[PATCH v6 7/8] IMA: add a built-in policy rule for critical data measurement
From: Tushar Sugandhi <hidden>
Date: 2020-11-19 23:26:50
Also in:
dm-devel, linux-integrity, lkml, selinux
Subsystem:
extended verification module (evm), integrity measurement architecture (ima), security subsystem, the rest · Maintainers:
Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
From: Lakshmi Ramasubramanian <redacted> The IMA hook to measure kernel critical data, namely ima_measure_critical_data(), could be called before a custom IMA policy is loaded. Define a new critical data builtin policy to allow measuring early kernel integrity critical data before a custom IMA policy is loaded. Add critical data to built-in IMA rules if the kernel command line contains "ima_policy=critical_data". Signed-off-by: Lakshmi Ramasubramanian <redacted> --- security/integrity/ima/ima_policy.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index c9e52dab0638..119604a3efa0 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 __ro_after_init; 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
@@ -875,6 +882,11 @@ 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(); }
--
2.17.1