我正试图销毁我的一个逻辑卷data1上的luks标头，在删除luks标头后，我仍然能够读取data1中的文件。我想情况不应该是这样吧？有人能帮我理解这个案子吗
lsblk输出
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 894.2G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 893.8G 0 part
├─vg0-root 251:0 0 758.7G 0 lvm
│ └─luks-45f803e5-3c17-4aaf-a9ad-d66c8b5458de 251:2 0 758.7G 0 crypt /
├─vg0-swap 251:1 0 75G 0 lvm [SWAP]
├─vg0-data3 251:3 0 20G 0 lvm
│ └─luks-6e168d35-26dc-429c-a3d6-8cb4f1c1d39e 251:7 0 20G 0 crypt /data3
├─vg0-data2 251:4 0 20G 0 lvm
│ └─luks-75727dd1-a332-423d-8c37-4cedf9cbe83c 251:8 0 20G 0 crypt /data2
└─vg0-data1 251:5 0 20G 0 lvm
└─luks-cf2d9729-2d1b-48b8-8502-dea937ef602f 251:6 0 20G 0 crypt /data1
Luksdump输出以检查luks标头是否存在：
-130-sapam@test-host:~ $ sudo cryptsetup luksDump /dev/mapper/vg0-data1
LUKS header information for /dev/mapper/vg0-data1
Version: 1
Cipher name: aes
Cipher mode: xts-plain64
Hash spec: sha256
Payload offset: 4096
MK bits: 256
MK digest: 9f e7 1a b3 0e fb 4e bc 6d 1b 9e 46 f8 bd 15 22 ea 04 6e c3
MK salt: 83 5e 90 5b b3 a1 c5 a5 d4 22 a0 3e 23 25 51 50
fc cd a8 ac db 9f d0 a8 8b 81 6e 9a 92 1f d8 d3
MK iterations: 43750
UUID: cf2d9729-2d1b-48b8-8502-dea937ef602f
Key Slot 0: ENABLED
Iterations: 439102
Salt: f1 6d 23 b0 b7 ee fc 09 8c 6b 92 ef b2 17 ef d9
0c 83 64 29 bf bc 98 3f f6 93 4b 45 06 49 a9 21
Key material offset: 8
AF stripes: 4000
Key Slot 1: DISABLED
Key Slot 2: DISABLED
Key Slot 3: DISABLED
Key Slot 4: DISABLED
Key Slot 5: DISABLED
Key Slot 6: DISABLED
Key Slot 7: DISABLED
摧毁卢克的头部：
-130-sapam@test-host:~ $ sudo dd bs=512 count=4096 if=/dev/zero of=/dev/mapper/vg0-data1
4096+0 records in
4096+0 records out
2097152 bytes (2.1 MB) copied, 0.00444235 s, 472 MB/s
-0-sapam@test-host:~ $ sudo cryptsetup luksDump /dev/mapper/vg0-data1
-1-sapam@test-host:~ $
我仍然能够读取/data1中的文件/
-1-sapam@test-host:~ $ cat /data1/foo
james
-0-sapam@test-host:~ $
根据我的理解，一旦标头被破坏，/data1应该就不能读取了，对吗？
您似乎正在破坏已经挂载的分区。
安装分区时，加密/解密密钥保存在内存中。你应该先卸载你的LUKS分区：
# umount /data1
然后擦除LUKS报头。您将无法再次安装它。
请注意，cryptsetup实用程序有一个擦除LUKS标头的命令：
# cryptsetup luksErase /dev/mapper/vg0-data1
此操作的优点是，如果以前进行过备份，则可以从备份中恢复LUKS标头。
来自cryptsetup(8):
erase <device>
luksErase <device>
Erase all keyslots and make the LUKS container permanently inac‐
cessible. You do not need to provide any password for this op‐
eration.
WARNING: This operation is irreversible.
