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No commits in common. "cfcbbb09625aec3a800e8ad40d1b417364037688" and "e311a94e98fd807167681ac214deda55ecde9eed" have entirely different histories.
cfcbbb0962
...
e311a94e98
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@ -27,7 +27,8 @@ func dropPrivileges(userToSwitchTo string) {
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// Check supplementary groups.
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groups, err := syscall.Getgroups()
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if err != nil {
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fatalError(err)
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fmt.Println(err)
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os.Exit(1)
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}
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for _, groupID := range groups {
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if groupID == 0 {
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@ -42,53 +43,60 @@ func dropPrivileges(userToSwitchTo string) {
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fmt.Println("When running as root, use the -u option to switch to an unprivileged user.")
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os.Exit(1)
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} else if rootPrimaryGroup || rootSupplementaryGroup {
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fatalError("The user running the program is in the root group;\n" +
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"use the -u option to switch to an unprivileged user.")
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fmt.Println("The user running the program is in the root group;")
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fmt.Println("use the -u option to switch to an unprivileged user.")
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os.Exit(1)
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}
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} else { // userToSwitchTo != ""
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} else { // userToSwitchTo != ""
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// Get user and group IDs for the user we want to switch to.
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userInfo, err := user.Lookup(userToSwitchTo)
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if err != nil {
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fatalError(err)
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fmt.Println(err)
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os.Exit(1)
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}
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// Convert group id and user id from string to int.
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gid, err := strconv.Atoi(userInfo.Gid)
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if err != nil {
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fatalError(err)
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fmt.Println(err)
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os.Exit(1)
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}
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uid, err := strconv.Atoi(userInfo.Uid)
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if err != nil {
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fatalError(err)
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fmt.Println(err)
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os.Exit(1)
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}
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// If the user we want to switch to has root privileges, stop execution.
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if uid == 0 || gid == 0 {
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fatalError("Running as root is not allowed.")
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fmt.Println("Running as root is not allowed.")
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os.Exit(1)
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}
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// Unset supplementary group IDs.
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err = syscall.Setgroups([]int{})
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if err != nil {
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fmt.Fprintln(os.Stderr,
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"Failed to unset supplementary group IDs: "+err.Error())
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fmt.Println("Failed to unset supplementary group IDs: " + err.Error())
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if rootSupplementaryGroup {
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fatalError("Failed to drop root privileges. Exiting...")
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fmt.Println("Failed to drop root privileges. Exiting...")
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os.Exit(1)
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}
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}
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// Set group ID (real and effective).
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err = syscall.Setgid(gid)
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if err != nil {
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fmt.Fprintln(os.Stderr, "Failed to set group ID: "+err.Error())
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fmt.Println("Failed to set group ID: " + err.Error())
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if rootPrimaryGroup {
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fatalError("Failed to drop root privileges. Exiting...")
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fmt.Println("Failed to drop root privileges. Exiting...")
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os.Exit(1)
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}
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}
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// Set user ID (real and effective).
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err = syscall.Setuid(uid)
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if err != nil {
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fmt.Fprintln(os.Stderr, "Failed to set user ID: "+err.Error())
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fmt.Println("Failed to set user ID: " + err.Error())
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if rootUser {
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fatalError("Failed to drop root privileges. Exiting...")
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fmt.Println("Failed to drop root privileges. Exiting...")
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os.Exit(1)
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}
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}
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22
index.gmi
22
index.gmi
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@ -1,22 +0,0 @@
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# TLS Client Hello Mirror
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=> /json/v1 Your browser's TLS Client Hello, reflected as JSON
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This test:
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* reflects the complete Client Hello message, preserving the order in which TLS parameters and extensions are sent;
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* can be used to check for TLS privacy pitfalls (session resumption, TLS fingerprinting, system time exposure);
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* supports multiple protocols (currently HTTP and Gemini);
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* is free as in freedom and trivial to self-host.
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JSON only, for now. The API is largely stable - fields may be added, but existing fields will not be modified or removed. IANA-assigned codes for TLS parameters and extensions are available at:
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=> https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml TLS parameters
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=> https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml TLS extensions
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Note that these lists do not include draft extensions and GREASE values. Missing values will be documented here as the project evolves.
