[PATCH v12 04/26] ima: Move arch_policy_entry into ima_namespace

Stefan Berger
2022-04-20T14:09:08Z

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@linux.ibm.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
---
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 69b19f4d5fee..0a7c61ca3265 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -228,9 +228,6 @@ 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)
@@ -859,9 +856,10 @@ 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 */
@@ -871,13 +869,13 @@ 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++;
@@ -925,7 +923,7 @@ 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);

/*
@@ -1005,7 +1003,8 @@ 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);

--
2.34.1