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authorLakshmi Ramasubramanian <nramas@linux.microsoft.com>2021-01-08 07:07:07 +0300
committerMimi Zohar <zohar@linux.ibm.com>2021-01-15 07:41:43 +0300
commit03cee168366621db85000cec47f5cefdb83e049b (patch)
tree8354f0f679bc9e85a986b26d803bfc9da0e5b9f8
parent9f5d7d23cc5ec61a92076b73665fcb9aaa5bb5a0 (diff)
downloadlinux-03cee168366621db85000cec47f5cefdb83e049b.tar.xz
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: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt5
-rw-r--r--security/integrity/ima/ima_policy.c12
2 files changed, 16 insertions, 1 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 9e3cdb271d06..65a0c4c9ab18 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -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
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 2c9db2d0b434..9b45d064a87d 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -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();
}