[RFC 08/20] ima: Move measurement list related variables into ima_namespace

[Stefan Berger <stefanb@linux.ibm.com>]

Move measurement list related variables into the ima_namespace. This way a
front-end like SecurityFS can show the measurement list inside an IMA
namespace.

Implement ima_free_measurements() to free a list of measurements
and call it when an IMA namespace is deleted.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
 include/linux/ima.h                      |  2 ++
 security/integrity/ima/ima.h             |  4 +--
 security/integrity/ima/ima_fs.c          |  6 +++--
 security/integrity/ima/ima_init_ima_ns.c |  5 ++++
 security/integrity/ima/ima_ns.c          |  1 +
 security/integrity/ima/ima_queue.c       | 33 ++++++++++++++----------
 6 files changed, 33 insertions(+), 18 deletions(-)

diff --git a/include/linux/ima.h b/include/linux/ima.h
index 96254dfacfa0..850a513834d2 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -260,6 +260,8 @@ struct ima_namespace {
 	int ima_policy_flag;
 
 	struct ima_h_table ima_htable;
+	struct list_head ima_measurements;
+	unsigned long binary_runtime_size;
 };
 
 extern struct ima_namespace init_ima_ns;
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index a7e6c8fb152a..bb9763cd5fb1 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -104,7 +104,6 @@ struct ima_queue_entry {
 	struct list_head later;		/* place in ima_measurements list */
 	struct ima_template_entry *entry;
 };
-extern struct list_head ima_measurements;	/* list of all measurements */
 
 /* Some details preceding the binary serialized measurement list */
 struct ima_kexec_hdr {
@@ -168,8 +167,9 @@ int ima_restore_measurement_entry(struct ima_namespace *ns,
 				  struct ima_template_entry *entry);
 int ima_restore_measurement_list(struct ima_namespace *ns,
 				 loff_t bufsize, void *buf);
+void ima_free_measurements(struct ima_namespace *ns);
 int ima_measurements_show(struct seq_file *m, void *v);
-unsigned long ima_get_binary_runtime_size(void);
+unsigned long ima_get_binary_runtime_size(struct ima_namespace *ns);
 int ima_init_template(void);
 void ima_init_template_list(void);
 int __init ima_init_digests(void);
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 9df8648ad64d..c35e15fb313f 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -80,12 +80,13 @@ static const struct file_operations ima_measurements_count_ops = {
 /* returns pointer to hlist_node */
 static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
 {
+	struct ima_namespace *ns = get_current_ns();
 	loff_t l = *pos;
 	struct ima_queue_entry *qe;
 
 	/* we need a lock since pos could point beyond last element */
 	rcu_read_lock();
-	list_for_each_entry_rcu(qe, &ima_measurements, later) {
+	list_for_each_entry_rcu(qe, &ns->ima_measurements, later) {
 		if (!l--) {
 			rcu_read_unlock();
 			return qe;
@@ -97,6 +98,7 @@ static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
 
 static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
 {
+	struct ima_namespace *ns = get_current_ns();
 	struct ima_queue_entry *qe = v;
 
 	/* lock protects when reading beyond last element
@@ -107,7 +109,7 @@ static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
 	rcu_read_unlock();
 	(*pos)++;
 
-	return (&qe->later == &ima_measurements) ? NULL : qe;
+	return (&qe->later == &ns->ima_measurements) ? NULL : qe;
 }
 
 static void ima_measurements_stop(struct seq_file *m, void *v)
diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c
index e13adc3287ed..57e46a10c001 100644
--- a/security/integrity/ima/ima_init_ima_ns.c
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -43,6 +43,11 @@ int ima_init_namespace(struct ima_namespace *ns)
 	atomic_long_set(&ns->ima_htable.len, 0);
 	atomic_long_set(&ns->ima_htable.violations, 0);
 	memset(&ns->ima_htable.queue, 0, sizeof(ns->ima_htable.queue));
+	INIT_LIST_HEAD(&ns->ima_measurements);
+	if (IS_ENABLED(CONFIG_IMA_KEXEC) && ns == &init_ima_ns)
+		ns->binary_runtime_size = 0;
+	else
+		ns->binary_runtime_size = ULONG_MAX;
 
