screentinker/server/config/cloudflareIps.js
ScreenTinker 4b13dadb4d fix(logging): gate CF-Connecting-IP on a Cloudflare peer, not any trusted proxy
getClientIp() decides the value every per-IP control keys on — the auth/pairing rate
limiters, lib/pair-lockout, and activity_log.ip_address — so a caller must never be able
to choose it. It believed CF-Connecting-IP whenever the immediate peer was in the
`trust proxy` list, which includes loopback/linklocal/uniquelocal.

Those entries are correct for X-Forwarded-For: a proxy APPENDS to that header and Express
walks the chain right-to-left, so a client-supplied value cannot become the resolved
address. CF-Connecting-IP has no chain — a local reverse proxy passes through whatever
single value the client sent — so treating a loopback peer as evidence the request came
through Cloudflare means trusting the client.

Gate it on the published Cloudflare ranges alone. This is also the portable behaviour:
most self-hosted installs are not behind Cloudflare, and for them the header is now
simply ignored, with attribution falling back to req.ip under whatever `trust proxy` the
operator configured. Installs that do front with Cloudflare are unaffected — their peer
really is a CF edge.

Documented the distinction at config/cloudflareIps.js so the two lists are not conflated
again. No response shape or DB change; no client impact.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-07-26 10:23:04 -05:00

45 lines
1.5 KiB
JavaScript

// Cloudflare published edge IP ranges.
// Source: https://www.cloudflare.com/ips-v4 and https://www.cloudflare.com/ips-v6
// Snapshot: 2026-05-07. Update by hand when Cloudflare publishes a new list.
const cloudflareIpv4 = [
'173.245.48.0/20',
'103.21.244.0/22',
'103.22.200.0/22',
'103.31.4.0/22',
'141.101.64.0/18',
'108.162.192.0/18',
'190.93.240.0/20',
'188.114.96.0/20',
'197.234.240.0/22',
'198.41.128.0/17',
'162.158.0.0/15',
'104.16.0.0/13',
'104.24.0.0/14',
'172.64.0.0/13',
'131.0.72.0/22',
];
const cloudflareIpv6 = [
'2400:cb00::/32',
'2606:4700::/32',
'2803:f800::/32',
'2405:b500::/32',
'2405:8100::/32',
'2a06:98c0::/29',
'2c0f:f248::/32',
];
const cloudflareIps = [...cloudflareIpv4, ...cloudflareIpv6];
// What Express's `trust proxy` honors. 'loopback', 'linklocal', 'uniquelocal' keep local
// dev and any LAN reverse proxy working without further config, and they are SAFE here
// because a proxy APPENDS to X-Forwarded-For and Express walks that chain right-to-left,
// so a client-supplied value can never end up as the resolved address.
//
// NOTE: this list is deliberately NOT the gate for CF-Connecting-IP. That header carries
// no chain — a local proxy passes through whatever single value the client sent — so
// services/activity.js gates it on `cloudflareIps` alone. See the comment there.
const trustedProxies = ['loopback', 'linklocal', 'uniquelocal', ...cloudflareIps];
module.exports = { cloudflareIpv4, cloudflareIpv6, cloudflareIps, trustedProxies };