On Wed, Aug 11, 2021 at 10:18:42PM -0400, Eric Snowberg wrote:
> Many UEFI Linux distributions boot using shim. The UEFI shim provides
> what is called Machine Owner Keys (MOK). Shim uses both the UEFI Secure
> Boot DB and MOK keys to validate the next step in the boot chain. The
> MOK facility can be used to import user generated keys. These keys can
> be used to sign an end-users development kernel build. When Linux
> boots, both UEFI Secure Boot DB and MOK keys get loaded in the Linux
> .platform keyring.
>
> Add a new Linux keyring called .mok. This keyring shall contain just
I would consider ".machine" instead. It holds MOK keys but is not a
MOK key.
> MOK keys and not the remaining keys in the platform keyring. This new
> .mok keyring will be used in follow on patches. Unlike keys in the
> platform keyring, keys contained in the .mok keyring will be trusted
> within the kernel if the end-user has chosen to do so.
>
> Signed-off-by: Eric Snowberg <eric.snowberg@xxxxxxxxxx>
> ---
> v1: Initial version
> v2: Removed destory keyring code
> v3: Unmodified from v2
> ---
> security/integrity/Makefile | 3 ++-
> security/integrity/digsig.c | 1 +
> security/integrity/integrity.h | 3 ++-
> .../integrity/platform_certs/mok_keyring.c | 21 +++++++++++++++++++
> 4 files changed, 26 insertions(+), 2 deletions(-)
> create mode 100644 security/integrity/platform_certs/mok_keyring.c
>
> diff --git a/security/integrity/Makefile b/security/integrity/Makefile
> index 7ee39d66cf16..8e2e98cba1f6 100644
> --- a/security/integrity/Makefile
> +++ b/security/integrity/Makefile
> @@ -9,7 +9,8 @@ integrity-y := iint.o
> integrity-$(CONFIG_INTEGRITY_AUDIT) += integrity_audit.o
> integrity-$(CONFIG_INTEGRITY_SIGNATURE) += digsig.o
> integrity-$(CONFIG_INTEGRITY_ASYMMETRIC_KEYS) += digsig_asymmetric.o
> -integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyring.o
> +integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyring.o \
> + platform_certs/mok_keyring.o
> integrity-$(CONFIG_LOAD_UEFI_KEYS) += platform_certs/efi_parser.o \
> platform_certs/load_uefi.o \
> platform_certs/keyring_handler.o
> diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
> index 3b06a01bd0fd..e07334504ef1 100644
> --- a/security/integrity/digsig.c
> +++ b/security/integrity/digsig.c
> @@ -30,6 +30,7 @@ static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = {
> ".ima",
> #endif
> ".platform",
> + ".mok",
> };
>
> #ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
> diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
> index 547425c20e11..e0e17ccba2e6 100644
> --- a/security/integrity/integrity.h
> +++ b/security/integrity/integrity.h
> @@ -151,7 +151,8 @@ int integrity_kernel_read(struct file *file, loff_t offset,
> #define INTEGRITY_KEYRING_EVM 0
> #define INTEGRITY_KEYRING_IMA 1
> #define INTEGRITY_KEYRING_PLATFORM 2
> -#define INTEGRITY_KEYRING_MAX 3
> +#define INTEGRITY_KEYRING_MOK 3
> +#define INTEGRITY_KEYRING_MAX 4
>
> extern struct dentry *integrity_dir;
>
> diff --git a/security/integrity/platform_certs/mok_keyring.c b/security/integrity/platform_certs/mok_keyring.c
> new file mode 100644
> index 000000000000..b1ee45b77731
> --- /dev/null
> +++ b/security/integrity/platform_certs/mok_keyring.c
> @@ -0,0 +1,21 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * MOK keyring routines.
> + *
> + * Copyright (c) 2021, Oracle and/or its affiliates.
> + */
> +
> +#include "../integrity.h"
> +
> +static __init int mok_keyring_init(void)
> +{
> + int rc;
> +
> + rc = integrity_init_keyring(INTEGRITY_KEYRING_MOK);
> + if (rc)
> + return rc;
> +
> + pr_notice("MOK Keyring initialized\n");
> + return 0;
> +}
> +device_initcall(mok_keyring_init);
> --
> 2.18.4
>
>
/Jarkko
