vendor.github.com.refraction-networking.utls.u_fingerprinter.go Maven / Gradle / Ivy
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// Copyright 2017 Google Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
// Fingerprinter is a struct largely for holding options for the FingerprintClientHello func
type Fingerprinter struct {
// AllowBluntMimicry will ensure that unknown extensions are
// passed along into the resulting ClientHelloSpec as-is
// WARNING: there could be numerous subtle issues with ClientHelloSpecs
// that are generated with this flag which could compromise security and/or mimicry
AllowBluntMimicry bool
// AlwaysAddPadding will always add a UtlsPaddingExtension with BoringPaddingStyle
// at the end of the extensions list if it isn't found in the fingerprinted hello.
// This could be useful in scenarios where the hello you are fingerprinting does not
// have any padding, but you suspect that other changes you make to the final hello
// (including things like different SNI lengths) would cause padding to be necessary
AlwaysAddPadding bool
RealPSKResumption bool // if set, PSK extension (if any) will be real PSK extension, otherwise it will be fake PSK extension
}
// FingerprintClientHello returns a ClientHelloSpec which is based on the
// ClientHello that is passed in as the data argument
//
// If the ClientHello passed in has extensions that are not recognized or cannot be handled
// it will return a non-nil error and a nil *ClientHelloSpec value
//
// The data should be the full tls record, including the record type/version/length header
// as well as the handshake type/length/version header
// https://tools.ietf.org/html/rfc5246#section-6.2
// https://tools.ietf.org/html/rfc5246#section-7.4
//
// It calls UnmarshalClientHello internally, and is kept for backwards compatibility
func (f *Fingerprinter) FingerprintClientHello(data []byte) (clientHelloSpec *ClientHelloSpec, err error) {
return f.RawClientHello(data)
}
// RawClientHello returns a ClientHelloSpec which is based on the
// ClientHello raw bytes that is passed in as the raw argument.
//
// It was renamed from FingerprintClientHello in v1.3.1 and earlier versions
// as a more precise name for the function
func (f *Fingerprinter) RawClientHello(raw []byte) (clientHelloSpec *ClientHelloSpec, err error) {
clientHelloSpec = &ClientHelloSpec{}
err = clientHelloSpec.FromRaw(raw, f.AllowBluntMimicry, f.RealPSKResumption)
if err != nil {
return nil, err
}
if f.AlwaysAddPadding {
clientHelloSpec.AlwaysAddPadding()
}
return clientHelloSpec, nil
}
// UnmarshalJSONClientHello returns a ClientHelloSpec which is based on the
// ClientHello JSON bytes that is passed in as the json argument.
func (f *Fingerprinter) UnmarshalJSONClientHello(json []byte) (clientHelloSpec *ClientHelloSpec, err error) {
clientHelloSpec = &ClientHelloSpec{}
err = clientHelloSpec.UnmarshalJSON(json)
if err != nil {
return nil, err
}
if f.AlwaysAddPadding {
clientHelloSpec.AlwaysAddPadding()
}
return clientHelloSpec, nil
}