SERVER-16659 Better error detection when parsing cursor cmd requests

1 files changed, 7 insertions, 5 deletions

diff --git a/src/mongo/db/commands.cpp b/src/mongo/db/commands.cpp
index 36bb2a37da6..7fcfeebf3e1 100644
--- a/src/mongo/db/commands.cpp
+++ b/src/mongo/db/commands.cpp
@@ -282,12 +282,14 @@ namespace mongo {
 
         BSONObj cursor = cursorElem.embeddedObject();
         BSONElement batchSizeElem = cursor["batchSize"];
-        if (batchSizeElem.eoo()) {
-            if (!cursor.isEmpty()) {
-                return Status(ErrorCodes::BadValue,
-                              "cursor object can't contain fields other than batchSize");
-            }
 
+        const int expectedNumberOfCursorFields = batchSizeElem.eoo() ? 0 : 1;
+        if (cursor.nFields() != expectedNumberOfCursorFields) {
+            return Status(ErrorCodes::BadValue,
+                          "cursor object can't contain fields other than batchSize");
+        }
+
+        if (batchSizeElem.eoo()) {
             return Status::OK();
         }