justin/netgiv
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Make buffer not eat all memory.

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This commit is contained in:
Justin Hawkins 2022-01-13 22:20:35 +10:30
parent f872453f16
commit 0261886b43
4 changed files with 144 additions and 66 deletions
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41
client.go
View File

@ -1,21 +1,26 @@
package main
import (
"bufio"
"encoding/gob"
"errors"
"fmt"
"io"
"log"
"net"
"os"
"github.com/tardisx/netgiv/secure"
)
type Client struct {
address string
port int
}
func (c *Client) Connect() error {
address := fmt.Sprintf("127.0.0.1:%d", c.port)
address := fmt.Sprintf("%s:%d", c.address, c.port)
serverAddress, _ := net.ResolveTCPAddr("tcp", address)
conn, err := net.DialTCP("tcp", nil, serverAddress)
@ -50,13 +55,45 @@ func (c *Client) Connect() error {
data := secure.PacketSendDataStart{
Filename: "foobar",
TotalSize: 3,
Data: []byte{0x20, 0x21, 0x22},
}
err = enc.Encode(data)
if err != nil {
panic(err)
}
log.Print("done that")
nBytes, nChunks := int64(0), int64(0)
reader := bufio.NewReader(os.Stdin)
buf := make([]byte, 0, 1024)
for {
n, err := reader.Read(buf[:cap(buf)])
buf = buf[:n]
if n == 0 {
if err == nil {
continue
}
if err == io.EOF {
break
}
log.Fatal(err)
}
nChunks++
nBytes += int64(len(buf))
// process buf
send := secure.PacketSendDataNext{
Size: 5000,
Data: buf,
}
enc.Encode(send)
// time.Sleep(time.Second)
if err != nil {
log.Fatal(err)
}
}
log.Println("Bytes:", nBytes, "Chunks:", nChunks)
conn.Close()
break

3
main.go
View File

@ -9,6 +9,7 @@ import (
func main() {
log.SetFlags(log.Lshortfile)
port := flag.Int("p", 9000, "Port to run server/client on.")
addr := flag.String("a", "61.245.149.58", "address to connect to.")
isServer := flag.Bool("s", false, "Set if running the server.")
flag.Parse()
@ -18,7 +19,7 @@ func main() {
s.Run()
} else {
fmt.Printf("Client running on %d\n", *port)
c := Client{port: *port}
c := Client{port: *port, address: *addr}
err := c.Connect()
if err != nil {
fmt.Print(err)

49
secure/secure.go
View File

@ -29,12 +29,10 @@ func (s *SecureMessage) toByteArray() []byte {
func DeterminePacketSize(data []byte) uint16 {
// first 24 bytes are the nonce, then the size
if len(data) < 26 {
log.Printf("packet is too small to be complete - %d bytes", len(data))
return 0
}
size := binary.BigEndian.Uint16(data[24:26])
size += 26 // add the length header and the nonce
log.Printf("size of packet inside the %d bytes is %d bytes", len(data), size)
return size
}
@ -57,11 +55,13 @@ type SecureConnection struct {
}
func (s *SecureConnection) Read(p []byte) (int, error) {
message := make([]byte, 20408)
message := make([]byte, 2048)
// Read the message from the buffer
eof := false
log.Printf("READ: Start, buffer contains %d bytes", s.Buffer.Len())
outputBytes := make([]byte, 0)
// log.Printf("READ: start, p %d/%d, buffer contains currently contains %d bytes", len(p), cap(p), s.Buffer.Len())
n, err := s.Conn.Read(message)
@ -82,13 +82,21 @@ func (s *SecureConnection) Read(p []byte) (int, error) {
s.Buffer.Write(message[:n])
// log.Printf("read: appended them to the buffer which is now %d bytes", len(s.Buffer.Bytes()))
for {
actualPacketEnd := DeterminePacketSize(s.Buffer.Bytes())
if actualPacketEnd == 0 {
log.Printf("packet too small?")
// panic("small")
// log.Printf("packet too small?")
break
return 0, io.EOF
}
if int(actualPacketEnd) > len(s.Buffer.Bytes()) {
// we must have half a packet
// log.Print("partial packet detected")
break
}
secureMessage := ConstructSecureMessage(s.Buffer.Bytes()[:actualPacketEnd])
// log.Printf("Secure message from wire bytes: \n nonce: %v\n msg: %v\n size: %d\n", secureMessage.Nonce, secureMessage.Msg, secureMessage.Size)
decryptedMessage, ok := box.OpenAfterPrecomputation(nil, secureMessage.Msg, &secureMessage.Nonce, s.SharedKey)
@ -97,7 +105,10 @@ func (s *SecureConnection) Read(p []byte) (int, error) {
return 0, errors.New("problem decrypting the message")
}
copy(p, decryptedMessage)
outputBytes = append(outputBytes, decryptedMessage...)
// log.Printf("OUT now: %d bytes", len(outputBytes))
// copy(p, decryptedMessage)
// trim what we used off the buffer
newBuffer := s.Buffer.Bytes()[actualPacketEnd:]
@ -105,28 +116,37 @@ func (s *SecureConnection) Read(p []byte) (int, error) {
if eof && s.Buffer.Len() == 0 {
log.Printf("returning the final packet")
return len(decryptedMessage), io.EOF
break
}
log.Printf("successfully read %d bytes", len(decryptedMessage))
return len(decryptedMessage), nil
}
err = io.EOF
if !eof {
err = nil
}
copy(p, outputBytes)
// log.Printf("returning %d decrypted bytes with err: %w", len(outputBytes), err)
// log.Printf("READ: end, p %d/%d, buffer contains currently contains %d bytes", len(p), cap(p), s.Buffer.Len())
return len(outputBytes), err
}
func (s *SecureConnection) Write(p []byte) (int, error) {
// func (s *SecureConnection) Write(o encoding.BinaryMarshaler) (int, error) {
var nonce [24]byte
log.Printf("clear bytes: %v", p)
// Create a new nonce for each message sent
rand.Read(nonce[:])
log.Printf("before encryption it is %d bytes", len(p))
// log.Printf("before encryption it is %d bytes", len(p))
encryptedMessage := box.SealAfterPrecomputation(nil, p, &nonce, s.SharedKey)
sm := SecureMessage{Msg: encryptedMessage, Nonce: nonce}
// Write it to the connection
wireBytes := sm.toByteArray()
log.Printf("putting %d bytes on the wire\n nonce: %v\n bytes: %v", len(wireBytes), nonce, wireBytes)
// log.Printf("putting %d bytes on the wire\n nonce: %v\n bytes: %v", len(wireBytes), nonce, wireBytes)
return s.Conn.Write(wireBytes)
}
@ -167,7 +187,6 @@ type PacketStart struct {
type PacketSendDataStart struct {
Filename string
TotalSize uint32
Data []byte
}
type PacketSendDataNext struct {

