syncthing/lib/protocol/fuzz.go

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2015-08-18 06:37:23 +00:00
// Copyright (C) 2015 The Protocol Authors.
// +build gofuzz
package protocol
import (
"bytes"
"encoding/binary"
"encoding/hex"
"fmt"
"reflect"
"sync"
)
func Fuzz(data []byte) int {
// Regenerate the length, or we'll most commonly exit quickly due to an
// unexpected eof which is unintestering.
if len(data) > 8 {
binary.BigEndian.PutUint32(data[4:], uint32(len(data))-8)
}
// Setup a rawConnection we'll use to parse the message.
c := rawConnection{
cr: &countingReader{Reader: bytes.NewReader(data)},
closed: make(chan struct{}),
pool: sync.Pool{
New: func() interface{} {
return make([]byte, BlockSize)
},
},
}
// Attempt to parse the message.
hdr, msg, err := c.readMessage()
if err != nil {
return 0
}
// If parsing worked, attempt to encode it again.
newBs, err := msg.AppendXDR(nil)
if err != nil {
panic("not encodable")
}
// Create an appriate header for the re-encoding.
newMsg := make([]byte, 8)
binary.BigEndian.PutUint32(newMsg, encodeHeader(hdr))
binary.BigEndian.PutUint32(newMsg[4:], uint32(len(newBs)))
newMsg = append(newMsg, newBs...)
// Use the rawConnection to parse the re-encoding.
c.cr = &countingReader{Reader: bytes.NewReader(newMsg)}
hdr2, msg2, err := c.readMessage()
if err != nil {
fmt.Println("Initial:\n" + hex.Dump(data))
fmt.Println("New:\n" + hex.Dump(newMsg))
panic("not parseable after re-encode: " + err.Error())
}
// Make sure the data is the same as it was before.
if hdr != hdr2 {
panic("headers differ")
}
if !reflect.DeepEqual(msg, msg2) {
panic("contents differ")
}
return 1
}