main.go

   1 /*
   2 Copyright (C) 2021 Sergey Matveev <stargrave@stargrave.org>
   3
   4 This program is free software: you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation, version 3 of the License.
   7
   8 This program is distributed in the hope that it will be useful,
   9 but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 GNU General Public License for more details.
  12
  13 You should have received a copy of the GNU General Public License
  14 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15 */
  16
  17 package main
  18
  19 import (
  20         "context"
  21         "crypto"
  22         "crypto/tls"
  23         "crypto/x509"
  24         "flag"
  25         "fmt"
  26         "io"
  27         "io/ioutil"
  28         "log"
  29         "net"
  30         "net/http"
  31         "os"
  32         "os/exec"
  33         "path/filepath"
  34         "strings"
  35         "time"
  36
  37         "github.com/dustin/go-humanize"
  38         "go.cypherpunks.ru/ucspi"
  39 )
  40
  41 var (
  42         tlsNextProtoS = make(map[string]func(*http.Server, *tls.Conn, http.Handler))
  43         caCert        *x509.Certificate
  44         caPrv         crypto.PrivateKey
  45         transport     = http.Transport{
  46                 DialTLSContext:    dialTLS,
  47                 ForceAttemptHTTP2: true,
  48         }
  49         sessionCache = tls.NewLRUClientSessionCache(1024)
  50
  51         CmdDWebP = "dwebp"
  52         CmdDJXL  = "djxl"
  53
  54         imageExts = map[string]struct{}{
  55                 ".apng": {},
  56                 ".avif": {},
  57                 ".gif":  {},
  58                 ".heic": {},
  59                 ".jp2":  {},
  60                 ".jpeg": {},
  61                 ".jpg":  {},
  62                 ".jxl":  {},
  63                 ".mng":  {},
  64                 ".png":  {},
  65                 ".svg":  {},
  66                 ".tif":  {},
  67                 ".tiff": {},
  68                 ".webp": {},
  69         }
  70 )
  71
  72 func dialTLS(ctx context.Context, network, addr string) (net.Conn, error) {
  73         host := strings.TrimSuffix(addr, ":443")
  74         cfg := tls.Config{
  75                 VerifyPeerCertificate: func(
  76                         rawCerts [][]byte,
  77                         verifiedChains [][]*x509.Certificate,
  78                 ) error {
  79                         return verifyCert(host, nil, rawCerts, verifiedChains)
  80                 },
  81                 ClientSessionCache: sessionCache,
  82                 NextProtos:         []string{"h2", "http/1.1"},
  83         }
  84         conn, dialErr := tls.Dial(network, addr, &cfg)
  85         if dialErr != nil {
  86                 if _, ok := dialErr.(ErrRejected); ok {
  87                         return nil, dialErr
  88                 }
  89                 cfg.InsecureSkipVerify = true
  90                 cfg.VerifyPeerCertificate = func(
  91                         rawCerts [][]byte,
  92                         verifiedChains [][]*x509.Certificate,
  93                 ) error {
  94                         return verifyCert(host, dialErr, rawCerts, verifiedChains)
  95                 }
  96                 var err error
  97                 conn, err = tls.Dial(network, addr, &cfg)
  98                 if err != nil {
  99                         sinkErr <- fmt.Sprintf("%s\t%s", addr, dialErr.Error())
 100                         return nil, err
 101                 }
 102         }
 103         connState := conn.ConnectionState()
 104         if connState.DidResume {
 105                 sinkTLS <- fmt.Sprintf(
 106                         "%s\t%s %s\t%s\t%s",
 107                         strings.TrimSuffix(addr, ":443"),
 108                         ucspi.TLSVersion(connState.Version),
 109                         tls.CipherSuiteName(connState.CipherSuite),
 110                         spkiHash(connState.PeerCertificates[0]),
 111                         connState.NegotiatedProtocol,
 112                 )
 113         }
