[PATCH v10 11/27] ima: Move ima_lsm_policy_notifier into ima_namespace

Stefan Berger
2022-02-01T20:38:05Z

Move the ima_lsm_policy_notifier into the ima_namespace. Each IMA
namespace can now register its own LSM policy change notifier callback.
The policy change notifier for the init_ima_ns still remains in init_ima()
and therefore handle the registration of the callback for all other
namespaces in init_ima_namespace().

Suppress the kernel warning 'rule for LSM is undefined` for all
other IMA namespaces than the init_ima_ns.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>

---
v10:
- Only call pr_warn('rule for LSM is undefined`) for init_ima_ns
---
security/integrity/ima/ima.h | 2 ++
security/integrity/ima/ima_init_ima_ns.c | 14 ++++++++++++++
security/integrity/ima/ima_main.c | 6 +-----
security/integrity/ima/ima_policy.c | 16 ++++++++++------
4 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 94c6e3a4d666..fb6bd054d899 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -144,6 +144,8 @@ struct ima_namespace {
int valid_policy;

struct dentry *ima_policy;
+
+ struct notifier_block ima_lsm_policy_notifier;
} __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 425eed1c6838..1cba545ae477 100644
--- a/security/integrity/ima/ima_init_ima_ns.c
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -10,6 +10,8 @@

static int ima_init_namespace(struct ima_namespace *ns)
{
+ int rc;
+
INIT_LIST_HEAD(&ns->ima_default_rules);
INIT_LIST_HEAD(&ns->ima_policy_rules);
INIT_LIST_HEAD(&ns->ima_temp_rules);
@@ -30,6 +32,15 @@ static int ima_init_namespace(struct ima_namespace *ns)
ns->valid_policy = 1;
ns->ima_fs_flags = 0;

+ if (ns != &init_ima_ns) {
+ ns->ima_lsm_policy_notifier.notifier_call =
+ ima_lsm_policy_change;
+ rc = register_blocking_lsm_notifier
+ (&ns->ima_lsm_policy_notifier);
+ if (rc)
+ return rc;
+ }
+
return 0;
}

@@ -39,5 +50,8 @@ int __init ima_ns_init(void)
}

struct ima_namespace init_ima_ns = {
+ .ima_lsm_policy_notifier = {
+ .notifier_call = ima_lsm_policy_change,
+ },
};
EXPORT_SYMBOL(init_ima_ns);
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 2cd5cc90ab79..ae0e9b14554a 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -38,10 +38,6 @@ int ima_appraise;
int __ro_after_init ima_hash_algo = HASH_ALGO_SHA1;
static int hash_setup_done;

-static struct notifier_block ima_lsm_policy_notifier = {
- .notifier_call = ima_lsm_policy_change,
-};
-
static int __init hash_setup(char *str)
{
struct ima_template_desc *template_desc = ima_template_desc_current();
@@ -1072,7 +1068,7 @@ static int __init init_ima(void)
if (error)
return error;

- error = register_blocking_lsm_notifier(&ima_lsm_policy_notifier);
+ error = register_blocking_lsm_notifier(&ns->ima_lsm_policy_notifier);
if (error)
pr_warn("Couldn't register LSM notifier, error %d\n", error);

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 05b2bc06ab0c..148ff5a98a8e 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -369,7 +369,8 @@ static void ima_free_rule(struct ima_rule_entry *entry)
kfree(entry);
}

-static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
+static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_namespace *ns,
+ struct ima_rule_entry *entry)
{
struct ima_rule_entry *nentry;
int i;
@@ -400,18 +401,19 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
nentry->lsm[i].args_p,
&nentry->lsm[i].rule);
- if (!nentry->lsm[i].rule)
+ if (!nentry->lsm[i].rule && ns == &init_ima_ns)
pr_warn("rule for LSM \'%s\' is undefined\n",
nentry->lsm[i].args_p);
}
return nentry;
}

-static int ima_lsm_update_rule(struct ima_rule_entry *entry)
+static int ima_lsm_update_rule(struct ima_namespace *ns,
+ struct ima_rule_entry *entry)
{
struct ima_rule_entry *nentry;

- nentry = ima_lsm_copy_rule(entry);
+ nentry = ima_lsm_copy_rule(ns, entry);
if (!nentry)
return -ENOMEM;

@@ -454,7 +456,7 @@ static void ima_lsm_update_rules(struct ima_namespace *ns)
if (!ima_rule_contains_lsm_cond(entry))
continue;

- result = ima_lsm_update_rule(entry);
+ result = ima_lsm_update_rule(ns, entry);
if (result) {
pr_err("lsm rule update error %d\n", result);
return;
@@ -465,12 +467,14 @@ static void ima_lsm_update_rules(struct ima_namespace *ns)
int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
void *lsm_data)
{
- struct ima_namespace *ns = &init_ima_ns;
+ struct ima_namespace *ns;

if (event != LSM_POLICY_CHANGE)
return NOTIFY_DONE;

+ ns = container_of(nb, struct ima_namespace, ima_lsm_policy_notifier);
ima_lsm_update_rules(ns);
+
return NOTIFY_OK;
}

--
2.31.1