1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434
|
// Portions of the TLS code are:
// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// TLS virtual hosting
package vhost
import (
"bytes"
"errors"
"io"
"net"
"strconv"
)
const (
maxPlaintext = 16384 // maximum plaintext payload length
maxCiphertext = 16384 + 2048 // maximum ciphertext payload length
recordHeaderLen = 5 // record header length
maxHandshake = 65536 // maximum handshake we support (protocol max is 16 MB)
)
type alert uint8
const (
alertUnexpectedMessage alert = 10
alertRecordOverflow alert = 22
alertInternalError alert = 80
)
var alertText = map[alert]string{
alertUnexpectedMessage: "unexpected message",
alertRecordOverflow: "record overflow",
alertInternalError: "internal error",
}
func (e alert) String() string {
s, ok := alertText[e]
if ok {
return s
}
return "alert(" + strconv.Itoa(int(e)) + ")"
}
func (e alert) Error() string {
return e.String()
}
// TLS record types.
type recordType uint8
const (
recordTypeHandshake recordType = 22
)
// TLS handshake message types.
const (
typeClientHello uint8 = 1
)
// TLS extension numbers
var (
extensionServerName uint16 = 0
extensionStatusRequest uint16 = 5
extensionSupportedCurves uint16 = 10
extensionSupportedPoints uint16 = 11
extensionSessionTicket uint16 = 35
extensionNextProtoNeg uint16 = 13172 // not IANA assigned
)
// TLS CertificateStatusType (RFC 3546)
const (
statusTypeOCSP uint8 = 1
)
// A Conn represents a secured connection.
// It implements the net.Conn interface.
type TLSConn struct {
*sharedConn
ClientHelloMsg *ClientHelloMsg
}
// TLS parses the ClientHello message on conn and returns
// a new, unread connection with metadata for virtual host muxing
func TLS(conn net.Conn) (tlsConn *TLSConn, err error) {
c, rd := newShared(conn)
tlsConn = &TLSConn{sharedConn: c}
if tlsConn.ClientHelloMsg, err = readClientHello(rd); err != nil {
return
}
return
}
func (c *TLSConn) Host() string {
if c.ClientHelloMsg == nil {
return ""
}
return c.ClientHelloMsg.ServerName
}
func (c *TLSConn) Free() {
c.ClientHelloMsg = nil
}
// A block is a simple data buffer.
type block struct {
data []byte
off int // index for Read
}
// resize resizes block to be n bytes, growing if necessary.
func (b *block) resize(n int) {
if n > cap(b.data) {
b.reserve(n)
}
b.data = b.data[0:n]
}
// reserve makes sure that block contains a capacity of at least n bytes.
func (b *block) reserve(n int) {
if cap(b.data) >= n {
return
}
m := cap(b.data)
if m == 0 {
m = 1024
}
for m < n {
m *= 2
}
data := make([]byte, len(b.data), m)
copy(data, b.data)
b.data = data
}
// readFromUntil reads from r into b until b contains at least n bytes
// or else returns an error.
func (b *block) readFromUntil(r io.Reader, n int) error {
// quick case
if len(b.data) >= n {
return nil
}
// read until have enough.
b.reserve(n)
for {
m, err := r.Read(b.data[len(b.data):cap(b.data)])
b.data = b.data[0 : len(b.data)+m]
if len(b.data) >= n {
break
}
if err != nil {
return err
}
}
return nil
}
func (b *block) Read(p []byte) (n int, err error) {
n = copy(p, b.data[b.off:])
b.off += n
return
}
// newBlock allocates a new block
func newBlock() *block {
return new(block)
}
// splitBlock splits a block after the first n bytes,
// returning a block with those n bytes and a
// block with the remainder. the latter may be nil.
func splitBlock(b *block, n int) (*block, *block) {
if len(b.data) <= n {
return b, nil
}
bb := newBlock()
bb.resize(len(b.data) - n)
copy(bb.data, b.data[n:])
b.data = b.data[0:n]
return b, bb
}
// readHandshake reads the next handshake message from
// the record layer.
func readClientHello(rd io.Reader) (*ClientHelloMsg, error) {
var nextBlock *block // raw input, right off the wire
var hand bytes.Buffer // handshake data waiting to be read
// readRecord reads the next TLS record from the connection
// and updates the record layer state.
readRecord := func() error {
// Caller must be in sync with connection:
// handshake data if handshake not yet completed,
// else application data. (We don't support renegotiation.)
if nextBlock == nil {
nextBlock = newBlock()
}
b := nextBlock
// Read header, payload.
if err := b.readFromUntil(rd, recordHeaderLen); err != nil {
return err
}
typ := recordType(b.data[0])
// No valid TLS record has a type of 0x80, however SSLv2 handshakes
// start with a uint16 length where the MSB is set and the first record
// is always < 256 bytes long. Therefore typ == 0x80 strongly suggests
// an SSLv2 client.
if typ == 0x80 {
return errors.New("tls: unsupported SSLv2 handshake received")
}
vers := uint16(b.data[1])<<8 | uint16(b.data[2])
n := int(b.data[3])<<8 | int(b.data[4])
if n > maxCiphertext {
return alertRecordOverflow
}
// First message, be extra suspicious:
// this might not be a TLS client.
// Bail out before reading a full 'body', if possible.
