1# SPDX-License-Identifier: GPL-2.0-only 2# IBM Integrity Measurement Architecture 3# 4config IMA 5 bool "Integrity Measurement Architecture(IMA)" 6 select SECURITYFS 7 select CRYPTO 8 select CRYPTO_HMAC 9 select CRYPTO_SHA1 10 select CRYPTO_HASH_INFO 11 select SECURITY_PATH 12 select TCG_TPM if HAS_IOMEM 13 select TCG_TIS if TCG_TPM && X86 14 select TCG_CRB if TCG_TPM && ACPI 15 select TCG_IBMVTPM if TCG_TPM && PPC_PSERIES 16 select INTEGRITY_AUDIT if AUDIT 17 help 18 The Trusted Computing Group(TCG) runtime Integrity 19 Measurement Architecture(IMA) maintains a list of hash 20 values of executables and other sensitive system files, 21 as they are read or executed. If an attacker manages 22 to change the contents of an important system file 23 being measured, we can tell. 24 25 If your system has a TPM chip, then IMA also maintains 26 an aggregate integrity value over this list inside the 27 TPM hardware, so that the TPM can prove to a third party 28 whether or not critical system files have been modified. 29 Read <https://www.usenix.org/events/sec04/tech/sailer.html> 30 to learn more about IMA. 31 If unsure, say N. 32 33if IMA 34 35config IMA_KEXEC 36 bool "Enable carrying the IMA measurement list across a soft boot" 37 depends on TCG_TPM && HAVE_IMA_KEXEC 38 default n 39 help 40 TPM PCRs are only reset on a hard reboot. In order to validate 41 a TPM's quote after a soft boot, the IMA measurement list of the 42 running kernel must be saved and restored on boot. 43 44 Depending on the IMA policy, the measurement list can grow to 45 be very large. 46 47config IMA_MEASURE_PCR_IDX 48 int 49 prompt "PCR Index for Aggregate" if EXPERT 50 range 8 14 51 default 10 52 help 53 IMA_MEASURE_PCR_IDX determines the TPM PCR register index 54 that IMA uses to maintain the integrity aggregate of the 55 measurement list. Most attestation tooling expects PCR 10. 56 57 The default is almost always what you want. Only change this 58 if you know what you are doing. 59 60config IMA_LSM_RULES 61 bool 62 depends on AUDIT && (SECURITY_SELINUX || SECURITY_SMACK || SECURITY_APPARMOR) 63 default y 64 help 65 Disabling this option will disregard LSM based policy rules. 66 67choice 68 prompt "Default template" 69 default IMA_NG_TEMPLATE 70 help 71 Select the default IMA measurement template. 72 73 The original 'ima' measurement list template contains a 74 hash, defined as 20 bytes, and a null terminated pathname, 75 limited to 255 characters. The 'ima-ng' measurement list 76 template permits both larger hash digests and longer 77 pathnames. The configured default template can be replaced 78 by specifying "ima_template=" on the boot command line. 79 80 config IMA_NG_TEMPLATE 81 bool "ima-ng (default)" 82 config IMA_SIG_TEMPLATE 83 bool "ima-sig" 84endchoice 85 86config IMA_DEFAULT_TEMPLATE 87 string 88 default "ima-ng" if IMA_NG_TEMPLATE 89 default "ima-sig" if IMA_SIG_TEMPLATE 90 91choice 92 prompt "Default integrity hash algorithm" 93 default IMA_DEFAULT_HASH_SHA1 94 help 95 Select the default hash algorithm used for the measurement 96 list, integrity appraisal and audit log. The compiled default 97 hash algorithm can be overwritten using the kernel command 98 line 'ima_hash=' option. 99 100 config IMA_DEFAULT_HASH_SHA1 101 bool "SHA1 (default)" 102 depends on CRYPTO_SHA1=y 103 104 config IMA_DEFAULT_HASH_SHA256 105 bool "SHA256" 106 depends on CRYPTO_SHA256=y 107 108 config IMA_DEFAULT_HASH_SHA512 109 bool "SHA512" 110 depends on CRYPTO_SHA512=y 111 112 config IMA_DEFAULT_HASH_WP512 113 bool "WP512" 114 depends on CRYPTO_WP512=y 115 116 config IMA_DEFAULT_HASH_SM3 117 bool "SM3" 118 depends on CRYPTO_SM3=y 119endchoice 120 121config IMA_DEFAULT_HASH 122 string 123 default "sha1" if IMA_DEFAULT_HASH_SHA1 124 default "sha256" if IMA_DEFAULT_HASH_SHA256 125 default "sha512" if IMA_DEFAULT_HASH_SHA512 126 default "wp512" if IMA_DEFAULT_HASH_WP512 127 default "sm3" if IMA_DEFAULT_HASH_SM3 128 129config IMA_WRITE_POLICY 130 bool "Enable multiple writes to the IMA policy" 131 default n 132 help 133 IMA policy can now be updated multiple times. The new rules get 134 appended to the original policy. Have in mind that the rules are 135 scanned in FIFO order so be careful when you design and add new ones. 136 137 If unsure, say N. 138 139config IMA_READ_POLICY 140 bool "Enable reading back the current IMA policy" 141 default y if IMA_WRITE_POLICY 142 default n if !IMA_WRITE_POLICY 143 help 144 It is often useful to be able to read back the IMA policy. It is 145 even more important after introducing CONFIG_IMA_WRITE_POLICY. 