Re: [PATCH 5/6] arm64/ima: add ima arch support

[Mimi Zohar]

On Fri, 2020-09-04 at 15:29 +0800, Chester Lin wrote:
> Add arm64 IMA arch support. The arch policy is inherited from x86.
> 
> Signed-off-by: Chester Lin <clin@xxxxxxxx>

The "secureboot arch rules" comment should be updated to reflect that
the policy is both "secure and trusted boot arch rules", both here and
in x86.

Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>

thanks,

Mimi

> ---
>  arch/arm64/Kconfig           |  1 +
>  arch/arm64/kernel/Makefile   |  2 ++
>  arch/arm64/kernel/ima_arch.c | 37 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 40 insertions(+)
>  create mode 100644 arch/arm64/kernel/ima_arch.c
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 6d232837cbee..b5518e7b604d 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -196,6 +196,7 @@ config ARM64
>  	select SWIOTLB
>  	select SYSCTL_EXCEPTION_TRACE
>  	select THREAD_INFO_IN_TASK
> +	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
>  	help
>  	  ARM 64-bit (AArch64) Linux support.
>  
> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> index a561cbb91d4d..0300ab60785d 100644
> --- a/arch/arm64/kernel/Makefile
> +++ b/arch/arm64/kernel/Makefile
> @@ -71,3 +71,5 @@ extra-y					+= $(head-y) vmlinux.lds
>  ifeq ($(CONFIG_DEBUG_EFI),y)
>  AFLAGS_head.o += -DVMLINUX_PATH="\"$(realpath $(objtree)/vmlinux)\""
>  endif
> +
> +obj-$(CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT)	+= ima_arch.o
> diff --git a/arch/arm64/kernel/ima_arch.c b/arch/arm64/kernel/ima_arch.c
> new file mode 100644
> index 000000000000..46f5641c3da5
> --- /dev/null
> +++ b/arch/arm64/kernel/ima_arch.c
> @@ -0,0 +1,37 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Copyright (C) 2018 IBM Corporation
> + */
> +#include <linux/efi.h>
> +#include <linux/module.h>
> +
> +bool arch_ima_get_secureboot(void)
> +{
> +	if (efi_enabled(EFI_SECURE_BOOT))
> +		return true;
> +
> +	return false;
> +}
> +
> +/* secureboot arch rules */
> +static const char * const sb_arch_rules[] = {
> +#if !IS_ENABLED(CONFIG_KEXEC_SIG)
> +	"appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig",
> +#endif /* CONFIG_KEXEC_SIG */
> +	"measure func=KEXEC_KERNEL_CHECK",
> +#if !IS_ENABLED(CONFIG_MODULE_SIG)
> +	"appraise func=MODULE_CHECK appraise_type=imasig",
> +#endif
> +	"measure func=MODULE_CHECK",
> +	NULL
> +};
> +
> +const char * const *arch_get_ima_policy(void)
> +{
> +	if (IS_ENABLED(CONFIG_IMA_ARCH_POLICY) && arch_ima_get_secureboot()) {
> +		if (IS_ENABLED(CONFIG_MODULE_SIG))
> +			set_module_sig_enforced();
> +		return sb_arch_rules;
> +	}
> +	return NULL;
> +}