integrity: IMA as an integrity service provider

IMA provides hardware (TPM) based measurement and attestation for
file measurements. As the Trusted Computing (TPM) model requires,
IMA measures all files before they are accessed in any way (on the
integrity_bprm_check, integrity_path_check and integrity_file_mmap
hooks), and commits the measurements to the TPM. Once added to the
TPM, measurements can not be removed.

In addition, IMA maintains a list of these file measurements, which
can be used to validate the aggregate value stored in the TPM.  The
TPM can sign these measurements, and thus the system can prove, to
itself and to a third party, the system's integrity in a way that
cannot be circumvented by malicious or compromised software.

- alloc ima_template_entry before calling ima_store_template()
- log ima_add_boot_aggregate() failure
- removed unused IMA_TEMPLATE_NAME_LEN
- replaced hard coded string length with #define name

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
new file mode 100644
index 00000000000..2a761c8ac99
--- /dev/null
+++ b/security/integrity/ima/Kconfig
@@ -0,0 +1,49 @@
+# IBM Integrity Measurement Architecture
+#
+config IMA
+        bool "Integrity Measurement Architecture(IMA)"
+        depends on ACPI
+        select SECURITYFS
+        select CRYPTO
+        select CRYPTO_HMAC
+        select CRYPTO_MD5
+        select CRYPTO_SHA1
+        select TCG_TPM
+        select TCG_TIS
+        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_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_AUDIT
+        bool
+        depends on IMA
+        default y
+        help
+          This option adds a kernel parameter 'ima_audit', which
+          allows informational auditing messages to be enabled
+          at boot.  If this option is selected, informational integrity
+          auditing messages can be enabled with 'ima_audit=1' on
+          the kernel command line.
+