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 cdcc9a7b4e24825bcc9c41d0e81c14b03993acb0..10032ef8d17902904a0f5e0f661809723fe836a8 100644 (file)
--- 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++) {