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Fix FUSE server buffer leaks in file gaps (#3472)

* Fix FUSE server buffer leaks in file gaps

This change zeros read buffers when encountering file gaps during
file/chunk reads in FUSE mounts.
It prevents leaking internal buffers of the FUSE server which could
otherwise reveal metadata, directory listings, file contents and
other data related to FUSE API calls.
The issue was that buffers are reused, but when a file gap was found
the buffer was not zeroed accordingly and the existing data of the
buffer was kept and returned.

* Move zero logic into its own method
This commit is contained in:
Patrick Schmidt 2022-08-21 20:33:58 +02:00 committed by GitHub
parent c7892bc7c4
commit 3f758820c1
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
2 changed files with 94 additions and 35 deletions

View file

@ -127,10 +127,11 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
nextChunks = c.chunkViews[i+1:]
}
if startOffset < chunk.LogicOffset {
gap := int(chunk.LogicOffset - startOffset)
gap := chunk.LogicOffset - startOffset
glog.V(4).Infof("zero [%d,%d)", startOffset, chunk.LogicOffset)
n += int(min(int64(gap), remaining))
startOffset, remaining = chunk.LogicOffset, remaining-int64(gap)
c.zero(p, startOffset-offset, gap)
n += int(min(gap, remaining))
startOffset, remaining = chunk.LogicOffset, remaining-gap
if remaining <= 0 {
break
}
@ -154,10 +155,19 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
// glog.V(4).Infof("doReadAt [%d,%d), n:%v, err:%v", offset, offset+int64(len(p)), n, err)
if err == nil && remaining > 0 && c.fileSize > startOffset {
delta := int(min(remaining, c.fileSize-startOffset))
glog.V(4).Infof("zero2 [%d,%d) of file size %d bytes", startOffset, startOffset+int64(delta), c.fileSize)
n += delta
// zero the remaining bytes if a gap exists at the end of the last chunk (or a fully sparse file)
if err == nil && remaining > 0 {
var delta int64
if c.fileSize > startOffset {
delta = min(remaining, c.fileSize-startOffset)
startOffset -= offset
} else {
delta = remaining
startOffset = max(startOffset-offset, startOffset-remaining-offset)
}
glog.V(4).Infof("zero2 [%d,%d) of file size %d bytes", startOffset, startOffset+delta, c.fileSize)
c.zero(p, startOffset, delta)
n += int(delta)
}
if err == nil && offset+int64(len(p)) >= c.fileSize {
@ -195,3 +205,12 @@ func (c *ChunkReadAt) readChunkSliceAt(buffer []byte, chunkView *ChunkView, next
c.lastChunkFid = chunkView.FileId
return
}
func (c *ChunkReadAt) zero(buffer []byte, start, length int64) {
end := min(start+length, int64(len(buffer)))
// zero the bytes
for o := start; o < end; o++ {
buffer[o] = 0
}
}

