# 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.