From 2ac27616bcc9f37adb22ccd00662584724d47a6d Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Sun, 16 Aug 2020 23:47:34 -0700
Subject: [PATCH] fix possible out of range bytes

avoid buff out of range resp.Data = buff[:totalRead]
---
 weed/filesys/dirty_page.go          |  2 +-
 weed/filesys/dirty_page_interval.go | 15 ++-------------
 weed/filesys/filehandle.go          | 11 +++++------
 3 files changed, 8 insertions(+), 20 deletions(-)

diff --git a/weed/filesys/dirty_page.go b/weed/filesys/dirty_page.go
index ba8f7ec41..9e8ec1702 100644
--- a/weed/filesys/dirty_page.go
+++ b/weed/filesys/dirty_page.go
@@ -172,7 +172,7 @@ func min(x, y int64) int64 {
 	return y
 }
 
-func (pages *ContinuousDirtyPages) ReadDirtyData(data []byte, startOffset int64) (offset int64, size int) {
+func (pages *ContinuousDirtyPages) ReadDirtyData(data []byte, startOffset int64) (maxStop int64) {
 
 	pages.lock.Lock()
 	defer pages.lock.Unlock()
diff --git a/weed/filesys/dirty_page_interval.go b/weed/filesys/dirty_page_interval.go
index ec94c6df1..10b74bb68 100644
--- a/weed/filesys/dirty_page_interval.go
+++ b/weed/filesys/dirty_page_interval.go
@@ -3,7 +3,6 @@ package filesys
 import (
 	"bytes"
 	"io"
-	"math"
 )
 
 type IntervalNode struct {
@@ -186,25 +185,15 @@ func (c *ContinuousIntervals) removeList(target *IntervalLinkedList) {
 
 }
 
-func (c *ContinuousIntervals) ReadData(data []byte, startOffset int64) (offset int64, size int) {
-	var minOffset int64 = math.MaxInt64
-	var maxStop int64
+func (c *ContinuousIntervals) ReadData(data []byte, startOffset int64) (maxStop int64) {
 	for _, list := range c.lists {
 		start := max(startOffset, list.Offset())
 		stop := min(startOffset+int64(len(data)), list.Offset()+list.Size())
-		if start <= stop {
+		if start < stop {
 			list.ReadData(data[start-startOffset:], start, stop)
-			minOffset = min(minOffset, start)
 			maxStop = max(maxStop, stop)
 		}
 	}
-
-	if minOffset == math.MaxInt64 {
-		return 0, 0
-	}
-
-	offset = minOffset
-	size = int(maxStop - offset)
 	return
 }
 
diff --git a/weed/filesys/filehandle.go b/weed/filesys/filehandle.go
index b6f350953..b0242fb19 100644
--- a/weed/filesys/filehandle.go
+++ b/weed/filesys/filehandle.go
@@ -54,7 +54,7 @@ var _ = fs.HandleReleaser(&FileHandle{})
 
 func (fh *FileHandle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
 
-	glog.V(5).Infof("%s read fh %d: [%d,%d) size %d resp.Data len=%d cap=%d", fh.f.fullpath(), fh.handle, req.Offset, req.Offset+int64(req.Size), req.Size, len(resp.Data), cap(resp.Data))
+	glog.V(4).Infof("%s read fh %d: [%d,%d) size %d resp.Data len=%d cap=%d", fh.f.fullpath(), fh.handle, req.Offset, req.Offset+int64(req.Size), req.Size, len(resp.Data), cap(resp.Data))
 
 	buff := resp.Data[:cap(resp.Data)]
 	if req.Size > cap(resp.Data) {
@@ -64,12 +64,11 @@ func (fh *FileHandle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fus
 
 	totalRead, err := fh.readFromChunks(buff, req.Offset)
 	if err == nil {
-		dirtyOffset, dirtySize := fh.readFromDirtyPages(buff, req.Offset)
-		if totalRead+req.Offset < dirtyOffset+int64(dirtySize) {
-			totalRead = dirtyOffset + int64(dirtySize) - req.Offset
-		}
+		maxStop := fh.readFromDirtyPages(buff, req.Offset)
+		totalRead = max(maxStop - req.Offset, totalRead)
 	}
 
+	totalRead = min(int64(len(buff)), totalRead)
 	resp.Data = buff[:totalRead]
 
 	if err != nil {
@@ -80,7 +79,7 @@ func (fh *FileHandle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fus
 	return err
 }
 
-func (fh *FileHandle) readFromDirtyPages(buff []byte, startOffset int64) (offset int64, size int) {
+func (fh *FileHandle) readFromDirtyPages(buff []byte, startOffset int64) (maxStop int64) {
 	return fh.dirtyPages.ReadDirtyData(buff, startOffset)
 }