When do TPM slots fail to unlock partitions and how to correctly update them?

I recently installed Ubuntu on an old SSD, as I wanted to test out some software on a different OS. After installing Ubuntu (using debootstrap, arch-chroot and apt), my EFI's NVRAM boot order got messed up, and the TPM2 will not now automatically unlock my Arch root and swap partitions. I am prompted to enter a recovery key or password. So, I know I need to update the PCR registers in the TPM. But I have a couple of questions: - How should I replace the entries in the old TPM2 PCR slots, instead of adding new ones? - Can someone explain why the TPM chip now fails to unlock my partitions, and what I should try and avoid doing again in future? My primary OS is Arch Linux, set up following a couple of articles: - [LUKS on a partition with TPM2 and Secure Boot](https://wiki.archlinux.org/title/Dm-crypt/Encrypting_an_entire_system#LUKS_on_a_partition_with_TPM2_and_Secure_Boot) . - [Installing Archlinux with LUKS, SecureBoot, TPM](https://jpetazzo.github.io/2024/02/23/archlinux-luks-tpm-secureboot-install/) systemd-boot is used as bootloader. Two dm-crypt partitions are unlocked with the TPM at boot: - root - swap (allows for suspend and resume). After installing Ubuntu, both the root and swap volumes would not unlock with the TPM. ---- # How to invalidate the TPM PCR Registers # One thing I realised that I'd done incorrectly done was to install Ubuntu (into /media/ubuntu) before mounting /efi onto /media/ubuntu/boot/efi. So, after first installing Ubuntu with debootstrap, I then ran: - mount --bind /efi /media/ubuntu/boot/efi - arch-chroot /media/ubuntu - apt install grub-efi-amd64 (This removes grub-pc) - grub-install So, I now have one /efi partition, an encrypted /boot partition for Arch Linux, and the Ubuntu partition has a /boot folder. (There's a Windows bootloader too, so yeah, it's a mess...) grub's os-probe doesn't detect my Arch Linux install, so I had to get back in by pressing F11 at early boot and selecting Linux Boot Manager. At this point, systemd asks me to enter the unlock password or recovery key for my root partition. (I have both currently, so getting in isn't an issue, unless and until I reboot remotely). # My setup # _I've put down quite a lengthy list of diagnostic commands, which should be pretty helpful for anyone diagnosing something similar in future (me included, no doubt!)_ **Update:** The TPM was enrolled to unlock the encrypted partition on PCR 7, like so:

# Install the TPM tools
pacman -S tpm2-tools

# Check the name of the kernel module for our TPM
systemd-cryptenroll --tpm2-device=list

# Generate a recovery key (not mandatory but strongly recommended)
systemd-cryptenroll --recovery-key /dev/gpt-auto-root-luks

# Generate a key in the TPM2 and add it to a key slot in the LUKS device
systemd-cryptenroll --tpm2-device=auto /dev/gpt-auto-root-luks --tpm2-pcrs=7

# This is the command to use later, to remove the (insecure) initial password
#systemd-cryptenroll /dev/gpt-auto-root-luks --wipe-slot=password

My partition tables are quite busy:

$ lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINTS
sdb           8:16   0 238.5G  0 disk  
├─sdb1        8:17   0   128G  0 part  /media/ubuntu
├─sdb2        8:18   0   110G  0 part  
└─sdb3        8:19   0   527M  0 part  
nvme0n1     259:0    0 931.5G  0 disk  
├─nvme0n1p1 259:1    0   100M  0 part  
├─nvme0n1p2 259:2    0    16M  0 part  
├─nvme0n1p3 259:3    0 165.4G  0 part  
├─nvme0n1p4 259:4    0   507M  0 part  
├─nvme0n1p5 259:5    0     1G  0 part  
├─nvme0n1p6 259:6    0    32G  0 part  
│ └─swap    254:1    0    32G  0 crypt [SWAP]
├─nvme0n1p7 259:7    0   227G  0 part  
│ └─root    254:0    0   227G  0 crypt /
└─nvme0n1p8 259:8    0 505.5G  0 part  
  └─data    254:3    0 505.5G  0 crypt /var/lib/docker
                                       /media/data

$ sudo fdisk -l /dev/nvme0n1 /dev/sdb
Disk /dev/nvme0n1: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: Samsung SSD 980 PRO 1TB                 
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt

Device             Start        End    Sectors   Size Type
/dev/nvme0n1p1      2048     206847     204800   100M EFI System (/efi)
/dev/nvme0n1p2    206848     239615      32768    16M Microsoft reserved
/dev/nvme0n1p3    239616  347119443  346879828 165.4G Microsoft basic data (Win 10)
/dev/nvme0n1p4 347119616  348157951    1038336   507M Windows recovery environment
/dev/nvme0n1p5 348157952  350255103    2097152     1G Linux extended boot (/boot)
/dev/nvme0n1p6 350255104  417363967   67108864    32G Linux swap
/dev/nvme0n1p7 417363968  893417471  476053504   227G Linux root (x86-64) (/)
/dev/nvme0n1p8 893417472 1953523711 1060106240 505.5G Linux filesystem (/media/data)

