[RFC PATCH 04/30] ima: Add ima policy related data to the ima namespace

krzysztof.struczynski
2020-08-18T15:27:11Z

From: Krzysztof Struczynski <krzysztof.struczynski@huawei.com>

Collate global variables describing the ima policy in one structure and
add it to the ima namespace. Collate setup data (parsed kernel boot
parameters) in a separate structure.

Per namespace policy is not yet properly set and it is not used. This
will be done in the following patches.

Signed-off-by: Krzysztof Struczynski <krzysztof.struczynski@huawei.com>
---
include/linux/ima.h | 2 ++
security/integrity/ima/ima.h | 24 +++++++++++++++++
security/integrity/ima/ima_init.c | 3 ++-
security/integrity/ima/ima_ns.c | 41 +++++++++++++++++++++++++++--
security/integrity/ima/ima_policy.c | 26 ++++++++++++++++++
5 files changed, 93 insertions(+), 3 deletions(-)

diff --git a/include/linux/ima.h b/include/linux/ima.h
index 3954cef57c00..d61c9c21ffb9 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -16,6 +16,7 @@ struct nsproxy;
struct task_struct;
struct list_head;
struct llist_node;
+struct ima_policy_data;

#ifdef CONFIG_IMA
extern int ima_bprm_check(struct linux_binprm *bprm);
@@ -188,6 +189,7 @@ struct ima_namespace {
struct llist_node cleanup_list; /* namespaces on a death row */
atomic_t inactive; /* set only when ns is added to the cleanup list */
bool frozen;
+ struct ima_policy_data *policy_data;
} __randomize_layout;

extern struct ima_namespace init_ima_ns;
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 092e87190c6d..0d88222e3500 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -60,6 +60,14 @@ extern int ima_appraise;
extern struct tpm_chip *ima_tpm_chip;
extern const char boot_aggregate_name[];

+/* IMA policy setup data */
+struct ima_policy_setup_data {
+ int ima_policy;
+ int ima_appraise;
+ bool ima_use_secure_boot;
+ bool ima_use_appraise_tcb;
+};
+
/* IMA event related data */
struct ima_event_data {
struct integrity_iint_cache *iint;
@@ -286,6 +294,8 @@ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
struct ima_template_desc **template_desc,
const char *keyring);
void ima_init_policy(void);
+void ima_init_ns_policy(struct ima_namespace *ima_ns,
+ const struct ima_policy_setup_data *policy_setup_data);
void ima_update_policy(void);
void ima_update_policy_flag(void);
ssize_t ima_parse_add_rule(char *);
@@ -372,6 +382,20 @@ static inline int ima_read_xattr(struct dentry *dentry,

#endif /* CONFIG_IMA_APPRAISE */

+struct ima_policy_data {
+ struct list_head ima_default_rules;
+ struct list_head ima_policy_rules;
+ struct list_head ima_temp_rules;
+ struct list_head *ima_rules;
+ bool ima_fail_unverifiable_sigs;
+ int ima_policy_flag; /* current content of the policy */
+ int ima_appraise;
+ int temp_ima_appraise;
+};
+
+extern struct ima_policy_data init_policy_data;
+extern struct ima_policy_setup_data init_policy_setup_data;
+
extern struct list_head ima_ns_list;
extern struct rw_semaphore ima_ns_list_lock;

diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 0ba04a1a68cc..ea5ff42eb7fe 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -32,7 +32,8 @@ struct ima_namespace init_ima_ns = {
#ifdef CONFIG_IMA_NS
.ns.ops = &imans_operations,
#endif
- .frozen = true
+ .frozen = true,
+ .policy_data = &init_policy_data,
};
EXPORT_SYMBOL(init_ima_ns);

diff --git a/security/integrity/ima/ima_ns.c b/security/integrity/ima/ima_ns.c
index 3a98cd536d05..1aeb9cfeb3a2 100644
--- a/security/integrity/ima/ima_ns.c
+++ b/security/integrity/ima/ima_ns.c
@@ -51,9 +51,38 @@ static struct ima_namespace *ima_ns_alloc(void)

