Message-Id: <20220201203735.164593-28-stefanb@linux.ibm.com>
Date:   Tue,  1 Feb 2022 15:37:35 -0500
From:   Stefan Berger <stefanb@...ux.ibm.com>
To:     linux-integrity@...r.kernel.org
Cc:     zohar@...ux.ibm.com, serge@...lyn.com,
        christian.brauner@...ntu.com, containers@...ts.linux.dev,
        dmitry.kasatkin@...il.com, ebiederm@...ssion.com,
        krzysztof.struczynski@...wei.com, roberto.sassu@...wei.com,
        mpeters@...hat.com, lhinds@...hat.com, lsturman@...hat.com,
        puiterwi@...hat.com, jejb@...ux.ibm.com, jamjoom@...ibm.com,
        linux-kernel@...r.kernel.org, paul@...l-moore.com, rgb@...hat.com,
        linux-security-module@...r.kernel.org, jmorris@...ei.org,
        Stefan Berger <stefanb@...ux.ibm.com>
Subject: [PATCH v10 27/27] ima: Enable IMA namespaces

Introduce the IMA_NS in Kconfig for IMA namespace enablement.

Enable the lazy initialization of an IMA namespace when a user mounts
SecurityFS and writes '1' into IMA's 'active' securityfs file. A
user_namespace will now get a pointer to an ima_namespace and therefore
implement get_current_ns() for the namespacing case that returns this
pointer. Use get_current_ns() in those places that require access to the
current IMA namespace. In some places, primarily those related to
IMA-appraisal and changes to file attributes, keep the pointer to
init_ima_ns, since there flags related to file measurements may be
affected, which are not supported in IMA namespaces, yet.

Before using the ima_namespace pointer test it with ns_is_active()
to check whether it is NULL and whether the ima_namespace is active.
If it's not active, it cannot be used, yet. Therefore, return early
from those functions that may now get either get a NULL pointer from
this call or where ns->active is still 0. The init_ima_ns is always
set to be active, thus passing the check.

Implement ima_ns_from_file() for SecurityFS-related files where we can
now get the IMA namespace via the user namespace pointer associated
with the superblock of the SecurityFS filesystem instance.

Return -EACCES to IMA's securityfs files, except for the 'active' file,
until the IMA namespace has been set to active.

Switch access to userns->ima_ns to use acquire/release semantics to ensure
that a newly created ima_namespace structure is fully visible upon access.

Only emit the kernel log message 'policy update completed' for the
init_ima_ns.

When parsing an IMA policy rule use the user namespace of the opener
to translate uid and gid values to kernel values rather than the user
namespace of the writer.

Gate access to ima_appraise variable to init_ima_ns in ima_load_data()
and ima_write_policy().

Gate access to temp_ima_appraise variable to init_ima_ns in
ima_delete_rules().

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

---
v10:
 - dropped ima_ns_to_user_ns(); using current_user_ns() instead
 - Pass user_namespace of file opener into ima_parse_rule and propagate
   this parameter back all the way to the initial caller in the chain
 - Gate access to ima_appraise to init_ima_ns in ima_write_policy()

v9:
 - ima_post_key_create_or_update: Only handle key if in init_ima_ns
 - Removed ns == NULL checks where user_namespace is now passed
 - Defer setting of user_ns->ima_ns until end of ima_fs_ns_init();
   required new ima_free_imans() and new user_ns_set_ima_ns()
 - Only emit log message 'policy update completed' for init_ima_ns
 - Introduce get_current_ns() only in this patch
 - Check for ns == &init_ima_ns in ima_load_data()
---
 include/linux/ima.h                          |  1 +
 init/Kconfig                                 | 13 +++
 kernel/user_namespace.c                      |  2 +
 security/integrity/ima/ima.h                 | 55 +++++++++++--
 security/integrity/ima/ima_appraise.c        |  3 +
 security/integrity/ima/ima_asymmetric_keys.c |  6 +-
 security/integrity/ima/ima_fs.c              | 87 ++++++++++++++++----
 security/integrity/ima/ima_init.c            |  2 +-
 security/integrity/ima/ima_init_ima_ns.c     |  2 +
 security/integrity/ima/ima_main.c            | 34 +++++---
 security/integrity/ima/ima_ns.c              | 15 +++-
 security/integrity/ima/ima_policy.c          | 43 ++++++----
 12 files changed, 202 insertions(+), 61 deletions(-)

