[PATCH v11 13/27] ima: Only accept AUDIT rules for non-init_ima_ns namespaces for now

[Stefan Berger]

Only accept AUDIT rules for non-init_ima_ns namespaces for now. Reject
all rules that require support for measuring, appraisal, and hashing.

Signed-off-by: Stefan Berger <stefanb at linux.ibm.com>
Acked-by: Christian Brauner <brauner at kernel.org>
Reviewed-by: Mimi Zohar <zohar at linux.ibm.com>

---
v9:
  - Jump to err_audit when unsupported rules are detected
---
 security/integrity/ima/ima_policy.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 060d45cf35a7..c30e1f4490ae 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -1813,6 +1813,17 @@ static int ima_parse_rule(struct ima_namespace *ns,
 			result = -EINVAL;
 			break;
 		}
+
+		/* IMA namespace only accepts AUDIT rules */
+		if (ns != &init_ima_ns && result == 0) {
+			switch (entry->action) {
+			case MEASURE:
+			case APPRAISE:
+			case HASH:
+				result = -EINVAL;
+				goto err_audit;
+			}
+		}
 	}
 	if (!result && !ima_validate_rule(entry))
 		result = -EINVAL;
@@ -1825,6 +1836,7 @@ static int ima_parse_rule(struct ima_namespace *ns,
 		check_template_modsig(template_desc);
 	}
 
+err_audit:
 	audit_log_format(ab, "res=%d", !result);
 	audit_log_end(ab);
 	return result;
-- 
2.31.1