mirror of
https://github.com/superseriousbusiness/gotosocial
synced 2025-06-05 21:59:39 +02:00
d8c4d9fc5a
This adds a proof-of-work based scraper deterrence to GoToSocial's middleware stack on profile and status web pages. Heavily inspired by https://github.com/TecharoHQ/anubis, but massively stripped back for our own usecase. Todo: - ~~add configuration option so this is disabled by default~~ - ~~fix whatever weirdness is preventing this working with CSP (even in debug)~~ - ~~use our standard templating mechanism going through apiutil helper func~~ - ~~probably some absurdly small performance improvements to be made in pooling re-used hex encode / hash encode buffers~~ the web endpoints aren't as hot a path as API / ActivityPub, will leave as-is for now as it is already very minimal and well optimized - ~~verify the cryptographic assumptions re: using a portion of token as challenge data~~ this isn't a serious application of cryptography, if it turns out to be a problem we'll fix it, but it definitely should not be easily possible to guess a SHA256 hash from the first 1/4 of it even if mathematically it might make it a bit easier - ~~theme / make look nice??~~ - ~~add a spinner~~ - ~~add entry in example configuration~~ - ~~add documentation~~ Verification page originally based on https://github.com/LucienV1/powtect Co-authored-by: tobi <tobi.smethurst@protonmail.com> Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4043 Reviewed-by: tobi <tsmethurst@noreply.codeberg.org> Co-authored-by: kim <grufwub@gmail.com> Co-committed-by: kim <grufwub@gmail.com>
54 lines
1.8 KiB
JavaScript
54 lines
1.8 KiB
JavaScript
/*
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GoToSocial
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Copyright (C) GoToSocial Authors admin@gotosocial.org
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SPDX-License-Identifier: AGPL-3.0-or-later
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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onmessage = async function(e) {
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console.log('worker started'); // eslint-disable-line no-console
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const challenge = e.data.challenge;
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const textEncoder = new TextEncoder();
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// Get difficulty and generate the expected
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// zero ASCII prefix to check for in hashes.
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const difficultyStr = e.data.difficulty;
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const difficulty = parseInt(difficultyStr, 10);
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const zeroPrefix = '0'.repeat(difficulty);
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let nonce = 0;
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while (true) { // eslint-disable-line no-constant-condition
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// Create possible solution string from challenge + nonce.
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const solution = textEncoder.encode(challenge + nonce.toString());
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// Generate SHA256 hashsum of solution string and hex encode the result.
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const hashBuffer = await crypto.subtle.digest('SHA-256', solution);
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const hashArray = Array.from(new Uint8Array(hashBuffer));
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const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
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// Check if the hex encoded hash has
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// difficulty defined zeroes prefix.
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if (hashHex.startsWith(zeroPrefix)) {
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postMessage({ nonce: nonce, done: true });
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break;
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}
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// Iter.
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nonce++;
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}
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};
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