[PATCH v8 13/19] ima: Add functions for creation and freeing of an ima_namespace

Stefan Berger
2022-01-04T17:04:53Z

From: Stefan Berger <stefanb@linux.ibm.com>

Implement create_ima_ns() to create and initialize an ima_namespace
and implement free_ima_ns() to free it.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
include/linux/ima.h | 13 +++++
security/integrity/ima/Makefile | 1 +
security/integrity/ima/ima.h | 16 +++++++
security/integrity/ima/ima_init_ima_ns.c | 2 +-
security/integrity/ima/ima_ns.c | 61 ++++++++++++++++++++++++
5 files changed, 92 insertions(+), 1 deletion(-)
create mode 100644 security/integrity/ima/ima_ns.c

diff --git a/include/linux/ima.h b/include/linux/ima.h
index e1d65162d1fb..06c88cb17b21 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -226,4 +226,17 @@ static inline bool ima_appraise_signature(enum kernel_read_file_id func)
return false;
}
#endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
+
+#ifdef CONFIG_IMA_NS
+
+void free_ima_ns(struct user_namespace *ns);
+
+#else
+
+static inline void free_ima_ns(struct user_namespace *user_ns)
+{
+}
+
+#endif /* CONFIG_IMA_NS */
+
#endif /* _LINUX_IMA_H */
diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
index f8a5e5f3975d..b86a35fbed60 100644
--- a/security/integrity/ima/Makefile
+++ b/security/integrity/ima/Makefile
@@ -14,6 +14,7 @@ ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o
ima-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o
ima-$(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) += ima_asymmetric_keys.o
ima-$(CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS) += ima_queue_keys.o
+ima-$(CONFIG_IMA_NS) += ima_ns.o

ifeq ($(CONFIG_EFI),y)
ima-$(CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT) += ima_efi.o
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index f63c6f22b853..4255301e5b96 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -163,6 +163,7 @@ extern bool ima_canonical_fmt;
int ima_init(void);
int ima_fs_init(void);
int ima_ns_init(void);
+int ima_init_namespace(struct ima_namespace *ns);
int ima_add_template_entry(struct ima_namespace *ns,
struct ima_template_entry *entry, int violation,
const char *op, struct inode *inode,
@@ -503,4 +504,19 @@ static inline struct ima_namespace *get_current_ns(void)
return &init_ima_ns;
}

+#ifdef CONFIG_IMA_NS
+
+struct ima_namespace *create_ima_ns(struct user_namespace *user_ns);
+
+#else
+
+static inline struct ima_namespace *
+create_ima_ns(struct user_namespace *user_ns)
+{
+ WARN(1, "Cannot create an IMA namespace\n");
+ return ERR_PTR(-EFAULT);
+}
+
+#endif /* CONFIG_IMA_NS */
+
#endif /* __LINUX_IMA_H */
diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c
index 68671f976756..6eac998781c3 100644
--- a/security/integrity/ima/ima_init_ima_ns.c
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -8,7 +8,7 @@

#include "ima.h"

-static int ima_init_namespace(struct ima_namespace *ns)
+int ima_init_namespace(struct ima_namespace *ns)
{
INIT_LIST_HEAD(&ns->ima_default_rules);
INIT_LIST_HEAD(&ns->ima_policy_rules);
diff --git a/security/integrity/ima/ima_ns.c b/security/integrity/ima/ima_ns.c
new file mode 100644
index 000000000000..675466d292e8
--- /dev/null
+++ b/security/integrity/ima/ima_ns.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016-2021 IBM Corporation
+ * Author:
+ * Yuqiong Sun <suny@us.ibm.com>
+ * Stefan Berger <stefanb@linux.vnet.ibm.com>
+ */
+
+#include <linux/ima.h>
+
+#include "ima.h"
+
+static struct kmem_cache *imans_cachep;
+
+struct ima_namespace *create_ima_ns(struct user_namespace *user_ns)
+{
+ struct ima_namespace *ns;
+ int err;
+
+ ns = kmem_cache_zalloc(imans_cachep, GFP_KERNEL);
+ if (!ns)
+ return ERR_PTR(-ENOMEM);
+ pr_debug("NEW ima_ns: %p\n", ns);
+
+ err = ima_init_namespace(ns);
+ if (err)
+ goto fail_free;
+
+ user_ns->ima_ns = ns;
+
+ return ns;
+
+fail_free:
+ kmem_cache_free(imans_cachep, ns);
+
+ return ERR_PTR(err);
+}
+
+static void destroy_ima_ns(struct ima_namespace *ns)
+{
+ pr_debug("DESTROY ima_ns: %p\n", ns);
+ ima_free_policy_rules(ns);
+ kmem_cache_free(imans_cachep, ns);
+}
+
+void free_ima_ns(struct user_namespace *user_ns)
+{
+ struct ima_namespace *ns = user_ns->ima_ns;
+
+ if (!ns || WARN_ON(ns == &init_ima_ns))
+ return;
+
+ destroy_ima_ns(ns);
+}
+
+static int __init imans_cache_init(void)
+{
+ imans_cachep = KMEM_CACHE(ima_namespace, SLAB_PANIC);
+ return 0;
+}
+subsys_initcall(imans_cache_init)
--
2.31.1