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Harden OIDC callback redirect handoff against open redirects #12

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Merged
wechuli merged 2 commits into from
Sep 18, 2026
Merged

Harden OIDC callback redirect handoff against open redirects #12

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b777f60
Initial plan
Copilot Sep 18, 2026
92596b3
fix: sanitize OIDC callback handoff redirect
Copilot Sep 18, 2026
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3 changes: 2 additions & 1 deletion app/api/auth/oidc/callback/route.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@ import {
discoverOidcProvider,
exchangeAuthorizationCode,
openOidcTransaction,
safeRelativePath,
sealOidcReauthGrant,
verifyOidcIdToken,
} from "@/lib/auth/oidc";
Expand Down Expand Up @@ -56,7 +57,7 @@ function escapeHtmlAttribute(value: string) {
}

function sessionHandoff(appOrigin: string, next: string) {
const destination = new URL(next, appOrigin).toString();
const destination = new URL(safeRelativePath(next), appOrigin).toString();
const serializedDestination = serializeForInlineScript(destination);
const escapedDestination = escapeHtmlAttribute(destination);
const nonce = randomBytes(16).toString("base64");
Expand Down
24 changes: 24 additions & 0 deletions tests/unit/oidc-route.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@ vi.mock("@/lib/auth/oidc", () => ({
discoverOidcProvider: vi.fn(),
exchangeAuthorizationCode: vi.fn(),
openOidcTransaction: vi.fn(),
safeRelativePath: vi.fn((value: string | null | undefined) => value ?? "/"),
sealOidcReauthGrant: vi.fn(),
sealOidcTransaction: vi.fn(),
verifyOidcIdToken: vi.fn(),
Expand Down Expand Up @@ -47,6 +48,7 @@ import {
discoverOidcProvider,
exchangeAuthorizationCode,
openOidcTransaction,
safeRelativePath,
sealOidcReauthGrant,
sealOidcTransaction,
verifyOidcIdToken,
Expand Down Expand Up @@ -277,6 +279,28 @@ describe("OIDC routes", () => {
);
});

test("callback re-sanitizes a stored redirect target before the handoff", async () => {
vi.mocked(openOidcTransaction).mockResolvedValueOnce({
...transaction,
next: "https://evil.example.test/phish",
});
vi.mocked(safeRelativePath).mockReturnValueOnce("/");

const response = await callbackGet(
request(
`/api/auth/oidc/callback?state=${transaction.state}&code=one-use-code`,
),
);

expect(safeRelativePath).toHaveBeenCalledWith(
"https://evil.example.test/phish",
);
expect(response.status).toBe(200);
expect(await response.text()).toContain(
'window.location.replace("https://wealth.example.test/")',
);
});

test("disabled internal users receive a generic access denial", async () => {
vi.mocked(resolveOidcLogin).mockReturnValueOnce(null);

Expand Down
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