start adding proof of work middleware

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kim 2025-04-22 16:06:51 +01:00
commit 2442c6fc41
2 changed files with 385 additions and 0 deletions

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<!DOCTYPE html>
<html>
<head>
<title>Verifying...</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:wght@480&display=swap');
@media (prefers-color-scheme: light) {
:root {
--color-1: #f9fafb;
--color-2: #2563eb;
}
}
@media (prefers-color-scheme: dark) {
:root {
--color-1: #f5a9b8;
--color-2: #000000;
}
}
@media (prefers-color-scheme: no-preference) {
:root {
--color-1: #f9fafb;
--color-2: #2563eb;
}
}
html, body {
height: 100%;
margin: 0;
color: var(--color-1);
background-color: var(--color-2);
font-family: "IBM Plex Sans", sans-serif;
font-optical-sizing: auto;
font-weight: 480;
font-style: normal;
font-variation-settings: "wdth" 100;
font-size: 120%;
}
.hidden {
display: none;
}
</style>
</head>
<body>
<script>
document.addEventListener('DOMContentLoaded', function() {
const jsOnlyElements = document.querySelectorAll('.hidden');
jsOnlyElements.forEach(el => {
el.classList.remove('hidden');
});
});
// Define our worker task func.
const workerTask = function() {
onmessage = async function(e) {
const challenge = e.data.challenge;
const textEncoder = new TextEncoder();
// Get difficult and generate the expected
// zero ASCII prefix to check for in hashes.
const difficultyStr = e.data.difficulty;
const difficulty = parseInt(diffStr, 10);
const zeroPrefix = '0'.repeat(difficulty);
let nonce = 0;
while (true) {
// Create possible solution string from challenge + nonce.
const solution = textEncoder.encode(challenge + nonce.toString());
// Generate SHA256 hashsum of solution string and hex encode the result.
const hashBuffer = await crypto.subtle.digest('SHA-256', solution);
const hashArray = Array.from(new Uint8Array(hashBuffer));
const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
// Check if the hex encoded hash has
// difficulty defined zeroes prefix.
if (hashHex.startsWith(zeroPrefix)) {
postMessage({ nonce: nonce, done: true });
break;
}
// Send status updates.
if (i % 1000 == 0) {
postMessage({nonce: nonce});
continue;
}
// Iter.
i++;
}
}
};
// Convert the worker task function to call-able base64 blob URL.
const workerTaskBlob = new Blob(['(',workerTask.toString(),')()'],
{ type: 'application/javascript' });
const workerTaskURL = URL.createObjectURL(workerTaskBlob);
const req = new XMLHttpRequest();
req.open('GET', window.location.href, false);
req.send(null);
// Read the incoming request headers for our challenge information.
const challenge = req.getResponseHeader('X-NoLLaMas-Challenge');
const difficulty = req.getResponseHeader('X-NoLLaMas-Difficulty');
console.log('received challenge:${challenge} difficulty:${difficulty}');
// Prepare the worker with task function.
const worker = new Worker(workerTaskURL);
// Set the main worker function.
worker.onmessage = function (e) {
if (e.data.done) {
console.log("solution found for: ${e.data.nonce}");
fetch(window.location.href, {
method: 'GET',
headers: { 'X-NoLLaMas-Solution': e.data.nonce },
credentials: 'include'
}).then(response => {
console.log("Server response:", response.status);
return response.text().then(() => {
setTimeout(() => {
window.location.href = window.location.href;
}, 300);
});
}).catch(error => {
console.error('Error on refresh:', error);
});
} else if (e.data.progress) {
console.log("search progress: ${e.data.nonce}");
}
};
// Post our challenge.
worker.postMessage({
challenge: challenge,
difficulty: difficulty,
});
</script>
<div style="display: flex; align-items: center; justify-content: center; min-width: 100%; min-height: 100%;">
<div style="display: flex; flex-direction: column; align-items: center; justify-content: center; width: 75%; text-align: center;">
<p class="hidden" style="margin-bottom: 0.25rem;"><svg fill="var(--color-1)" style="width: clamp(64px, 15%, 96px); height: auto;" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg"><style>.spinner_d9Sa{transform-origin:center}.spinner_qQQY{animation:spinner_ZpfF 9s linear infinite}.spinner_pote{animation:spinner_ZpfF .75s linear infinite}@keyframes spinner_ZpfF{100%{transform:rotate(360deg)}}</style><path d="M12,1A11,11,0,1,0,23,12,11,11,0,0,0,12,1Zm0,20a9,9,0,1,1,9-9A9,9,0,0,1,12,21Z"/><rect class="spinner_d9Sa spinner_qQQY" x="11" y="6" rx="1" width="2" height="7"/><rect class="spinner_d9Sa spinner_pote" x="11" y="11" rx="1" width="2" height="9"/></svg></p>
<p class="hidden" style="margin-top: 0.5rem; max-width: 24rem;">One moment while we verify your connection...</p>
<noscript>
<p style="display: flex; align-items: center; gap: 0.5rem;">
<svg width="24px" height="24px" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg" stroke="#000000"><g id="SVGRepo_bgCarrier" stroke-width="0"></g><g id="SVGRepo_tracerCarrier" stroke-linecap="round" stroke-linejoin="round"></g><g id="SVGRepo_iconCarrier"><path d="M12 10V13" stroke="#ff7800" stroke-width="2" stroke-linecap="round"></path><path d="M12 16V15.9888" stroke="#ff7800" stroke-width="2" stroke-linecap="round"></path><path d="M10.2518 5.147L3.6508 17.0287C2.91021 18.3618 3.87415 20 5.39912 20H18.6011C20.126 20 21.09 18.3618 20.3494 17.0287L13.7484 5.147C12.9864 3.77538 11.0138 3.77538 10.2518 5.147Z" stroke="#ff7800" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"></path></g></svg>
Javascript must be enabled to verify your browser.
</p>
</noscript>
</div>
</div>
</body>
</html>

