registry auth survives an http to https token realm redirect behind a TLS proxy

src/lib/server/registry-auth.ts

@@ -1,3 +1,5 @@
+import { isSafeNotificationUrl } from './url-safety';
+
 /**
  * Encode the AuthConfig JSON as base64url **with `=` padding** for the
  * Docker X-Registry-Auth header. The Docker daemon decodes the header with
@@ -14,6 +16,19 @@ export function encodeRegistryAuth(authConfig: object): string {
 	return unpadded + '='.repeat((4 - (unpadded.length % 4)) % 4);
 }
 
+/**
+ * SSRF guard for a registry HOST derived from a user-controlled image reference
+ * (e.g. `169.254.169.254:80/x/y:latest` in a container image or compose stack).
+ * The update-check path fetches `https://<registry>/v2/...`, so a crafted image
+ * name could point the server at loopback/metadata. A registry legitimately lives
+ * on a LAN (self-hosted Harbor / `registry:5000`), so allow private ranges but
+ * block loopback + cloud metadata (169.254.169.254) + reserved. Returns { ok } or
+ * { ok:false, reason }. `registry` is a bare host[:port], no scheme.
+ */
+export function isSafeRegistryHost(registry: string): { ok: boolean; reason?: string } {
+	return isSafeNotificationUrl(`https://${registry}`);
+}
+
 /**
  * Whether Basic credentials may be re-attached when a registry token request
  * redirects. True only when the host is unchanged. A Harbor behind a
@@ -34,12 +49,26 @@ export function canReattachAuthOnRedirect(from: string, to: string): boolean {
 /** Injectable fetch, so the redirect-follow loop is unit-testable without a network. */
 export type FetchLike = (url: string, init?: { headers?: Record<string, string>; redirect?: 'manual' }) => Promise<Response>;
 
+/**
+ * Host-safety check for a registry token URL, applied to the initial URL and every
+ * redirect hop (the realm and any redirect target are host-controlled, so each hop
+ * is re-checked, not just the outer registry host). Registries live on public or
+ * LAN hosts, so this uses the permissive policy (block loopback/metadata/reserved,
+ * allow private ranges). Throws on a blocked host; callers degrade a thrown token
+ * fetch to anonymous/null.
+ */
+function assertSafeRegistryUrl(u: string): void {
+	const r = isSafeNotificationUrl(u);
+	if (!r.ok) throw new Error(`registry token URL blocked: ${r.reason}`);
+}
+
 /**
  * Fetch a registry token URL, manually following up to a few same-host redirects
  * with the Authorization header re-attached. `authHeader` is the full header value
  * (e.g. `Basic abc...`) or null for anonymous. Cross-host redirects drop the header
  * (see canReattachAuthOnRedirect). Manual redirect handling is what fixes #1428:
  * undici's automatic follow strips Authorization across an http->https origin change.
+ * Every hop (incl. the initial URL) passes assertSafeRegistryUrl.
  */
 export async function fetchRegistryToken(
 	tokenUrl: string,
@@ -47,6 +76,7 @@ export async function fetchRegistryToken(
 	fetchImpl: FetchLike = fetch as unknown as FetchLike
 ): Promise<Response> {
 	let url = tokenUrl;
+	assertSafeRegistryUrl(url);
 	for (let hop = 0; hop < 4; hop++) {
 		const headers: Record<string, string> = { 'User-Agent': 'Dockhand/1.0' };
 		if (authHeader) headers['Authorization'] = authHeader;
@@ -55,6 +85,7 @@ export async function fetchRegistryToken(
 		if (!location) return res;
 		await res.body?.cancel().catch(() => {});
 		const next = new URL(location, url).toString();
+		assertSafeRegistryUrl(next);
 		// Drop credentials if the redirect leaves the original host.
 		if (!canReattachAuthOnRedirect(url, next)) authHeader = null;
 		url = next;

src/lib/server/semver/release-notes.ts

@@ -7,6 +7,7 @@
 
 import { parseTag, compareParts } from './tag-parser';
 import type { ReleaseSource } from './release-source';
+import { isSafeNotificationUrl } from '../url-safety';
 
 export interface ReleaseNote {
 	/** The requested version tag this note is for, e.g. `16.4-alpine`. */
@@ -74,12 +75,39 @@ const MAX_PAGES = 3; // 300 recent releases is plenty to cover a handful of skip
  * query param differs (`per_page` vs `limit`). Walks pages until every wanted
  * version is matched or the page budget is spent. Never throws.
  */
+export interface ReleaseNotesResult {
+	notes: ReleaseNote[];
+	/** True when GitHub refused the request because the (usually unauthenticated)
+	 *  rate limit is exhausted - the UI can then suggest setting a token. Only ever
+	 *  set for the github.com source; a self-hosted forge doesn't have this limit. */
+	rateLimited: boolean;
+}
+
+/** True for a GitHub response that means "you're rate limited": a 403/429 whose
+ *  X-RateLimit-Remaining header is 0 (the primary-limit signal). */
+function isRateLimited(res: { status: number; headers: { get(name: string): string | null } }): boolean {
+	if (res.status !== 403 && res.status !== 429) return false;
+	const remaining = res.headers.get('x-ratelimit-remaining');
+	// If the header is present it must be 0; if absent (429 without it), treat as limited.
+	return remaining === null || remaining.trim() === '0';
+}
+
 export async function fetchReleaseNotes(
 	src: ReleaseSource,
 	wanted: string[],
 	fetchImpl: typeof fetch = fetch
-): Promise<ReleaseNote[]> {
-	if (wanted.length === 0) return [];
+): Promise<ReleaseNotesResult> {
+	if (wanted.length === 0) return { notes: [], rateLimited: false };
+
+	// SSRF guard: for a Gitea/Forgejo forge, apiBase's host comes from the
+	// container's org.opencontainers.image.source LABEL (user-controllable), so a
+	// crafted label could point the fetch at loopback/metadata. Block those but
+	// allow LAN forges (a self-hosted Gitea legitimately lives on 192.168.x). The
+	// github.com branch is hardcoded to api.github.com and needs no guard.
+	if (src.kind !== 'github') {
+		const safety = isSafeNotificationUrl(src.apiBase);
+		if (!safety.ok) return { notes: [], rateLimited: false };
+	}
 