diff --git a/include/linux/ima.h b/include/linux/ima.h
index c584527c0f47..a8cb2c269f61 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -11,6 +11,7 @@
 #include <linux/fs.h>
 #include <linux/security.h>
 #include <linux/kexec.h>
+#include <linux/user_namespace.h>
 #include <crypto/hash_info.h>
 struct linux_binprm;
 
diff --git a/init/Kconfig b/init/Kconfig
index 4b7bac10c72d..e27155e0ddba 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1247,6 +1247,19 @@ config NET_NS
 	  Allow user space to create what appear to be multiple instances
 	  of the network stack.
 
+config IMA_NS
+	bool "IMA namespace"
+	depends on USER_NS
+	depends on IMA
+	default n
+	help
+	  Allow the creation of an IMA namespace for each user namespace.
+	  Namespaced IMA enables having IMA features work separately
+	  in each IMA namespace.
+	  Currently, only the audit status flags are stored in the namespace,
+	  which allows the same file to be audited each time it is accessed
+	  in a new namespace.
+
 endif # NAMESPACES
 
 config CHECKPOINT_RESTORE
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 6b2e3ca7ee99..653f8fa83b69 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -20,6 +20,7 @@
 #include <linux/fs_struct.h>
 #include <linux/bsearch.h>
 #include <linux/sort.h>
+#include <linux/ima.h>
 
 static struct kmem_cache *user_ns_cachep __read_mostly;
 static DEFINE_MUTEX(userns_state_mutex);
@@ -196,6 +197,7 @@ static void free_user_ns(struct work_struct *work)
 			kfree(ns->projid_map.forward);
 			kfree(ns->projid_map.reverse);
 		}
+		free_ima_ns(ns);
 		retire_userns_sysctls(ns);
 		key_free_user_ns(ns);
 		ns_free_inum(&ns->ns);
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 05e2de7697da..73df1d8a2ece 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -337,10 +337,10 @@ int ima_match_policy(struct ima_namespace *ns,
 		     int mask, int flags, int *pcr,
 		     struct ima_template_desc **template_desc,
 		     const char *func_data, unsigned int *allowed_algos);
-void ima_init_policy(struct ima_namespace *ns);
+void ima_init_policy(struct user_namespace *user_ns);
 void ima_update_policy(struct ima_namespace *ns);
 void ima_update_policy_flags(struct ima_namespace *ns);
-ssize_t ima_parse_add_rule(struct ima_namespace *ns, char *rule);
+ssize_t ima_parse_add_rule(struct user_namespace *user_ns, char *rule);
 void ima_delete_rules(struct ima_namespace *ns);
 int ima_check_policy(struct ima_namespace *ns);
 void ima_free_policy_rules(struct ima_namespace *ns);
@@ -538,32 +538,70 @@ struct user_namespace *ima_user_ns_from_file(const struct file *filp)
 	return file_inode(filp)->i_sb->s_user_ns;
 }
 
+#ifdef CONFIG_IMA_NS
+
 static inline struct ima_namespace
 *ima_ns_from_user_ns(struct user_namespace *user_ns)
 {
-	if (user_ns == &init_user_ns)
-		return &init_ima_ns;
-	return NULL;
+	/* Pairs with smp_store_releases() in user_ns_set_ima_ns(). */
+	return smp_load_acquire(&user_ns->ima_ns);
 }
 
-#ifdef CONFIG_IMA_NS
+static inline void user_ns_set_ima_ns(struct user_namespace *user_ns,
+				      struct ima_namespace *ns)
+{
+	/* Pairs with smp_load_acquire() in ima_ns_from_user_ns() */
+	smp_store_release(&user_ns->ima_ns, ns);
+}
+
+static inline struct ima_namespace *get_current_ns(void)
+{
+	return ima_ns_from_user_ns(current_user_ns());
+}
 
 struct ima_namespace *create_ima_ns(void);
 