虽然luksErase擦除keyslots区域很好，但请注意，它实际上并没有破坏整个LUKS Header。它使元数据保持不变。
我提交了一个功能请求，要求luksErase命令也能够擦除头部中的明文元数据，但开发人员拒绝了&关闭它：(
LUKS收割台碎纸机
您可以使用以下BASH脚本查找系统上的每个LUKS设备，擦除标头，然后关闭机器。
免责声明下面的脚本包含实验性软件，这些软件可能会也可能不会导致损坏或完全永久删除您的部分或全部数据。我对因遵循本指南而导致的任何数据丢失概不负责。
本答案的内容是公开提供的，并根据CC-BY-SA许可证获得许可。本指南中包含的软件是根据GNU GPLv3许可证获得许可的。此处的所有内容都符合其各自许可证中列出的责任限制。
我强烈建议，使用本答案中包含的脚本进行的任何实验都只能在不包含有价值数据的一次性机器上使用。
如果您担心数据丢失，请立即离开，不要继续。您已收到警告。
#!/bin/bash
#set -x
################################################################################
# File: buskill-selfdestruct.sh
# Purpose: Self-destruct trigger script for BusKill Kill Cord
# For more info, see: https://buskill.in/
# WARNING: THIS IS EXPERIMENTAL SOFTWARE THAT IS DESIGNED TO CAUSE PERMANENT,
# COMPLETE AND IRREVERSIBLE DATA LOSS!
# Note : This script will *not* execute unless it's passed the '--yes'
# argument. Be sure to test this trigger before depending on it!
# Authors: Michael Altfield <michael@buskill.in>
# Created: 2020-03-11
# Updated: 2020-03-11
# Version: 0.1
################################################################################
############
# SETTINGS #
############
BUSKILL_LOCK='/usr/local/bin/buskill-lock.sh'
[ -f ${BUSKILL_LOCK} ] || echo "ERROR: Unable to find buskill-lock.sh"
CRYPTSETUP=`which cryptsetup` || echo "ERROR: Unable to find cryptsetup"
LS=`which ls` || echo "ERROR: Unable to find ls"
CAT=`which cat` || echo "ERROR: Unable to find cat"
GREP=`which grep` || echo "ERROR: Unable to find grep"
ECHO=`which echo` || echo "ERROR: Unable to find echo"
AWK=`which awk` || echo "ERROR: Unable to find awk"
HEAD=`which head` || echo "ERROR: Unable to find head"
LSBLK=`which lsblk` || echo "ERROR: Unable to find lsblk"
OD=`which od` || echo "ERROR: Unable to find od"
##############
# ROOT CHECK #
##############
# re-run as root
if [[ $EUID -ne 0 ]]; then
exec sudo /bin/bash "$0" "$@"
fi
###########
# CONFIRM #
###########
# for safety, exit if this script is executed without a '--yes' argument
${ECHO} "${@}" | ${GREP} '--yes' &> /dev/null
if [ $? -ne 0 ]; then
${ECHO} "WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING"
${ECHO} "================================================================================"
${ECHO} "WARNING: THIS IS EXPERIMENTAL SOFTWARE THAT IS DESIGNED TO CAUSE PERMANENT, COMPLETE AND IRREVERSIBLE DATA LOSS!"
${ECHO} "================================================================================"
${ECHO} "WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING"
${ECHO}
${ECHO} "cowardly refusing to execute without the '--yes' argument for your protection. If really you want to proceed with damaging your system, retry with the '--yes' argument"
