The builtin and single custom templates are currently stored in an
array. In preparation for being able to restore a measurement list
containing multiple builtin/custom templates, this patch stores the
builtin and custom templates as a linked list. This will permit
defining more than one custom template per boot.
Changelog v4:
- fix "spinlock bad magic" BUG - reported by Dmitry Vyukov
Changelog v3:
- initialize template format list in ima_template_desc_current(), as it
might be called during __setup before normal initialization. (kernel
test robot)
- remove __init annotation of ima_init_template_list()
Changelog v2:
- fix lookup_template_desc() preemption imbalance (kernel test robot)
Signed-off-by: Mimi Zohar <zohar at linux.vnet.ibm.com>
---
security/integrity/ima/ima.h | 2 ++
security/integrity/ima/ima_main.c | 1 +
security/integrity/ima/ima_template.c | 52 +++++++++++++++++++++++++++--------
3 files changed, 44 insertions(+), 11 deletions(-)
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 634d140..e8303c9 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -81,6 +81,7 @@ struct ima_template_field {
/* IMA template descriptor definition */
struct ima_template_desc {
+ struct list_head list;
char *name;
char *fmt;
int num_fields;
@@ -136,6 +137,7 @@ int ima_restore_measurement_list(loff_t bufsize, void *buf);
int ima_measurements_show(struct seq_file *m, void *v);
unsigned long ima_get_binary_runtime_size(void);
int ima_init_template(void);
+void ima_init_template_list(void);
#ifdef CONFIG_KEXEC_FILE
void ima_load_kexec_buffer(void);
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 596ef61..592f318 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -418,6 +418,7 @@ static int __init init_ima(void)
{
int error;
+ ima_init_template_list();
hash_setup(CONFIG_IMA_DEFAULT_HASH);
error = ima_init();
if (!error) {
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index 7c90075..804bb95 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -15,16 +15,20 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/rculist.h>
#include "ima.h"
#include "ima_template_lib.h"
-static struct ima_template_desc defined_templates[] = {
+static struct ima_template_desc builtin_templates[] = {
{.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
{.name = "ima-ng", .fmt = "d-ng|n-ng"},
{.name = "ima-sig", .fmt = "d-ng|n-ng|sig"},
{.name = "", .fmt = ""}, /* placeholder for a custom format */
};
+static LIST_HEAD(defined_templates);
+static DEFINE_SPINLOCK(template_list);
+
static struct ima_template_field supported_fields[] = {
{.field_id = "d", .field_init = ima_eventdigest_init,
.field_show = ima_show_template_digest},
@@ -53,6 +57,8 @@ static int __init ima_template_setup(char *str)
if (ima_template)
return 1;
+ ima_init_template_list();
+
/*
* Verify that a template with the supplied name exists.
* If not, use CONFIG_IMA_DEFAULT_TEMPLATE.
@@ -81,7 +87,7 @@ __setup("ima_template=", ima_template_setup);
static int __init ima_template_fmt_setup(char *str)
{
- int num_templates = ARRAY_SIZE(defined_templates);
+ int num_templates = ARRAY_SIZE(builtin_templates);
if (ima_template)
return 1;
@@ -92,22 +98,28 @@ static int __init ima_template_fmt_setup(char *str)
return 1;
}
- defined_templates[num_templates - 1].fmt = str;
- ima_template = defined_templates + num_templates - 1;
+ builtin_templates[num_templates - 1].fmt = str;
+ ima_template = builtin_templates + num_templates - 1;
+
return 1;
}
__setup("ima_template_fmt=", ima_template_fmt_setup);
static struct ima_template_desc *lookup_template_desc(const char *name)
{
- int i;
+ struct ima_template_desc *template_desc;
+ int found = 0;
- for (i = 0; i < ARRAY_SIZE(defined_templates); i++) {
- if (strcmp(defined_templates[i].name, name) == 0)
- return defined_templates + i;
+ rcu_read_lock();
+ list_for_each_entry_rcu(template_desc, &defined_templates, list) {
+ if ((strcmp(template_desc->name, name) == 0) ||
+ (strcmp(template_desc->fmt, name) == 0)) {
+ found = 1;
+ break;
+ }
}
-
- return NULL;
+ rcu_read_unlock();
+ return found ? template_desc : NULL;
}
static struct ima_template_field *lookup_template_field(const char *field_id)
@@ -183,11 +195,29 @@ static int template_desc_init_fields(const char *template_fmt,
return 0;
}
+void ima_init_template_list(void)
+{
+ int i;
+
+ if (!list_empty(&defined_templates))
+ return;
+
+ spin_lock(&template_list);
+ for (i = 0; i < ARRAY_SIZE(builtin_templates); i++) {
+ list_add_tail_rcu(&builtin_templates[i].list,
+ &defined_templates);
+ }
+ spin_unlock(&template_list);
+ synchronize_rcu();
+}
+
struct ima_template_desc *ima_template_desc_current(void)
{
- if (!ima_template)
+ if (!ima_template) {
+ ima_init_template_list();
ima_template =
lookup_template_desc(CONFIG_IMA_DEFAULT_TEMPLATE);
+ }
return ima_template;
}
--
2.1.0