+void ima_free_ima_ns(struct ima_namespace *ns);
+
 struct ns_status *ima_get_ns_status(struct ima_namespace *ns,
 				    struct inode *inode,
 				    struct integrity_iint_cache *iint);
 
 void ima_free_ns_status_tree(struct ima_namespace *ns);
 
+static inline struct ima_namespace *ima_ns_from_file(const struct file *filp)
+{
+	return ima_user_ns_from_file(filp)->ima_ns;
+}
+
 #else
 
+static inline struct ima_namespace
+*ima_ns_from_user_ns(struct user_namespace *user_ns)
+{
+	if (user_ns == &init_user_ns)
+		return &init_ima_ns;
+	return NULL;
+}
+
+static inline void user_ns_set_ima_ns(struct user_namespace *user_ns,
+				      struct ima_namespace *ns)
+{
+}
+
+static inline struct ima_namespace *get_current_ns(void)
+{
+	return &init_ima_ns;
+}
+
 static inline struct ima_namespace *create_ima_ns(void)
 {
 	WARN(1, "Cannot create an IMA namespace\n");
 	return ERR_PTR(-EFAULT);
 }
 
+static inline void ima_free_ima_ns(struct ima_namespace *ns) {}
+
 static inline struct ns_status *ima_get_ns_status(struct ima_namespace *ns,
 						  struct inode *inode,
 						  struct integrity_iint_cache *iint)
@@ -578,6 +616,11 @@ static inline struct ns_status *ima_get_ns_status(struct ima_namespace *ns,
 	return ns_status;
 }
 
+static inline struct ima_namespace *ima_ns_from_file(const struct file *filp)
+{
+	return &init_ima_ns;
+}
+
 #endif /* CONFIG_IMA_NS */
 
 #endif /* __LINUX_IMA_H */
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 3461025f671b..2ad3327d7ce6 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -74,6 +74,9 @@ int ima_must_appraise(struct ima_namespace *ns,
 {
 	u32 secid;
 
+	if (ns != &init_ima_ns)
+		return 0;
+
 	if (!ima_appraise)
 		return 0;
 
diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c
index 70d87df26068..0d2cc1e23cde 100644
--- a/security/integrity/ima/ima_asymmetric_keys.c
+++ b/security/integrity/ima/ima_asymmetric_keys.c
@@ -30,9 +30,13 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key,
 				   const void *payload, size_t payload_len,
 				   unsigned long flags, bool create)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = get_current_ns();
 	bool queued = false;
 
+	/* only handle key if related to init_ima_ns */
+	if (ns != &init_ima_ns)
+		return;
+
 	/* Only asymmetric keys are handled by this hook. */
 	if (key->type != &key_type_asymmetric)
 		return;
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index cd102bbd4677..b0e0d37a18cf 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -49,7 +49,10 @@ static ssize_t ima_show_htable_violations(struct file *filp,
 					  char __user *buf,
 					  size_t count, loff_t *ppos)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = ima_ns_from_file(filp);
+
+	if (!ns_is_active(ns))
+		return -EACCES;
 
 	return ima_show_htable_value(buf, count, ppos,
 				     &ns->ima_htable.violations);
@@ -64,7 +67,10 @@ static ssize_t ima_show_measurements_count(struct file *filp,
 					   char __user *buf,
 					   size_t count, loff_t *ppos)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = ima_ns_from_file(filp);
+
+	if (!ns_is_active(ns))
+		return -EACCES;
 
 	return ima_show_htable_value(buf, count, ppos, &ns->ima_htable.len);
 }
@@ -77,7 +83,7 @@ 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 = &init_ima_ns;
+	struct ima_namespace *ns = ima_ns_from_file(m->file);
 	loff_t l = *pos;
 	struct ima_queue_entry *qe;
 
@@ -95,7 +101,7 @@ 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 = &init_ima_ns;
+	struct ima_namespace *ns = ima_ns_from_file(m->file);
 	struct ima_queue_entry *qe = v;
 
