Merge pull request #176 from codl/175

move known instance buttons entirely client-side
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codl 2019-03-15 21:50:36 +01:00 committed by GitHub
commit 8b1af6ecb6
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11 changed files with 214 additions and 167 deletions

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@ -1,6 +1,8 @@
## next ## next
* back off before hitting rate limit on mastodon instances * back off before hitting rate limit on mastodon instances
* tracking of used instances for the login buttons on the front page is now entirely client-side,
avoiding a potential information disclosure vulnerability ([GH-175](https://github.com/codl/forget/issues/175))
* fix: fetch\_acc running multiple copies fetching the same posts * fix: fetch\_acc running multiple copies fetching the same posts
* internals: increased frequency of refresh jobs, decreased frequency of bookkeeping jobs * internals: increased frequency of refresh jobs, decreased frequency of bookkeeping jobs

2
app.py
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@ -68,7 +68,7 @@ def install_security_headers(resp):
csp += "script-src 'self' https://cdn.ravenjs.com/;" csp += "script-src 'self' https://cdn.ravenjs.com/;"
csp += "connect-src 'self' https://sentry.io/;" csp += "connect-src 'self' https://sentry.io/;"
else: else:
csp += "script-src 'self';" csp += "script-src 'self' 'unsafe-eval';"
csp += "connect-src 'self';" csp += "connect-src 'self';"
if 'CSP_REPORT_URI' in app.config: if 'CSP_REPORT_URI' in app.config:

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@ -0,0 +1,71 @@
import {SLOTS, normalize_known, known_load, known_save} from './known_instances.js';
(function instance_buttons(){
const container = document.querySelector('#mastodon_instance_buttons');
const button_template = Function('first', 'instance',
'return `' + document.querySelector('#instance_button_template').innerHTML + '`;');
const another_button_template = Function(
'return `' +
document.querySelector('#another_instance_button_template').innerHTML + '`;');
const top_instances =
Function('return JSON.parse(`' + document.querySelector('#top_instances').innerHTML + '`);')();
async function get_known(){
let known = known_load();
if(!known){
let resp = await fetch('/api/known_instances');
if(resp.ok && resp.headers.get('content-type') == 'application/json'){
known = await resp.json();
}
else {
known = [{
"instance": "mastodon.social",
"hits": 0
}];
}
known_save(known)
fetch('/api/known_instances', {method: 'DELETE'})
}
return known;
}
async function replace_buttons(){
let known = await get_known();
known = normalize_known(known);
known_save(known);
let filtered_top_instances = []
for(let instance of top_instances){
let found = false;
for(let k of known){
if(k['instance'] == instance['instance']){
found = true;
break;
}
}
if(!found){
filtered_top_instances.push(instance)
}
}
let instances = known.concat(filtered_top_instances).slice(0, SLOTS);
let html = '';
let first = true;
for(let instance of instances){
html += button_template(first, instance['instance'])
first = false;
}
html += another_button_template();
container.innerHTML = html;
}
replace_buttons();
})();

44
assets/known_instances.js Normal file
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@ -0,0 +1,44 @@
const STORAGE_KEY = 'forget_known_instances';
export const SLOTS = 5;
export function known_save(known){
localStorage.setItem(STORAGE_KEY, JSON.stringify(known));
}
export function known_load(){
let known = localStorage.getItem(STORAGE_KEY);
if(known){
known = JSON.parse(known);
}
return known;
}
export function normalize_known(known){
/*
move instances with the most hits to the top SLOTS slots,
making sure not to reorder anything that is already there
*/
let head = known.slice(0, SLOTS);
let tail = known.slice(SLOTS);
if(tail.length == 0){
return known;
}
for(let i = 0; i < SLOTS; i++){
let head_min = head.reduce((acc, cur) => acc.hits < cur.hits ? acc : cur);
let tail_max = tail.reduce((acc, cur) => acc.hits > cur.hits ? acc : cur);
if(head_min.hits < tail_max.hits){
// swappy
let i = head.indexOf(head_min);
let j = tail.indexOf(tail_max);
let buf = head[i];
head[i] = tail[j];
tail[j] = buf;
}
}
return head.concat(tail)
}