// The current max version is 3.1.
// If the version is >= 16.0, it's probably not real.
// Similarly, a clientHello message encodes in
// well under a kilobyte. If the length is >= 12 kB,
// it's probably not real.
if (typ != recordTypeHandshake) || vers >= 0x1000 || n >= 0x3000 {
return alertUnexpectedMessage
}
if err := b.readFromUntil(rd, recordHeaderLen+n); err != nil {
return err
}
// Process message.
b, nextBlock = splitBlock(b, recordHeaderLen+n)
b.off = recordHeaderLen
data := b.data[b.off:]
if len(data) > maxPlaintext {
return alertRecordOverflow
}
hand.Write(data)
return nil
}
if err := readRecord(); err != nil {
return nil, err
}
data := hand.Bytes()
n := int(data[1])<<16 | int(data[2])<<8 | int(data[3])
if n > maxHandshake {
return nil, alertInternalError
}
for hand.Len() < 4+n {
if err := readRecord(); err != nil {
return nil, err
}
}
data = hand.Next(4 + n)
if data[0] != typeClientHello {
return nil, alertUnexpectedMessage
}
msg := new(ClientHelloMsg)
if !msg.unmarshal(data) {
return nil, alertUnexpectedMessage
}
return msg, nil
}
type ClientHelloMsg struct {
Raw []byte
Vers uint16
Random []byte
SessionId []byte
CipherSuites []uint16
CompressionMethods []uint8
NextProtoNeg bool
ServerName string
OcspStapling bool
SupportedCurves []uint16
SupportedPoints []uint8
TicketSupported bool
SessionTicket []uint8
}
func (m *ClientHelloMsg) unmarshal(data []byte) bool {
if len(data) < 42 {
return false
}
m.Raw = data
m.Vers = uint16(data[4])<<8 | uint16(data[5])
m.Random = data[6:38]
sessionIdLen := int(data[38])
if sessionIdLen > 32 || len(data) < 39+sessionIdLen {
return false
}
m.SessionId = data[39 : 39+sessionIdLen]
data = data[39+sessionIdLen:]
if len(data) < 2 {
return false
}
// cipherSuiteLen is the number of bytes of cipher suite numbers. Since
// they are uint16s, the number must be even.
cipherSuiteLen := int(data[0])<<8 | int(data[1])
if cipherSuiteLen%2 == 1 || len(data) < 2+cipherSuiteLen {
return false
}
numCipherSuites := cipherSuiteLen / 2
m.CipherSuites = make([]uint16, numCipherSuites)
for i := 0; i < numCipherSuites; i++ {
m.CipherSuites[i] = uint16(data[2+2*i])<<8 | uint16(data[3+2*i])
}
data = data[2+cipherSuiteLen:]
if len(data) < 1 {
return false
}
compressionMethodsLen := int(data[0])
if len(data) < 1+compressionMethodsLen {
return false
}
m.CompressionMethods = data[1 : 1+compressionMethodsLen]
data = data[1+compressionMethodsLen:]
m.NextProtoNeg = false
m.ServerName = ""
m.OcspStapling = false
m.TicketSupported = false
m.SessionTicket = nil
if len(data) == 0 {
// ClientHello is optionally followed by extension data
return true
}
if len(data) < 2 {
return false
}
extensionsLength := int(data[0])<<8 | int(data[1])
data = data[2:]
if extensionsLength != len(data) {
return false
}
for len(data) != 0 {
if len(data) < 4 {
return false
}
extension := uint16(data[0])<<8 | uint16(data[1])
length := int(data[2])<<8 | int(data[3])
data = data[4:]
if len(data) < length {
return false
}
switch extension {
case extensionServerName:
if length < 2 {
return false
}
numNames := int(data[0])<<8 | int(data[1])
d := data[2:]
for i := 0; i < numNames; i++ {
if len(d) < 3 {
return false
}
nameType := d[0]
nameLen := int(d[1])<<8 | int(d[2])
d = d[3:]
if len(d) < nameLen {
return false
}
if nameType == 0 {
m.ServerName = string(d[0:nameLen])
break
}
d = d[nameLen:]
}
case extensionNextProtoNeg:
if length > 0 {
return false
}
m.NextProtoNeg = true
case extensionStatusRequest:
m.OcspStapling = length > 0 && data[0] == statusTypeOCSP
case extensionSupportedCurves:
// http://tools.ietf.org/html/rfc4492#section-5.5.1
if length < 2 {
return false
}
l := int(data[0])<<8 | int(data[1])
if l%2 == 1 || length != l+2 {
return false
}
numCurves := l / 2
m.SupportedCurves = make([]uint16, numCurves)
d := data[2:]
for i := 0; i < numCurves; i++ {
m.SupportedCurves[i] = uint16(d[0])<<8 | uint16(d[1])
d = d[2:]
}
case extensionSupportedPoints:
// http://tools.ietf.org/html/rfc4492#section-5.5.2
if length < 1 {
return false
}
l := int(data[0])
if length != l+1 {
return false
}
m.SupportedPoints = make([]uint8, l)
copy(m.SupportedPoints, data[1:])
case extensionSessionTicket:
// http://tools.ietf.org/html/rfc5077#section-3.2
m.TicketSupported = true
m.SessionTicket = data[:length]
}
data = data[length:]
}
return true
}
|