GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: crypto/crypto_clienthello.cc Lines: 87 116 75.0 %
Date: 2022-10-07 04:22:37 Branches: 43 77 55.8 %

Line Branch Exec Source
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// Copyright Joyent, Inc. and other Node contributors.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to permit
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// persons to whom the Software is furnished to do so, subject to the
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// following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
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// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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// USE OR OTHER DEALINGS IN THE SOFTWARE.
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#include "crypto/crypto_clienthello.h"  // NOLINT(build/include_inline)
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#include "crypto/crypto_clienthello-inl.h"
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namespace node {
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namespace crypto {
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void ClientHelloParser::Parse(const uint8_t* data, size_t avail) {
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  switch (state_) {
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    case kWaiting:
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      if (!ParseRecordHeader(data, avail))
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        break;
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      // Fall through
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    case kTLSHeader:
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      ParseHeader(data, avail);
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      break;
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    case kPaused:
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      // Just nop
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    case kEnded:
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      // Already ended, just ignore it
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      break;
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    default:
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      break;
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  }
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}
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bool ClientHelloParser::ParseRecordHeader(const uint8_t* data, size_t avail) {
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  // >= 5 bytes for header parsing
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  if (avail < 5)
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    return false;
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  if (data[0] == kChangeCipherSpec ||
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      data[0] == kAlert ||
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      data[0] == kHandshake ||
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      data[0] == kApplicationData) {
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    frame_len_ = (data[3] << 8) + data[4];
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    state_ = kTLSHeader;
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    body_offset_ = 5;
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  } else {
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    End();
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    return false;
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  }
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  // Sanity check (too big frame, or too small)
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  // Let OpenSSL handle it
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  if (frame_len_ >= kMaxTLSFrameLen) {
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    End();
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    return false;
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  }
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  return true;
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}
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void ClientHelloParser::ParseHeader(const uint8_t* data, size_t avail) {
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  ClientHello hello;
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  // We need at least six bytes (one byte for kClientHello, three bytes for the
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  // length of the handshake message, and two bytes for the protocol version).
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  // If the client sent a frame that suggests a smaller ClientHello, give up.
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  if (frame_len_ < 6) return End();
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  // >= 5 + frame size bytes for frame parsing
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  if (body_offset_ + frame_len_ > avail)
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    return;
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  // Check hello protocol version.  Protocol tuples that we know about:
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  //
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  // (3,1) TLS v1.0
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  // (3,2) TLS v1.1
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  // (3,3) TLS v1.2
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  //
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  // Note that TLS v1.3 uses a TLS v1.2 handshake so requires no specific
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  // support here.
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  if (data[body_offset_ + 4] != 0x03 ||
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      data[body_offset_ + 5] < 0x01 ||
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      data[body_offset_ + 5] > 0x03) {
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    return End();
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  }
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  if (data[body_offset_] == kClientHello) {
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    if (state_ == kTLSHeader) {
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      if (!ParseTLSClientHello(data, avail))
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        return End();
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    } else {
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      // We couldn't get here, but whatever
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      return End();
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    }
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    // Check if we overflowed (do not reply with any private data)
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    if (session_id_ == nullptr ||
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        session_size_ > 32 ||
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        session_id_ + session_size_ > data + avail) {
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      return End();
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    }
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  }
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  state_ = kPaused;
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  hello.session_id_ = session_id_;
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  hello.session_size_ = session_size_;
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  hello.has_ticket_ = tls_ticket_ != nullptr && tls_ticket_size_ != 0;
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  hello.servername_ = servername_;
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  hello.servername_size_ = static_cast<uint8_t>(servername_size_);
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  onhello_cb_(cb_arg_, hello);
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}
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void ClientHelloParser::ParseExtension(const uint16_t type,
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                                       const uint8_t* data,
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                                       size_t len) {
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  // NOTE: In case of anything we're just returning back, ignoring the problem.
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  // That's because we're heavily relying on OpenSSL to solve any problem with
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  // incoming data.
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  switch (type) {
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    case kServerName:
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      {
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        if (len < 2)
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          return;
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        uint32_t server_names_len = (data[0] << 8) + data[1];
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        if (server_names_len + 2 > len)
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          return;
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        for (size_t offset = 2; offset < 2 + server_names_len; ) {
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          if (offset + 3 > len)
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            return;
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          uint8_t name_type = data[offset];
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          if (name_type != kServernameHostname)
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            return;
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          uint16_t name_len = (data[offset + 1] << 8) + data[offset + 2];
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          offset += 3;
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          if (offset + name_len > len)
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            return;
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          servername_ = data + offset;
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          servername_size_ = name_len;
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          offset += name_len;
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        }
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      }
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      break;
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    case kTLSSessionTicket:
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      tls_ticket_size_ = len;
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      tls_ticket_ = data + len;
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      break;
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    default:
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      // Ignore
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      break;
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  }
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}
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bool ClientHelloParser::ParseTLSClientHello(const uint8_t* data, size_t avail) {
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  const uint8_t* body;
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  // Skip frame header, hello header, protocol version and random data
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  size_t session_offset = body_offset_ + 4 + 2 + 32;
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  if (session_offset + 1 >= avail)
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    return false;
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  body = data + session_offset;
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  session_size_ = *body;
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  session_id_ = body + 1;
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  size_t cipher_offset = session_offset + 1 + session_size_;
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  // Session OOB failure
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  if (cipher_offset + 1 >= avail)
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    return false;
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  uint16_t cipher_len =
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      (data[cipher_offset] << 8) + data[cipher_offset + 1];
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  size_t comp_offset = cipher_offset + 2 + cipher_len;
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  // Cipher OOB failure
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  if (comp_offset >= avail)
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    return false;
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  uint8_t comp_len = data[comp_offset];
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  size_t extension_offset = comp_offset + 1 + comp_len;
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  // Compression OOB failure
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  if (extension_offset > avail)
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    return false;
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  // No extensions present
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  if (extension_offset == avail)
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    return true;
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  size_t ext_off = extension_offset + 2;
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  // Parse known extensions
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  while (ext_off < avail) {
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    // Extension OOB
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    if (ext_off + 4 > avail)
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      return false;
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    uint16_t ext_type = (data[ext_off] << 8) + data[ext_off + 1];
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    uint16_t ext_len = (data[ext_off + 2] << 8) + data[ext_off + 3];
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    ext_off += 4;
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    // Extension OOB
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    if (ext_off + ext_len > avail)
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      return false;
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    ParseExtension(ext_type,
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                   data + ext_off,
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                   ext_len);
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    ext_off += ext_len;
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  }
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  // Extensions OOB failure
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  if (ext_off > avail)
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    return false;
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  return true;
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}
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}  // namespace crypto
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}  // namespace node