 	return 0;
 }
diff --git a/security/integrity/ima/ima_ns.c b/security/integrity/ima/ima_ns.c
index 709db86f285f..e4f4cf84a6b5 100644
--- a/security/integrity/ima/ima_ns.c
+++ b/security/integrity/ima/ima_ns.c
@@ -69,6 +69,7 @@ static void destroy_ima_ns(struct ima_namespace *ns)
 	pr_debug("DESTROY ima_ns: 0x%p\n", ns);
 	ima_free_policy_rules(ns);
 	free_ns_status_cache(ns);
+	ima_free_measurements(ns);
 	kmem_cache_free(imans_cachep, ns);
 }
 
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index 373154039b91..f15f776918ec 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -25,13 +25,6 @@
 /* pre-allocated array of tpm_digest structures to extend a PCR */
 static struct tpm_digest *digests;
 
-LIST_HEAD(ima_measurements);	/* list of all measurements */
-#ifdef CONFIG_IMA_KEXEC
-static unsigned long binary_runtime_size;
-#else
-static unsigned long binary_runtime_size = ULONG_MAX;
-#endif
-
 /* mutex protects atomicity of extending measurement list
  * and extending the TPM PCR aggregate. Since tpm_extend can take
  * long (and the tpm driver uses a mutex), we can't use the spinlock.
@@ -107,7 +100,7 @@ static int ima_add_digest_entry(struct ima_namespace *ns,
 	qe->entry = entry;
 
 	INIT_LIST_HEAD(&qe->later);
-	list_add_tail_rcu(&qe->later, &ima_measurements);
+	list_add_tail_rcu(&qe->later, &ns->ima_measurements);
 
 	atomic_long_inc(&ns->ima_htable.len);
 	if (update_htable) {
@@ -116,12 +109,12 @@ static int ima_add_digest_entry(struct ima_namespace *ns,
 	} else
 		INIT_HLIST_NODE(&qe->hnext);
 
-	if (binary_runtime_size != ULONG_MAX) {
+	if (ns->binary_runtime_size != ULONG_MAX) {
 		int size;
 
 		size = get_binary_runtime_size(entry);
-		binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ?
-		     binary_runtime_size + size : ULONG_MAX;
+		ns->binary_runtime_size = (ns->binary_runtime_size < ULONG_MAX - size) ?
+		     ns->binary_runtime_size + size : ULONG_MAX;
 	}
 	return 0;
 }
@@ -131,12 +124,12 @@ static int ima_add_digest_entry(struct ima_namespace *ns,
  * entire binary_runtime_measurement list, including the ima_kexec_hdr
  * structure.
  */
-unsigned long ima_get_binary_runtime_size(void)
+unsigned long ima_get_binary_runtime_size(struct ima_namespace *ns)
 {
-	if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
+	if (ns->binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr)))
 		return ULONG_MAX;
 	else
-		return binary_runtime_size + sizeof(struct ima_kexec_hdr);
+		return ns->binary_runtime_size + sizeof(struct ima_kexec_hdr);
 }
 
 static int ima_pcr_extend(struct tpm_digest *digests_arg, int pcr)
@@ -217,6 +210,18 @@ int ima_restore_measurement_entry(struct ima_namespace *ns,
 	return result;
 }
 
+void ima_free_measurements(struct ima_namespace *ns)
+{
+	struct ima_queue_entry *qe, *tmp;
+
+	list_for_each_entry_safe(qe, tmp, &ns->ima_measurements, later) {
+		list_del(&qe->later);
+		if (!hlist_unhashed(&qe->hnext))
+			hlist_del(&qe->hnext);
+		kfree(qe);
+	}
+}
+
 int __init ima_init_digests(void)
 {
 	u16 digest_size;
-- 
2.31.1