 	/* lock protects when reading beyond last element
@@ -198,6 +204,11 @@ static const struct seq_operations ima_measurments_seqops = {
 
 static int ima_measurements_open(struct inode *inode, struct file *file)
 {
+	struct ima_namespace *ns = ima_ns_from_file(file);
+
+	if (!ns_is_active(ns))
+		return -EACCES;
+
 	return seq_open(file, &ima_measurments_seqops);
 }
 
@@ -264,6 +275,11 @@ static const struct seq_operations ima_ascii_measurements_seqops = {
 
 static int ima_ascii_measurements_open(struct inode *inode, struct file *file)
 {
+	struct ima_namespace *ns = ima_ns_from_file(file);
+
+	if (!ns_is_active(ns))
+		return -EACCES;
+
 	return seq_open(file, &ima_ascii_measurements_seqops);
 }
 
@@ -274,7 +290,7 @@ static const struct file_operations ima_ascii_measurements_ops = {
 	.release = seq_release,
 };
 
-static ssize_t ima_read_policy(struct ima_namespace *ns, char *path)
+static ssize_t ima_read_policy(struct user_namespace *user_ns, char *path)
 {
 	void *data = NULL;
 	char *datap;
@@ -299,7 +315,7 @@ static ssize_t ima_read_policy(struct ima_namespace *ns, char *path)
 	datap = data;
 	while (size > 0 && (p = strsep(&datap, "\n"))) {
 		pr_debug("rule: %s\n", p);
-		rc = ima_parse_add_rule(ns, p);
+		rc = ima_parse_add_rule(user_ns, p);
 		if (rc < 0)
 			break;
 		size -= rc;
@@ -317,10 +333,14 @@ static ssize_t ima_read_policy(struct ima_namespace *ns, 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 = &init_ima_ns;
+	struct user_namespace *user_ns = ima_user_ns_from_file(file);
+	struct ima_namespace *ns = ima_ns_from_user_ns(user_ns);
 	char *data;
 	ssize_t result;
 
+	if (!ns_is_active(ns))
+		return -EACCES;
+
 	if (datalen >= PAGE_SIZE)
 		datalen = PAGE_SIZE - 1;
 
@@ -340,15 +360,16 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
 		goto out_free;
 
 	if (data[0] == '/') {
-		result = ima_read_policy(ns, data);
-	} else if (ima_appraise & IMA_APPRAISE_POLICY) {
+		result = ima_read_policy(user_ns, data);
+	} else if (ns == &init_ima_ns &&
+		   (ima_appraise & IMA_APPRAISE_POLICY)) {
 		pr_err("signed policy file (specified as an absolute pathname) required\n");
 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
 				    "policy_update", "signed policy required",
 				    1, 0);
 		result = -EACCES;
 	} else {
-		result = ima_parse_add_rule(ns, data);
+		result = ima_parse_add_rule(user_ns, data);
 	}
 	mutex_unlock(&ns->ima_write_mutex);
 out_free:
@@ -381,7 +402,10 @@ static int ima_open_policy(struct inode *inode, struct file *filp)
 #ifdef CONFIG_IMA_READ_POLICY
 	struct user_namespace *user_ns = ima_user_ns_from_file(filp);
 #endif
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = ima_ns_from_file(filp);
+
+	if (!ns_is_active(ns))
+		return -EACCES;
 
 	if (!(filp->f_flags & O_WRONLY)) {
 #ifndef	CONFIG_IMA_READ_POLICY
@@ -408,7 +432,7 @@ static int ima_open_policy(struct inode *inode, struct file *filp)
  */
 static int ima_release_policy(struct inode *inode, struct file *file)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = ima_ns_from_file(file);
 	const char *cause = ns->valid_policy ? "completed" : "failed";
 	int err = 0;
 
@@ -426,7 +450,8 @@ static int ima_release_policy(struct inode *inode, struct file *file)
 		}
 	}
 