 	const pageSizeParam = src.kind === 'github' ? 'per_page' : 'limit';
 	// Unauthenticated GitHub is 60 req/h per IP; a token raises it to 5000/h. Optional -
@@ -96,11 +124,19 @@ export async function fetchReleaseNotes(
 	if (ghToken) headers.Authorization = `Bearer ${ghToken}`;
 
 	const collected: GithubRelease[] = [];
+	// Only flag rate limiting for github.com with no token configured - that's the
+	// case a token would actually fix.
+	const canBeRateLimited = src.kind === 'github' && !ghToken;
+	let rateLimited = false;
 	try {
 		for (let page = 1; page <= MAX_PAGES; page++) {
 			const url = `${src.apiBase}?${pageSizeParam}=${PER_PAGE}&page=${page}`;
-			const res = await fetchImpl(url, { headers });
-			if (!res.ok) break;
+			const res = await fetchImpl(url, { headers, redirect: 'manual' });
+			if (res.status >= 300 && res.status < 400) break; // refuse to follow a redirect to a possibly-private host
+			if (!res.ok) {
+				if (canBeRateLimited && isRateLimited(res)) rateLimited = true;
+				break;
+			}
 			const batch = (await res.json()) as GithubRelease[];
 			if (!Array.isArray(batch) || batch.length === 0) break;
 			collected.push(...batch.filter((r) => !r.draft));
@@ -111,8 +147,8 @@ export async function fetchReleaseNotes(
 			if (batch.length < PER_PAGE) break;
 		}
 	} catch {
-		return matchReleasesToVersions(collected, wanted);
+		return { notes: matchReleasesToVersions(collected, wanted), rateLimited };
 	}
 
-	return matchReleasesToVersions(collected, wanted);
+	return { notes: matchReleasesToVersions(collected, wanted), rateLimited };
 }

src/lib/server/semver/strategies/generic-v2.ts

@@ -6,6 +6,7 @@
  * works anonymously for public repos.
  */
 import { getRegistryAuthHeader } from '../../docker';
+import { isSafeRegistryHost } from '../../registry-auth';
 
 /** Stop after this many pages — a guard against pathological repos, not a real limit. */
 const MAX_PAGES = 50;
@@ -26,6 +27,10 @@ export async function fetchGenericV2Tags(
 	repo: string,
 	credentials?: { username: string; password: string } | null
 ): Promise<string[]> {
+	// SSRF guard: `registry` comes from a user-controlled image reference. Block
+	// loopback/metadata/reserved but allow LAN registries (self-hosted Harbor).
+	if (!isSafeRegistryHost(registry).ok) return [];
+
 	const base = `https://${registry}`;
 	const authHeader = await getRegistryAuthHeader(base, `repository:${repo}:pull`, credentials ?? undefined);
 	const headers: Record<string, string> = { Accept: 'application/json', 'User-Agent': 'Dockhand/1.0' };
@@ -35,7 +40,8 @@ export async function fetchGenericV2Tags(
 	let path: string | null = `/v2/${repo}/tags/list?n=${PAGE_SIZE}`;
 
 	for (let page = 0; page < MAX_PAGES && path; page++) {
-		const response = await fetch(`${base}${path}`, { headers });
+		const response = await fetch(`${base}${path}`, { headers, redirect: 'manual' });
+		if (response.status >= 300 && response.status < 400) break; // don't follow a redirect off the guarded host
 		if (!response.ok) break; // 4xx/5xx: stop with whatever we have.
 
 		const data = (await response.json()) as TagsListResponse;

src/lib/server/url-safety.ts

@@ -95,7 +95,9 @@ export function ipCategory(host: string): IpCategory | null {
 	// IPv6 loopback / unspecified, then link-local / unique-local (private).
 	if (h === '::1') return 'loopback';
 	if (h === '::' || h === '::0') return 'reserved'; // unspecified / all-interfaces
-	if (h.startsWith('fe80:') || h.startsWith('fc') || h.startsWith('fd')) return 'private';
+	// Require a colon so real IPv6 unique-local/link-local literals match but public
+	// DNS names starting "fc"/"fd" (fcm.googleapis.com, fdroid.link) do not.
+	if (h.startsWith('fe80:') || /^f[cd][0-9a-f]{0,2}:/.test(h)) return 'private';
 	// IPv4-mapped/compatible IPv6 — judge the embedded v4 (see embeddedV4).
 	const v4 = embeddedV4(h) ?? h;
 	const m = v4.match(/^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/);