exit 1
fi
###########################
# (DELAYED) HARD SHUTDOWN #
###########################
# The most secure encrypted computer is an encrypted computer that is *off*
# This is our highest priority; initiate a hard-shutdown to occur in 5 minutes regardless
# of what happens later in this script
nohup sleep 60 && echo o > /proc/sysrq-trigger &
nohup sleep 61 && shutdown -h now &
nohup sleep 62 && poweroff --force --no-sync &
###############
# LOCK SCREEN #
###############
# first action: lock the screen!
${BUSKILL_LOCK} &
#####################
# WIPE LUKS VOLUMES #
#####################
# overwrite luks headers
${ECHO} "INFO: shredding LUKS header (plaintext metadata and keyslots with encrypted master decryption key)"
writes=''
IFS=$'n'
for line in $( ${LSBLK} --list --output 'PATH,FSTYPE' | ${GREP} 'crypt' ); do
device="`${ECHO} "${line}" | ${AWK} '{print $1}'`"
${ECHO} -e "t${device}"
###########################
# OVERWRITE LUKS KEYSLOTS #
###########################
# erases all keyslots, making the LUKS container "permanently inaccessible"
${CRYPTSETUP} luksErase --batch-mode "${device}" || ${HEAD} --bytes 20M /dev/urandom > ${device} &
# store the pid of the above write tasks so we can try to wait for it to
# flush to disk later -- before triggering a brutal hard-shutdown
writes="${writes} $!"
#####################################
# OVERWRITE LUKS PLAINTEXT METADATA #
#####################################
luksVersion=`${OD} --skip-bytes 6 --read-bytes 2 --format d2 --endian=big --address-radix "n" "${device}"`
# get the end byte to overwrite. For more info, see:
# https://security.stackexchange.com/questions/227359/how-to-determine-start-and-end-bytes-of-luks-header
if [[ $luksVersion -eq 1 ]]; then
# LUKS1: https://gitlab.com/cryptsetup/cryptsetup/-/wikis/LUKS-standard/on-disk-format.pdf
# in LUKS1, the whole header ends at 512 * the `payload-offset`
# this is actually more than we need (includes keyslots), but
# it's the fastest/easiest to bound to fetch in LUKS1
payloadOffset=`${OD} --skip-bytes 104 --read-bytes 4 --format d4 --endian=big --address-radix "n" "${device}"`
luksEndByte=$(( 512 * ${payloadOffset} ))
elif [[ $luksVersion -eq 2 ]]; then
# LUKS2: https://gitlab.com/cryptsetup/LUKS2-docs/blob/master/luks2_doc_wip.pdf
# in LUKS2, the end of the plaintext metadata area is twice the
# size of the `hdr_size` field
hdr_size=`${OD} --skip-bytes 8 --read-bytes 8 --format d8 --endian=big --address-radix "n" "${device}"`
luksEndByte=$(( 2 * ${hdr_size} ))
else
# version unclear; just overwrite 20 MiB
luksEndByte=20971520
fi
# finally, shred that plaintext metadata; we do this in a new file descriptor
# to prevent bash from truncating if ${device} is a file
exec 5<> "${device}"
${HEAD} --bytes "${luksEndByte}" /dev/urandom >&5 &
writes="${writes} $!"
exec 5>&-
done
#######################
# WAIT ON DISK WRITES #
#######################
# wait until all the write tasks above have completed
# note: do *not* put quotes around this arg or the whitespace will break wait
wait ${writes}
# clear write buffer to ensure headers overwrites are actually synced to disks
sync; echo 3 > /proc/sys/vm/drop_caches
#################################
# WIPE DECRYPTION KEYS FROM RAM #
#################################
# suspend each currently-decrypted LUKS volume
${ECHO} "INFO: removing decryption keys from memory"
for device in $( ${LS} -1 "/dev/mapper" ); do
${ECHO} -e "t${device}";
${CRYPTSETUP} luksSuspend "${device}" &
# clear page caches in memory (again)
sync; echo 3 > /proc/sys/vm/drop_caches
done
#############################
# (IMMEDIATE) HARD SHUTDOWN #
#############################
# do whatever works; this is important.
echo o > /proc/sysrq-trigger &
sleep 1
shutdown -h now &
sleep 1
poweroff --force --no-sync &
# exit cleanly (lol)
exit 0
来源
- LUKS头部碎纸机(BusKill自毁触发器(
- https://github.com/BusKill/buskill-linux/blob/master/triggers/buskill-selfdestruct.sh