-	pr_info("policy update %s\n", cause);
+	if (ns == &init_ima_ns)
+		pr_info("policy update %s\n", cause);
 	integrity_audit_message(AUDIT_INTEGRITY_STATUS, NULL, NULL,
 				"policy_update", cause, !ns->valid_policy, 0,
 				-err);
@@ -463,7 +488,7 @@ static ssize_t ima_show_active(struct file *filp,
 			       char __user *buf,
 			       size_t count, loff_t *ppos)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = ima_ns_from_file(filp);
 	char tmpbuf[2];
 	ssize_t len;
 
@@ -476,7 +501,7 @@ static ssize_t ima_write_active(struct file *filp,
 				const char __user *buf,
 				size_t count, loff_t *ppos)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = ima_ns_from_file(filp);
 	unsigned int active;
 	char *kbuf;
 	int err;
@@ -500,7 +525,9 @@ static ssize_t ima_write_active(struct file *filp,
 	if (active != 1)
 		return -EINVAL;
 
-	atomic_set(&ns->active, 1);
+	err = ima_init_namespace(ns);
+	if (err)
+		return -EINVAL;
 
 	return count;
 }
@@ -536,11 +563,28 @@ int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root)
 	struct dentry *violations = NULL;
 	int ret;
 
+	/*
+	 * While multiple superblocks can exist they are keyed by userns in
+	 * s_fs_info for securityfs. The first time a userns mounts a
+	 * securityfs instance we lazily allocate the ima_namespace for the
+	 * userns since that's the only way a userns can meaningfully use ima.
+	 * The vfs ensures we're the only one to call fill_super() and hence
+	 * ima_fs_ns_init(), so we don't need any memory barriers here, i.e.
+	 * user_ns->ima_ns can't change while we're in here.
+	 */
+	if (!ns) {
+		ns = create_ima_ns();
+		if (IS_ERR(ns))
+			return PTR_ERR(ns);
+	}
+
 	/* FIXME: update when evm and integrity are namespaced */
 	if (user_ns != &init_user_ns) {
 		int_dir = securityfs_create_dir("integrity", root);
-		if (IS_ERR(int_dir))
-			return PTR_ERR(int_dir);
+		if (IS_ERR(int_dir)) {
+			ret = PTR_ERR(int_dir);
+			goto free_ns;
+		}
 	} else {
 		int_dir = integrity_dir;
 	}
@@ -610,6 +654,9 @@ int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root)
 			goto out;
 	}
 
+	if (!ima_ns_from_user_ns(user_ns))
+		user_ns_set_ima_ns(user_ns, ns);
+
 	return 0;
 out:
 	securityfs_remove(ns->ima_policy);
@@ -622,6 +669,10 @@ int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root)
 	if (user_ns != &init_user_ns)
 		securityfs_remove(int_dir);
 
+free_ns:
+	if (!ima_ns_from_user_ns(user_ns))
+		ima_free_ima_ns(ns);
+
 	return ret;
 }
 
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 22ca5d872be0..a14193c8f99b 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -150,7 +150,7 @@ int __init ima_init(void)
 	if (rc != 0)
 		return rc;
 
-	ima_init_policy(&init_ima_ns);
+	ima_init_policy(&init_user_ns);
 
 	rc = ima_fs_init();
 	if (rc != 0)
diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c
index 39ee0c2477a6..0ff587b874bd 100644
--- a/security/integrity/ima/ima_init_ima_ns.c
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -46,6 +46,8 @@ int ima_init_namespace(struct ima_namespace *ns)
 			return rc;
 	}
 
+	atomic_set(&ns->active, 1);
+
 	return 0;
 }
 
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 9ca9223bbcf6..1ffac9c04df1 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -506,7 +506,7 @@ int ima_file_mmap(struct file *file, unsigned long prot)
  */
 int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = get_current_ns();
 	struct ima_template_desc *template = NULL;
 	struct file *file = vma->vm_file;
 	char filename[NAME_MAX];
@@ -519,7 +519,8 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 	int pcr;
 
 	/* Is mprotect making an mmap'ed file executable? */
-	if (!(ns->ima_policy_flag & IMA_APPRAISE) || !vma->vm_file ||
+	if (!ns_is_active(ns) ||
+	    !(ns->ima_policy_flag & IMA_APPRAISE) || !vma->vm_file ||
 	    !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
 		return 0;
 
