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