Messages in this thread | | | Subject | Re: [RFC PATCH v1 1/1] Add support for arm64 to carry ima measurement log in kexec_file_load | From | prsriva <> | Date | Tue, 24 Sep 2019 12:54:26 -0700 |
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On 9/19/19 8:07 PM, Thiago Jung Bauermann wrote: > Hello Prakhar, > > Prakhar Srivastava <prsriva@linux.microsoft.com> writes: > >> During kexec_file_load, carrying forward the ima measurement log allows >> a verifying party to get the entire runtime event log since the last >> full reboot since that is when PCRs were last reset. >> >> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com> >> --- >> arch/arm64/Kconfig | 7 + >> arch/arm64/include/asm/ima.h | 29 ++++ >> arch/arm64/include/asm/kexec.h | 5 + >> arch/arm64/kernel/Makefile | 3 +- >> arch/arm64/kernel/ima_kexec.c | 213 +++++++++++++++++++++++++ >> arch/arm64/kernel/machine_kexec_file.c | 6 + >> 6 files changed, 262 insertions(+), 1 deletion(-) >> create mode 100644 arch/arm64/include/asm/ima.h >> create mode 100644 arch/arm64/kernel/ima_kexec.c >> >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> index 3adcec05b1f6..f39b12dbf9e8 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -976,6 +976,13 @@ config KEXEC_VERIFY_SIG >> verification for the corresponding kernel image type being >> loaded in order for this to work. >> >> +config HAVE_IMA_KEXEC >> + bool "Carry over IMA measurement log during kexec_file_load() syscall" >> + depends on KEXEC_FILE >> + help >> + Select this option to carry over IMA measurement log during >> + kexec_file_load. >> + >> config KEXEC_IMAGE_VERIFY_SIG >> bool "Enable Image signature verification support" >> default y > This is not right. As it stands, HAVE_IMA_KEXEC is essentially a synonym > for IMA_KEXEC. > > It's not meant to be user-visible in the config process. Instead, it's > meant to be selected by the arch Kconfig (probably by the ARM64 config > symbol) to signal to IMA's Kconfig that it can offer the IMA_KEXEC > option. > > I also mentioned in my previous review that config HAVE_IMA_KEXEC should > be defined in arch/Kconfig, not separately in both arch/arm64/Kconfig > and arch/powerpc/Kconfig.
I see the entry exists in arch/Kconfig and is overwritten. I will remove entries both from powerpc and arm64.
How do i cross-compile for powerpc?
> >> diff --git a/arch/arm64/include/asm/ima.h b/arch/arm64/include/asm/ima.h >> new file mode 100644 >> index 000000000000..e23cee84729f >> --- /dev/null >> +++ b/arch/arm64/include/asm/ima.h >> @@ -0,0 +1,29 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +#ifndef _ASM_ARM64_IMA_H >> +#define _ASM_ARM64_IMA_H >> + >> +struct kimage; >> + >> +int ima_get_kexec_buffer(void **addr, size_t *size); >> +int ima_free_kexec_buffer(void); >> + >> +#ifdef CONFIG_IMA >> +void remove_ima_buffer(void *fdt, int chosen_node); >> +#else >> +static inline void remove_ima_buffer(void *fdt, int chosen_node) {} >> +#endif > I mentioned in my previous review that remove_ima_buffer() should exist > even if CONFIG_IMA isn't set. Did you arrive at a different conclusion?
I made the needed changed in makefile, missed removing the
configs here. Thanks for pointing this out.
>> + >> +#ifdef CONFIG_IMA_KEXEC >> +int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr, >> + size_t size); >> + >> +int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node); >> +#else >> +static inline int setup_ima_buffer(const struct kimage *image, void *fdt, >> + int chosen_node) >> +{ >> + remove_ima_buffer(fdt, chosen_node); >> + return 0; >> +} >> +#endif /* CONFIG_IMA_KEXEC */ >> +#endif /* _ASM_ARM64_IMA_H */ >> diff --git a/arch/arm64/kernel/ima_kexec.c b/arch/arm64/kernel/ima_kexec.c >> new file mode 100644 >> index 000000000000..b14326d541f3 >> --- /dev/null >> +++ b/arch/arm64/kernel/ima_kexec.c > In the previous patch, you took the powerpc file and made a few > modifications to fit your needs. This file is now somewhat different > than the powerpc version, but I don't understand to what purpose. It's > not different in any significant way. > > Based on review comments from your previous patch, I was expecting to > see code from the powerpc file moved to an arch-independent part of the > the kernel and possibly adapted so that both arm64 and powerpc could use > it. Can you explain why you chose this approach instead? What is the > advantage of having superficially different but basically equivalent > code in the two architectures? > > Actually, there's one change that is significant: instead of a single > linux,ima-kexec-buffer property holding the start address and size of > the buffer, ARM64 is now using two properties (linux,ima-kexec-buffer > and linux,ima-kexec-buffer-end) for the start and end addresses. In my > opinion, unless there's a good reason for it Linux should be consistent > accross architectures when possible. > > -- > Thiago Jung Bauermann > IBM Linux Technology Center > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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