mirror of
https://github.com/bulwarkmail/webmail.git
synced 2026-10-31 16:13:15 +00:00
Linus Rath
cf0eb03c4a
Stalwart does no BIMI, so sender icons were only ever favicons, which anyone controls for any domain. The webmail server now does the receiver side itself at /api/bimi, and avatars ask it only for messages whose own Authentication-Results say dmarc=pass for the exact From domain. - `lib/bimi/`: DMARC policy check (quarantine or reject, pct=100, the parent domain's sp and p for subdomains), the assertion record with fallback to the parent domain, mark certificate validation (chain to pinned DigiCert, GlobalSign and SSL.com VMC roots, BIMI key purpose, validity, SAN, SCTs present, CRL revocation, logo from the logotype extension), SVG Tiny PS checks and rendering to PNG, caching - logos backed only by the DNS record show by default; the admin setting "Require a mark certificate" (`BIMI_REQUIRE_CERTIFICATE`) limits them to VMC and CMC backed ones - a check mark beside the sender's name for certificate-backed logos - avatars try contact photo, BIMI logo, plugin avatar, favicon; the sender warning shield still wins, and logos follow the sender icons setting and the no-third-party-traffic mode - the two-label public suffix list moved to `lib/root-domain.ts` SCT signatures are not verified and only the default selector is used.
72 lines
2.9 KiB
TypeScript
72 lines
2.9 KiB
TypeScript
import { NextRequest, NextResponse } from 'next/server';
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import { configManager } from '@/lib/admin/config-manager';
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import { isNoThirdPartyTrafficOn, thirdPartyRefusal } from '@/lib/admin/third-party-mode';
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import { bimiResolver, normalizeBimiDomain, type BimiIndicator } from '@/lib/bimi/lookup';
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import type { BimiInfo } from '@/lib/bimi/types';
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/**
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* BIMI sender logos. GET ?domain=<From domain> answers the logo as a PNG, or
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* the same 1x1 transparent PNG /api/favicon sends when there is none (the
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* avatar falls through on naturalWidth <= 1). With &format=json it answers
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* what backs the logo, for the verified badge in the message view.
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*
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* Ask only for messages that passed DMARC for that domain (see
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* brandIndicatorDomain in lib/email-headers.ts): the logo says who the domain
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* is, not that a given message came from it.
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*/
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const TRANSPARENT_PNG = Buffer.from(
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'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNgAAIAAAUAAen63NgAAAAASUVORK5CYII=',
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'base64',
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);
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const IMAGE_HEADERS = {
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'Content-Type': 'image/png',
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'X-Content-Type-Options': 'nosniff',
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'Content-Security-Policy': "default-src 'none'; sandbox",
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};
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// Short enough that switching "Require a mark certificate" reaches browsers
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// the same day.
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const LOGO_MAX_AGE = 6 * 60 * 60;
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const MISSING_MAX_AGE = 60 * 60;
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async function requireCertificate(): Promise<boolean> {
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await configManager.ensureLoaded();
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return configManager.get<boolean>('bimiRequireCertificate', false) === true;
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}
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function info(indicator: BimiIndicator | null): BimiInfo {
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if (!indicator) return { status: 'none' };
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const { status, markType, organization, issuer } = indicator;
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return { status, markType, organization, issuer };
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}
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export async function GET(request: NextRequest) {
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// The lookups reach the sender's DNS and whatever hosts its record names.
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if (await isNoThirdPartyTrafficOn()) return thirdPartyRefusal('Brand logos');
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const domain = normalizeBimiDomain(request.nextUrl.searchParams.get('domain'));
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const asJson = request.nextUrl.searchParams.get('format') === 'json';
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if (!domain) {
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return new NextResponse(null, { status: 400, headers: { 'Cache-Control': 'public, max-age=86400' } });
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}
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let indicator = await bimiResolver().resolve(domain);
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if (indicator && indicator.status !== 'verified' && await requireCertificate()) indicator = null;
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if (asJson) {
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return NextResponse.json(info(indicator), {
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headers: { 'Cache-Control': `public, max-age=${indicator ? LOGO_MAX_AGE : MISSING_MAX_AGE}` },
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});
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}
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if (!indicator) {
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return new NextResponse(new Uint8Array(TRANSPARENT_PNG), {
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headers: { ...IMAGE_HEADERS, 'Cache-Control': `public, max-age=${MISSING_MAX_AGE}`, 'X-Bulwark-Bimi': 'missing' },
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});
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}
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return new NextResponse(new Uint8Array(indicator.png), {
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headers: { ...IMAGE_HEADERS, 'Cache-Control': `public, max-age=${LOGO_MAX_AGE}`, 'X-Bulwark-Bimi': indicator.status },
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});
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}
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