Disk /dev/sdb: 238.47 GiB, 256060514304 bytes, 500118192 sectors
Disk model: M4-CT256M4SSD2  
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos

Device     Boot     Start       End   Sectors  Size Id Type
/dev/sdb1            2048 268437503 268435456  128G 83 Linux (/media/ubuntu)
/dev/sdb2  *    268437504 499035680 230598177  110G  7 HPFS/NTFS/exFAT
/dev/sdb3       499036160 500115455   1079296  527M 27 Hidden NTFS WinRE

Secure Boot is installed, but not enabled:

$ sbctl status
Installed:	✓ sbctl is installed
Owner GUID:	1fd4cb4a-55ff-42f6-8dbb-285bfedf56de
Setup Mode:	✓ Disabled
Secure Boot:	✗ Disabled
Vendor Keys:	microsoft

My boot logs showing kernel command line and TPM related entries (showing it's loaded early):

$ sudo journalctl -k --grep='Command line|tpm|TPM'
Aug 30 06:10:03 archlinux kernel: Command line: initcall_blacklist=acpi_cpufreq_init amd_pstate=passive nvidia_drm.modeset=1 nvidia_drm.fbdev=1 ip=:::::eth0:dhcp
Aug 30 06:10:03 archlinux kernel: efi: ACPI=0xbd440000 ACPI 2.0=0xbd440014 TPMFinalLog=0xbd40a000 SMBIOS=0xbde22000 SMBIOS 3.0=0xbde21000 MEMATTR=0xb7f14018 ESRT=0xb7f14898 RNG=0xbcd38f18 INITRD=0xb6d12f18 TPMEvent>
Aug 30 06:10:03 archlinux kernel: ACPI: TPM2 0x00000000BCD50000 00004C (v04 ALASKA A M I    00000001 AMI  00000000)
Aug 30 06:10:03 archlinux kernel: ACPI: Reserving TPM2 table memory at [mem 0xbcd50000-0xbcd5004b]
Aug 30 06:10:03 archlinux kernel: tpm_crb MSFT0101:00: Disabling hwrng
Aug 30 06:10:03 archlinux systemd: systemd 256.5-1-arch running in system mode (+PAM +AUDIT -SELINUX -APPARMOR -IMA +SMACK +SECCOMP +GCRYPT +GNUTLS +OPENSSL +ACL +BLKID +CURL +ELFUTILS +FIDO2 +IDN2 -IDN +IPTC +K>
Aug 30 06:10:03 archlinux systemd: Starting TPM PCR Barrier (initrd)...
Aug 30 06:13:19 ryzenbeast systemd: systemd 256.5-1-arch running in system mode (+PAM +AUDIT -SELINUX -APPARMOR -IMA +SMACK +SECCOMP +GCRYPT +GNUTLS +OPENSSL +ACL +BLKID +CURL +ELFUTILS +FIDO2 +IDN2 -IDN +IPTC +>
Aug 30 06:13:19 ryzenbeast systemd: Expecting device /dev/tpm0...
Aug 30 06:13:19 ryzenbeast systemd: Listening on TPM PCR Measurements.
Aug 30 06:13:19 ryzenbeast systemd: Listening on Make TPM PCR Policy.
Aug 30 06:13:19 ryzenbeast systemd: Starting TPM PCR Machine ID Measurement...
Aug 30 06:13:19 ryzenbeast systemd: Starting Early TPM SRK Setup...

Kernel Modules and Hooks:

# mkinitcpio.conf
MODULES=(nvidia nvidia_modeset nvidia_uvm nvidia_drm)
HOOKS=(base systemd autodetect microcode modconf keyboard keymap consolefont sd-vconsole block sd-tinyssh encryptssh sd-encrypt filesystems resume fsck)

LUKS header key slots:

$ sudo systemd-cryptenroll /dev/disk/by-partlabel/archlinux
SLOT TYPE    
   0 password
   1 recovery
   2 tpm2
$ sudo systemd-cryptenroll /dev/disk/by-partlabel/swap
SLOT TYPE    
   0 password
   1 tpm2

Signed files:

