diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 55ee639703ff..bec9a84572c0 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -7617,11 +7617,16 @@ int smb2_ioctl(struct ksmbd_work *work)
 			goto out;
 		}
 
-		if (in_buf_len < sizeof(struct validate_negotiate_info_req))
-			return -EINVAL;
+		if (in_buf_len < offsetof(struct validate_negotiate_info_req,
+					  Dialects)) {
+			ret = -EINVAL;
+			goto out;
+		}
 
-		if (out_buf_len < sizeof(struct validate_negotiate_info_rsp))
-			return -EINVAL;
+		if (out_buf_len < sizeof(struct validate_negotiate_info_rsp)) {
+			ret = -EINVAL;
+			goto out;
+		}
 
 		ret = fsctl_validate_negotiate_info(conn,
 			(struct validate_negotiate_info_req *)&req->Buffer[0],