[PATCH v15 07/26] ima: Move some IMA policy and filesystem related variables into ima_namespace

Stefan Berger
2023-02-06T14:04:15Z

Move the variables ima_write_mutex, ima_fs_flag, and valid_policy, which
are related to updating the IMA policy, into the ima_namespace. This way
each IMA namespace can set these variables independently in its instance
of securityfs.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
---
security/integrity/ima/ima.h | 5 ++++
security/integrity/ima/ima_fs.c | 32 +++++++++++-------------
security/integrity/ima/ima_init_ima_ns.c | 4 +++
3 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 9b751f796c77..4141a219bdd6 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -137,6 +137,11 @@ struct ima_namespace {
struct ima_h_table ima_htable;
struct list_head ima_measurements; /* list of all measurements */
unsigned long binary_runtime_size; /* used by init_ima_ns */
+
+ /* securityfs support related variables */
+ struct mutex ima_write_mutex;
+ unsigned long ima_fs_flags;
+ int valid_policy;
} __randomize_layout;
extern struct ima_namespace init_ima_ns;

diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 5ef0e2b2cf64..4cf786f0bba8 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -24,8 +24,6 @@

#include "ima.h"

-static DEFINE_MUTEX(ima_write_mutex);
-
bool ima_canonical_fmt;
static int __init default_canonical_fmt_setup(char *str)
{
@@ -36,8 +34,6 @@ 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)
{
@@ -338,7 +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;

@@ -353,12 +349,12 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
} else {
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;
}
@@ -375,8 +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,
@@ -391,6 +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 = &init_ima_ns;
+
if (!(filp->f_flags & O_WRONLY)) {
#ifndef CONFIG_IMA_READ_POLICY
return -EACCES;
@@ -402,7 +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;
}
@@ -416,25 +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 = &init_ima_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;
}

@@ -443,7 +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 a7477072c587..425eed1c6838 100644
--- a/security/integrity/ima/ima_init_ima_ns.c
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -26,6 +26,10 @@ static 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;
}

--
2.37.3