From e451dc5f65492fc323b7cdbc480e69dbe3e2d0f9 Mon Sep 17 00:00:00 2001
From: Naren Venkataraman <naren@doorul.com>
Date: Wed, 4 Nov 2015 04:33:32 -0500
Subject: [PATCH] Make sure Upload-Offset in PATCH request is greater than 0

---
 handler.go | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/handler.go b/handler.go
index 9051b43..a44be99 100644
--- a/handler.go
+++ b/handler.go
@@ -284,6 +284,13 @@ func (handler *Handler) patchFile(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	//Check for presence of a valid Upload-Offset Header
+	offset, err := strconv.ParseInt(r.Header.Get("Upload-Offset"), 10, 64)
+	if err != nil || offset < 0 {
+		handler.sendError(w, r, ErrInvalidOffset)
+		return
+	}
+
 	id := r.URL.Query().Get(":id")
 
 	// Ensure file is not locked
@@ -312,13 +319,6 @@ func (handler *Handler) patchFile(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Ensure the offsets match
-	offset, err := strconv.ParseInt(r.Header.Get("Upload-Offset"), 10, 64)
-	if err != nil {
-		handler.sendError(w, r, ErrInvalidOffset)
-		return
-	}
-
 	if offset != info.Offset {
 		handler.sendError(w, r, ErrIllegalOffset)
 		return