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Subject[PATCH v7 08/14] ima: Implement hierarchical processing of file accesses
Date
From: Stefan Berger <stefanb@linux.ibm.com>

Implement hierarchical processing of file accesses in IMA namespaces by
walking the list of IMA namespaces towards the init_ima_ns. This way
file accesses can be audited in an IMA namespace and also be evaluated
against the IMA policies of parent IMA namespaces.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
include/linux/ima.h | 9 +++++++++
security/integrity/ima/ima_main.c | 30 ++++++++++++++++++++++++++----
2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/include/linux/ima.h b/include/linux/ima.h
index 61461ee5b208..f9e592bb9560 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -66,6 +66,15 @@ static inline const char * const *arch_get_ima_policy(void)
}
#endif

+static inline struct user_namespace *ima_user_ns(struct ima_namespace *ns)
+{
+ struct user_namespace *user_ns;
+
+ user_ns = current_user_ns();
+ WARN_ON(user_ns->ima_ns != ns);
+ return user_ns;
+}
+
#else
static inline enum hash_algo ima_get_current_hash_algo(void)
{
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 98be891c2621..4c85a8df3c86 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -200,10 +200,10 @@ void ima_file_free(struct file *file)
ima_check_last_writer(iint, inode, file);
}

-static int process_measurement(struct ima_namespace *ns,
- struct file *file, const struct cred *cred,
- u32 secid, char *buf, loff_t size, int mask,
- enum ima_hooks func)
+static int __process_measurement(struct ima_namespace *ns,
+ struct file *file, const struct cred *cred,
+ u32 secid, char *buf, loff_t size, int mask,
+ enum ima_hooks func)
{
struct inode *inode = file_inode(file);
struct integrity_iint_cache *iint = NULL;
@@ -405,6 +405,28 @@ static int process_measurement(struct ima_namespace *ns,
return 0;
}

+static int process_measurement(struct ima_namespace *ns,
+ struct file *file, const struct cred *cred,
+ u32 secid, char *buf, loff_t size, int mask,
+ enum ima_hooks func)
+{
+ struct user_namespace *user_ns = ima_user_ns(ns);
+ int ret = 0;
+
+ while (user_ns) {
+ ns = user_ns->ima_ns;
+
+ ret = __process_measurement(ns, file, cred, secid, buf, size,
+ mask, func);
+ if (ret)
+ break;
+
+ user_ns = user_ns->parent;
+ };
+
+ return ret;
+}
+
/**
* ima_file_mmap - based on policy, collect/store measurement.
* @file: pointer to the file to be measured (May be NULL)
--
2.31.1
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