Lakshmi Ramasubramanian <nramas@xxxxxxxxxxxxxxxxxxx> writes: > 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. Sounds good, with one additional change: So far, CONFIG_HAVE_IMA_KEXEC was tested only in files that were built when CONFIG_IMA was set. With this series this is not the case anymore (in drivers/of/kexec.c). The simplest way to keep this consistent is to only enable CONFIG_HAVE_IMA_KEXEC if CONFIG_IMA is also set. For example, with this: diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index e9f13fe08492..4ddd17215ecf 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -548,7 +548,7 @@ config KEXEC config KEXEC_FILE bool "kexec file based system call" select KEXEC_CORE - select HAVE_IMA_KEXEC + select HAVE_IMA_KEXEC if IMA select BUILD_BIN2C select KEXEC_ELF depends on PPC64 And then the same thing on the arm64 patch. -- Thiago Jung Bauermann IBM Linux Technology Center