View file

@ -1,7 +1,7 @@
package filer
import (
"fmt"
"bytes"
"io"
"math"
"strconv"
@ -75,29 +75,28 @@ func TestReaderAt(t *testing.T) {
readerPattern: NewReaderPattern(),
}
testReadAt(t, readerAt, 0, 10, 10, io.EOF)
testReadAt(t, readerAt, 0, 12, 10, io.EOF)
testReadAt(t, readerAt, 2, 8, 8, io.EOF)
testReadAt(t, readerAt, 3, 6, 6, nil)
testReadAt(t, readerAt, 0, 10, 10, io.EOF, nil, nil)
testReadAt(t, readerAt, 0, 12, 12, io.EOF, nil, nil)
testReadAt(t, readerAt, 2, 8, 8, io.EOF, nil, nil)
testReadAt(t, readerAt, 3, 6, 6, nil, nil, nil)
}
func testReadAt(t *testing.T, readerAt *ChunkReadAt, offset int64, size int, expected int, expectedErr error) {
data := make([]byte, size)
func testReadAt(t *testing.T, readerAt *ChunkReadAt, offset int64, size int, expectedN int, expectedErr error, data, expectedData []byte) {
if data == nil {
data = make([]byte, size)
}
n, err := readerAt.doReadAt(data, offset)
for _, d := range data {
fmt.Printf("%x", d)
}
fmt.Println()
if expected != n {
t.Errorf("unexpected read size: %d, expect: %d", n, expected)
if expectedN != n {
t.Errorf("unexpected read size: %d, expect: %d", n, expectedN)
}
if err != expectedErr {
t.Errorf("unexpected read error: %v, expect: %v", err, expectedErr)
}
if expectedData != nil && !bytes.Equal(data, expectedData) {
t.Errorf("unexpected read data: %v, expect: %v", data, expectedData)
}
}
func TestReaderAt0(t *testing.T) {
@ -125,12 +124,12 @@ func TestReaderAt0(t *testing.T) {
readerPattern: NewReaderPattern(),
}
testReadAt(t, readerAt, 0, 10, 10, io.EOF)
testReadAt(t, readerAt, 3, 16, 7, io.EOF)
testReadAt(t, readerAt, 3, 5, 5, nil)
testReadAt(t, readerAt, 0, 10, 10, io.EOF, nil, nil)
testReadAt(t, readerAt, 3, 16, 7, io.EOF, nil, nil)
testReadAt(t, readerAt, 3, 5, 5, nil, nil, nil)
testReadAt(t, readerAt, 11, 5, 0, io.EOF)
testReadAt(t, readerAt, 10, 5, 0, io.EOF)
testReadAt(t, readerAt, 11, 5, 5, io.EOF, nil, nil)
testReadAt(t, readerAt, 10, 5, 5, io.EOF, nil, nil)
}
@ -153,13 +152,54 @@ func TestReaderAt1(t *testing.T) {
readerPattern: NewReaderPattern(),
}
testReadAt(t, readerAt, 0, 20, 20, io.EOF)
testReadAt(t, readerAt, 1, 7, 7, nil)
testReadAt(t, readerAt, 0, 1, 1, nil)
testReadAt(t, readerAt, 18, 4, 2, io.EOF)
testReadAt(t, readerAt, 12, 4, 4, nil)
testReadAt(t, readerAt, 4, 20, 16, io.EOF)
testReadAt(t, readerAt, 4, 10, 10, nil)
testReadAt(t, readerAt, 1, 10, 10, nil)
testReadAt(t, readerAt, 0, 20, 20, io.EOF, nil, nil)
testReadAt(t, readerAt, 1, 7, 7, nil, nil, nil)
testReadAt(t, readerAt, 0, 1, 1, nil, nil, nil)
testReadAt(t, readerAt, 18, 4, 2, io.EOF, nil, nil)
testReadAt(t, readerAt, 12, 4, 4, nil, nil, nil)
testReadAt(t, readerAt, 4, 20, 16, io.EOF, nil, nil)
testReadAt(t, readerAt, 4, 10, 10, nil, nil, nil)
testReadAt(t, readerAt, 1, 10, 10, nil, nil, nil)
}
func TestReaderAtGappedChunksDoNotLeak(t *testing.T) {
visibles := []VisibleInterval{
{
start: 2,
stop: 3,
fileId: "1",
chunkSize: 5,
},
{
start: 7,
stop: 9,
fileId: "1",
chunkSize: 4,
},
}
readerAt := &ChunkReadAt{
chunkViews: ViewFromVisibleIntervals(visibles, 0, math.MaxInt64),
readerLock: sync.Mutex{},
fileSize: 9,
readerCache: newReaderCache(3, &mockChunkCache{}, nil),
readerPattern: NewReaderPattern(),
}
testReadAt(t, readerAt, 0, 9, 9, io.EOF, []byte{2, 2, 2, 2, 2, 2, 2, 2, 2}, []byte{0, 0, 1, 0, 0, 0, 0, 1, 1})
testReadAt(t, readerAt, 1, 8, 8, io.EOF, []byte{2, 2, 2, 2, 2, 2, 2, 2}, []byte{0, 1, 0, 0, 0, 0, 1, 1})
}
func TestReaderAtSparseFileDoesNotLeak(t *testing.T) {
readerAt := &ChunkReadAt{
chunkViews: ViewFromVisibleIntervals([]VisibleInterval{}, 0, math.MaxInt64),
readerLock: sync.Mutex{},
fileSize: 3,
readerCache: newReaderCache(3, &mockChunkCache{}, nil),
readerPattern: NewReaderPattern(),
}
testReadAt(t, readerAt, 0, 3, 3, io.EOF, []byte{2, 2, 2}, []byte{0, 0, 0})
testReadAt(t, readerAt, 1, 2, 2, io.EOF, []byte{2, 2}, []byte{0, 0})
}