Hi Ard & Mimi, On Tue, Oct 13, 2020 at 06:59:21PM +0200, Ard Biesheuvel wrote: > On Tue, 13 Oct 2020 at 18:46, Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote: > > > > [Cc'ing linuxppc-dev@xxxxxxxxxxxxxxxx] > > > > On Tue, 2020-10-13 at 10:18 +0200, Ard Biesheuvel wrote: > > > Chester reports that it is necessary to introduce a new way to pass > > > the EFI secure boot status between the EFI stub and the core kernel > > > on ARM systems. The usual way of obtaining this information is by > > > checking the SecureBoot and SetupMode EFI variables, but this can > > > only be done after the EFI variable workqueue is created, which > > > occurs in a subsys_initcall(), whereas arch_ima_get_secureboot() > > > is called much earlier by the IMA framework. > > > > > > However, the IMA framework itself is started as a late_initcall, > > > and the only reason the call to arch_ima_get_secureboot() occurs > > > so early is because it happens in the context of a __setup() > > > callback that parses the ima_appraise= command line parameter. > > > > > > So let's refactor this code a little bit, by using a core_param() > > > callback to capture the command line argument, and deferring any > > > reasoning based on its contents to the IMA init routine. > > > > > > Cc: Chester Lin <clin@xxxxxxxx> > > > Cc: Mimi Zohar <zohar@xxxxxxxxxxxxx> > > > Cc: Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxx> > > > Cc: James Morris <jmorris@xxxxxxxxx> > > > Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx> > > > Link: https://lore.kernel.org/linux-arm-kernel/20200904072905.25332-2-clin@xxxxxxxx/ > > > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > > > --- > > > v2: rebase onto series 'integrity: improve user feedback for invalid bootparams' > > > > Thanks, Ard. Based on my initial, limited testing on Power, it looks > > good, but I'm hesistant to include it in the integrity 5.10 pull > > request without it having been in linux-next and some additional > > testing. It's now queued in the next-integrity-testing branch awaiting > > some tags. > > Tested-by: Chester Lin <clin@xxxxxxxx> I have tested this patch on x86 VM. * System configuration: - Platform: QEMU/KVM - Firmware: EDK2/OVMF + secure boot enabled. - OS: SLE15-SP2 + SUSE's kernel-vanilla (=linux v5.9) + the follow commits from linux-next and upstream: * [PATCH v2] ima: defer arch_ima_get_secureboot() call to IMA init time https://www.spinics.net/lists/linux-efi/msg20645.html * e4d7e2df3a09 "ima: limit secure boot feedback scope for appraise" * 7fe2bb7e7e5c "integrity: invalid kernel parameters feedback" * 4afb28ab03d5 "ima: add check for enforced appraise option" * Logs with UEFI secure boot enabled: [ 0.000000] Linux version 5.9.0-858-g865c50e1d279-1.g8764d18-vanilla (geeko@b uildhost) (gcc (SUSE Linux) 10.2.1 20200825 [revision c0746a1beb1ba073c7981eb09f 55b3d993b32e5c], GNU ld (GNU Binutils; openSUSE Tumbleweed) 2.34.0.20200325-1) # 1 SMP Wed Oct 14 04:00:11 UTC 2020 (8764d18) [ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.9.0-858-g865c50e1d279-1. g8764d18-vanilla root=UUID=5304c03e-4d8a-4d67-873a-32a32e57cdeb console=ttyS0,11 5200 resume=/dev/disk/by-path/pci-0000:04:00.0-part4 mitigations=auto ignore_log level crashkernel=192M,high crashkernel=72M,low ima_appraise=off [ 0.000000] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point regi sters' [ 0.000000] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers' [ 0.000000] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers' .... .... [ 1.720309] ima: Secure boot enabled: ignoring ima_appraise=off option [ 1.720314] ima: No TPM chip found, activating TPM-bypass! [ 1.722129] ima: Allocated hash algorithm: sha256 .... > > Thanks. No rush as far as I am concerned, although I suppose Chester > may want to rebase his arm64 IMA enablement series on this. Yes, I've finished coding but still verifying it. As you have suggested, My v2 patch will separate the get_sb_mode() from arch/x86 so that other architectures can reuse it. Thanks, Chester > > Suggestion: can we take the get_sb_mode() code from ima_arch.c in > arch/x86, and generalize it for all EFI architectures? That way, we > can enable 32-bit ARM and RISC-V seamlessly once someone gets around > to enabling IMA on those platforms. In fact, get_sb_mode() itself > should probably be factored out into a generic helper for use outside > of IMA as well (Xen/x86 has code that does roughly the same already) >
