From: Mimi Zohar <zohar@linux.vnet.ibm.com>
Date: Wed, 8 Nov 2017 15:11:32 +0000 (+0000)
Subject: ima: require secure_boot rules in lockdown mode
X-Git-Tag: archive/raspbian/4.18.10-2+rpi1^2~53
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=fcd5465bba42bc93d7f47a632de3a738c0431b6b;p=linux.git

ima: require secure_boot rules in lockdown mode

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 <zohar@linux.vnet.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
[bwh: Adjust context to apply after commit 6f0911a666d1
 "ima: fix updating the ima_appraise flag"]

Gbp-Pq: Topic features/all/lockdown
Gbp-Pq: Name 0003-ima-require-secure_boot-rules-in-lockdown-mode.patch
---

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index cdcc9a7b4e2..10032ef8d17 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -459,14 +459,21 @@ static int ima_appraise_flag(enum ima_hooks func)
  */
 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);
@@ -487,12 +494,24 @@ 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++) {
+		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);
+		}
 	}
 
 	for (i = 0; i < appraise_entries; i++) {