modelcontextprotocol/inspector
Watch
1
0
Fork
You've already forked inspector
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 3

fix: exempt loopback hosts from the CIMD metadata URL HTTPS requirement

Browse source 
`getCimdClientMetadataUrlError` rejected every non-HTTPS CIMD client metadata
URL with no loopback exemption, and the same check runs against `client.json`
on disk through `refineCimdMetadataUrl`, so it could not be worked around by
hand-editing the file either. Every test server in this repo speaks plain HTTP,
so CIMD could not be driven against any local fixture: #2242 shipped verified by
tests alone, and reproducing it by hand meant standing up a self-signed HTTPS
listener plus `NODE_TLS_REJECT_UNAUTHORIZED=0` in the test server's environment.

Accept plain `http:` on the three literals the SDK itself exempts from its
token-endpoint TLS assertion — `localhost`, `127.0.0.1` and `[::1]`. That is
option 1 in #2305 and matches what the runtime already tolerated:
`core/auth/cimd.ts` notes that an already-stored `client_id` may be an `http://`
URL used by local dev/test metadata servers. Anything outside those three,
`localhost.` and `tenant.app.localhost` included, is still rejected — matching
the SDK literal for literal keeps the two allow-lists from disagreeing about one
URL.

The exemption is a literal set rather than `isLoopbackHost` because
`core/client/config-parse.ts` is browser-safe and `core/node/hostUrl.ts` imports
`node:net`.

The field error now names the exemption instead of saying only "must use
HTTPS", and the form's hint and description say the same, so a developer
pointing the field at a local fixture is told which spellings work.

Closes #2305

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GfHQ8vMm5NBgzbUJ6UwxmB
Signed-off-by: cliffhall <cliff@futurescale.com>
This commit is contained in:
cliffhall 2026-09-11 02:31:47 -04:00
commit a1cad93ed9
3 changed files with 146 additions and 20 deletions
Download patch file Download diff file Expand all files Collapse all files

7
clients/web/src/components/groups/ClientSettingsForm/ClientSettingsForm.tsx
View file

@ -307,15 +307,16 @@ export function ClientSettingsForm({
{settings.cimdEnabled && (
<>
<HintText>
The metadata document must be served over HTTPS and list
this redirect URI:{" "}
The metadata document must be served over HTTPS — or over
plain HTTP from localhost, 127.0.0.1 or [::1], for a local
fixture — and list this redirect URI:{" "}
{typeof window !== "undefined"
? `${window.location.origin}/oauth/callback`
: "http://localhost:6274/oauth/callback"}
</HintText>
<ClearableTextInput
label="Client ID metadata document URL"
description="Public HTTPS URL of your OAuth client metadata JSON document."
description="HTTPS URL of your OAuth client metadata JSON document (http:// is accepted only on localhost, 127.0.0.1 or [::1])."
value={settings.clientMetadataUrl}
onChange={(e) =>
patch({ clientMetadataUrl: e.currentTarget.value })

