From d542e2cc9cb8b8b5859deaf0e97e73102231249b Mon Sep 17 00:00:00 2001
From: Jonas Green <jgr@hms.se>
Date: Thu, 16 Jun 2022 14:49:19 +0200
Subject: [PATCH] fix(server): Reading a range when using ValueBackend External
 failed

Changed to first read the complete DataValue to get timestamps and
status. Then if a range is requested the requested range of
the variant is copied into the DataValue.
---
 include/open62541/types.h          | 12 ++++++++++++
 src/server/ua_services_attribute.c |  8 ++++----
 src/ua_types.c                     | 11 +++++++++++
 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/include/open62541/types.h b/include/open62541/types.h
index bd0be5620..0d54d08b3 100644
--- a/include/open62541/types.h
+++ b/include/open62541/types.h
@@ -913,6 +913,18 @@ typedef struct {
     UA_Boolean    hasServerPicoseconds : 1;
 } UA_DataValue;
 
+/* Copy the DataValue, but use only a subset of the (multidimensional) array of
+ * of the variant of the source DataValue. Returns an error code if the variant
+ * of the DataValue is not an array or if the indicated range does not fit.
+ *
+ * @param src The source DataValue
+ * @param dst The target DataValue
+ * @param range The range of the variant of the DataValue to copy
+ * @return Returns UA_STATUSCODE_GOOD or an error code */
+UA_StatusCode UA_EXPORT
+UA_DataValue_copyVariantRange(const UA_DataValue *src, UA_DataValue * UA_RESTRICT dst,
+                              const UA_NumericRange range);
+
 /**
  * DiagnosticInfo
  * ^^^^^^^^^^^^^^
diff --git a/src/server/ua_services_attribute.c b/src/server/ua_services_attribute.c
index 9f996b771..2b2b2c249 100644
--- a/src/server/ua_services_attribute.c
+++ b/src/server/ua_services_attribute.c
@@ -216,10 +216,10 @@ readValueAttributeComplete(UA_Server *server, UA_Session *session,
             }
             /* Set the result */
             if(rangeptr)
-                return UA_Variant_copyRange(
-                    (const UA_Variant *)&vn->valueBackend.backend.external.value,
-                    &v->value, *rangeptr);
-            retval = UA_DataValue_copy(*vn->valueBackend.backend.external.value, v);
+                retval = UA_DataValue_copyVariantRange(
+                    *vn->valueBackend.backend.external.value, v, *rangeptr);
+            else
+                retval = UA_DataValue_copy(*vn->valueBackend.backend.external.value, v);
             break;
         case UA_VALUEBACKENDTYPE_NONE:
             /* Read the value */
diff --git a/src/ua_types.c b/src/ua_types.c
index 5b281b25c..acd412032 100644
--- a/src/ua_types.c
+++ b/src/ua_types.c
@@ -947,6 +947,17 @@ DataValue_copy(UA_DataValue const *src, UA_DataValue *dst,
     return retval;
 }
 
+UA_StatusCode
+UA_DataValue_copyVariantRange(const UA_DataValue *src, UA_DataValue * UA_RESTRICT dst,
+                              const UA_NumericRange range) {
+    memcpy(dst, src, sizeof(UA_DataValue));
+    UA_Variant_init(&dst->value);
+    UA_StatusCode retval = UA_Variant_copyRange(&src->value, &dst->value, range);
+    if(retval != UA_STATUSCODE_GOOD)
+        DataValue_clear(dst, NULL);
+    return retval;
+}
+
 /* DiagnosticInfo */
 static void
 DiagnosticInfo_clear(UA_DiagnosticInfo *p, const UA_DataType *_) {