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@ -1,5 +1,6 @@
import Banner from '../components/Banner.html'; import Banner from '../components/Banner.html';
import ArchiveForm from '../components/ArchiveForm.html'; import ArchiveForm from '../components/ArchiveForm.html';
import {known_load, known_save} from './known_instances.js'
(function settings_init(){ (function settings_init(){
if(!('fetch' in window)){ if(!('fetch' in window)){
@ -142,10 +143,11 @@ import ArchiveForm from '../components/ArchiveForm.html';
let last_viewer = {}; let last_viewer = {};
function update_viewer(viewer){ function update_viewer(viewer){
if(last_viewer == JSON.stringify(viewer)){ let dumped = JSON.stringify(viewer);
if(last_viewer == dumped){
return; return;
} }
last_viewer = JSON.stringify(viewer); last_viewer = dumped;
document.querySelector('#post-count').textContent = viewer.post_count; document.querySelector('#post-count').textContent = viewer.post_count;
document.querySelector('#eligible-estimate').textContent = viewer.eligible_for_delete_estimate; document.querySelector('#eligible-estimate').textContent = viewer.eligible_for_delete_estimate;
@ -163,7 +165,9 @@ import ArchiveForm from '../components/ArchiveForm.html';
banner.set(viewer); banner.set(viewer);
} }
update_viewer(JSON.parse(document.querySelector('script[data-viewer]').textContent)) let viewer_from_dom = JSON.parse(document.querySelector('script[data-viewer]').textContent)
update_viewer(viewer_from_dom)
function set_viewer_timeout(){ function set_viewer_timeout(){
setTimeout(() => fetch_viewer().then(update_viewer).then(set_viewer_timeout, set_viewer_timeout), setTimeout(() => fetch_viewer().then(update_viewer).then(set_viewer_timeout, set_viewer_timeout),
@ -202,4 +206,30 @@ import ArchiveForm from '../components/ArchiveForm.html';
}, },
}) })
} }
function bump_instance(instance_name){
let known_instances = known_load();
let found = false;
for(let instance of known_instances){
if(instance['instance'] == instance_name){
instance.hits ++;
found = true;
break;
}
}
if(!found){
let instance = {"instance": instance_name, "hits": 1};
known_instances.push(instance);
}
known_save(known_instances);
}
if(viewer_from_dom['service'] == 'mastodon' && location.hash == '#bump_instance'){
bump_instance(viewer_from_dom['id'].split('@')[1])
let url = new URL(location.href)
url.hash = '';
history.replaceState('', '', url);
}
})(); })();

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@ -116,10 +116,11 @@ def task_minify_css():
def task_rollup(): def task_rollup():
"""rollup javascript bundle""" """rollup javascript bundle"""
filenames = ['settings.js'] filenames = ['settings.js', 'instance_buttons.js']
for filename in filenames: for filename in filenames:
src = 'assets/{}'.format(filename) src = 'assets/{}'.format(filename)
dst = 'static/{}'.format(filename) dst = 'static/{}'.format(filename)
name = filename.split('.')[0]
yield dict( yield dict(
name=filename, name=filename,
file_dep=list(chain( file_dep=list(chain(
@ -130,7 +131,7 @@ def task_rollup():
clean=True, clean=True,
actions=[ actions=[
['node_modules/.bin/rollup', '-c', ['node_modules/.bin/rollup', '-c',
'-i', src, '-o', dst, '-f', 'iife'], '-i', src, '-o', dst, '-n', name, '-f', 'iife'],
], ],
) )

