[PATCH v11 05/27] ima: Move arch_policy_entry into ima_namespace

[Stefan Berger]

The architecture-specific policy rules, currently defined for EFI and
powerpc, require the kexec kernel image and kernel modules to be
validly signed and measured, based on the system's secure boot and/or
trusted boot mode and the IMA_ARCH_POLICY Kconfig option being enabled.

To avoid special-casing init_ima_ns as much as possible, move the
arch_policy_entry into the ima_namespace.

When freeing the arch_policy_entry set the pointer to NULL.

Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
Acked-by: Christian Brauner <brauner@xxxxxxxxxx>
Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
---
 security/integrity/ima/ima.h             |  3 +++
 security/integrity/ima/ima_init_ima_ns.c |  1 +
 security/integrity/ima/ima_policy.c      | 23 +++++++++++------------
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 9bcde1a24e74..2305bf223a98 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -125,6 +125,9 @@ struct ima_namespace {
 
 	struct list_head __rcu *ima_rules;  /* Pointer to the current policy */
 	int ima_policy_flag;
+
+	/* An array of architecture specific rules */
+	struct ima_rule_entry *arch_policy_entry;
 } __randomize_layout;
 extern struct ima_namespace init_ima_ns;
 
diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c
index c919a456b525..ae33621c3955 100644
--- a/security/integrity/ima/ima_init_ima_ns.c
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -15,6 +15,7 @@ static int ima_init_namespace(struct ima_namespace *ns)
 	INIT_LIST_HEAD(&ns->ima_temp_rules);
 	ns->ima_rules = (struct list_head __rcu *)(&ns->ima_default_rules);
 	ns->ima_policy_flag = 0;
+	ns->arch_policy_entry = NULL;
 
 	return 0;
 }
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index b0e1c16b7f37..05b2bc06ab0c 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -229,9 +229,6 @@ static struct ima_rule_entry critical_data_rules[] __ro_after_init = {
 	{.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC},
 };
 
-/* An array of architecture specific rules */
-static struct ima_rule_entry *arch_policy_entry __ro_after_init;
-
 static int ima_policy __initdata;
 
 static int __init default_measure_policy_setup(char *str)
@@ -860,9 +857,10 @@ static int __init ima_init_arch_policy(struct ima_namespace *ns)
 	for (rules = arch_rules; *rules != NULL; rules++)
 		arch_entries++;
 
-	arch_policy_entry = kcalloc(arch_entries + 1,
-				    sizeof(*arch_policy_entry), GFP_KERNEL);
-	if (!arch_policy_entry)
+	ns->arch_policy_entry = kcalloc(arch_entries + 1,
+					sizeof(*ns->arch_policy_entry),
+					GFP_KERNEL);
+	if (!ns->arch_policy_entry)
 		return 0;
 
 	/* Convert each policy string rules to struct ima_rule_entry format */
@@ -872,13 +870,13 @@ static int __init ima_init_arch_policy(struct ima_namespace *ns)
 
 		result = strscpy(rule, *rules, sizeof(rule));
 
-		INIT_LIST_HEAD(&arch_policy_entry[i].list);
-		result = ima_parse_rule(ns, rule, &arch_policy_entry[i]);
+		INIT_LIST_HEAD(&ns->arch_policy_entry[i].list);
+		result = ima_parse_rule(ns, rule, &ns->arch_policy_entry[i]);
 		if (result) {
 			pr_warn("Skipping unknown architecture policy rule: %s\n",
 				rule);
-			memset(&arch_policy_entry[i], 0,
-			       sizeof(*arch_policy_entry));
+			memset(&ns->arch_policy_entry[i], 0,
+			       sizeof(ns->arch_policy_entry[i]));
 			continue;
 		}
 		i++;
@@ -926,7 +924,7 @@ void __init ima_init_policy(struct ima_namespace *ns)
 	if (!arch_entries)
 		pr_info("No architecture policies found\n");
 	else
-		add_rules(ns, arch_policy_entry, arch_entries,
+		add_rules(ns, ns->arch_policy_entry, arch_entries,
 			  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 
 	/*
@@ -1006,7 +1004,8 @@ void ima_update_policy(struct ima_namespace *ns)
 		 * on boot.  After loading a custom policy, free the
 		 * architecture specific rules stored as an array.
 		 */
-		kfree(arch_policy_entry);
+		kfree(ns->arch_policy_entry);
+		ns->arch_policy_entry = NULL;
 	}
 	ima_update_policy_flags(ns);
 
-- 
2.31.1