57
clients/web/src/test/core/client/config.test.ts
View file

@ -206,6 +206,19 @@ describe("client config", () => {
).toThrow(/HTTPS/);
});
it("parseClientConfig accepts a loopback http CIMD URL", () => {
for (const clientMetadataUrl of [
"http://localhost:8090/client-metadata.json",
"http://127.0.0.1:8090/client-metadata.json",
"http://[::1]:8090/client-metadata.json",
]) {
const config = parseClientConfig({
cimd: { enabled: true, clientMetadataUrl },
});
expect(config.cimd?.clientMetadataUrl).toBe(clientMetadataUrl);
}
});
it("parseClientConfig rejects CIMD URL without path", () => {
expect(() =>
parseClientConfig({
@ -299,6 +312,50 @@ describe("client config", () => {
CIMD_METADATA_URL_PATH_ERROR,
);
});
it("accepts plain http on the three exempt loopback literals", () => {
expect(
getCimdClientMetadataUrlError(
"http://localhost:8090/client-metadata.json",
),
).toBeUndefined();
expect(
getCimdClientMetadataUrlError(
"http://127.0.0.1:8090/client-metadata.json",
),
).toBeUndefined();
expect(
getCimdClientMetadataUrlError("http://[::1]:8090/client-metadata.json"),
).toBeUndefined();
});
it("still requires a path on an exempt loopback host", () => {
expect(getCimdClientMetadataUrlError("http://localhost:8090")).toBe(
CIMD_METADATA_URL_PATH_ERROR,
);
});
it("does not widen the exemption beyond the three literals", () => {
// `localhost.` and `*.localhost` resolve to loopback on every resolver,
// but they are outside the SDK's allow-list — so they are outside ours
// too, deliberately, rather than the two disagreeing about one URL.
for (const value of [
"http://tenant.app.localhost:3300/client-metadata.json",
"http://127.0.0.2:8090/client-metadata.json",
"http://localhost.example.com/client-metadata.json",
]) {
expect(getCimdClientMetadataUrlError(value)).toBe(
CIMD_METADATA_URL_HTTPS_ERROR,
);
}
// The root-anchored spelling never reaches the protocol check at all:
// `isAbsoluteHttpUrl` rejects its trailing empty label first, so it is
// flagged as unparseable rather than as non-HTTPS. Pinned so a later
// change to either check has to decide about this case on purpose.
expect(
getCimdClientMetadataUrlError("http://localhost./client-metadata.json"),
).toBe(CIMD_METADATA_URL_INVALID_ERROR);
});
});
it("formatClientConfigLoadError summarizes Zod validation failures", () => {

32
clients/web/src/test/integration/mcp/oauth-cimd-fixture.test.ts
View file

@ -10,6 +10,10 @@ import {
loadConfig,
resolveConfig,
} from "@modelcontextprotocol/inspector-test-server";
import {
getCimdClientMetadataUrlError,
parseClientConfig,
} from "@inspector/core/client/config-parse.js";
/**
* Live coverage of `test-servers/configs/oauth-cimd-http.json` — the fixture
@ -34,11 +38,13 @@ import {
* - the document's `client_id` equals the URL it was fetched from, which is
* what makes it a legal CIMD client id rather than an arbitrary blob.
*
* The document is served over plain HTTP here. That is deliberate and is *not*
* a usable `clientMetadataUrl` for the Inspector, which requires HTTPS with no
* loopback exemption (#2305) — driving the UI needs a self-signed HTTPS
* listener, as `docs/test-servers.md` describes. This endpoint exists for the
* authorization-server side of the flow and for exactly these assertions.
* The document is served over plain HTTP here, on `localhost`. Since #2305 that
* *is* a usable `clientMetadataUrl`: the Inspector's HTTPS requirement now
* exempts the same three loopback literals the SDK exempts for token endpoints,
* so the fixture can be driven from the web client with no self-signed HTTPS
* listener. The last case below pins that, because it is the property the
* fixture's whole reason for existing rests on — a re-tightened validator would
* put the manual repro back out of reach without failing anything else here.
*/
describe("CIMD showcase fixture (#2242)", () => {
let server: TestServerHttp | null = null;
@ -121,6 +127,22 @@ describe("CIMD showcase fixture (#2242)", () => {
expect(doc.token_endpoint_auth_method).toBe("none");
});
it("serves the document at a URL the Inspector accepts as a clientMetadataUrl", async () => {
const started = await startShowcase();
const documentUrl = `${originOf(started)}/client-metadata.json`;
// The #2305 property: no self-signed HTTPS listener, no
// NODE_TLS_REJECT_UNAUTHORIZED=0 — the served URL is legal config as-is,
// both inline in the settings form and in `client.json` on disk.
expect(new URL(documentUrl).protocol).toBe("http:");
expect(getCimdClientMetadataUrlError(documentUrl)).toBeUndefined();
expect(
parseClientConfig({
cimd: { enabled: true, clientMetadataUrl: documentUrl },
}).cimd?.clientMetadataUrl,
).toBe(documentUrl);
});
it("preserves a query-bearing document URL in the client_id it publishes", async () => {
const started = await startShowcase();
const documentUrl = `${originOf(started)}/client-metadata.json?profile=a`;