 114         return conn, nil
 115 }
 116
 117 func roundTrip(w http.ResponseWriter, req *http.Request) {
 118         if req.Method == http.MethodHead {
 119                 http.Error(w, "go away", http.StatusMethodNotAllowed)
 120                 return
 121         }
 122         sinkReq <- fmt.Sprintf("%s %s", req.Method, req.URL.String())
 123         host := strings.TrimSuffix(req.URL.Host, ":443")
 124
 125         for _, spy := range SpyDomains {
 126                 if strings.HasSuffix(host, spy) {
 127                         http.NotFound(w, req)
 128                         sinkOther <- fmt.Sprintf(
 129                                 "%s %s\t%d\tspy one",
 130                                 req.Method,
 131                                 req.URL.String(),
 132                                 http.StatusNotFound,
 133                         )
 134                         return
 135                 }
 136         }
 137
 138         if strings.HasPrefix(req.URL.Host, "www.reddit.com") {
 139                 req.URL.Host = "old.reddit.com"
 140                 http.Redirect(w, req, req.URL.String(), http.StatusMovedPermanently)
 141                 return
 142         }
 143
 144         resp, err := transport.RoundTrip(req)
 145         if err != nil {
 146                 sinkErr <- fmt.Sprintf("%s\t%s", req.URL.Host, err.Error())
 147                 w.WriteHeader(http.StatusBadGateway)
 148                 w.Write([]byte(err.Error()))
 149                 return
 150         }
 151
 152         for k, vs := range resp.Header {
 153                 if k == "Location" || k == "Content-Type" || k == "Content-Length" {
 154                         continue
 155                 }
 156                 for _, v := range vs {
 157                         w.Header().Add(k, v)
 158                 }
 159         }
 160
 161         switch resp.Header.Get("Content-Type") {
 162         case "application/font-woff", "application/font-sfnt":
 163                 // Those are deprecated types
 164                 fallthrough
 165         case "font/otf", "font/ttf", "font/woff", "font/woff2":
 166                 http.NotFound(w, req)
 167                 sinkOther <- fmt.Sprintf(
 168                         "%s %s\t%d\tfonts are not allowed",
 169                         req.Method,
 170                         req.URL.String(),
 171                         http.StatusNotFound,
 172                 )
 173                 resp.Body.Close()
 174                 return
 175         case "image/webp":
 176                 if strings.Contains(req.Header.Get("User-Agent"), "AppleWebKit/538.15") {
 177                         // My Xombrero
 178                         break
 179                 }
 180                 tmpFd, err := ioutil.TempFile("", "tofuproxy.*.webp")
 181                 if err != nil {
 182                         log.Fatalln(err)
 183                 }
 184                 defer tmpFd.Close()
 185                 defer os.Remove(tmpFd.Name())
 186                 defer resp.Body.Close()
 187                 if _, err = io.Copy(tmpFd, resp.Body); err != nil {
 188                         log.Printf("Error during %s: %+v\n", req.URL, err)
 189                         http.Error(w, err.Error(), http.StatusBadGateway)
 190                         return
 191                 }
 192                 tmpFd.Close()
 193                 cmd := exec.Command(CmdDWebP, tmpFd.Name(), "-o", "-")
 194                 data, err := cmd.Output()
 195                 if err != nil {
 196                         http.Error(w, err.Error(), http.StatusBadGateway)
 197                         return
 198                 }
 199                 w.Header().Add("Content-Type", "image/png")
 200                 w.WriteHeader(http.StatusOK)
 201                 w.Write(data)
 202                 sinkOther <- fmt.Sprintf(
 203                         "%s %s\t%d\tWebP transcoded to PNG",
 204                         req.Method,
 205                         req.URL.String(),
 206                         http.StatusOK,
 207                 )
