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|
# SPDX-License-Identifier: GPL-2.0-only
# IBM Integrity Measurement Architecture
#
config IMA
bool "Integrity Measurement Architecture(IMA)"
select SECURITYFS
select CRYPTO
select CRYPTO_HMAC
select CRYPTO_SHA1
select CRYPTO_HASH_INFO
select TCG_TPM if HAS_IOMEM
select TCG_TIS if TCG_TPM && X86
select TCG_CRB if TCG_TPM && ACPI
select TCG_IBMVTPM if TCG_TPM && PPC_PSERIES
select INTEGRITY_AUDIT if AUDIT
help
The Trusted Computing Group(TCG) runtime Integrity
Measurement Architecture(IMA) maintains a list of hash
values of executables and other sensitive system files,
as they are read or executed. If an attacker manages
to change the contents of an important system file
being measured, we can tell.
If your system has a TPM chip, then IMA also maintains
an aggregate integrity value over this list inside the
TPM hardware, so that the TPM can prove to a third party
whether or not critical system files have been modified.
Read <https://www.usenix.org/events/sec04/tech/sailer.html>
to learn more about IMA.
If unsure, say N.
if IMA
config IMA_KEXEC
bool "Enable carrying the IMA measurement list across a soft boot"
depends on TCG_TPM && HAVE_IMA_KEXEC
default n
help
TPM PCRs are only reset on a hard reboot. In order to validate
a TPM's quote after a soft boot, the IMA measurement list of the
running kernel must be saved and restored on boot.
Depending on the IMA policy, the measurement list can grow to
be very large.
config IMA_MEASURE_PCR_IDX
int
range 8 14
default 10
help
IMA_MEASURE_PCR_IDX determines the TPM PCR register index
that IMA uses to maintain the integrity aggregate of the
measurement list. If unsure, use the default 10.
config IMA_LSM_RULES
bool
depends on AUDIT && (SECURITY_SELINUX || SECURITY_SMACK || SECURITY_APPARMOR)
default y
help
Disabling this option will disregard LSM based policy rules.
choice
prompt "Default template"
default IMA_NG_TEMPLATE
help
Select the default IMA measurement template.
The original 'ima' measurement list template contains a
hash, defined as 20 bytes, and a null terminated pathname,
limited to 255 characters. The 'ima-ng' measurement list
template permits both larger hash digests and longer
pathnames. The configured default template can be replaced
by specifying "ima_template=" on the boot command line.
config IMA_NG_TEMPLATE
bool "ima-ng (default)"
config IMA_SIG_TEMPLATE
bool "ima-sig"
endchoice
config IMA_DEFAULT_TEMPLATE
string
default "ima-ng" if IMA_NG_TEMPLATE
default "ima-sig" if IMA_SIG_TEMPLATE
choice
prompt "Default integrity hash algorithm"
default IMA_DEFAULT_HASH_SHA1
help
Select the default hash algorithm used for the measurement
list, integrity appraisal and audit log. The compiled default
hash algorithm can be overwritten using the kernel command
line 'ima_hash=' option.
config IMA_DEFAULT_HASH_SHA1
bool "SHA1 (default)"
depends on CRYPTO_SHA1=y
config IMA_DEFAULT_HASH_SHA256
bool "SHA256"
depends on CRYPTO_SHA256=y
config IMA_DEFAULT_HASH_SHA512
bool "SHA512"
depends on CRYPTO_SHA512=y
config IMA_DEFAULT_HASH_WP512
bool "WP512"
depends on CRYPTO_WP512=y
config IMA_DEFAULT_HASH_SM3
bool "SM3"
depends on CRYPTO_SM3=y
endchoice
config IMA_DEFAULT_HASH
string
default "sha1" if IMA_DEFAULT_HASH_SHA1
default "sha256" if IMA_DEFAULT_HASH_SHA256
default "sha512" if IMA_DEFAULT_HASH_SHA512
default "wp512" if IMA_DEFAULT_HASH_WP512
default "sm3" if IMA_DEFAULT_HASH_SM3
config IMA_WRITE_POLICY
bool "Enable multiple writes to the IMA policy"
default n
help
IMA policy can now be updated multiple times. The new rules get
appended to the original policy. Have in mind that the rules are
scanned in FIFO order so be careful when you design and add new ones.
If unsure, say N.
config IMA_READ_POLICY
bool "Enable reading back the current IMA policy"
default y if IMA_WRITE_POLICY
default n if !IMA_WRITE_POLICY
help
It is often useful to be able to read back the IMA policy. It is
even more important after introducing CONFIG_IMA_WRITE_POLICY.
This option allows the root user to see the current policy rules.
config IMA_APPRAISE
bool "Appraise integrity measurements"
default n
help
This option enables local measurement integrity appraisal.
It requires the system to be labeled with a security extended
attribute containing the file hash measurement. To protect
the security extended attributes from offline attack, enable
and configure EVM.