@@ -655,9 +656,9 @@ static int __ima_inode_hash(struct ima_namespace *ns,
  */
 int ima_file_hash(struct file *file, char *buf, size_t buf_size)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = get_current_ns();
 
-	if (!file)
+	if (!ns_is_active(ns) || !file)
 		return -EINVAL;
 
 	return __ima_inode_hash(ns, file_inode(file), buf, buf_size);
@@ -684,9 +685,9 @@ EXPORT_SYMBOL_GPL(ima_file_hash);
  */
 int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = get_current_ns();
 
-	if (!inode)
+	if (!ns_is_active(ns) || !inode)
 		return -EINVAL;
 
 	return __ima_inode_hash(ns, inode, buf, buf_size);
@@ -705,11 +706,11 @@ EXPORT_SYMBOL_GPL(ima_inode_hash);
 void ima_post_create_tmpfile(struct user_namespace *mnt_userns,
 			     struct inode *inode)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = get_current_ns();
 	struct integrity_iint_cache *iint;
 	int must_appraise;
 
-	if (!ns->ima_policy_flag || !S_ISREG(inode->i_mode))
+	if (!ns_is_active(ns) || !ns->ima_policy_flag || !S_ISREG(inode->i_mode))
 		return;
 
 	must_appraise = ima_must_appraise(ns, mnt_userns, inode, MAY_ACCESS,
@@ -738,12 +739,12 @@ void ima_post_create_tmpfile(struct user_namespace *mnt_userns,
 void ima_post_path_mknod(struct user_namespace *mnt_userns,
 			 struct dentry *dentry)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = get_current_ns();
 	struct integrity_iint_cache *iint;
 	struct inode *inode = dentry->d_inode;
 	int must_appraise;
 
-	if (!ns->ima_policy_flag || !S_ISREG(inode->i_mode))
+	if (!ns_is_active(ns) || !ns->ima_policy_flag || !S_ISREG(inode->i_mode))
 		return;
 
 	must_appraise = ima_must_appraise(ns, mnt_userns, inode, MAY_ACCESS,
@@ -862,8 +863,12 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
  */
 int ima_load_data(enum kernel_load_data_id id, bool contents)
 {
+	struct ima_namespace *ns = get_current_ns();
 	bool ima_enforce, sig_enforce;
 
+	if (ns != &init_ima_ns)
+		return 0;
+
 	ima_enforce =
 		(ima_appraise & IMA_APPRAISE_ENFORCE) == IMA_APPRAISE_ENFORCE;
 
@@ -1071,10 +1076,10 @@ int process_buffer_measurement(struct ima_namespace *ns,
  */
 void ima_kexec_cmdline(int kernel_fd, const void *buf, int size)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = get_current_ns();
 	struct fd f;
 
-	if (!buf || !size)
+	if (!ns_is_active(ns) || !buf || !size)
 		return;
 
 	f = fdget(kernel_fd);
@@ -1112,7 +1117,10 @@ int ima_measure_critical_data(const char *event_label,
 			      const void *buf, size_t buf_len,
 			      bool hash, u8 *digest, size_t digest_len)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = get_current_ns();
+
+	if (!ns_is_active(ns))
+		return -EINVAL;
 
 	if (!event_name || !event_label || !buf || !buf_len)
 		return -ENOPARAM;
diff --git a/security/integrity/ima/ima_ns.c b/security/integrity/ima/ima_ns.c
index 29af6fea2d74..244dc9d66fb1 100644
--- a/security/integrity/ima/ima_ns.c
+++ b/security/integrity/ima/ima_ns.c
@@ -26,22 +26,29 @@ struct ima_namespace *create_ima_ns(void)
 /* destroy_ima_ns() must only be called after ima_init_namespace() was called */
 static void destroy_ima_ns(struct ima_namespace *ns)
 {
+	atomic_set(&ns->active, 0);
 	unregister_blocking_lsm_notifier(&ns->ima_lsm_policy_notifier);
 	kfree(ns->arch_policy_entry);
 	ima_free_policy_rules(ns);
 	ima_free_ns_status_tree(ns);
 }
 
