systemd systemd-measure 1 systemd-measure Pre-calculate expected TPM2 PCR values for booted unified kernel images /usr/lib/systemd/systemd-measure OPTIONS Note: this command is experimental for now. While it is likely to become a regular component of systemd, it might still change in behaviour and interface. systemd-measure is a tool that may be used to pre-calculate the expected TPM2 PCR 11 values that should be seen when a unified Linux kernel image based on systemd-stub7 is booted up. It accepts paths to the ELF kernel image file, initial ram disk image file, devicetree file, kernel command line file, os-release5 file, and boot splash file that make up the unified kernel image, and determines the PCR values expected to be in place after booting the image. Calculation starts with a zero-initialized PCR 11, and is executed in a fashion compatible with what systemd-stub does at boot. The following commands are understood: status This is the default command if none is specified. This queries the local system's TPM2 PCR 11+12+13 values and displays them. The data is written in a similar format as the calculate command below, and may be used to quickly compare expectation with reality. calculate Pre-calculate the expected value seen in PCR register 11 after boot-up of a unified kernel image consisting of the components specified with --linux=, --osrel=, --cmdline=, --initrd=, --splash=, --dtb=, see below. Only --linux= is mandatory. The following options are understood: --linux=PATH --osrel=PATH --cmdline=PATH --initrd=PATH --splash=PATH --dtb=PATH When used with the calculate verb, configures the files to read the unified kernel image components from. Each option corresponds with the equally named section in the unified kernel PE file. The --linux= switch expects the path to the ELF kernel file that the unified PE kernel will wrap. All switches except --linux= are optional. Each option may be used at most once. --current When used with the calculate verb, takes the PCR 11 values currently in effect for the system (which should typically reflect the hashes of the currently booted kernel). This can be used in place of --linux= and the other switches listed above. --bank=DIGEST Controls the PCR banks to pre-calculate the PCR values for – in case calculate is invoked –, or the banks to show in the status output. May be used more then once to specify multiple banks. If not specified, defaults to the four banks sha1, sha256, sha384, sha512. # objcopy \ --add-section .linux=vmlinux --change-section-vma .linux=0x2000000 \ --add-section .osrel=os-release.txt --change-section-vma .osrel=0x20000 \ --add-section .cmdline=cmdline.txt --change-section-vma .cmdline=0x30000 \ --add-section .initrd=initrd.cpio --change-section-vma .initrd=0x3000000 \ --add-section .splash=splash.bmp --change-section-vma .splash=0x100000 \ --add-section .dtb=devicetree.dtb --change-section-vma .dtb=0x40000 \ /usr/lib/systemd/boot/efi/linuxx64.efi.stub \ foo.efi # systemd-measure calculate \ --linux=vmlinux \ --osrel=os-release \ --cmdline=cmdline.txt \ --initrd=initrd.cpio \ --splash=splash.bmp \ --dtb=devicetree.dtb 11:sha1=d775a7b4482450ac77e03ee19bda90bd792d6ec7 11:sha256=bc6170f9ce28eb051ab465cd62be8cf63985276766cf9faf527ffefb66f45651 11:sha384=1cf67dff4757e61e5a73d2a21a6694d668629bbc3761747d493f7f49ad720be02fd07263e1f93061243aec599d1ee4b4 11:sha512=8e79acd3ddbbc8282e98091849c3530f996303c8ac8e87a3b2378b71c8b3a6e86d5c4f41ecea9e1517090c3e8ec0c714821032038f525f744960bcd082d937da On success, 0 is returned, a non-zero failure code otherwise. systemd1, systemd-stub7, objcopy1