[RFC 14/20] ima: Move some IMA policy and filesystem related variables into ima_namespace

[Stefan Berger]

Move the ima_write_mutex, ima_fs_flag, and valid_policy variables into
ima_namespace. This way each IMA namespace can set those variables
independently.

Signed-off-by: Stefan Berger <stefanb at linux.ibm.com>
---
 include/linux/ima.h                      |  5 ++++
 security/integrity/ima/ima_fs.c          | 35 +++++++++++-------------
 security/integrity/ima/ima_init_ima_ns.c |  4 +++
 3 files changed, 25 insertions(+), 19 deletions(-)

diff --git a/include/linux/ima.h b/include/linux/ima.h
index 850a513834d2..fe08919df326 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -262,6 +262,11 @@ struct ima_namespace {
 	struct ima_h_table ima_htable;
 	struct list_head ima_measurements;
 	unsigned long binary_runtime_size;
+
+	/* IMA's filesystem */
+	struct mutex ima_write_mutex;
+	unsigned long ima_fs_flags;
+	int valid_policy;
 };
 
 extern struct ima_namespace init_ima_ns;
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index c35e15fb313f..6c86f81c9998 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -25,8 +25,6 @@
 
 #include "ima.h"
 
-static DEFINE_MUTEX(ima_write_mutex);
-
 bool ima_canonical_fmt;
 static int __init default_canonical_fmt_setup(char *str)
 {
@@ -37,8 +35,6 @@ static int __init default_canonical_fmt_setup(char *str)
 }
 __setup("ima_canonical_fmt", default_canonical_fmt_setup);
 
-static int valid_policy = 1;
-
 static ssize_t ima_show_htable_value(char __user *buf, size_t count,
 				     loff_t *ppos, atomic_long_t *val)
 {
@@ -320,6 +316,7 @@ static ssize_t ima_read_policy(char *path)
 static ssize_t ima_write_policy(struct file *file, const char __user *buf,
 				size_t datalen, loff_t *ppos)
 {
+	struct ima_namespace *ns = get_current_ns();
 	char *data;
 	ssize_t result;
 
@@ -337,7 +334,7 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
 		goto out;
 	}
 
-	result = mutex_lock_interruptible(&ima_write_mutex);
+	result = mutex_lock_interruptible(&ns->ima_write_mutex);
 	if (result < 0)
 		goto out_free;
 
@@ -350,14 +347,14 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
 				    1, 0);
 		result = -EACCES;
 	} else {
-		result = ima_parse_add_rule(get_current_ns(), data);
+		result = ima_parse_add_rule(ns, data);
 	}
-	mutex_unlock(&ima_write_mutex);
+	mutex_unlock(&ns->ima_write_mutex);
 out_free:
 	kfree(data);
 out:
 	if (result < 0)
-		valid_policy = 0;
+		ns->valid_policy = 0;
 
 	return result;
 }
@@ -374,8 +371,6 @@ enum ima_fs_flags {
 	IMA_FS_BUSY,
 };
 
-static unsigned long ima_fs_flags;
-
 #ifdef	CONFIG_IMA_READ_POLICY
 static const struct seq_operations ima_policy_seqops = {
 		.start = ima_policy_start,
@@ -390,6 +385,8 @@ static const struct seq_operations ima_policy_seqops = {
  */
 static int ima_open_policy(struct inode *inode, struct file *filp)
 {
+	struct ima_namespace *ns = get_current_ns();
+
 	if (!(filp->f_flags & O_WRONLY)) {
 #ifndef	CONFIG_IMA_READ_POLICY
 		return -EACCES;
@@ -401,7 +398,7 @@ static int ima_open_policy(struct inode *inode, struct file *filp)
 		return seq_open(filp, &ima_policy_seqops);
 #endif
 	}
-	if (test_and_set_bit(IMA_FS_BUSY, &ima_fs_flags))
+	if (test_and_set_bit(IMA_FS_BUSY, &ns->ima_fs_flags))
 		return -EBUSY;
 	return 0;
 }
@@ -415,25 +412,25 @@ static int ima_open_policy(struct inode *inode, struct file *filp)
  */
 static int ima_release_policy(struct inode *inode, struct file *file)
 {
-	const char *cause = valid_policy ? "completed" : "failed";
 	struct ima_namespace *ns = get_current_ns();
+	const char *cause = ns->valid_policy ? "completed" : "failed";
 
 	if ((file->f_flags & O_ACCMODE) == O_RDONLY)
 		return seq_release(inode, file);
 
-	if (valid_policy && ima_check_policy(ns) < 0) {
+	if (ns->valid_policy && ima_check_policy(ns) < 0) {
 		cause = "failed";
-		valid_policy = 0;
+		ns->valid_policy = 0;
 	}
 
 	pr_info("policy update %s\n", cause);
 	integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
-			    "policy_update", cause, !valid_policy, 0);
+			    "policy_update", cause, !ns->valid_policy, 0);
 
-	if (!valid_policy) {
+	if (!ns->valid_policy) {
 		ima_delete_rules(ns);
-		valid_policy = 1;
-		clear_bit(IMA_FS_BUSY, &ima_fs_flags);
+		ns->valid_policy = 1;
+		clear_bit(IMA_FS_BUSY, &ns->ima_fs_flags);
 		return 0;
 	}
 
@@ -442,7 +439,7 @@ static int ima_release_policy(struct inode *inode, struct file *file)
 	securityfs_remove(ima_policy);
 	ima_policy = NULL;
 #elif defined(CONFIG_IMA_WRITE_POLICY)
-	clear_bit(IMA_FS_BUSY, &ima_fs_flags);
+	clear_bit(IMA_FS_BUSY, &ns->ima_fs_flags);
 #elif defined(CONFIG_IMA_READ_POLICY)
 	inode->i_mode &= ~S_IWUSR;
 #endif
diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c
index 57e46a10c001..22ff74e85a5f 100644
--- a/security/integrity/ima/ima_init_ima_ns.c
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -49,6 +49,10 @@ int ima_init_namespace(struct ima_namespace *ns)
 	else
 		ns->binary_runtime_size = ULONG_MAX;
 
+	mutex_init(&ns->ima_write_mutex);
+	ns->valid_policy = 1;
+	ns->ima_fs_flags = 0;
+
 	return 0;
 }
 
-- 
2.31.1