[PATCH 03/24] ima: require secure_boot rules in lockdown mode
From: David Howells <dhowells@redhat.com>
Date: 2018-04-11 16:25:05
Also in:
linux-man, linux-security-module, lkml
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: Mimi Zohar <redacted> Require the "secure_boot" rules, whether or not it is specified on the boot command line, for both the builtin and custom policies in secure boot lockdown mode. Signed-off-by: Mimi Zohar <redacted> Signed-off-by: David Howells <dhowells@redhat.com> --- security/integrity/ima/ima_policy.c | 39 ++++++++++++++++++++++++++--------- 1 file changed, 29 insertions(+), 10 deletions(-)
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index d89bebf85421..da6f55c96a61 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c@@ -443,14 +443,21 @@ void ima_update_policy_flag(void) */ void __init ima_init_policy(void) { - int i, measure_entries, appraise_entries, secure_boot_entries; + int i; + int measure_entries = 0; + int appraise_entries = 0; + int secure_boot_entries = 0; + bool kernel_locked_down = __kernel_is_locked_down(NULL, false); /* if !ima_policy set entries = 0 so we load NO default rules */ - measure_entries = ima_policy ? ARRAY_SIZE(dont_measure_rules) : 0; - appraise_entries = ima_use_appraise_tcb ? - ARRAY_SIZE(default_appraise_rules) : 0; - secure_boot_entries = ima_use_secure_boot ? - ARRAY_SIZE(secure_boot_rules) : 0; + if (ima_policy) + measure_entries = ARRAY_SIZE(dont_measure_rules); + + if (ima_use_appraise_tcb) + appraise_entries = ARRAY_SIZE(default_appraise_rules); + + if (ima_use_secure_boot || kernel_locked_down) + secure_boot_entries = ARRAY_SIZE(secure_boot_rules); for (i = 0; i < measure_entries; i++) list_add_tail(&dont_measure_rules[i].list, &ima_default_rules);
@@ -471,11 +478,23 @@ void __init ima_init_policy(void) /* * Insert the appraise rules requiring file signatures, prior to - * any other appraise rules. + * any other appraise rules. In secure boot lock-down mode, also + * require these appraise rules for custom policies. */ - for (i = 0; i < secure_boot_entries; i++) - list_add_tail(&secure_boot_rules[i].list, - &ima_default_rules); + for (i = 0; i < secure_boot_entries; i++) { + struct ima_rule_entry *entry; + + /* Include for builtin policies */ + list_add_tail(&secure_boot_rules[i].list, &ima_default_rules); + + /* Include for custom policies */ + if (kernel_locked_down) { + entry = kmemdup(&secure_boot_rules[i], sizeof(*entry), + GFP_KERNEL); + if (entry) + list_add_tail(&entry->list, &ima_policy_rules); + } + } for (i = 0; i < appraise_entries; i++) { list_add_tail(&default_appraise_rules[i].list,