package main import ( "bytes" "compress/gzip" "flag" "fmt" "github.com/andybalholm/brotli" "github.com/klauspost/compress/zstd" "io" "math/rand/v2" "os" "path" "slices" "strings" "sync" ) type poisonCharacterGenerator struct { Header []byte AllowedBytes []byte Repeat int counter int } func (r *poisonCharacterGenerator) Read(p []byte) (n int, err error) { if len(r.Header) > 0 { copy(p, r.Header) nn := min(len(r.Header), len(p)) r.Header = r.Header[nn:] p = p[nn:] } stride := min(len(p), r.Repeat) for i := 0; i < len(p); i += stride { copy(p[i:], bytes.Repeat([]byte{r.AllowedBytes[r.counter]}, stride)) r.counter = (r.counter + 1) % len(r.AllowedBytes) } return len(p), nil } type poisonValuesGenerator struct { Header []byte AllowedValues [][]byte counter int } func (r *poisonValuesGenerator) Read(p []byte) (n int, err error) { var i int if len(r.Header) > 0 { copy(p, r.Header) nn := min(len(r.Header), len(p)) r.Header = r.Header[nn:] i += nn for i < len(p) { copy(p[i:], r.AllowedValues[r.counter]) i += len(r.AllowedValues[r.counter]) r.counter = (r.counter + 1) % len(r.AllowedValues) if r.counter == 0 { break } } } for i < len(p) { buf := slices.Repeat(r.AllowedValues[r.counter], len(r.AllowedValues)-r.counter) copy(p[i:], buf) i += len(buf) r.counter = (r.counter + 1) % len(r.AllowedValues) } return len(p), nil } func main() { outputPath := flag.String("path", "./", "path to poison files") flag.Parse() const Gigabyte = 1024 * 1024 * 1024 compressPoison(*outputPath, "text/html", &poisonValuesGenerator{ Header: []byte(fmt.Sprintf("%d", rand.Uint64())), AllowedValues: [][]byte{ []byte("

\n"), []byte("

"), []byte("

\n"), []byte("

"), []byte("

Are you a bot?

\n"), []byte(""), }, }, Gigabyte) } var poisonEncodings = []string{"br", "zstd", "gzip"} func compressPoison(outputPath, mime string, r io.Reader, maxSize int64) { r = io.LimitReader(r, maxSize) var closers []func() var encoders []io.Writer var writers []io.Writer var readers []io.Reader for _, encoding := range poisonEncodings { f, err := os.Create(path.Join(outputPath, strings.ReplaceAll(mime, "/", "_")+"."+encoding+".poison")) if err != nil { panic(err) } switch encoding { case "zstd": w, err := zstd.NewWriter(f, zstd.WithEncoderLevel(zstd.SpeedBestCompression), zstd.WithEncoderCRC(false), zstd.WithWindowSize(zstd.MaxWindowSize)) if err != nil { panic(err) } encoders = append(encoders, w) closers = append(closers, func() { w.Close() f.Close() }) case "br": w := brotli.NewWriterLevel(f, brotli.BestCompression) encoders = append(encoders, w) closers = append(closers, func() { w.Close() f.Close() }) case "gzip": w, err := gzip.NewWriterLevel(f, gzip.BestCompression) if err != nil { panic(err) } encoders = append(encoders, w) closers = append(closers, func() { w.Close() f.Close() }) } r, w := io.Pipe() readers = append(readers, r) writers = append(writers, w) } var wg sync.WaitGroup for i := range poisonEncodings { wg.Add(1) go func() { defer wg.Done() _, err := io.Copy(encoders[i], readers[i]) if err != nil { panic(err) } closers[i]() // discard remaining data _, _ = io.Copy(io.Discard, readers[i]) }() } _, err := io.Copy(io.MultiWriter(writers...), r) if err != nil { panic(err) } for _, w := range writers { if pw, ok := w.(io.Closer); ok { pw.Close() } else { panic("writer is not a Closer") } } wg.Wait() }