the config file a non-empty KEYFILE_PATTERN value +# implies CRYPTSETUP=y +if [ -z "${CRYPTSETUP-}" ] && [ -z "${KEYFILE_PATTERN-}" ] && [ -z "$CRYPTO_MODULES" ]; then + cryptsetup_message "WARNING: The initramfs image may not contain cryptsetup binaries nor crypto modules." \ + "If that's on purpose, you may want to uninstall the 'cryptsetup-initramfs' package in" \ + "order to disable the cryptsetup initramfs integration and avoid this warning." +else + # add required components + manual_add_modules dm_mod + manual_add_modules dm_crypt + + copy_exec /sbin/cryptsetup + copy_exec /sbin/dmsetup + copy_exec /lib/cryptsetup/askpass + + # libargon2 uses pthread_cancel + LIBC_DIR="$(ldd /sbin/cryptsetup | sed -nr 's#.* => (/lib.*)/libc\.so\.[0-9.-]+ \(0x[[:xdigit:]]+\)$#\1#p')" + find -L "$LIBC_DIR" -maxdepth 1 -name 'libgcc_s.*' -type f | while read so; do + copy_exec "$so" + done + + # We need sed. Either via busybox or as standalone binary. + if [ "$BUSYBOX" = n ] || [ ! -e "$BUSYBOXDIR/busybox" ]; then + copy_exec /bin/sed + fi + + # detect whether the host CPU has AES-NI support + if grep -Eq '^flags\s*:(.*\s)?aes(\s.*)?$' /proc/cpuinfo; then + CRYPTO_MODULES="${CRYPTO_MODULES:+$CRYPTO_MODULES }aesni" + fi + + # add userspace crypto module (only required for opening LUKS2 devices + # we add the module unconditionally as it's the default format) + CRYPTO_MODULES="${CRYPTO_MODULES:+$CRYPTO_MODULES }algif_skcipher" + + if [ "$MODULES" = most ]; then + for d in "$MODULESDIR"/kernel/arch/*/crypto; do + copy_modules_dir "${d#"$MODULESDIR/"}" + done + copy_modules_dir "kernel/crypto" + else + if [ "$MODULES" != "dep" ]; then + # with large initramfs, we always add a basic subset of modules + add_crypto_modules aes cbc chainiv cryptomgr krng sha256 xts + fi + add_crypto_modules $(printf '%s' "${CRYPTO_MODULES-}" | tr ' ' '\n' | sort -u) + fi + copy_file library /lib/cryptsetup/functions /lib/cryptsetup/functions +fi |