| 1 | # SPDX-License-Identifier: GPL-2.0-only |
| 2 | # IBM Integrity Measurement Architecture |
| 3 | # |
| 4 | config 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 | |
| 33 | if IMA |
| 34 | |
| 35 | config 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 | |
| 47 | config 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 | |
| 60 | config 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 | |
| 67 | choice |
| 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" |
| 84 | endchoice |
| 85 | |
| 86 | config IMA_DEFAULT_TEMPLATE |
| 87 | string |
| 88 | default "ima-ng" if IMA_NG_TEMPLATE |
| 89 | default "ima-sig" if IMA_SIG_TEMPLATE |
| 90 | |
| 91 | choice |
| 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 |
| 119 | endchoice |
| 120 | |
| 121 | config 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 | |
| 129 | config 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 | |
| 139 | config 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 | |
| 148 | config 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 | |
| 162 | config 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 | |
| 171 | config 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 | |
| 186 | config 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 | |
| 196 | config 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 | |
| 209 | config 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 | |
| 221 | config 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 | |
| 229 | config 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 | |
| 237 | config 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 | |
| 250 | config 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 | |
| 268 | config 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 | |
| 279 | config 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 | |
| 290 | config 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 | |
| 297 | config 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 | |
| 304 | config IMA_MEASURE_ASYMMETRIC_KEYS |
| 305 | bool |
| 306 | depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE=y |
| 307 | default y |
| 308 | |
| 309 | config IMA_QUEUE_EARLY_BOOT_KEYS |
| 310 | bool |
| 311 | depends on IMA_MEASURE_ASYMMETRIC_KEYS |
| 312 | depends on SYSTEM_TRUSTED_KEYRING |
| 313 | default y |
| 314 | |
| 315 | config 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 | |
| 322 | config 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 | |
| 328 | config 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 | |
| 339 | config 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 | |
| 354 | config 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. |
| 364 | endif |