146 This option allows the root user to see the current policy rules. 147 148config IMA_APPRAISE 149 bool "Appraise integrity measurements" 150 default n 151 help 152 This option enables local measurement integrity appraisal. 153 It requires the system to be labeled with a security extended 154 attribute containing the file hash measurement. To protect 155 the security extended attributes from offline attack, enable 156 and configure EVM. 157 158 For more information on integrity appraisal refer to: 159 <http://linux-ima.sourceforge.net> 160 If unsure, say N. 161 162config IMA_ARCH_POLICY 163 bool "Enable loading an IMA architecture specific policy" 164 depends on (KEXEC_SIG && IMA) || IMA_APPRAISE \ 165 && INTEGRITY_ASYMMETRIC_KEYS 166 default n 167 help 168 This option enables loading an IMA architecture specific policy 169 based on run time secure boot flags. 170 171config IMA_APPRAISE_BUILD_POLICY 172 bool "IMA build time configured policy rules" 173 depends on IMA_APPRAISE && INTEGRITY_ASYMMETRIC_KEYS 174 default n 175 help 176 This option defines an IMA appraisal policy at build time, which 177 is enforced at run time without having to specify a builtin 178 policy name on the boot command line. The build time appraisal 179 policy rules persist after loading a custom policy. 180 181 Depending on the rules configured, this policy may require kernel 182 modules, firmware, the kexec kernel image, and/or the IMA policy 183 to be signed. Unsigned files might prevent the system from 184 booting or applications from working properly. 185 186config IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS 187 bool "Appraise firmware signatures" 188 depends on IMA_APPRAISE_BUILD_POLICY 189 default n 190 help 191 This option defines a policy requiring all firmware to be signed, 192 including the regulatory.db. If both this option and 193 CFG80211_REQUIRE_SIGNED_REGDB are enabled, then both signature 194 verification methods are necessary. 195 196config IMA_APPRAISE_REQUIRE_KEXEC_SIGS 197 bool "Appraise kexec kernel image signatures" 198 depends on IMA_APPRAISE_BUILD_POLICY 199 default n 200 help 201 Enabling this rule will require all kexec'ed kernel images to 202 be signed and verified by a public key on the trusted IMA 203 keyring. 204 205 Kernel image signatures can not be verified by the original 206 kexec_load syscall. Enabling this rule will prevent its 207 usage. 208 209config IMA_APPRAISE_REQUIRE_MODULE_SIGS 210 bool "Appraise kernel modules signatures" 211 depends on IMA_APPRAISE_BUILD_POLICY 212 default n 213 help 214 Enabling this rule will require all kernel modules to be signed 215 and verified by a public key on the trusted IMA keyring. 216 217 Kernel module signatures can only be verified by IMA-appraisal, 218 via the finit_module syscall. Enabling this rule will prevent 219 the usage of the init_module syscall. 220 221config IMA_APPRAISE_REQUIRE_POLICY_SIGS 222 bool "Appraise IMA policy signature" 223 depends on IMA_APPRAISE_BUILD_POLICY 224 default n 225 help 226 Enabling this rule will require the IMA policy to be signed and 227 and verified by a key on the trusted IMA keyring. 228 229config IMA_APPRAISE_BOOTPARAM 230 bool "ima_appraise boot parameter" 231 depends on IMA_APPRAISE 232 default y 233 help 234 This option enables the different "ima_appraise=" modes 235 (eg. fix, log) from the boot command line. 236 237config IMA_APPRAISE_MODSIG 238 bool "Support module-style signatures for appraisal" 239 depends on IMA_APPRAISE 240 depends on INTEGRITY_ASYMMETRIC_KEYS 241 select PKCS7_MESSAGE_PARSER 242 select MODULE_SIG_FORMAT 243 default n 244 help 245 Adds support for signatures appended to files. The format of the 246 appended signature is the same used for signed kernel modules. 247 The modsig keyword can be used in the IMA policy to allow a hook 248 to accept such signatures. 