linux/security/integrity/Kconfig
Eric Snowberg 099f26f22f integrity: machine keyring CA configuration
Add machine keyring CA restriction options to control the type of
keys that may be added to it. The motivation is separation of
certificate signing from code signing keys. Subsquent work will
limit certificates being loaded into the IMA keyring to code
signing keys used for signature verification.

When no restrictions are selected, all Machine Owner Keys (MOK) are added
to the machine keyring.  When CONFIG_INTEGRITY_CA_MACHINE_KEYRING is
selected, the CA bit must be true.  Also the key usage must contain
keyCertSign, any other usage field may be set as well.

When CONFIG_INTEGRITY_CA_MACHINE_KEYRING_MAX is selected, the CA bit must
be true. Also the key usage must contain keyCertSign and the
digitialSignature usage may not be set.

Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
2023-04-24 16:15:53 +03:00

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# SPDX-License-Identifier: GPL-2.0-only
#
config INTEGRITY
bool "Integrity subsystem"
depends on SECURITY
default y
help
This option enables the integrity subsystem, which is comprised
of a number of different components including the Integrity
Measurement Architecture (IMA), Extended Verification Module
(EVM), IMA-appraisal extension, digital signature verification
extension and audit measurement log support.
Each of these components can be enabled/disabled separately.
Refer to the individual components for additional details.
if INTEGRITY
config INTEGRITY_SIGNATURE
bool "Digital signature verification using multiple keyrings"
default n
select KEYS
select SIGNATURE
help
This option enables digital signature verification support
using multiple keyrings. It defines separate keyrings for each
of the different use cases - evm, ima, and modules.
Different keyrings improves search performance, but also allow
to "lock" certain keyring to prevent adding new keys.
This is useful for evm and module keyrings, when keys are
usually only added from initramfs.
config INTEGRITY_ASYMMETRIC_KEYS
bool "Enable asymmetric keys support"
depends on INTEGRITY_SIGNATURE
default n
select ASYMMETRIC_KEY_TYPE
select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
select CRYPTO_RSA
select X509_CERTIFICATE_PARSER
help
This option enables digital signature verification using
asymmetric keys.
config INTEGRITY_TRUSTED_KEYRING
bool "Require all keys on the integrity keyrings be signed"
depends on SYSTEM_TRUSTED_KEYRING
depends on INTEGRITY_ASYMMETRIC_KEYS
default y
help
This option requires that all keys added to the .ima and
.evm keyrings be signed by a key on the system trusted
keyring.
config INTEGRITY_PLATFORM_KEYRING
bool "Provide keyring for platform/firmware trusted keys"
depends on INTEGRITY_ASYMMETRIC_KEYS
depends on SYSTEM_BLACKLIST_KEYRING
help
Provide a separate, distinct keyring for platform trusted keys, which
the kernel automatically populates during initialization from values
provided by the platform for verifying the kexec'ed kerned image
and, possibly, the initramfs signature.
config INTEGRITY_MACHINE_KEYRING
bool "Provide a keyring to which Machine Owner Keys may be added"
depends on SECONDARY_TRUSTED_KEYRING
depends on INTEGRITY_ASYMMETRIC_KEYS
depends on SYSTEM_BLACKLIST_KEYRING
depends on LOAD_UEFI_KEYS
help
If set, provide a keyring to which Machine Owner Keys (MOK) may
be added. This keyring shall contain just MOK keys. Unlike keys
in the platform keyring, keys contained in the .machine keyring will
be trusted within the kernel.
config INTEGRITY_CA_MACHINE_KEYRING
bool "Enforce Machine Keyring CA Restrictions"
depends on INTEGRITY_MACHINE_KEYRING
default n
help
The .machine keyring can be configured to enforce CA restriction
on any key added to it. By default no restrictions are in place
and all Machine Owner Keys (MOK) are added to the machine keyring.
If enabled only CA keys are added to the machine keyring, all
other MOK keys load into the platform keyring.
config INTEGRITY_CA_MACHINE_KEYRING_MAX
bool "Only CA keys without DigitialSignature usage set"
depends on INTEGRITY_CA_MACHINE_KEYRING
default n
help
When selected, only load CA keys are loaded into the machine
keyring that contain the CA bit set along with the keyCertSign
Usage field. Keys containing the digitialSignature Usage field
will not be loaded. The remaining MOK keys are loaded into the
.platform keyring.
config LOAD_UEFI_KEYS
depends on INTEGRITY_PLATFORM_KEYRING
depends on EFI
def_bool y
config LOAD_IPL_KEYS
depends on INTEGRITY_PLATFORM_KEYRING
depends on S390
def_bool y
config LOAD_PPC_KEYS
bool "Enable loading of platform and blacklisted keys for POWER"
depends on INTEGRITY_PLATFORM_KEYRING
depends on PPC_SECURE_BOOT
default y
help
Enable loading of keys to the .platform keyring and blacklisted
hashes to the .blacklist keyring for powerpc based platforms.
config INTEGRITY_AUDIT
bool "Enables integrity auditing support "
depends on AUDIT
default y
help
In addition to enabling integrity auditing support, this
option adds a kernel parameter 'integrity_audit', which
controls the level of integrity auditing messages.
0 - basic integrity auditing messages (default)
1 - additional integrity auditing messages
Additional informational integrity auditing messages would
be enabled by specifying 'integrity_audit=1' on the kernel
command line.
source "security/integrity/ima/Kconfig"
source "security/integrity/evm/Kconfig"
endif # if INTEGRITY