$ sbctl verify
Verifying file database and EFI images in /efi...
✓ /boot/EFI/Linux/arch-linux-fallback.efi is signed
✓ /boot/EFI/Linux/arch-linux.efi is signed
✗ /efi/EFI/Boot/bootx64.efi is not signed (this became signed after running bootctl install)
✓ /efi/EFI/systemd/systemd-bootx64.efi is signed
✓ /usr/lib/systemd/boot/efi/systemd-bootx64.efi.signed is signed
✗ /efi/EFI/GRUB/grubx64.efi is not signed
✗ /efi/EFI/Manjaro/grubx64.efi is not signed
✗ /efi/EFI/Microsoft/Boot/Resources/bootres.dll is not signed
✗ /efi/EFI/Microsoft/Boot/Resources/en-US/bootres.dll.mui is not signed
✗ /efi/EFI/Microsoft/Boot/bg-BG/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/bg-BG/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/bootmgfw.efi is not signed
✗ /efi/EFI/Microsoft/Boot/bootmgr.efi is not signed
✗ /efi/EFI/Microsoft/Boot/cs-CZ/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/cs-CZ/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/cs-CZ/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/da-DK/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/da-DK/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/da-DK/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/de-DE/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/de-DE/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/de-DE/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/el-GR/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/el-GR/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/el-GR/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/en-GB/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/en-GB/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/en-US/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/en-US/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/en-US/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/es-ES/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/es-ES/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/es-ES/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/es-MX/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/es-MX/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/et-EE/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/et-EE/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/fi-FI/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/fi-FI/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/fi-FI/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/fr-CA/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/fr-CA/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/fr-FR/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/fr-FR/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/fr-FR/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/hr-HR/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/hr-HR/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/hu-HU/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/hu-HU/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/hu-HU/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/it-IT/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/it-IT/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/it-IT/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/ja-JP/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/ja-JP/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/ja-JP/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/kd_02_10df.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kd_02_10ec.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kd_02_1137.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kd_02_14e4.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kd_02_15b3.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kd_02_1969.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kd_02_19a2.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kd_02_1af4.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kd_02_8086.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kd_07_1415.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kd_0C_8086.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kdnet_uart16550.dll is not signed
✗ /efi/EFI/Microsoft/Boot/kdstub.dll is not signed
✗ /efi/EFI/Microsoft/Boot/ko-KR/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/ko-KR/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/ko-KR/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/lt-LT/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/lt-LT/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/lv-LV/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/lv-LV/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/memtest.efi is not signed
✗ /efi/EFI/Microsoft/Boot/nb-NO/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/nb-NO/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/nb-NO/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/nl-NL/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/nl-NL/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/nl-NL/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/pl-PL/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/pl-PL/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/pl-PL/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/pt-BR/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/pt-BR/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/pt-BR/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/pt-PT/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/pt-PT/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/pt-PT/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/qps-ploc/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/ro-RO/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/ro-RO/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/ru-RU/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/ru-RU/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/ru-RU/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/sk-SK/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/sk-SK/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/sl-SI/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/sl-SI/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/sr-Latn-RS/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/sr-Latn-RS/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/sv-SE/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/sv-SE/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/sv-SE/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/tr-TR/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/tr-TR/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/tr-TR/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/uk-UA/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/uk-UA/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/zh-CN/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/zh-CN/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/zh-CN/memtest.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/zh-TW/bootmgfw.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/zh-TW/bootmgr.efi.mui is not signed
✗ /efi/EFI/Microsoft/Boot/zh-TW/memtest.efi.mui is not signed
✗ /efi/EFI/ubuntu/grubx64.efi is not signed

Systemd measurements

$ sudo /usr/lib/systemd/systemd-measure status
# PCR kernel-boot
11:sha1=
11:sha256=
# PCR kernel-config (NOT SET!)
12:sha1=0000000000000000000000000000000000000000
12:sha256=0000000000000000000000000000000000000000000000000000000000000000
# PCR sysexts (NOT SET!)
13:sha1=0000000000000000000000000000000000000000
13:sha256=0000000000000000000000000000000000000000000000000000000000000000

$ sudo /usr/lib/systemd/systemd-measure calculate --current --bank=sha1 --bank=sha256
# PCR Phase 
11:sha1=
11:sha256=
# PCR Phase 
11:sha1=
11:sha256=
# PCR Phase 
11:sha1=
11:sha256=
# PCR Phase 
11:sha1=
11:sha256=

Test opening the root partition with TPM

$ sudo cryptsetup open --test-passphrase /dev/nvme0n1p7
Failed to unseal secret using TPM2: Operation not permitted
Enter passphrase for /dev/nvme0n1p7:

