ima: require signed IMA policy

Require the IMA policy to be signed when additional rules can be added.

v1:
- initialize the policy flag
- include IMA_APPRAISE_POLICY in the policy flag

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Petko Manolov <petkan@mip-labs.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index c1b5d00fe5d4..be09e2cacf82 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -129,6 +129,10 @@ static struct ima_rule_entry default_appraise_rules[] = {
         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
         {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+#ifdef CONFIG_IMA_WRITE_POLICY
+        {.action = APPRAISE, .func = POLICY_CHECK,
+        .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
+#endif
 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER},
 #else
@@ -412,9 +416,12 @@ void __init ima_init_policy(void)
         for (i = 0; i < appraise_entries; i++) {
                 list_add_tail(&default_appraise_rules[i].list,
                               &ima_default_rules);
+                if (default_appraise_rules[i].func == POLICY_CHECK)
+                        temp_ima_appraise |= IMA_APPRAISE_POLICY;
         }
 
         ima_rules = &ima_default_rules;
+        ima_update_policy_flag();
 }
 
 /* Make sure we have a valid policy, at least containing some rules. */