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@ -1,86 +0,0 @@
import json
def find(predicate, iterator, default=None):
"""
returns the first element of iterator that matches predicate
or default if none is found
"""
try:
return next((el for el in iterator if predicate(el)))
except StopIteration:
return default
class KnownInstances(object):
def __init__(self, serialised=None, top_slots=5):
self.instances = list()
self.top_slots = top_slots
try:
unserialised = json.loads(serialised)
if not isinstance(unserialised, list):
self.__default()
return
for instance in unserialised:
if 'instance' in instance and 'hits' in instance:
self.instances.append(dict(
instance=instance['instance'],
hits=instance['hits']
))
except (json.JSONDecodeError, TypeError):
self.__default()
return
def __default(self):
self.instances = [{
"instance": "mastodon.social",
"hits": 0
}]
def clear(self):
self.instances = []
def bump(self, instance_name, bump_by=1):
instance = find(
lambda i: i['instance'] == instance_name,
self.instances)
if not instance:
instance = dict(instance=instance_name, hits=0)
self.instances.append(instance)
instance['hits'] += bump_by
def normalize(self):
"""
raises the top `top_slots` instances to the top,
making sure not to move instances that were already at
the top
"""
top_slots = self.top_slots
head = self.instances[:top_slots]
tail = self.instances[top_slots:]
if len(tail) == 0:
return
def key(instance):
return instance['hits']
for _ in range(top_slots):
head_min = min(head, key=key)
tail_max = max(tail, key=key)
if tail_max['hits'] > head_min['hits']:
# swap them
i = head.index(head_min)
j = tail.index(tail_max)
buf = head[i]
head[i] = tail[j]
tail[j] = buf
else:
break
self.instances = head + tail
def top(self):
head = self.instances[:self.top_slots]
return tuple((i['instance'] for i in head))
def serialize(self):
return json.dumps(self.instances)

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@ -6,7 +6,6 @@ import libforget.mastodon
from libforget.auth import require_auth, csrf,\ from libforget.auth import require_auth, csrf,\
get_viewer get_viewer
from model import Session, TwitterArchive, MastodonApp from model import Session, TwitterArchive, MastodonApp
from libforget.known_instances import KnownInstances
from app import app, db, sentry, imgproxy from app import app, db, sentry, imgproxy
import tasks import tasks
from zipfile import BadZipFile from zipfile import BadZipFile
@ -35,10 +34,7 @@ def index():
@app.route('/about/') @app.route('/about/')
def about(): def about():
ki = KnownInstances(request.cookies.get('forget_known_instances', '')) instances = libforget.mastodon.suggested_instances()
instances = ki.top()
instances += libforget.mastodon.suggested_instances(blacklist=instances)
instances = instances[:5]
return render_template( return render_template(
'about.html', 'about.html',
mastodon_instances=instances, mastodon_instances=instances,
@ -269,15 +265,7 @@ def mastodon_login_step2(instance_url):
g.viewer = session g.viewer = session
ki = KnownInstances(request.cookies.get('forget_known_instances', '')) resp = redirect(url_for('index', _anchor='bump_instance'))
ki.bump(instance_url)
resp = redirect(url_for('index'))
resp.set_cookie(
'forget_known_instances', ki.serialize(),
max_age=60*60*24*365,
httponly=True
)
return resp return resp

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@ -1,9 +1,10 @@
from app import app, db from app import app, db
from libforget.auth import require_auth_api, get_viewer from libforget.auth import require_auth_api, get_viewer
from flask import jsonify, redirect, make_response, request from flask import jsonify, redirect, make_response, request, Response
from model import Account from model import Account
import libforget.settings import libforget.settings
import libforget.json import libforget.json
import random
@app.route('/api/health_check') @app.route('/api/health_check')
def health_check(): def health_check():
@ -59,3 +60,22 @@ def users_badge():
return redirect( return redirect(
"https://img.shields.io/badge/active%20users-{}-blue.svg" "https://img.shields.io/badge/active%20users-{}-blue.svg"
.format(count)) .format(count))
@app.route('/api/known_instances', methods=('GET', 'DELETE'))
def known_instances():
if request.method == 'GET':
known = request.cookies.get('forget_known_instances', '')
if not known:
return Response('[]', 404, mimetype='application/json')
# pad to avoid oracle attacks
for _ in range(random.randint(0, 1000)):
known += random.choice((' ', '\t', '\n'))
return Response(known, mimetype='application/json')
elif request.method == 'DELETE':
resp = Response('', 204)
resp.set_cookie('forget_known_instances', '', max_age=0)
return resp