For more information on integrity appraisal refer to:
<http://linux-ima.sourceforge.net>
If unsure, say N.
config IMA_ARCH_POLICY
bool "Enable loading an IMA architecture specific policy"
depends on (KEXEC_SIG && IMA) || IMA_APPRAISE \
&& INTEGRITY_ASYMMETRIC_KEYS
default n
help
This option enables loading an IMA architecture specific policy
based on run time secure boot flags.
config IMA_APPRAISE_BUILD_POLICY
bool "IMA build time configured policy rules"
depends on IMA_APPRAISE && INTEGRITY_ASYMMETRIC_KEYS
default n
help
This option defines an IMA appraisal policy at build time, which
is enforced at run time without having to specify a builtin
policy name on the boot command line. The build time appraisal
policy rules persist after loading a custom policy.
Depending on the rules configured, this policy may require kernel
modules, firmware, the kexec kernel image, and/or the IMA policy
to be signed. Unsigned files might prevent the system from
booting or applications from working properly.
config IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
bool "Appraise firmware signatures"
depends on IMA_APPRAISE_BUILD_POLICY
default n
help
This option defines a policy requiring all firmware to be signed,
including the regulatory.db. If both this option and
CFG80211_REQUIRE_SIGNED_REGDB are enabled, then both signature
verification methods are necessary.
config IMA_APPRAISE_REQUIRE_KEXEC_SIGS
bool "Appraise kexec kernel image signatures"
depends on IMA_APPRAISE_BUILD_POLICY
default n
help
Enabling this rule will require all kexec'ed kernel images to
be signed and verified by a public key on the trusted IMA
keyring.
Kernel image signatures can not be verified by the original
kexec_load syscall. Enabling this rule will prevent its
usage.
config IMA_APPRAISE_REQUIRE_MODULE_SIGS
bool "Appraise kernel modules signatures"
depends on IMA_APPRAISE_BUILD_POLICY
default n
help
Enabling this rule will require all kernel modules to be signed
and verified by a public key on the trusted IMA keyring.
Kernel module signatures can only be verified by IMA-appraisal,
via the finit_module syscall. Enabling this rule will prevent
the usage of the init_module syscall.
config IMA_APPRAISE_REQUIRE_POLICY_SIGS
bool "Appraise IMA policy signature"
depends on IMA_APPRAISE_BUILD_POLICY
default n
help
Enabling this rule will require the IMA policy to be signed and
and verified by a key on the trusted IMA keyring.
config IMA_APPRAISE_BOOTPARAM
bool "ima_appraise boot parameter"
depends on IMA_APPRAISE
default y
help
This option enables the different "ima_appraise=" modes
(eg. fix, log) from the boot command line.
config IMA_APPRAISE_MODSIG
bool "Support module-style signatures for appraisal"
depends on IMA_APPRAISE
depends on INTEGRITY_ASYMMETRIC_KEYS
select PKCS7_MESSAGE_PARSER
select MODULE_SIG_FORMAT
default n
help
Adds support for signatures appended to files. The format of the
appended signature is the same used for signed kernel modules.
The modsig keyword can be used in the IMA policy to allow a hook
to accept such signatures.
config IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
bool "Permit keys validly signed by a built-in or secondary CA cert (EXPERIMENTAL)"
depends on SYSTEM_TRUSTED_KEYRING
depends on SECONDARY_TRUSTED_KEYRING
depends on INTEGRITY_ASYMMETRIC_KEYS
select INTEGRITY_TRUSTED_KEYRING
default n
help
Keys may be added to the IMA or IMA blacklist keyrings, if the
key is validly signed by a CA cert in the system built-in or
secondary trusted keyrings.
Intermediate keys between those the kernel has compiled in and the
IMA keys to be added may be added to the system secondary keyring,
provided they are validly signed by a key already resident in the
built-in or secondary trusted keyrings.
config IMA_BLACKLIST_KEYRING
bool "Create IMA machine owner blacklist keyrings (EXPERIMENTAL)"
depends on SYSTEM_TRUSTED_KEYRING
depends on INTEGRITY_TRUSTED_KEYRING
default n
help
This option creates an IMA blacklist keyring, which contains all
revoked IMA keys. It is consulted before any other keyring. If
the search is successful the requested operation is rejected and
an error is returned to the caller.
config IMA_LOAD_X509
bool "Load X509 certificate onto the '.ima' trusted keyring"
depends on INTEGRITY_TRUSTED_KEYRING
default n
help
File signature verification is based on the public keys
loaded on the .ima trusted keyring. These public keys are
X509 certificates signed by a trusted key on the
.system keyring. This option enables X509 certificate
loading from the kernel onto the '.ima' trusted keyring.
config IMA_X509_PATH
string "IMA X509 certificate path"
depends on IMA_LOAD_X509
default "/etc/keys/x509_ima.der"
help
This option defines IMA X509 certificate path.
config IMA_APPRAISE_SIGNED_INIT
bool "Require signed user-space initialization"
depends on IMA_LOAD_X509
default n
help
This option requires user-space init to be signed.
config IMA_MEASURE_ASYMMETRIC_KEYS
bool
depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE=y
default y
config IMA_QUEUE_EARLY_BOOT_KEYS
bool
depends on IMA_MEASURE_ASYMMETRIC_KEYS
depends on SYSTEM_TRUSTED_KEYRING
default y
config IMA_SECURE_AND_OR_TRUSTED_BOOT
bool
depends on IMA_ARCH_POLICY
help
This option is selected by architectures to enable secure and/or
trusted boot based on IMA runtime policies.
endif
|