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_____________________
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=> https://nervuri.net/ Author: nervuri
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=> https://tildegit.org/nervuri/client-hello-mirror Source (contributions welcome)
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=> https://www.gnu.org/licenses/agpl-3.0.en.html License: AGPL-3.0-or-later
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62
index.html
62
index.html
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@ -1,62 +0,0 @@
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<!DOCTYPE html>
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<html lang="en">
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, initial-scale=1">
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<meta name="theme-color" content="#000">
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<meta name="referrer" content="no-referrer">
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<title>TLS Client Hello Mirror</title>
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<style>
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:root {
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color-scheme: dark;
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}
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::selection {
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color: #FFF;
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background-color: #070;
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}
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body {
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color: #DDD;
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background-color: #000;
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margin: 1em auto;
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max-width: 38em;
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padding: 0 .62em;
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font: 1.1em/1.62 sans-serif;
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}
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@media print{
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body{
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max-width: none;
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}
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}
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a:link {color:#EEE;}
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a:visited {color:#EEE;}
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a:hover {color:#FFF;}
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a:active {color:#FFF;}
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</style>
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<main>
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<center>
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<h1>TLS Client Hello Mirror</h1>
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</center>
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<h3><a href="/json/v1">Your browser's TLS Client Hello, reflected as JSON</a></h3>
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<p>This test:
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<ul>
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<li>reflects the complete Client Hello message, preserving the order in which TLS parameters and extensions are sent;</li>
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<li>can be used to check for TLS privacy pitfalls (<a href="https://svs.informatik.uni-hamburg.de/publications/2018/2018-12-06-Sy-ACSAC-Tracking_Users_across_the_Web_via_TLS_Session_Resumption.pdf">session resumption</a>, <a href="https://tlsfingerprint.io/">TLS fingerprinting</a>, <a href="https://datatracker.ietf.org/doc/html/draft-mathewson-no-gmtunixtime">system time exposure</a>);</li>
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<li>supports both HTTP and <a href="https://gemini.circumlunar.space/">Gemini</a>;</li>
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<li>is <a href="https://www.gnu.org/philosophy/free-sw.en.html">free as in freedom</a> and trivial to self-host.</li>
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</ul>
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</p>
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<p>JSON only, for now, but a UI is on <a href="https://tildegit.org/nervuri/client-hello-mirror#roadmap">the roadmap</a>.</p>
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<p>The API is largely stable - fields may be added, but existing fields will not be modified or removed. IANA-assigned codes for TLS parameters and extensions are documented at:
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<ul>
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<li><a href="https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml">TLS parameters</a></li>
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<li><a href="https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml">TLS extensions</a></li>
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</ul>
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Note that these lists do not include draft extensions and <a href="https://datatracker.ietf.org/doc/html/rfc8701">GREASE</a> values. Missing values will be documented here as the project evolves.
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</p>
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</main>
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<hr>
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<footer>
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Author: <a href="https://nervuri.net/">nervuri</a><br>
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<a href="https://tildegit.org/nervuri/client-hello-mirror">Source</a> (contributions welcome)<br>
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License: <a href="https://www.gnu.org/licenses/agpl-3.0.en.html">AGPL-3.0-or-later</a>
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</footer>
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</html>
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140
server.go
140
server.go
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@ -6,22 +6,18 @@ import (
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"bufio"
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"bytes"
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"crypto/tls"
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_ "embed"
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"encoding/binary"
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"encoding/json"
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"flag"
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"fmt"
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"io"
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"log"
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"net"
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"net/url"
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"os"
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"strings"
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"time"
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)
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const readTimeout = 10 // seconds
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const writeTimeout = 10 // seconds
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type tlsConnectionInfo struct {
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TlsVersion uint16 `json:"tls_version"`
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CipherSuite uint16 `json:"cipher_suite"`
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@ -29,9 +25,6 @@ type tlsConnectionInfo struct {
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NegotiatedProtocol string `json:"alpn_negotiated_protocol"` // ALPN
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}
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// Connection wrapper that enables exposing the Client Hello to the
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// request handler.
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// See https://github.com/FiloSottile/mostly-harmless/tree/main/talks/asyncnet
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type prefixConn struct {
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net.Conn
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io.Reader
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@ -41,19 +34,91 @@ func (c prefixConn) Read(p []byte) (int, error) {
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return c.Reader.Read(p)
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}
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// Output to stderr and exit with error code 1.
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// Like log.Fatal, but without the date&time prefix.
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// Used before starting the server loop.
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func fatalError(err ...any) {
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logger := log.New(os.Stderr, "", 0)
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logger.Fatal(err...)