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@ -34,7 +34,7 @@
</a> </a>
</p> </p>
<p> <p id='mastodon_instance_buttons'>
{% for instance in mastodon_instances %} {% for instance in mastodon_instances %}
<a style='background-color:#282c37' class='btn primary' href="{{ url_for('mastodon_login_step1', instance_url=instance) }}"> <a style='background-color:#282c37' class='btn primary' href="{{ url_for('mastodon_login_step1', instance_url=instance) }}">
@ -59,5 +59,41 @@
</p> </p>
</section> </section>
<script type="application/json" id="top_instances">
[
{% for instance in mastodon_instances %}
{"instance": "{{instance}}"}
{%- if not loop.last -%}
,
{%- endif %}
{% endfor %}
]
</script>
<script type="text/html+template" id="instance_button_template">
<a style='background-color:#282c37' class='btn primary'
href="{{ url_for('mastodon_login_step1') }}?instance_url=${encodeURIComponent(instance)}">
${ !first? '' : `
{{picture(st, 'mastodon', (20,40,80), ('webp', 'png'))}}
Log in with
`}
${ instance }
</a>
</script>
<script type="text/html+template" id="another_instance_button_template">
<a class='btn secondary' href="{{ url_for('mastodon_login_step1') }}">
Another Mastodon instance
</a>
</script>
{% endif %} {% endif %}
{% endblock %} {% endblock %}
{% block scripts %}
<script defer src="{{st('instance_buttons.js')}}"></script>
{% endblock %}

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@ -1,59 +0,0 @@
from libforget.known_instances import KnownInstances
def test_known_instances_defaults():
ki = KnownInstances()
assert len(ki.instances) == 1
assert ki.instances[0]['instance'] == 'mastodon.social'
assert isinstance(ki.instances[0]['hits'], int)
def test_known_instances_clear():
ki = KnownInstances()
ki.clear()
assert len(ki.instances) == 0
def test_known_instances_deserialize():
ki = KnownInstances(""" [
{"instance": "chitter.xyz", "hits": 666, "foo": "bar"},
{"instance": "invalid"}
] """)
assert len(ki.instances) == 1
assert ki.instances[0]['instance'] == "chitter.xyz"
assert ki.instances[0]['hits'] == 666
def test_known_instances_bump():
ki = KnownInstances()
ki.bump('chitter.xyz')
assert len(ki.instances) == 2
assert ki.instances[1]['instance'] == "chitter.xyz"
assert ki.instances[1]['hits'] == 1
ki.bump('chitter.xyz')
assert len(ki.instances) == 2
assert ki.instances[1]['instance'] == "chitter.xyz"
assert ki.instances[1]['hits'] == 2
def test_known_instances_normalize_top():
ki = KnownInstances(None, top_slots=3)
ki.clear()
ki.normalize()
assert len(ki.instances) == 0
ki.bump("a", 1)
ki.bump("b", 2)
ki.bump("c", 3)
ki.normalize()
assert ki.instances[0]['instance'] == "a"
assert ki.instances[1]['instance'] == "b"
assert ki.instances[2]['instance'] == "c"
ki.bump("d", 4)
ki.normalize()
assert ki.instances[0]['instance'] == "d"
assert ki.instances[3]['instance'] == "a"
assert ki.top() == ("d", "b", "c")