Made DoT use io.ReadFull to make sure it reads all the bytes

internal/protocols/dot/dot.go

@@ -5,6 +5,7 @@ import (
 	"crypto/tls"
 	"encoding/binary"
 	"fmt"
+	"io"
 	"net"
 	"os"
 
@@ -74,31 +75,39 @@ func (c *DoTClient) Query(domain, queryType, target string, dnssec bool) error {
 	}
 
 	var lengthPrefixedMessage bytes.Buffer
-	binary.Write(&lengthPrefixedMessage, binary.BigEndian, uint16(len(DNSMessage)))
-	lengthPrefixedMessage.Write(DNSMessage)
+	err = binary.Write(&lengthPrefixedMessage, binary.BigEndian, uint16(len(DNSMessage)))
+	if err != nil {
+		return fmt.Errorf("failed to write message length: %v", err)
+	}
+	_, err = lengthPrefixedMessage.Write(DNSMessage)
+	if err != nil {
+		return fmt.Errorf("failed to write DNS message: %v", err)
+	}
 
 	_, err = c.tlsConn.Write(lengthPrefixedMessage.Bytes())
 	if err != nil {
 		return fmt.Errorf("failed writing TLS request: %v", err)
 	}
 
-	// Read the 2-byte length prefix
 	lengthBuf := make([]byte, 2)
-	_, err = c.tlsConn.Read(lengthBuf)
+	_, err = io.ReadFull(c.tlsConn, lengthBuf)
 	if err != nil {
 		return fmt.Errorf("failed reading response length: %v", err)
 	}
 
 	messageLength := binary.BigEndian.Uint16(lengthBuf)
+	if messageLength == 0 {
+		return fmt.Errorf("received zero-length message")
+	}
 
 	responseBuf := make([]byte, messageLength)
-	n, err := c.tlsConn.Read(responseBuf)
+	_, err = io.ReadFull(c.tlsConn, responseBuf)
 	if err != nil {
 		return fmt.Errorf("failed reading TLS response: %v", err)
 	}
 
 	recvMsg := new(dns.Msg)
-	err = recvMsg.Unpack(responseBuf[:n])
+	err = recvMsg.Unpack(responseBuf)
 	if err != nil {
 		return fmt.Errorf("failed to parse DNS response: %v", err)
 	}