Harden scan robustness and tests

plugins/services/jdwp_test.go

@@ -0,0 +1,67 @@
+//go:build plugin_jdwp || !plugin_selective
+
+package services
+
+import (
+	"encoding/binary"
+	"io"
+	"strings"
+	"testing"
+	"time"
+	"unicode/utf8"
+)
+
+type chunkedJDWPConn struct {
+	data      []byte
+	chunkSize int
+}
+
+func (c *chunkedJDWPConn) Read(p []byte) (int, error) {
+	if len(c.data) == 0 {
+		return 0, io.EOF
+	}
+	n := c.chunkSize
+	if n <= 0 || n > len(c.data) {
+		n = len(c.data)
+	}
+	if n > len(p) {
+		n = len(p)
+	}
+	copy(p, c.data[:n])
+	c.data = c.data[n:]
+	return n, nil
+}
+
+func (c *chunkedJDWPConn) Write([]byte) (int, error) { return 0, nil }
+func (c *chunkedJDWPConn) SetDeadline(time.Time) error {
+	return nil
+}
+
+func TestJDWPGetVersionHandlesChunkedReads(t *testing.T) {
+	const version = "Java Debug Wire Protocol"
+	body := make([]byte, 4+len(version))
+	binary.BigEndian.PutUint32(body[:4], uint32(len(version)))
+	copy(body[4:], version)
+
+	reply := make([]byte, 11+len(body))
+	binary.BigEndian.PutUint32(reply[:4], uint32(len(reply)))
+	copy(reply[11:], body)
+
+	p := NewJDWPPlugin()
+	got := p.getVersion(&chunkedJDWPConn{data: reply, chunkSize: 3}, time.Second)
+	if got != version {
+		t.Fatalf("getVersion() = %q, want %q", got, version)
+	}
+}
+
+func TestParseJDWPVersionStringTruncatesByRune(t *testing.T) {
+	version := strings.Repeat("界", 205)
+	body := make([]byte, 4+len(version))
+	binary.BigEndian.PutUint32(body[:4], uint32(len(version)))
+	copy(body[4:], version)
+
+	got := parseJDWPVersionString(body)
+	if !utf8.ValidString(got) || len([]rune(got)) != 203 || !strings.HasSuffix(got, "...") {
+		t.Fatalf("parseJDWPVersionString() = %q", got)
+	}
+}