Commit 03cee168 authored by Lakshmi Ramasubramanian's avatar Lakshmi Ramasubramanian Committed by Mimi Zohar
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IMA: define a builtin critical data measurement policy 



Define a new critical data builtin policy to allow measuring
early kernel integrity critical data before a custom IMA policy
is loaded.

Update the documentation on kernel parameters to document
the new critical data builtin policy.

Signed-off-by: default avatarLakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reviewed-by: default avatarTyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: default avatarMimi Zohar <zohar@linux.ibm.com>
parent 9f5d7d23

Documentation/admin-guide/kernel-parameters.txt

+4 −1
Original line number Diff line number Diff line
@@ -1746,7 +1746,7 @@ 
	ima_policy=	[IMA]

			The builtin policies to load during IMA setup.

			Format: "tcb | appraise_tcb | secure_boot |

				 fail_securely"

				 fail_securely | critical_data"



			The "tcb" policy measures all programs exec'd, files

			mmap'd for exec, and all files opened with the read
@@ -1765,6 +1765,9 @@ 
			filesystems with the SB_I_UNVERIFIABLE_SIGNATURE

			flag.



			The "critical_data" policy measures kernel integrity

			critical data.



	ima_tcb		[IMA] Deprecated.  Use ima_policy= instead.

			Load a policy which meets the needs of the Trusted

			Computing Base.  This means IMA will measure all

security/integrity/ima/ima_policy.c

+12 −0
Original line number Diff line number Diff line
@@ -206,6 +206,10 @@ static struct ima_rule_entry secure_boot_rules[] __ro_after_init = { 
	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},

};



static struct ima_rule_entry critical_data_rules[] __ro_after_init = {

	{.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC},

};



/* An array of architecture specific rules */

static struct ima_rule_entry *arch_policy_entry __ro_after_init;
@@ -228,6 +232,7 @@ __setup("ima_tcb", default_measure_policy_setup); 


static bool ima_use_appraise_tcb __initdata;

static bool ima_use_secure_boot __initdata;

static bool ima_use_critical_data __initdata;

static bool ima_fail_unverifiable_sigs __ro_after_init;

static int __init policy_setup(char *str)

{
@@ -242,6 +247,8 @@ static int __init policy_setup(char *str) 
			ima_use_appraise_tcb = true;

		else if (strcmp(p, "secure_boot") == 0)

			ima_use_secure_boot = true;

		else if (strcmp(p, "critical_data") == 0)

			ima_use_critical_data = true;

		else if (strcmp(p, "fail_securely") == 0)

			ima_fail_unverifiable_sigs = true;

		else
@@ -871,6 +878,11 @@ void __init ima_init_policy(void) 
			  ARRAY_SIZE(default_appraise_rules),

			  IMA_DEFAULT_POLICY);



	if (ima_use_critical_data)

		add_rules(critical_data_rules,

			  ARRAY_SIZE(critical_data_rules),

			  IMA_DEFAULT_POLICY);



	ima_update_policy_flag();

}