From: Mimi Zohar Date: Wed, 8 Nov 2017 15:11:32 +0000 Subject: [03/29] ima: require secure_boot rules in lockdown mode Origin: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit?id=29c55d71a8185208c7962843a29c9a84ae27b2b0 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 Signed-off-by: David Howells [bwh: Adjust context to apply after commits 6f0911a666d1 "ima: fix updating the ima_appraise flag" and ef96837b0de4 "ima: add build time policy"] --- security/integrity/ima/ima_policy.c | 39 +++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-) Index: linux/security/integrity/ima/ima_policy.c =================================================================== --- linux.orig/security/integrity/ima/ima_policy.c +++ linux/security/integrity/ima/ima_policy.c @@ -481,14 +481,21 @@ static int ima_appraise_flag(enum ima_ho */ 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); @@ -510,11 +517,24 @@ void __init ima_init_policy(void) /* * Insert the builtin "secure_boot" policy rules requiring file * signatures, prior to 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++) { + struct ima_rule_entry *entry; + + /* Include for builtin policies */ list_add_tail(&secure_boot_rules[i].list, &ima_default_rules); temp_ima_appraise |= ima_appraise_flag(secure_boot_rules[i].func); + + /* 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); + } } /*