ima_ns = kzalloc(sizeof(*ima_ns), GFP_KERNEL);
if (!ima_ns)
- return NULL;
+ goto out;
+
+ ima_ns->policy_data = kzalloc(sizeof(struct ima_policy_data),
+ GFP_KERNEL);
+ if (!ima_ns->policy_data)
+ goto out_free;

return ima_ns;
+
+out_free:
+ kfree(ima_ns);
+out:
+ return NULL;
+}
+
+static void ima_set_ns_policy(struct ima_namespace *ima_ns,
+ char *policy_setup_str)
+{
+ struct ima_policy_setup_data setup_data;
+
+#ifdef CONFIG_IMA_APPRAISE
+ setup_data.ima_appraise = IMA_APPRAISE_ENFORCE;
+#endif
+ /* Configuring IMA namespace will be implemented in the following
+ * patches. When it is done, parse configuration string and store result
+ * in setup_data. Temporarily use init_policy_setup_data.
+ */
+ setup_data = init_policy_setup_data;
+ ima_ns->policy_data->ima_fail_unverifiable_sigs =
+ init_ima_ns.policy_data->ima_fail_unverifiable_sigs;
+
+ ima_init_ns_policy(ima_ns, &setup_data);
}

/**
@@ -64,7 +93,7 @@ static struct ima_namespace *ima_ns_alloc(void)
* Return: ERR_PTR(-ENOMEM) on error (failure to kmalloc), new ns otherwise
*/
static struct ima_namespace *clone_ima_ns(struct user_namespace *user_ns,
- struct ima_namespace *old_ns)
+ struct ima_namespace *old_ns)
{
struct ima_namespace *ns;
struct ucounts *ucounts;
@@ -91,9 +120,14 @@ static struct ima_namespace *clone_ima_ns(struct user_namespace *user_ns,
ns->ucounts = ucounts;
ns->frozen = false;

+ INIT_LIST_HEAD(&ns->policy_data->ima_default_rules);
+ INIT_LIST_HEAD(&ns->policy_data->ima_policy_rules);
+ INIT_LIST_HEAD(&ns->policy_data->ima_temp_rules);
+
return ns;

fail_free:
+ kfree(ns->policy_data);
kfree(ns);
fail_dec:
dec_ima_namespaces(ucounts);
@@ -139,6 +173,7 @@ static void destroy_ima_ns(struct ima_namespace *ns)
dec_ima_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
ns_free_inum(&ns->ns);
+ kfree(ns->policy_data);
kfree(ns);
}

@@ -238,6 +273,8 @@ static int imans_activate(struct ima_namespace *ima_ns)
if (ima_ns->frozen)
goto out;

+ ima_set_ns_policy(ima_ns, NULL);
+
ima_ns->frozen = true;

down_write(&ima_ns_list_lock);
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 07f033634b27..6b56741ec1c9 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -212,6 +212,17 @@ static size_t ima_keyrings_len;

static int ima_policy __initdata;

+struct ima_policy_setup_data init_policy_setup_data = {
+#ifdef CONFIG_IMA_APPRAISE
+ .ima_appraise = IMA_APPRAISE_ENFORCE,
+#endif
+};
+struct ima_policy_data init_policy_data = {
+ .ima_default_rules = LIST_HEAD_INIT(init_policy_data.ima_default_rules),
+ .ima_policy_rules = LIST_HEAD_INIT(init_policy_data.ima_policy_rules),
+ .ima_temp_rules = LIST_HEAD_INIT(init_policy_data.ima_temp_rules),
+};
+
static int __init default_measure_policy_setup(char *str)
{
if (ima_policy)
@@ -715,6 +726,21 @@ static int __init ima_init_arch_policy(void)
return i;
}

+/**
+ * ima_init_ns_policy - initialize the default measure rules.
+ * @ima_ns: pointer to the namespace whose rules are being initialized
+ * @setup_data: pointer to the policy setup data
+ */
+void ima_init_ns_policy(struct ima_namespace *ima_ns,
+ const struct ima_policy_setup_data *setup_data)
+{
+ /* Set policy rules to the empty set of default rules. The rest will be
+ * implemented after namespacing policy.
+ */
+ ima_ns->policy_data->ima_rules =
+ &ima_ns->policy_data->ima_default_rules;
+}
+
/**
* ima_init_policy - initialize the default measure rules.
*
--
2.20.1