 208                 return
 209         case "image/jxl":
 210                 tmpFd, err := ioutil.TempFile("", "tofuproxy.*.jxl")
 211                 if err != nil {
 212                         log.Fatalln(err)
 213                 }
 214                 defer tmpFd.Close()
 215                 defer os.Remove(tmpFd.Name())
 216                 defer resp.Body.Close()
 217                 if _, err = io.Copy(tmpFd, resp.Body); err != nil {
 218                         log.Printf("Error during %s: %+v\n", req.URL, err)
 219                         http.Error(w, err.Error(), http.StatusBadGateway)
 220                         return
 221                 }
 222                 tmpFd.Close()
 223                 dstFn := tmpFd.Name() + ".png"
 224                 cmd := exec.Command(CmdDJXL, tmpFd.Name(), dstFn)
 225                 err = cmd.Run()
 226                 defer os.Remove(dstFn)
 227                 if err != nil {
 228                         http.Error(w, err.Error(), http.StatusBadGateway)
 229                         return
 230                 }
 231                 data, err := ioutil.ReadFile(dstFn)
 232                 if err != nil {
 233                         http.Error(w, err.Error(), http.StatusBadGateway)
 234                         return
 235                 }
 236                 w.Header().Add("Content-Type", "image/png")
 237                 w.WriteHeader(http.StatusOK)
 238                 w.Write(data)
 239                 sinkOther <- fmt.Sprintf(
 240                         "%s %s\t%d\tJPEG XL transcoded to PNG",
 241                         req.Method,
 242                         req.URL.String(),
 243                         http.StatusOK,
 244                 )
 245                 return
 246         }
 247
 248         if req.Method == http.MethodGet {
 249                 var redirType string
 250                 switch resp.StatusCode {
 251                 case http.StatusMovedPermanently, http.StatusPermanentRedirect:
 252                         redirType = "permanent"
 253                         goto Redir
 254                 case http.StatusFound, http.StatusSeeOther, http.StatusTemporaryRedirect:
 255                         if strings.Contains(req.Header.Get("User-Agent"), "newsboat/") {
 256                                 goto NoRedir
 257                         }
 258                         if _, ok := imageExts[filepath.Ext(req.URL.Path)]; ok {
 259                                 goto NoRedir
 260                         }
 261                         redirType = "temporary"
 262                 default:
 263                         goto NoRedir
 264                 }
 265         Redir:
 266                 resp.Body.Close()
 267                 w.Header().Add("Content-Type", "text/html")
 268                 w.WriteHeader(http.StatusOK)
 269                 location := resp.Header.Get("Location")
 270                 w.Write([]byte(
 271                         fmt.Sprintf(
 272                                 `<html>
 273 <head><title>%d %s: %s redirection</title></head>
 274 <body>Redirection to <a href="%s">%s</a>
 275 </body></html>`,
 276                                 resp.StatusCode, http.StatusText(resp.StatusCode),
 277                                 redirType, location, location,
 278                         )))
 279                 sinkRedir <- fmt.Sprintf(
 280                         "%s %s\t%s\t%s", req.Method, resp.Status, req.URL.String(), location,
 281                 )
 282                 return
 283         }
 284
 285 NoRedir:
 286         for _, h := range []string{"Location", "Content-Type", "Content-Length"} {
 287                 if v := resp.Header.Get(h); v != "" {
 288                         w.Header().Add(h, v)
 289                 }
 290         }
 291         w.WriteHeader(resp.StatusCode)
 292         n, err := io.Copy(w, resp.Body)
 293         if err != nil {
 294                 log.Printf("Error during %s: %+v\n", req.URL, err)
 295         }
 296         resp.Body.Close()
 297         msg := fmt.Sprintf(
 298                 "%s %s\t%s\t%s\t%s",
