Messages in this thread | | | Subject | Re: [PATCH v13 2/6] powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c | From | Lakshmi Ramasubramanian <> | Date | Tue, 22 Dec 2020 13:02:10 -0800 |
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On 12/22/20 11:45 AM, Mimi Zohar wrote: > On Tue, 2020-12-22 at 10:53 -0800, Lakshmi Ramasubramanian wrote: >> On 12/22/20 6:26 AM, Mimi Zohar wrote: >> >> Hi Mimi, >> >>> >>> On Sat, 2020-12-19 at 09:57 -0800, Lakshmi Ramasubramanian wrote: >>>> >>>> diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile >>>> index 4aff6846c772..b6c52608cb49 100644 >>>> --- a/arch/powerpc/kexec/Makefile >>>> +++ b/arch/powerpc/kexec/Makefile >>>> @@ -9,13 +9,6 @@ obj-$(CONFIG_PPC32) += relocate_32.o >>>> >>>> obj-$(CONFIG_KEXEC_FILE) += file_load.o ranges.o file_load_$(BITS).o elf_$(BITS).o >>>> >>>> -ifdef CONFIG_HAVE_IMA_KEXEC >>>> -ifdef CONFIG_IMA >>>> -obj-y += ima.o >>>> -endif >>>> -endif >>> >>> Notice how "kexec/ima.o" is only included if the architecture supports >>> it and IMA is configured. In addition only if CONFIG_IMA_KEXEC is >>> configured, is the IMA measurement list carried across kexec. After >>> moving the rest of ima.c to drivers/of/kexec.c, this changes. Notice >>> how drivers/of/Kconfig includes kexec.o: >>> >>> obj-$(CONFIG_KEXEC_FILE) += kexec.o >>> >>> It is not dependent on CONFIG_HAVE_IMA_KEXEC. Shouldn't all of the >>> functions defined in ima.c being moved to kexec.o be defined within a >>> CONFIG_HAVE_IMA_KEXEC ifdef? >>> >> >> Thanks for reviewing the changes. >> >> In "drivers/of/kexec.c" the function remove_ima_buffer() is defined >> under "#ifdef CONFIG_HAVE_IMA_KEXEC" >> >> setup_ima_buffer() is defined under "#ifdef CONFIG_IMA_KEXEC" - the same >> way it was defined in "arch/powerpc/kexec/ima.c". >> >> As you know, CONFIG_IMA_KEXEC depends on CONFIG_HAVE_IMA_KEXEC (as >> defined in "security/integrity/ima/Kconfig"). >> >> ima_get_kexec_buffer() and ima_free_kexec_buffer() are unconditionally >> defined in "drivers/of/kexec.c" even though they are called only when >> CONFIG_HAVE_IMA_KEXEC is enabled. I will update these two functions to >> be moved under "#ifdef CONFIG_HAVE_IMA_KEXEC" > > The issue is the reverse. CONFIG_HAVE_IMA_KEXEC may be enabled without > CONFIG_IMA_KEXEC being enabled. This allows the architecture to > support carrying the measurement list across kexec, but requires > enabling it at build time. > > Only if CONFIG_HAVE_IMA_KEXEC is enabled should any of these functions > be compiled at build. This allows restoring the previous IMA > measurement list, even if CONFIG_IMA_KEXEC is not enabled. > > Only if CONFIG_IMA_KEXEC is enabled, should carrying the measurement > list across kexec be enabled. See how arch_ima_add_kexec_buffer, > write_number, setup_ima_buffer are ifdef'ed in > arch/powerpc/kexec/ima.c. >
Yes - I agree. I will make the following changes:
=> Enable the functions moved from "arch/powerpc/kexec/ima.c" to "drivers/of/kexec.c" only when CONFIG_HAVE_IMA_KEXEC is enabled.
=> Also, compile write_number() and setup_ima_buffer() only when CONFIG_IMA_KEXEC is enabled.
thanks, -lakshmi
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