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// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package middleware
import (
"crypto/sha256"
"crypto/subtle"
"encoding/hex"
"hash"
"net/http"
"strconv"
"time"
"codeberg.org/gruf/go-byteutil"
"github.com/gin-gonic/gin"
apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
"github.com/superseriousbusiness/gotosocial/internal/oauth"
)
//go:embed challenge.html
var challengeHTML []byte
func NoLLaMas() gin.HandlerFunc {
var nollamas nollamas
return nollamas.Serve
}
// i.e. outputted hash slice length.
const hashLen = sha256.BlockSize
// i.e. hex.EncodedLen(hashLen).
const encodedHashLen = 2 * hashLen
func newHash() hash.Hash { return sha256.New() }
type nollamas struct {
seed []byte // securely hashed instance private key
ttl time.Duration
diff uint8
}
func (m *nollamas) Serve(c *gin.Context) {
if c.Request.Method != http.MethodGet {
// Only interested in protecting
// crawlable 'GET' endpoints.
c.Next()
return
}
if _, ok := c.Get(oauth.SessionAuthorizedToken); ok {
// Don't guard against requests
// providing valid OAuth tokens.
c.Next()
return
}
// Get new hasher.
hash := newHash()
// Reset hash.
hash.Reset()
// Generate a unique token for
// this request only valid for
// a period of now +- m.ttl.
token := m.token(c, hash)
// For unique challenge string just use a
// portion of their unique 'success' token.
// SHA256 is not yet cracked, this is not an
// application of a hash requiring serious
// cryptographic security and it rotates on
// a TTL basis, so it should be fine.
challenge := token[:len(token)/2]
// Check for a provided success token.
cookie, _ := c.Cookie("gts-nollamas")
if len(cookie) == 0 || len(cookie) > encodedHashLen {
// If they provide no cookie, or
// obviously wrong cookie, just
// present them with new challenge.
m.renderChallenge(c, challenge)
return
}
// Check whether passed cookie
// is the expected success token.
if subtle.ConstantTimeCompare(
byteutil.S2B(token),
byteutil.S2B(cookie),
) == 1 {
// They passed us a valid, expected
// token. They already passed checks.
c.Next()
return
}
// Check headers to see if is in-progress challenge.
nonce := c.Request.Header.Get("X-NoLLaMas-Solution")
if nonce == "" {
// No attempted solution, just
// present them with new challenge.
m.renderChallenge(c, challenge)
return
}
// Reset hash.
hash.Reset()
// Hash and encode input challenge with
// proposed nonce as a possible solution.
_, _ = hash.Write(byteutil.S2B(challenge))
_, _ = hash.Write(byteutil.S2B(nonce))
solution := hex.AppendEncode(nil, hash.Sum(nil))
// Check that the first 'diff'
// many chars are indeed zeroes.
for i := range m.diff {
if subtle.ConstantTimeByteEq(solution[i], '0') == 0 {
// They failed challenge,
// present them fail page.
m.renderFail(c)
return
}
}
// They passed the challenge! Set success
// token cookie and allow them to continue.
c.SetCookie("gts-nollamas", token, int(m.ttl/time.Second),
"", "", false, false)
c.Next()
}
func (m *nollamas) renderChallenge(c *gin.Context, challenge string) {
// Don't pass to further
// handlers, they only get
// our challenge page.
c.Abort()
// Set the challenge we expect them to use in header.
c.Request.Header.Set("X-NoLLaMas-Challenge", challenge)
c.Request.Header.Set("X-NoLLaMas-Difficulty", strconv.FormatUint(uint64(m.diff), 10))
// Write the challenge HTML response to client.
apiutil.Data(c, http.StatusOK, "text/html", challengeHTML)
}
func (m *nollamas) renderFail(c *gin.Context) {
// Don't pass to further
// handlers, they only get
// our failure page.
c.Abort()
apiutil.Data(c, http.StatusOK, apiutil.AppJSON, []byte(`{"error": "failed nollamas challenge"}`))
}
func (m *nollamas) token(c *gin.Context, hash hash.Hash) string {
// Use our safe, unique input seed which
// is already hashed, but will get rehashed.
// This ensures we don't leak private keys,
// but also we have cryptographically safe
// deterministic tokens for comparisons.
_, _ = hash.Write(m.seed)
// Include difficulty level in
// hash input data so if config
// changes then token invalidates.
_, _ = hash.Write([]byte{m.diff})
// Also seed the generated input with
// current time rounded to TTL, so with
// our single comparison handles expiries.
now := time.Now().Round(m.ttl).Unix()
_, _ = hash.Write([]byte{
byte(now >> 56),
byte(now >> 48),
byte(now >> 40),
byte(now >> 32),
byte(now >> 24),
byte(now >> 16),
byte(now >> 8),
byte(now),
})
// Finally append unique client request data.
userAgent := c.Request.Header.Get("User-Agent")
_, _ = hash.Write(byteutil.S2B(userAgent))
clientIP := c.ClientIP()
_, _ = hash.Write(byteutil.S2B(clientIP))
// Return hex encoded hash output.
return hex.EncodeToString(hash.Sum(nil))
}
// appendTime will append time as seconds in binary.
// func appendTime(b []byte, t time.Time) []byte {
// sec := t.Unix()
// return append(b,
// byte(sec>>56),
// byte(sec>>48),
// byte(sec>>40),
// byte(sec>>32),
// byte(sec>>24),
// byte(sec>>16),
// byte(sec>>8),
// byte(sec),
// )
// }