Current PCR slots

$ systemd-analyze pcrs
NR NAME                SHA256                                                          
 0 platform-code       
 1 platform-config     
 2 external-code       
 3 external-config     
 4 boot-loader-code    
 5 boot-loader-config  
 6 host-platform       
 7 secure-boot-policy  
 8 -                   0000000000000000000000000000000000000000000000000000000000000000
 9 kernel-initrd       
10 ima                 0000000000000000000000000000000000000000000000000000000000000000
11 kernel-boot         
12 kernel-config       0000000000000000000000000000000000000000000000000000000000000000
13 sysexts             0000000000000000000000000000000000000000000000000000000000000000
14 shim-policy         0000000000000000000000000000000000000000000000000000000000000000
15 system-identity     
16 debug               0000000000000000000000000000000000000000000000000000000000000000
17 -                   ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
18 -                   ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
19 -                   ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
20 -                   ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
21 -                   ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
22 -                   ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
23 application-support 0000000000000000000000000000000000000000000000000000000000000000

# Adding a new TPM entry # I know I can add a new TPM entry and delete the old one with the following command:

# Enroll TPM (again).
$ sudo systemd-cryptenroll --tpm2-device=auto /dev/nvme0n1p7`
🔐 Please enter current passphrase for disk /dev/nvme0n1p7:
New TPM2 token enrolled as key slot 3.

# List LUKS unlock slots on my root partition.
$ sudo systemd-cryptenroll /dev/nvme0n1p7 
SLOT TYPE    
   0 password
   1 recovery
   2 tpm2
   3 tpm2

# Wipe the old tpm2 entry
$ sudo systemd-cryptenroll /dev/nvme0n1p7 --wipe-slot=2
Wiped slot 2.

# Test I can open it
$ sudo cryptsetup open --test-passphrase /dev/nvme0n1p7
$

# Update: System Journal Entries # I checked journalctl -u systemd-cryptsetup@root to see if I can hunt down some more info before and after the first failed boot. On a successful boot:

Aug 27 09:46:02 archlinux systemd: Starting Cryptography Setup for root...
Aug 27 09:46:02 archlinux systemd-cryptsetup: Set cipher aes, mode xts-plain64, key size 512 bits for device /dev/gpt-auto-root-luks.
Aug 27 09:46:02 archlinux systemd-cryptsetup: Automatically discovered security TPM2 token unlocks volume.
Aug 27 09:46:04 archlinux systemd-cryptsetup: Successfully extended PCR index 15 with 'cryptsetup:root:' and volume key (banks sha1, sha256).
Aug 27 09:46:04 archlinux systemd: Finished Cryptography Setup for root.

On the next, failed boot:

Aug 28 08:09:52 archlinux systemd: Starting Cryptography Setup for root...
Aug 28 08:09:52 archlinux systemd-cryptsetup: Set cipher aes, mode xts-plain64, key size 512 bits for device /dev/gpt-auto-root-luks.
Aug 28 08:09:52 archlinux systemd-cryptsetup: Automatically discovered security TPM2 token unlocks volume.
Aug 28 08:09:53 archlinux systemd-cryptsetup: Failed to unseal secret using TPM2: Operation not permitted
Aug 28 08:09:53 archlinux systemd-cryptsetup: No valid TPM2 token data found.
Aug 28 08:09:53 archlinux systemd-cryptsetup: No TPM2 metadata matching the current system state found in LUKS2 header, falling back to traditional unlocking.
Aug 28 08:10:21 archlinux systemd-cryptsetup: Set cipher aes, mode xts-plain64, key size 512 bits for device /dev/gpt-auto-root-luks.
Aug 28 08:10:24 archlinux systemd-cryptsetup: Failed to activate with specified passphrase. (Passphrase incorrect?)
Aug 28 08:10:30 archlinux systemd-cryptsetup: Set cipher aes, mode xts-plain64, key size 512 bits for device /dev/gpt-auto-root-luks.
Aug 28 08:10:33 archlinux systemd-cryptsetup: Successfully extended PCR index 15 with 'cryptsetup:root:' and volume key (banks sha1, sha256).
Aug 28 08:10:33 archlinux systemd: Finished Cryptography Setup for root.

Seeing mention of PCR15 here, explained in man systemd-cryptenroll as: > systemd-cryptsetup(8) optionally measures the volume key of activated > LUKS volumes into this PCR. systemd-pcrmachine.service(8) measures > the machine-id(5) into this PCR. systemd-pcrfs@.service(8) measures > mount points, file system UUIDs, labels, partition UUIDs of the > root and /var/ filesystems into this PCR. It would appear that these measurements would have changed by (re-)formatting a partition and would be enough to corrupt this PCR register... # Overhanging Questions # Now I've looked into fixing this and effectively have done, I have questions! - What caused the TPM slot value to become incorrect? - If I update Ubuntu's kernel or initrd, will it happen again? - How to prevent this from happening again? - I see systemd introduced a [pcrlock tool](https://www.freedesktop.org/software/systemd/man/latest/systemd-pcrlock.html) in [November 2023](https://github.com/systemd/systemd/pull/28891) , but (I think) it is still experimental and I don't fully understand it, nor do I know if it would help. Would it? - **Update:** How should I update PCR 15 after formatting a partition?