[PATCH v8 02/19] ima: Define ima_namespace structure and implement basic functions

[Stefan Berger <stefanb@xxxxxxxxxxxxxxxxxx>]

From: Stefan Berger <stefanb@xxxxxxxxxxxxx>

Define the initial ima_namespace structure and the ima_namespace
variable init_ima_ns for the host's IMA namespace. Implement basic
functions for namespacing support.

For now let get_current_ns() always returns a pointer to init_ima_ns.

Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
---
 security/integrity/ima/Makefile          |  2 +-
 security/integrity/ima/ima.h             | 10 ++++++++++
 security/integrity/ima/ima_init.c        |  4 ++++
 security/integrity/ima/ima_init_ima_ns.c | 23 +++++++++++++++++++++++
 4 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 security/integrity/ima/ima_init_ima_ns.c

diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
index 2499f2485c04..f8a5e5f3975d 100644
--- a/security/integrity/ima/Makefile
+++ b/security/integrity/ima/Makefile
@@ -7,7 +7,7 @@
 obj-$(CONFIG_IMA) += ima.o
 
 ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
-	 ima_policy.o ima_template.o ima_template_lib.o
+	 ima_policy.o ima_template.o ima_template_lib.o ima_init_ima_ns.o
 ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o
 ima-$(CONFIG_IMA_APPRAISE_MODSIG) += ima_modsig.o
 ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index be965a8715e4..c4af3275f015 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -119,6 +119,10 @@ struct ima_kexec_hdr {
 	u64 count;
 };
 
+struct ima_namespace {
+} __randomize_layout;
+extern struct ima_namespace init_ima_ns;
+
 extern const int read_idmap[];
 
 #ifdef CONFIG_HAVE_IMA_KEXEC
@@ -136,6 +140,7 @@ extern bool ima_canonical_fmt;
 /* Internal IMA function definitions */
 int ima_init(void);
 int ima_fs_init(void);
+int ima_ns_init(void);
 int ima_add_template_entry(struct ima_template_entry *entry, int violation,
 			   const char *op, struct inode *inode,
 			   const unsigned char *filename);
@@ -450,4 +455,9 @@ static inline int ima_filter_rule_match(u32 secid, u32 field, u32 op,
 #define	POLICY_FILE_FLAGS	S_IWUSR
 #endif /* CONFIG_IMA_READ_POLICY */
 
+static inline struct ima_namespace *get_current_ns(void)
+{
+	return &init_ima_ns;
+}
+
 #endif /* __LINUX_IMA_H */
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index b26fa67476b4..f6ae4557a0da 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -120,6 +120,10 @@ int __init ima_init(void)
 {
 	int rc;
 
+	rc = ima_ns_init();
+	if (rc)
+		return rc;
+
 	ima_tpm_chip = tpm_default_chip();
 	if (!ima_tpm_chip)
 		pr_info("No TPM chip found, activating TPM-bypass!\n");
diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c
new file mode 100644
index 000000000000..daa609892849
--- /dev/null
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016-2021 IBM Corporation
+ * Author:
+ *   Yuqiong Sun <suny@xxxxxxxxxx>
+ *   Stefan Berger <stefanb@xxxxxxxxxxxxxxxxxx>
+ */
+
+#include "ima.h"
+
+static int ima_init_namespace(struct ima_namespace *ns)
+{
+	return 0;
+}
+
+int __init ima_ns_init(void)
+{
+	return ima_init_namespace(&init_ima_ns);
+}
+
+struct ima_namespace init_ima_ns = {
+};
+EXPORT_SYMBOL(init_ima_ns);
-- 
2.31.1