Free Electrons

Embedded Linux Experts

# IBM Integrity Measurement Architecture
#
config IMA
	bool "Integrity Measurement Architecture(IMA)"
	select SECURITYFS
	select CRYPTO
	select CRYPTO_HMAC
	select CRYPTO_MD5
	select CRYPTO_SHA1
	select CRYPTO_HASH_INFO
	select TCG_TPM if HAS_IOMEM && !UML
	select TCG_TIS if TCG_TPM && X86
	select TCG_IBMVTPM if TCG_TPM && PPC_PSERIES
	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 <http://www.usenix.org/events/sec04/tech/sailer.html>
	  to learn more about IMA.
	  If unsure, say N.

config IMA_KEXEC
	bool "Enable carrying the IMA measurement list across a soft boot"
	depends on IMA && 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
	depends on IMA
	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 IMA && AUDIT && (SECURITY_SELINUX || SECURITY_SMACK)
	default y
	help
	  Disabling this option will disregard LSM based policy rules.

choice
	prompt "Default template"
	default IMA_NG_TEMPLATE
	depends on IMA
	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.

	config IMA_TEMPLATE
		bool "ima"
	config IMA_NG_TEMPLATE
		bool "ima-ng (default)"
	config IMA_SIG_TEMPLATE
		bool "ima-sig"
endchoice

config IMA_DEFAULT_TEMPLATE
	string
	depends on IMA
	default "ima" if IMA_TEMPLATE
	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
	depends on IMA
	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

	config IMA_DEFAULT_HASH_SHA256
		bool "SHA256"
		depends on CRYPTO_SHA256 && !IMA_TEMPLATE

	config IMA_DEFAULT_HASH_SHA512
		bool "SHA512"
		depends on CRYPTO_SHA512 && !IMA_TEMPLATE

	config IMA_DEFAULT_HASH_WP512
		bool "WP512"
		depends on CRYPTO_WP512 && !IMA_TEMPLATE
endchoice

config IMA_DEFAULT_HASH
	string
	depends on IMA
	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

config IMA_WRITE_POLICY
	bool "Enable multiple writes to the IMA policy"
	depends on IMA
	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"
	depends on IMA
	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"
	depends on IMA
	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_TRUSTED_KEYRING
	bool "Require all keys on the .ima keyring be signed (deprecated)"
	depends on IMA_APPRAISE && SYSTEM_TRUSTED_KEYRING
	depends on INTEGRITY_ASYMMETRIC_KEYS
	select INTEGRITY_TRUSTED_KEYRING
	default y
	help
	   This option requires that all keys added to the .ima
	   keyring be signed by a key on the system trusted keyring.

	   This option is deprecated in favor of INTEGRITY_TRUSTED_KEYRING

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 IMA_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 IMA_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.