249 250config IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY 251 bool "Permit keys validly signed by a built-in, machine (if configured) or secondary" 252 depends on SYSTEM_TRUSTED_KEYRING 253 depends on SECONDARY_TRUSTED_KEYRING 254 depends on INTEGRITY_ASYMMETRIC_KEYS 255 select INTEGRITY_TRUSTED_KEYRING 256 default n 257 help 258 Keys may be added to the IMA or IMA blacklist keyrings, if the 259 key is validly signed by a CA cert in the system built-in, 260 machine (if configured), or secondary trusted keyrings. The 261 key must also have the digitalSignature usage set. 262 263 Intermediate keys between those the kernel has compiled in and the 264 IMA keys to be added may be added to the system secondary keyring, 265 provided they are validly signed by a key already resident in the 266 built-in, machine (if configured) or secondary trusted keyrings. 267 268config IMA_BLACKLIST_KEYRING 269 bool "Create IMA machine owner blacklist keyrings (EXPERIMENTAL)" 270 depends on SYSTEM_TRUSTED_KEYRING 271 depends on INTEGRITY_TRUSTED_KEYRING 272 default n 273 help 274 This option creates an IMA blacklist keyring, which contains all 275 revoked IMA keys. It is consulted before any other keyring. If 276 the search is successful the requested operation is rejected and 277 an error is returned to the caller. 278 279config IMA_LOAD_X509 280 bool "Load X509 certificate onto the '.ima' trusted keyring" 281 depends on INTEGRITY_TRUSTED_KEYRING 282 default n 283 help 284 File signature verification is based on the public keys 285 loaded on the .ima trusted keyring. These public keys are 286 X509 certificates signed by a trusted key on the 287 .system keyring. This option enables X509 certificate 288 loading from the kernel onto the '.ima' trusted keyring. 289 290config IMA_X509_PATH 291 string "IMA X509 certificate path" 292 depends on IMA_LOAD_X509 293 default "/etc/keys/x509_ima.der" 294 help 295 This option defines IMA X509 certificate path. 296 297config IMA_APPRAISE_SIGNED_INIT 298 bool "Require signed user-space initialization" 299 depends on IMA_LOAD_X509 300 default n 301 help 302 This option requires user-space init to be signed. 303 304config IMA_MEASURE_ASYMMETRIC_KEYS 305 bool 306 depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE=y 307 default y 308 309config IMA_QUEUE_EARLY_BOOT_KEYS 310 bool 311 depends on IMA_MEASURE_ASYMMETRIC_KEYS 312 depends on SYSTEM_TRUSTED_KEYRING 313 default y 314 315config IMA_SECURE_AND_OR_TRUSTED_BOOT 316 bool 317 depends on IMA_ARCH_POLICY 318 help 319 This option is selected by architectures to enable secure and/or 320 trusted boot based on IMA runtime policies. 321 322config IMA_DISABLE_HTABLE 323 bool "Disable htable to allow measurement of duplicate records" 324 default n 325 help 326 This option disables htable to allow measurement of duplicate records. 327 328config IMA_KEXEC_EXTRA_MEMORY_KB 329 int "Extra memory for IMA measurements added during kexec soft reboot" 330 range 0 40 331 depends on IMA_KEXEC 332 default 0 333 help 334 IMA_KEXEC_EXTRA_MEMORY_KB determines the extra memory to be 335 allocated (in kb) for IMA measurements added during kexec soft reboot. 336 If set to the default value of 0, an extra half page of memory for those 337 additional measurements will be allocated. 338 339config IMA_STAGING 340 bool "Support for staging the measurements list" 341 default n 342 help 343 Add support for staging the measurements list. 344 345 It allows user space to stage the measurements list for deletion and 346 to delete the staged measurements after confirmation. 347 348 Or, alternatively, it allows user space to specify N measurements 349 records to stage internally, so that they can be immediately deleted. 350 351 On kexec, staging is aborted and any staged measurement records are 352 copied to the secondary kernel. 353 354config IMA_INIT_LATE_SYNC 355 bool "Initialise IMA at late_initcall_sync" 356 default n 357 help 358 This option initialises IMA at late_initcall_sync for platforms 359 where TPM device probing is deferred. 360 When this option is enabled, modules that access files in the 361 initramfs through usermode helper calls such as request_module() 362 during initcall must not be built-in. Otherwise, IMA may miss 363 file measurements for them. 364endif 365