alistair23-linux/security/integrity/ima/Kconfig

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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_MD5
select CRYPTO_SHA1
select CRYPTO_HASH_INFO
select TCG_TPM if HAS_IOMEM && !UML
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.
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 || SECURITY_APPARMOR)
default y
help
Disabling this option will disregard LSM based policy rules.
ima: integrity appraisal extension IMA currently maintains an integrity measurement list used to assert the integrity of the running system to a third party. The IMA-appraisal extension adds local integrity validation and enforcement of the measurement against a "good" value stored as an extended attribute 'security.ima'. The initial methods for validating 'security.ima' are hashed based, which provides file data integrity, and digital signature based, which in addition to providing file data integrity, provides authenticity. This patch creates and maintains the 'security.ima' xattr, containing the file data hash measurement. Protection of the xattr is provided by EVM, if enabled and configured. Based on policy, IMA calls evm_verifyxattr() to verify a file's metadata integrity and, assuming success, compares the file's current hash value with the one stored as an extended attribute in 'security.ima'. Changelov v4: - changed iint cache flags to hex values Changelog v3: - change appraisal default for filesystems without xattr support to fail Changelog v2: - fix audit msg 'res' value - removed unused 'ima_appraise=' values Changelog v1: - removed unused iint mutex (Dmitry Kasatkin) - setattr hook must not reset appraised (Dmitry Kasatkin) - evm_verifyxattr() now differentiates between no 'security.evm' xattr (INTEGRITY_NOLABEL) and no EVM 'protected' xattrs included in the 'security.evm' (INTEGRITY_NOXATTRS). - replace hash_status with ima_status (Dmitry Kasatkin) - re-initialize slab element ima_status on free (Dmitry Kasatkin) - include 'security.ima' in EVM if CONFIG_IMA_APPRAISE, not CONFIG_IMA - merged half "ima: ima_must_appraise_or_measure API change" (Dmitry Kasatkin) - removed unnecessary error variable in process_measurement() (Dmitry Kasatkin) - use ima_inode_post_setattr() stub function, if IMA_APPRAISE not configured (moved ima_inode_post_setattr() to ima_appraise.c) - make sure ima_collect_measurement() can read file Changelog: - add 'iint' to evm_verifyxattr() call (Dimitry Kasatkin) - fix the race condition between chmod, which takes the i_mutex and then iint->mutex, and ima_file_free() and process_measurement(), which take the locks in the reverse order, by eliminating iint->mutex. (Dmitry Kasatkin) - cleanup of ima_appraise_measurement() (Dmitry Kasatkin) - changes as a result of the iint not allocated for all regular files, but only for those measured/appraised. - don't try to appraise new/empty files - expanded ima_appraisal description in ima/Kconfig - IMA appraise definitions required even if IMA_APPRAISE not enabled - add return value to ima_must_appraise() stub - unconditionally set status = INTEGRITY_PASS *after* testing status, not before. (Found by Joe Perches) Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2012-02-13 08:15:05 -07:00
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=y
config IMA_DEFAULT_HASH_SHA256
bool "SHA256"
depends on CRYPTO_SHA256=y && !IMA_TEMPLATE
config IMA_DEFAULT_HASH_SHA512
bool "SHA512"
depends on CRYPTO_SHA512=y && !IMA_TEMPLATE
config IMA_DEFAULT_HASH_WP512
bool "WP512"
depends on CRYPTO_WP512=y && !IMA_TEMPLATE
config IMA_DEFAULT_HASH_SM3
bool "SM3"
depends on CRYPTO_SM3=y && !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
default "sm3" if IMA_DEFAULT_HASH_SM3
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.
ima: integrity appraisal extension IMA currently maintains an integrity measurement list used to assert the integrity of the running system to a third party. The IMA-appraisal extension adds local integrity validation and enforcement of the measurement against a "good" value stored as an extended attribute 'security.ima'. The initial methods for validating 'security.ima' are hashed based, which provides file data integrity, and digital signature based, which in addition to providing file data integrity, provides authenticity. This patch creates and maintains the 'security.ima' xattr, containing the file data hash measurement. Protection of the xattr is provided by EVM, if enabled and configured. Based on policy, IMA calls evm_verifyxattr() to verify a file's metadata integrity and, assuming success, compares the file's current hash value with the one stored as an extended attribute in 'security.ima'. Changelov v4: - changed iint cache flags to hex values Changelog v3: - change appraisal default for filesystems without xattr support to fail Changelog v2: - fix audit msg 'res' value - removed unused 'ima_appraise=' values Changelog v1: - removed unused iint mutex (Dmitry Kasatkin) - setattr hook must not reset appraised (Dmitry Kasatkin) - evm_verifyxattr() now differentiates between no 'security.evm' xattr (INTEGRITY_NOLABEL) and no EVM 'protected' xattrs included in the 'security.evm' (INTEGRITY_NOXATTRS). - replace hash_status with ima_status (Dmitry Kasatkin) - re-initialize slab element ima_status on free (Dmitry Kasatkin) - include 'security.ima' in EVM if CONFIG_IMA_APPRAISE, not CONFIG_IMA - merged half "ima: ima_must_appraise_or_measure API change" (Dmitry Kasatkin) - removed unnecessary error variable in process_measurement() (Dmitry Kasatkin) - use ima_inode_post_setattr() stub function, if IMA_APPRAISE not configured (moved ima_inode_post_setattr() to ima_appraise.c) - make sure ima_collect_measurement() can read file Changelog: - add 'iint' to evm_verifyxattr() call (Dimitry Kasatkin) - fix the race condition between chmod, which takes the i_mutex and then iint->mutex, and ima_file_free() and process_measurement(), which take the locks in the reverse order, by eliminating iint->mutex. (Dmitry Kasatkin) - cleanup of ima_appraise_measurement() (Dmitry Kasatkin) - changes as a result of the iint not allocated for all regular files, but only for those measured/appraised. - don't try to appraise new/empty files - expanded ima_appraisal description in ima/Kconfig - IMA appraise definitions required even if IMA_APPRAISE not enabled - add return value to ima_must_appraise() stub - unconditionally set status = INTEGRITY_PASS *after* testing status, not before. (Found by Joe Perches) Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2012-02-13 08:15:05 -07:00
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_ARCH_POLICY
bool "Enable loading an IMA architecture specific policy"
Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull kernel lockdown mode from James Morris: "This is the latest iteration of the kernel lockdown patchset, from Matthew Garrett, David Howells and others. From the original description: This patchset introduces an optional kernel lockdown feature, intended to strengthen the boundary between UID 0 and the kernel. When enabled, various pieces of kernel functionality are restricted. Applications that rely on low-level access to either hardware or the kernel may cease working as a result - therefore this should not be enabled without appropriate evaluation beforehand. The majority of mainstream distributions have been carrying variants of this patchset for many years now, so there's value in providing a doesn't meet every distribution requirement, but gets us much closer to not requiring external patches. There are two major changes since this was last proposed for mainline: - Separating lockdown from EFI secure boot. Background discussion is covered here: https://lwn.net/Articles/751061/ - Implementation as an LSM, with a default stackable lockdown LSM module. This allows the lockdown feature to be policy-driven, rather than encoding an implicit policy within the mechanism. The new locked_down LSM hook is provided to allow LSMs to make a policy decision around whether kernel functionality that would allow tampering with or examining the runtime state of the kernel should be permitted. The included lockdown LSM provides an implementation with a simple policy intended for general purpose use. This policy provides a coarse level of granularity, controllable via the kernel command line: lockdown={integrity|confidentiality} Enable the kernel lockdown feature. If set to integrity, kernel features that allow userland to modify the running kernel are disabled. If set to confidentiality, kernel features that allow userland to extract confidential information from the kernel are also disabled. This may also be controlled via /sys/kernel/security/lockdown and overriden by kernel configuration. New or existing LSMs may implement finer-grained controls of the lockdown features. Refer to the lockdown_reason documentation in include/linux/security.h for details. The lockdown feature has had signficant design feedback and review across many subsystems. This code has been in linux-next for some weeks, with a few fixes applied along the way. Stephen Rothwell noted that commit 9d1f8be5cf42 ("bpf: Restrict bpf when kernel lockdown is in confidentiality mode") is missing a Signed-off-by from its author. Matthew responded that he is providing this under category (c) of the DCO" * 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (31 commits) kexec: Fix file verification on S390 security: constify some arrays in lockdown LSM lockdown: Print current->comm in restriction messages efi: Restrict efivar_ssdt_load when the kernel is locked down tracefs: Restrict tracefs when the kernel is locked down debugfs: Restrict debugfs when the kernel is locked down kexec: Allow kexec_file() with appropriate IMA policy when locked down lockdown: Lock down perf when in confidentiality mode bpf: Restrict bpf when kernel lockdown is in confidentiality mode lockdown: Lock down tracing and perf kprobes when in confidentiality mode lockdown: Lock down /proc/kcore x86/mmiotrace: Lock down the testmmiotrace module lockdown: Lock down module params that specify hardware parameters (eg. ioport) lockdown: Lock down TIOCSSERIAL lockdown: Prohibit PCMCIA CIS storage when the kernel is locked down acpi: Disable ACPI table override if the kernel is locked down acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down ACPI: Limit access to custom_method when the kernel is locked down x86/msr: Restrict MSR access when the kernel is locked down x86: Lock down IO port access when the kernel is locked down ...
2019-09-28 09:14:15 -06:00
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"
ima: move APPRAISE_BOOTPARAM dependency on ARCH_POLICY to runtime The IMA_APPRAISE_BOOTPARAM config allows enabling different "ima_appraise=" modes - log, fix, enforce - at run time, but not when IMA architecture specific policies are enabled.  This prevents properly labeling the filesystem on systems where secure boot is supported, but not enabled on the platform.  Only when secure boot is actually enabled should these IMA appraise modes be disabled. This patch removes the compile time dependency and makes it a runtime decision, based on the secure boot state of that platform. Test results as follows: -> x86-64 with secure boot enabled [ 0.015637] Kernel command line: <...> ima_policy=appraise_tcb ima_appraise=fix [ 0.015668] ima: Secure boot enabled: ignoring ima_appraise=fix boot parameter option -> powerpc with secure boot disabled [ 0.000000] Kernel command line: <...> ima_policy=appraise_tcb ima_appraise=fix [ 0.000000] Secure boot mode disabled -> Running the system without secure boot and with both options set: CONFIG_IMA_APPRAISE_BOOTPARAM=y CONFIG_IMA_ARCH_POLICY=y Audit prompts "missing-hash" but still allow execution and, consequently, filesystem labeling: type=INTEGRITY_DATA msg=audit(07/09/2020 12:30:27.778:1691) : pid=4976 uid=root auid=root ses=2 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 op=appraise_data cause=missing-hash comm=bash name=/usr/bin/evmctl dev="dm-0" ino=493150 res=no Cc: stable@vger.kernel.org Fixes: d958083a8f64 ("x86/ima: define arch_get_ima_policy() for x86") Signed-off-by: Bruno Meneguele <bmeneg@redhat.com> Cc: stable@vger.kernel.org # 5.0 Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-13 10:48:30 -06:00
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_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.
config IMA_MEASURE_ASYMMETRIC_KEYS
bool
depends on IMA
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.