e7a2ad7eb6
The IMA measurement list contains two hashes - a template data hash and a filedata hash. The template data hash is committed to the TPM, which is limited, by the TPM v1.2 specification, to 20 bytes. The filedata hash is defined as 20 bytes as well. Now that support for variable length measurement list templates was added, the filedata hash is not limited to 20 bytes. This patch adds Kconfig support for defining larger default filedata hash algorithms and replacing the builtin default with one specified on the kernel command line. <uapi/linux/hash_info.h> contains a list of hash algorithms. The Kconfig default hash algorithm is a subset of this list, but any hash algorithm included in the list can be specified at boot, using the 'ima_hash=' kernel command line option. Changelog v2: - update Kconfig Changelog: - support hashes that are configured - use generic HASH_ALGO_ definitions - add Kconfig support - hash_setup must be called only once (Dmitry) - removed trailing whitespaces (Roberto Sassu) Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
123 lines
3.4 KiB
Plaintext
123 lines
3.4 KiB
Plaintext
# IBM Integrity Measurement Architecture
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#
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config IMA
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bool "Integrity Measurement Architecture(IMA)"
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depends on SECURITY
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select INTEGRITY
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select SECURITYFS
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select CRYPTO
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select CRYPTO_HMAC
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select CRYPTO_MD5
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select CRYPTO_SHA1
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select CRYPTO_HASH_INFO
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select TCG_TPM if HAS_IOMEM && !UML
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select TCG_TIS if TCG_TPM && X86
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select TCG_IBMVTPM if TCG_TPM && PPC64
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help
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The Trusted Computing Group(TCG) runtime Integrity
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Measurement Architecture(IMA) maintains a list of hash
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values of executables and other sensitive system files,
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as they are read or executed. If an attacker manages
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to change the contents of an important system file
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being measured, we can tell.
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If your system has a TPM chip, then IMA also maintains
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an aggregate integrity value over this list inside the
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TPM hardware, so that the TPM can prove to a third party
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whether or not critical system files have been modified.
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Read <http://www.usenix.org/events/sec04/tech/sailer.html>
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to learn more about IMA.
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If unsure, say N.
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config IMA_MEASURE_PCR_IDX
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int
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depends on IMA
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range 8 14
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default 10
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help
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IMA_MEASURE_PCR_IDX determines the TPM PCR register index
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that IMA uses to maintain the integrity aggregate of the
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measurement list. If unsure, use the default 10.
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config IMA_LSM_RULES
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bool
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depends on IMA && AUDIT && (SECURITY_SELINUX || SECURITY_SMACK)
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default y
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help
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Disabling this option will disregard LSM based policy rules.
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choice
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prompt "Default template"
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default IMA_NG_TEMPLATE
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depends on IMA
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help
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Select the default IMA measurement template.
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The original 'ima' measurement list template contains a
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hash, defined as 20 bytes, and a null terminated pathname,
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limited to 255 characters. The 'ima-ng' measurement list
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template permits both larger hash digests and longer
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pathnames.
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config IMA_TEMPLATE
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bool "ima"
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config IMA_NG_TEMPLATE
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bool "ima-ng (default)"
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endchoice
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config IMA_DEFAULT_TEMPLATE
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string
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depends on IMA
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default "ima" if IMA_TEMPLATE
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default "ima-ng" if IMA_NG_TEMPLATE
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choice
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prompt "Default integrity hash algorithm"
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default IMA_DEFAULT_HASH_SHA1
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depends on IMA
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help
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Select the default hash algorithm used for the measurement
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list, integrity appraisal and audit log. The compiled default
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hash algorithm can be overwritten using the kernel command
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line 'ima_hash=' option.
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config IMA_DEFAULT_HASH_SHA1
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bool "SHA1 (default)"
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depends on CRYPTO_SHA1
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config IMA_DEFAULT_HASH_SHA256
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bool "SHA256"
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depends on CRYPTO_SHA256 && !IMA_TEMPLATE
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config IMA_DEFAULT_HASH_SHA512
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bool "SHA512"
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depends on CRYPTO_SHA512 && !IMA_TEMPLATE
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config IMA_DEFAULT_HASH_WP512
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bool "WP512"
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depends on CRYPTO_WP512 && !IMA_TEMPLATE
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endchoice
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config IMA_DEFAULT_HASH
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string
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depends on IMA
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default "sha1" if IMA_DEFAULT_HASH_SHA1
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default "sha256" if IMA_DEFAULT_HASH_SHA256
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default "sha512" if IMA_DEFAULT_HASH_SHA512
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default "wp512" if IMA_DEFAULT_HASH_WP512
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config IMA_APPRAISE
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bool "Appraise integrity measurements"
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depends on IMA
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default n
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help
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This option enables local measurement integrity appraisal.
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It requires the system to be labeled with a security extended
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attribute containing the file hash measurement. To protect
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the security extended attributes from offline attack, enable
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and configure EVM.
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For more information on integrity appraisal refer to:
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<http://linux-ima.sourceforge.net>
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If unsure, say N.
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