-void free_ima_ns(struct user_namespace *user_ns)
+void ima_free_ima_ns(struct ima_namespace *ns)
 {
-	struct ima_namespace *ns = user_ns->ima_ns;
-
 	if (!ns || WARN_ON(ns == &init_ima_ns))
 		return;
 
-	destroy_ima_ns(ns);
+	if (ns_is_active(ns))
+		destroy_ima_ns(ns);
 
 	kmem_cache_free(imans_cachep, ns);
+}
+
+void free_ima_ns(struct user_namespace *user_ns)
+{
+	struct ima_namespace *ns = ima_ns_from_user_ns(user_ns);
+
+	ima_free_ima_ns(ns);
 
 	user_ns->ima_ns = NULL;
 }
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 3f84d04f101d..c0bbae550994 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -474,7 +474,8 @@ int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
 		return NOTIFY_DONE;
 
 	ns = container_of(nb, struct ima_namespace, ima_lsm_policy_notifier);
-	ima_lsm_update_rules(ns);
+	if (ns_is_active(ns))
+		ima_lsm_update_rules(ns);
 
 	return NOTIFY_OK;
 }
@@ -844,11 +845,12 @@ static void add_rules(struct ima_namespace *ns,
 	}
 }
 
-static int ima_parse_rule(struct ima_namespace *ns,
+static int ima_parse_rule(struct user_namespace *user_ns,
 			  char *rule, struct ima_rule_entry *entry);
 
-static int __init ima_init_arch_policy(struct ima_namespace *ns)
+static int __init ima_init_arch_policy(struct user_namespace *user_ns)
 {
+	struct ima_namespace *ns = ima_ns_from_user_ns(user_ns);
 	const char * const *arch_rules;
 	const char * const *rules;
 	int arch_entries = 0;
@@ -876,7 +878,7 @@ static int __init ima_init_arch_policy(struct ima_namespace *ns)
 		result = strscpy(rule, *rules, sizeof(rule));
 
 		INIT_LIST_HEAD(&ns->arch_policy_entry[i].list);
-		result = ima_parse_rule(ns, rule, &ns->arch_policy_entry[i]);
+		result = ima_parse_rule(user_ns, rule, &ns->arch_policy_entry[i]);
 		if (result) {
 			pr_warn("Skipping unknown architecture policy rule: %s\n",
 				rule);
@@ -891,11 +893,12 @@ static int __init ima_init_arch_policy(struct ima_namespace *ns)
 
 /**
  * ima_init_policy - initialize the default measure rules.
- * @ns: IMA namespace to which the policy belongs to
+ * @user_ns: User namespace pointig to IMA namespace to which the policy belongs
  * ima_rules points to either the ima_default_rules or the new ima_policy_rules.
  */
-void __init ima_init_policy(struct ima_namespace *ns)
+void __init ima_init_policy(struct user_namespace *user_ns)
 {
+	struct ima_namespace *ns = ima_ns_from_user_ns(user_ns);
 	int build_appraise_entries, arch_entries;
 
 	/* if !ima_policy, we load NO default rules */
@@ -925,7 +928,7 @@ void __init ima_init_policy(struct ima_namespace *ns)
 	 * and custom policies, prior to other appraise rules.
 	 * (Highest priority)
 	 */
-	arch_entries = ima_init_arch_policy(ns);
+	arch_entries = ima_init_arch_policy(user_ns);
 	if (!arch_entries)
 		pr_info("No architecture policies found\n");
 	else
@@ -1346,9 +1349,10 @@ static unsigned int ima_parse_appraise_algos(char *arg)
 	return res;
 }
 