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const html = `<!DOCTYPE html>
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<html lang="en">
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<meta charset="utf-8">
|
||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||
<meta name="theme-color" content="#000">
|
||||
<meta name="referrer" content="no-referrer">
|
||||
<title>TLS Client Hello Mirror</title>
|
||||
<style>
|
||||
:root {
|
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color-scheme: dark;
|
||||
}
|
||||
::selection {
|
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color: #FFF;
|
||||
background-color: #070;
|
||||
}
|
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body {
|
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color: #DDD;
|
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background-color: #000;
|
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margin: 1em auto;
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max-width: 38em;
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padding: 0 .62em;
|
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font: 1.1em/1.62 sans-serif;
|
||||
}
|
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@media print{
|
||||
body{
|
||||
max-width: none;
|
||||
}
|
||||
}
|
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a:link {color:#EEE;}
|
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a:visited {color:#EEE;}
|
||||
a:hover {color:#FFF;}
|
||||
a:active {color:#FFF;}
|
||||
</style>
|
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<main>
|
||||
<center>
|
||||
<h1>TLS Client Hello Mirror</h1>
|
||||
</center>
|
||||
<h3><a href="/json/v1">Your browser's TLS Client Hello, reflected as JSON</a></h3>
|
||||
<p>This test:
|
||||
<ul>
|
||||
<li>reflects the complete Client Hello message, preserving the order in which TLS parameters and extensions are sent;</li>
|
||||
<li>can be used to check for TLS privacy pitfalls (<a href="https://svs.informatik.uni-hamburg.de/publications/2018/2018-12-06-Sy-ACSAC-Tracking_Users_across_the_Web_via_TLS_Session_Resumption.pdf">session resumption</a>, <a href="https://tlsfingerprint.io/">TLS fingerprinting</a>, <a href="https://datatracker.ietf.org/doc/html/draft-mathewson-no-gmtunixtime">system time exposure</a>);</li>
|
||||
<li>supports both HTTP and <a href="https://gemini.circumlunar.space/">Gemini</a>;</li>
|
||||
<li>is <a href="https://www.gnu.org/philosophy/free-sw.en.html">free as in freedom</a> and trivial to self-host.</li>
|
||||
</ul>
|
||||
</p>
|
||||
<p>JSON only, for now, but a UI is on <a href="https://tildegit.org/nervuri/client-hello-mirror#roadmap">the roadmap</a>.</p>
|
||||
<p>The API is largely stable - fields may be added, but existing fields will not be modified or removed. IANA-assigned codes for TLS parameters and extensions are documented at:
|
||||
<ul>
|
||||
<li><a href="https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml">TLS parameters</a></li>
|
||||
<li><a href="https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml">TLS extensions</a></li>
|
||||
</ul>
|
||||
Note that these lists do not include draft extensions and <a href="https://datatracker.ietf.org/doc/html/rfc8701">GREASE</a> values. Missing values will be documented here as the project evolves.
|
||||
</p>
|
||||
</main>
|
||||
<hr>
|
||||
<footer>
|
||||
Author: <a href="https://nervuri.net/">nervuri</a><br>
|
||||
<a href="https://tildegit.org/nervuri/client-hello-mirror">Source</a> (contributions welcome)<br>
|
||||
License: <a href="https://www.gnu.org/licenses/agpl-3.0.en.html">AGPL-3.0-or-later</a>
|
||||
</footer>
|
||||
</html>`
|
||||
|
||||
//go:embed index.html
|
||||
var html string
|
||||
const gemtext = `# TLS Client Hello Mirror
|
||||
|
||||
//go:embed index.gmi
|
||||
var gemtext string
|
||||
=> /json/v1 Your browser's TLS Client Hello, reflected as JSON
|
||||
|
||||
This test:
|
||||
|
||||
* reflects the complete Client Hello message, preserving the order in which TLS parameters and extensions are sent;
|
||||
* can be used to check for TLS privacy pitfalls (session resumption, TLS fingerprinting, system time exposure);
|
||||
* supports multiple protocols (currently HTTP and Gemini);
|
||||
* is free as in freedom and trivial to self-host.
|
||||
|
||||
JSON only, for now. The API is largely stable - fields may be added, but existing fields will not be modified or removed. IANA-assigned codes for TLS parameters and extensions are available at:
|
||||
|
||||
=> https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml TLS parameters
|
||||
=> https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml TLS extensions
|
||||
|
||||
Note that these lists do not include draft extensions and GREASE values. Missing values will be documented here as the project evolves.
