On Mon, Apr 25, 2022 at 12:29:17PM -0400, Mimi Zohar wrote: > Hi Jonathan, > > On Fri, 2022-04-22 at 13:50 +0000, Jonathan McDowell wrote: > > On kexec file load Integrity Measurement Architecture (IMA) subsystem > > may verify the IMA signature of the kernel and initramfs, and measure > > it. The command line parameters passed to the kernel in the kexec call > > may also be measured by IMA. A remote attestation service can verify > > a TPM quote based on the TPM event log, the IMA measurement list, and > > the TPM PCR data. This can be achieved only if the IMA measurement log > > is carried over from the current kernel to the next kernel across > > the kexec call. > > > > powerpc and ARM64 both achieve this using device tree with a > > "linux,ima-kexec-buffer" node. x86 platforms generally don't make use of > > device tree, so the IMA infrastructure is extended to allow non device > > tree platforms to provide a log buffer. x86 then passes the IMA buffer > > to the new kernel via the setup_data mechanism. > > > > Signed-off-by: Jonathan McDowell <noodles@xxxxxx> > > FYI, after applying, building, and booting a kernel with this patch, > "kexec -s -l /boot/vmlinuz-5.18.0-rc4+ --reuse-cmdline -- > initrd=/boot/initramfs-5.18.0-rc4+.img" properly loads the kernel, but > "kexec -s -e" fails to reboot, at least on a test laptop even with only > the "boot_aggregate" measurement record. > > Without enabling CONFIG_IMA_KEXEC, kexec boots properly. Thanks for giving it a try. At a guess your laptop is booting with EFI, whereas for my testing I was using qemu with legacy BIOS. I've managed to reproduce the issue with qemu+OVMF and isolated the mistake in the setup data calculation I made when EFI is involved. If you have time can you try with the below on top of the original patch? diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c index 07625da33075..cdc73e081585 100644 --- a/arch/x86/kernel/kexec-bzimage64.c +++ b/arch/x86/kernel/kexec-bzimage64.c @@ -277,7 +277,9 @@ setup_boot_parameters(struct kimage *image, struct boot_params *params, #ifdef CONFIG_IMA_KEXEC /* Setup IMA log buffer state */ setup_ima_state(image, params, params_load_addr, - efi_setup_data_offset + ALIGN(efi_map_sz, 16) + sizeof(struct setup_data)); + efi_setup_data_offset + + sizeof(struct setup_data) + + sizeof(struct efi_setup_data)); #endif /* Setup EDD info */