-static int ima_parse_rule(struct ima_namespace *ns,
+static int ima_parse_rule(struct user_namespace *user_ns,
 			  char *rule, struct ima_rule_entry *entry)
 {
+	struct ima_namespace *ns = ima_ns_from_user_ns(user_ns);
 	struct audit_buffer *ab;
 	char *from;
 	char *p;
@@ -1598,7 +1602,7 @@ static int ima_parse_rule(struct ima_namespace *ns,
 
 			result = kstrtoul(args[0].from, 10, &lnum);
 			if (!result) {
-				entry->uid = make_kuid(current_user_ns(),
+				entry->uid = make_kuid(user_ns,
 						       (uid_t) lnum);
 				if (!uid_valid(entry->uid) ||
 				    (uid_t)lnum != lnum)
@@ -1633,7 +1637,7 @@ static int ima_parse_rule(struct ima_namespace *ns,
 
 			result = kstrtoul(args[0].from, 10, &lnum);
 			if (!result) {
-				entry->gid = make_kgid(current_user_ns(),
+				entry->gid = make_kgid(user_ns,
 						       (gid_t)lnum);
 				if (!gid_valid(entry->gid) ||
 				    (((gid_t)lnum) != lnum))
@@ -1660,7 +1664,7 @@ static int ima_parse_rule(struct ima_namespace *ns,
 
 			result = kstrtoul(args[0].from, 10, &lnum);
 			if (!result) {
-				entry->fowner = make_kuid(current_user_ns(),
+				entry->fowner = make_kuid(user_ns,
 							  (uid_t)lnum);
 				if (!uid_valid(entry->fowner) ||
 				    (((uid_t)lnum) != lnum))
@@ -1686,7 +1690,7 @@ static int ima_parse_rule(struct ima_namespace *ns,
 
 			result = kstrtoul(args[0].from, 10, &lnum);
 			if (!result) {
-				entry->fgroup = make_kgid(current_user_ns(),
+				entry->fgroup = make_kgid(user_ns,
 							  (gid_t)lnum);
 				if (!gid_valid(entry->fgroup) ||
 				    (((gid_t)lnum) != lnum))
@@ -1840,14 +1844,15 @@ static int ima_parse_rule(struct ima_namespace *ns,
 
 /**
  * ima_parse_add_rule - add a rule to ima_policy_rules
- * @ns: IMA namespace that has the policy
+ * @user_ns: User namespace referencing the IMA namespace that has the policy
  * @rule - ima measurement policy rule
  *
  * Avoid locking by allowing just one writer at a time in ima_write_policy()
  * Returns the length of the rule parsed, an error code on failure
  */
-ssize_t ima_parse_add_rule(struct ima_namespace *ns, char *rule)
+ssize_t ima_parse_add_rule(struct user_namespace *user_ns, char *rule)
 {
+	struct ima_namespace *ns = ima_ns_from_user_ns(user_ns);
 	static const char op[] = "update_policy";
 	char *p;
 	struct ima_rule_entry *entry;
@@ -1870,7 +1875,7 @@ ssize_t ima_parse_add_rule(struct ima_namespace *ns, char *rule)
 
 	INIT_LIST_HEAD(&entry->list);
 
-	result = ima_parse_rule(ns, p, entry);
+	result = ima_parse_rule(user_ns, p, entry);
 	if (result) {
 		ima_free_rule(entry);
 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
@@ -1895,7 +1900,9 @@ void ima_delete_rules(struct ima_namespace *ns)
 {
 	struct ima_rule_entry *entry, *tmp;
 
-	temp_ima_appraise = 0;
+	if (ns == &init_ima_ns)
+		temp_ima_appraise = 0;
+
 	list_for_each_entry_safe(entry, tmp, &ns->ima_temp_rules, list) {
 		list_del(&entry->list);
 		ima_free_rule(entry);
@@ -1936,7 +1943,7 @@ static const char *const mask_tokens[] = {
 
 void *ima_policy_start(struct seq_file *m, loff_t *pos)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = ima_ns_from_file(m->file);
 	loff_t l = *pos;
 	struct ima_rule_entry *entry;
 	struct list_head *ima_rules_tmp;
@@ -1955,7 +1962,7 @@ void *ima_policy_start(struct seq_file *m, loff_t *pos)
 
 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
 {
-	struct ima_namespace *ns = &init_ima_ns;
+	struct ima_namespace *ns = ima_ns_from_file(m->file);
 	struct ima_rule_entry *entry = v;
 
 	rcu_read_lock();
-- 
2.31.1

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