|
||||
|
||||
_____________________
|
||||
=> https://nervuri.net/ Author: nervuri
|
||||
=> https://tildegit.org/nervuri/client-hello-mirror Source (contributions welcome)
|
||||
=> https://www.gnu.org/licenses/agpl-3.0.en.html License: AGPL-3.0-or-later`
|
||||
|
||||
// Copy the Client Hello message before starting the TLS handshake.
|
||||
func peek(conn net.Conn, tlsConfig *tls.Config) {
|
||||
|
|
@ -79,24 +144,21 @@ func peek(conn net.Conn, tlsConfig *tls.Config) {
|
|||
}
|
||||
rawClientHello := buf.Bytes()
|
||||
|
||||
// "Put back" the Client Hello bytes we just read, so that they can be
|
||||
// used in the TLS handshake. Concatenate the read bytes with the
|
||||
// unread bytes using a MultiReader, inside a connection wrapper.
|
||||
pConn := prefixConn{
|
||||
Conn: conn,
|
||||
Reader: io.MultiReader(&buf, conn),
|
||||
}
|
||||
|
||||
tlsConnection := tls.Server(pConn, tlsConfig)
|
||||
err = tlsConnection.Handshake()
|
||||
server := tls.Server(pConn, tlsConfig)
|
||||
err = server.Handshake()
|
||||
if err != nil {
|
||||
log.Println(err)
|
||||
return
|
||||
}
|
||||
requestHandler(tlsConnection, rawClientHello)
|
||||
tlsHandler(server, rawClientHello)
|
||||
}
|
||||
|
||||
func requestHandler(conn *tls.Conn, rawClientHello []byte) {
|
||||
func tlsHandler(conn *tls.Conn, rawClientHello []byte) {
|
||||
defer conn.Close()
|
||||
|
||||
scanner := bufio.NewScanner(conn)
|
||||
|
|
@ -107,6 +169,7 @@ func requestHandler(conn *tls.Conn, rawClientHello []byte) {
|
|||
log.Println(err)
|
||||
return
|
||||
}
|
||||
//log.Println(line)
|
||||
|
||||
var protocol string
|
||||
var path string // requested page
|
||||
|
|
@ -212,25 +275,28 @@ func main() {
|
|||
flag.Parse()
|
||||
hostAndPort = flag.Arg(0)
|
||||
if certFile == "" || keyFile == "" || hostAndPort == "" {
|
||||
fatalError("usage: client-hello-mirror -c cert.pem -k key.pem [-u user] host:port")
|
||||
fmt.Println("usage: client-hello-mirror -c cert.pem -k key.pem [-u user] host:port")
|
||||
return
|
||||
}
|
||||
|
||||
// Load cert
|
||||
cert, err := tls.LoadX509KeyPair(certFile, keyFile)
|
||||
if err != nil {
|
||||
fatalError(err)
|
||||
log.Fatal(err)
|
||||
return
|
||||
}
|
||||
// TLS config
|
||||
tlsConfig := tls.Config{
|
||||
Certificates: []tls.Certificate{cert},
|
||||
MinVersion: tls.VersionTLS10,
|
||||
NextProtos: []string{"http/1.1"},
|
||||
//MaxVersion: tls.VersionTLS12,
|
||||
NextProtos: []string{"http/1.1"},
|
||||
}
|
||||
|
||||
// Listen for connections
|
||||
ln, err := net.Listen("tcp", hostAndPort)
|
||||
if err != nil {
|
||||
fatalError(err)
|
||||
log.Println(err)
|
||||
return
|
||||
}
|
||||
defer ln.Close()
|
||||
|
||||
|
|
@ -239,24 +305,12 @@ func main() {
|
|||
log.Println("Server started")
|
||||
|
||||
for {
|
||||
// Wait for a connection.
|
||||
conn, err := ln.Accept()
|
||||
if err != nil {
|
||||
log.Println("Error accepting: ", err.Error())
|
||||
continue
|
||||
}
|
||||
// Set connection timeouts.
|
||||
err = conn.SetReadDeadline(time.Now().Add(readTimeout * time.Second))
|
||||
if err != nil {
|
||||
log.Println("SetReadDeadline error: ", err.Error())
|
||||
continue
|
||||
}
|
||||
err = conn.SetWriteDeadline(time.Now().Add(writeTimeout * time.Second))
|
||||
if err != nil {
|
||||
log.Println("SetWriteDeadline error: ", err.Error())
|
||||
continue
|
||||
}
|
||||
// Process the request.
|
||||
conn.SetReadDeadline(time.Now().Add(5 * time.Second)) // timeout
|
||||
go peek(conn, &tlsConfig)
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue