Thread (40 messages) 40 messages, 5 authors, 2021-12-16

[PATCH v4 10/16] ima: Implement hierarchical processing of file accesses

STALE1752d

From: Stefan Berger <stefanb@linux.ibm.com>
Date: 2021-12-07 20:22:55
Also in: linux-security-module, lkml
Subsystem: extended verification module (evm), integrity measurement architecture (ima), security subsystem, the rest · Maintainers: Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds

Revision v4 of 10 in this series.

Revisions (10)
  1. v3 [diff vs current]
  2. v4 current
  3. v5 [diff vs current]
  4. v6 [diff vs current]
  5. v10 [diff vs current]
  6. v11 [diff vs current]
  7. v12 [diff vs current]
  8. v13 [diff vs current]
  9. v14 [diff vs current]
  10. v15 [diff vs current]
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>
---
 security/integrity/ima/ima_main.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 2121a831f38a..e9fa46eedd27 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 +405,27 @@ 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)
+{
+	int ret = 0;
+	struct user_namespace *user_ns;
+
+	do {
+		ret = _process_measurement(ns, file, cred, secid, buf, size, mask, func);
+		if (ret)
+			break;
+		user_ns = ns->user_ns->parent;
+		if (!user_ns)
+			break;
+		ns = user_ns->ima_ns;
+	} while (1);
+
+	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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