 299                 req.Method,
 300                 req.URL.String(),
 301                 resp.Status,
 302                 resp.Header.Get("Content-Type"),
 303                 humanize.IBytes(uint64(n)),
 304         )
 305         if resp.StatusCode == http.StatusOK {
 306                 sinkOK <- msg
 307         } else {
 308                 sinkOther <- msg
 309         }
 310 }
 311
 312 type Handler struct{}
 313
 314 func (h *Handler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 315         if req.Method != http.MethodConnect {
 316                 roundTrip(w, req)
 317                 return
 318         }
 319         hj, ok := w.(http.Hijacker)
 320         if !ok {
 321                 log.Fatalln("no hijacking")
 322         }
 323         conn, _, err := hj.Hijack()
 324         if err != nil {
 325                 log.Fatalln(err)
 326         }
 327         defer conn.Close()
 328         conn.Write([]byte(fmt.Sprintf(
 329                 "%s %d %s\r\n\r\n",
 330                 req.Proto,
 331                 http.StatusOK, http.StatusText(http.StatusOK),
 332         )))
 333         host := strings.Split(req.Host, ":")[0]
 334         hostCertsM.Lock()
 335         keypair, ok := hostCerts[host]
 336         if !ok || !keypair.cert.NotAfter.After(time.Now().Add(time.Hour)) {
 337                 keypair = newKeypair(host, caCert, caPrv)
 338                 hostCerts[host] = keypair
 339         }
 340         hostCertsM.Unlock()
 341         tlsConn := tls.Server(conn, &tls.Config{
 342                 Certificates: []tls.Certificate{{
 343                         Certificate: [][]byte{keypair.cert.Raw},
 344                         PrivateKey:  keypair.prv,
 345                 }},
 346         })
 347         if err = tlsConn.Handshake(); err != nil {
 348                 log.Printf("TLS error %s: %+v\n", host, err)
 349                 return
 350         }
 351         srv := http.Server{
 352                 Handler:      &HTTPSHandler{host: req.Host},
 353                 TLSNextProto: tlsNextProtoS,
 354         }
 355         err = srv.Serve(&SingleListener{conn: tlsConn})
 356         if err != nil {
 357                 if _, ok := err.(AlreadyAccepted); !ok {
 358                         log.Printf("TLS serve error %s: %+v\n", host, err)
 359                         return
 360                 }
 361         }
 362 }
 363
 364 type HTTPSHandler struct {
 365         host string
 366 }
 367
 368 func (h *HTTPSHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 369         req.URL.Scheme = "https"
 370         req.URL.Host = h.host
 371         roundTrip(w, req)
 372 }
 373
 374 func main() {
 375         crtPath := flag.String("cert", "cert.pem", "Path to server X.509 certificate")
 376         prvPath := flag.String("key", "prv.pem", "Path to server PKCS#8 private key")
 377         bind := flag.String("bind", "[::1]:8080", "Bind address")
 378         certs = flag.String("certs", "certs", "Directory with pinned certificates")
 379         dnsSrv = flag.String("dns", "[::1]:53", "DNS server")
 380         fifos = flag.String("fifos", "fifos", "Directory with FIFOs")
 381         notai = flag.Bool("notai", false, "Do not prepend TAI64N to logs")
 382         flag.Parse()
 383         log.SetFlags(log.Lshortfile)
 384         fifoInit()
 385
 386         var err error
 387         _, caCert, err = ucspi.CertificateFromFile(*crtPath)
 388         if err != nil {
 389                 log.Fatalln(err)
 390         }
 391         caPrv, err = ucspi.PrivateKeyFromFile(*prvPath)
 392         if err != nil {
 393                 log.Fatalln(err)
 394         }
 395
 396         ln, err := net.Listen("tcp", *bind)
 397         if err != nil {
 398                 log.Fatalln(err)
 399         }
 400         srv := http.Server{
 401                 Handler:      &Handler{},
 402                 TLSNextProto: tlsNextProtoS,
 403         }
 404         log.Println("listening:", *bind)
 405         if err := srv.Serve(ln); err != nil {
 406                 log.Fatalln(err)
 407         }
 408 }