Re: [PATCH v3 3/3] arm64/ima: add ima_arch support

Ard Biesheuvel
2020-10-30T11:53:43Z

On Fri, 30 Oct 2020 at 07:09, Chester Lin <clin@suse.com> wrote:
>
> Add arm64 IMA arch support. The code and arch policy is mainly inherited
> from x86.
>
> Signed-off-by: Chester Lin <clin@suse.com>
> ---
> arch/arm64/Kconfig | 1 +
> arch/arm64/kernel/Makefile | 2 ++
> arch/arm64/kernel/ima_arch.c | 43 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 46 insertions(+)
> create mode 100644 arch/arm64/kernel/ima_arch.c
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index a42e8d13cc88..496a4a26afc6 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -201,6 +201,7 @@ 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 bbaf0bc4ad60..0f6cbb50668c 100644
> --- a/arch/arm64/kernel/Makefile
> +++ b/arch/arm64/kernel/Makefile
> @@ -69,3 +69,5 @@ 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..564236d77adc
> --- /dev/null
> +++ b/arch/arm64/kernel/ima_arch.c
> @@ -0,0 +1,43 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2018 IBM Corporation
> + */
> +#include <linux/efi.h>
> +#include <linux/module.h>
> +#include <linux/ima.h>
> +
> +bool arch_ima_get_secureboot(void)
> +{
> + static bool sb_enabled;
> + static bool initialized;
> +
> + if (!initialized & efi_enabled(EFI_BOOT)) {
> + sb_enabled = ima_get_efi_secureboot();
> + initialized = true;
> + }
> +
> + return sb_enabled;
> +}
> +
> +/* secure and trusted boot 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;
> +}
> --
> 2.28.0
>

Can we move all this stuff into security/integrity/ima/ima_efi.c instead?