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