The focus of Trechboot project (https://github.com/TrenchBoot) is to enhance the boot security and integrity. This requires the linux kernel to be directly invoked by x86 Dynamic launch measurements to establish Dynamic Root of Trust for Measurement (DRTM). The dynamic launch will be initiated by a boot loader with associated support added to it, for example the first targeted boot loader will be GRUB2. An integral part of establishing the DRTM involves measuring everything that is intended to be run (kernel image, initrd, etc) and everything that will configure that kernel to run (command line, boot params, etc) into specific PCRs, the DRTM PCRs (17-22), in the TPM. Another key aspect is the dynamic launch is rooted in hardware, that is to say the hardware (CPU) is what takes the first measurement for the chain of integrity measurements. On Intel this is done using the GETSEC instruction provided by Intel's TXT and the SKINIT instruction provided by AMD's AMD-V. Information on these technologies can be readily found online. This patchset introduces Intel TXT support. To enable the kernel to be launched by GETSEC, a stub must be built into the setup section of the compressed kernel to handle the specific state that the dynamic launch process leaves the BSP in. Also this stub must measure everything that is going to be used as early as possible. This stub code and subsequent code must also deal with the specific state that the dynamic launch leaves the APs in. A quick note on terminology. The larger open source project itself is called Trenchboot, which is hosted on Github (links below). The kernel feature enabling the use of the x86 technology is referred to as "Secure Launch" within the kernel code. As such the prefixes sl_/SL_ or slaunch/SLAUNCH will be seen in the code. The stub code discussed above is referred to as the SL stub. Note that patch 1 was authored by Arvind Sankar. We were not able to get a status on this patch but Secure Launch depends on it so it is included with the set. The basic flow is: - Entry from the dynamic launch jumps to the SL stub - SL stub fixes up the world on the BSP - For TXT, SL stub wakes the APs, fixes up their worlds - For TXT, APs are left halted waiting for an NMI to wake them - SL stub jumps to startup_32 - SL main locates the TPM event log and writes the measurements of configuration and module information into it. - Kernel boot proceeds normally from this point. - During early setup, slaunch_setup() runs to finish some validation and setup tasks. - The SMP bringup code is modified to wake the waiting APs. APs vector to rmpiggy and start up normally from that point. - SL platform module is registered as a late initcall module. It reads the TPM event log and extends the measurements taken into the TPM PCRs. - SL platform module initializes the securityfs interface to allow asccess to the TPM event log and TXT public registers. - Kernel boot finishes booting normally - SEXIT support to leave SMX mode is present on the kexec path and the various reboot paths (poweroff, reset, halt). Links: The Trenchboot project including documentation: https://github.com/trenchboot Intel TXT is documented in its own specification and in the SDM Instruction Set volume: https://www.intel.com/content/dam/www/public/us/en/documents/guides/intel-txt-software-development-guide.pdf https://software.intel.com/en-us/articles/intel-sdm AMD SKINIT is documented in the System Programming manual: https://www.amd.com/system/files/TechDocs/24593.pdf GRUB2 pre-launch support patchset (WIP): https://lists.gnu.org/archive/html/grub-devel/2020-05/msg00011.html Thanks Ross Philipson and Daniel P. Smith Changes in v2: - Modified 32b entry code to prevent causing relocations in the compressed kernel. - Dropped patches for compressed kernel TPM PCR extender. - Modified event log code to insert log delimiter events and not rely on TPM access. - Stop extending PCRs in the early Secure Launch stub code. - Removed Kconfig options for hash algorithms and use the algorithms the ACM used. - Match Secure Launch measurement algorithm use to those reported in the TPM 2.0 event log. - Read the TPM events out of the TPM and extend them into the PCRs using the mainline TPM driver. This is done in the late initcall module. - Allow use of alternate PCR 19 and 20 for post ACM measurements. - Add Kconfig constraints needed by Secure Launch (disable KASLR and add x2apic dependency). - Fix testing of SL_FLAGS when determining if Secure Launch is active and the architecture is TXT. - Use SYM_DATA_START_LOCAL macros in early entry point code. - Security audit changes: - Validate buffers passed to MLE do not overlap the MLE and are properly laid out. - Validate buffers and memory regions used by the MLE are protected by IOMMU PMRs. - Force IOMMU to not use passthrough mode during a Secure Launch. - Prevent KASLR use during a Secure Launch. Arvind Sankar (1): x86/boot: Place kernel_info at a fixed offset Daniel P. Smith (2): x86: Add early SHA support for Secure Launch early measurements x86: Secure Launch late initcall platform module Ross Philipson (9): x86: Secure Launch Kconfig x86: Secure Launch main header file x86: Secure Launch kernel early boot stub x86: Secure Launch kernel late boot stub x86: Secure Launch SMP bringup support kexec: Secure Launch kexec SEXIT support reboot: Secure Launch SEXIT support on reboot paths tpm: Allow locality 2 to be set when initializing the TPM for Secure Launch iommu: Do not allow IOMMU passthrough with Secure Launch Documentation/x86/boot.rst | 13 + arch/x86/Kconfig | 32 ++ arch/x86/boot/compressed/Makefile | 3 + arch/x86/boot/compressed/early_sha1.c | 103 +++++ arch/x86/boot/compressed/early_sha1.h | 17 + arch/x86/boot/compressed/early_sha256.c | 7 + arch/x86/boot/compressed/head_64.S | 37 ++ arch/x86/boot/compressed/kaslr.c | 11 + arch/x86/boot/compressed/kernel_info.S | 52 ++- arch/x86/boot/compressed/kernel_info.h | 12 + arch/x86/boot/compressed/sl_main.c | 523 +++++++++++++++++++++++++ arch/x86/boot/compressed/sl_stub.S | 667 ++++++++++++++++++++++++++++++++ arch/x86/boot/compressed/vmlinux.lds.S | 6 + arch/x86/include/asm/realmode.h | 3 + arch/x86/kernel/Makefile | 2 + arch/x86/kernel/asm-offsets.c | 19 + arch/x86/kernel/reboot.c | 10 + arch/x86/kernel/setup.c | 3 + arch/x86/kernel/slaunch.c | 543 ++++++++++++++++++++++++++ arch/x86/kernel/slmodule.c | 495 ++++++++++++++++++++++++ arch/x86/kernel/smpboot.c | 86 ++++ arch/x86/realmode/rm/header.S | 3 + arch/x86/realmode/rm/trampoline_64.S | 37 ++ drivers/char/tpm/tpm-chip.c | 13 +- drivers/iommu/intel/dmar.c | 4 + drivers/iommu/intel/iommu.c | 5 + drivers/iommu/iommu.c | 6 +- include/linux/slaunch.h | 540 ++++++++++++++++++++++++++ kernel/kexec_core.c | 4 + lib/crypto/sha256.c | 8 + lib/sha1.c | 4 + 31 files changed, 3261 insertions(+), 7 deletions(-) create mode 100644 arch/x86/boot/compressed/early_sha1.c create mode 100644 arch/x86/boot/compressed/early_sha1.h create mode 100644 arch/x86/boot/compressed/early_sha256.c create mode 100644 arch/x86/boot/compressed/kernel_info.h create mode 100644 arch/x86/boot/compressed/sl_main.c create mode 100644 arch/x86/boot/compressed/sl_stub.S create mode 100644 arch/x86/kernel/slaunch.c create mode 100644 arch/x86/kernel/slmodule.c create mode 100644 include/linux/slaunch.h -- 1.8.3.1