71
server.go
View File

@ -18,7 +18,7 @@ type Server struct {
}
func (s *Server) Run() {
address := fmt.Sprintf("127.0.0.1:%d", s.port)
address := fmt.Sprintf(":%d", s.port)
networkAddress, _ := net.ResolveTCPAddr("tcp", address)
listener, err := net.ListenTCP("tcp", networkAddress)
@ -41,7 +41,7 @@ func (s *Server) Run() {
func handleConnection(conn *net.TCPConn) {
defer conn.Close()
conn.SetDeadline(time.Now().Add(time.Second))
conn.SetDeadline(time.Now().Add(time.Second * 5))
sharedKey := secure.Handshake(conn)
secureConnection := secure.SecureConnection{Conn: conn, SharedKey: sharedKey, Buffer: &bytes.Buffer{}}
@ -51,35 +51,56 @@ func handleConnection(conn *net.TCPConn) {
dec := gob.NewDecoder(&secureConnection)
// At this point we are in
// Get the start packet
start := secure.PacketStart{}
err := dec.Decode(&start)
if err == io.EOF {
log.Printf("connection has been closed after start packet")
return
}
if err != nil {
log.Printf("some error with start packet: %w", err)
return
}
log.Printf("Decoded packet:\n%#v", start)
conn.SetDeadline(time.Now().Add(time.Second * 5))
if start.OperationType == secure.OperationTypeSend {
log.Printf("client wants to send us something, expecting a send start")
sendStart := secure.PacketSendDataStart{}
err = dec.Decode(&sendStart)
if err != nil {
log.Printf("error at send data start: %w", err)
return
}
log.Printf("send start looks like: %v", sendStart)
file, err := os.CreateTemp("", "netgiv_")
if err != nil {
log.Printf("got error with temp file: %w", err)
return
}
log.Printf("writing data to file: %s", file.Name())
sendData := secure.PacketSendDataNext{}
for {
p1 := secure.PacketStart{}
log.Print("trying to decode something from wire")
err := dec.Decode(&p1)
conn.SetDeadline(time.Now().Add(time.Second * 5))
err = dec.Decode(&sendData)
if err == io.EOF {
log.Printf("connection has been closed")
return
log.Printf("WE ARE DONE writing to: %s", file.Name())
break
}
if err != nil {
panic(err)
}
log.Printf("Decoded packet:\n%#v", p1)
p2 := secure.PacketSendDataStart{}
err = dec.Decode(&p2)
if err == io.EOF {
log.Printf("connection has been closed")
log.Printf("error decoding data next: %s", err)
return
}
if err != nil {
panic(err)
file.Write(sendData.Data)
}
return
} else {
log.Printf("bad operation")
return
}
log.Printf("Decoded packet:\n%#v", p2)
}
}