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`saml-signature.test.ts`

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45ef109ccantynz-alt	1	/**
	2	* SAML assertion verification.
	3	*
	4	* Two defects, both allowing account takeover:
	5	*
	6	* 1. Fail-open. Signature verification ran only `if (idpCertPem && trim())`,
	7	* so an org whose SAML config had a blank idp_certificate accepted ANY
	8	* forged SAMLResponse. The assertion's email selects the account to log
	9	* in as, so that is unauthenticated takeover of any account in the org.
	10	*
	11	* 2. Signature wrapping. verifySamlSignature checks only that SignedInfo
	12	* carries a valid RSA signature; the Reference DigestValue is never
	13	* recomputed. A genuinely-signed assertion could be edited — or a second
	14	* forged Assertion added beside the signed one — and still verify.
	15	*
	16	* Full XML-DSig needs exclusive c14n and a vetted library. These lock in the
	17	* fail-closed behaviour and the structural anti-wrapping checks that stand in
	18	* until then.
	19	*/
	20
	21	import { describe, expect, it } from "bun:test";
	22	import { readFileSync } from "fs";
	23
	24	const SRC = readFileSync("src/routes/saml-sso.tsx", "utf8");
	25
	26	describe("verification is mandatory (fail-closed)", () => {
	27	it("refuses when no IdP certificate is configured", () => {
	28	expect(SRC).toContain("if (!idpCertPem \|\| !idpCertPem.trim())");
	29	expect(SRC).toContain("Refusing to accept an unverified assertion");
	30	});
	31
	32	it("no longer makes verification conditional on the cert being present", () => {
	33	// The original bug shape.
	34	expect(SRC).not.toMatch(/if \(idpCertPem && idpCertPem\.trim\(\)\) \{\s\n\sconst sigValid/);
	35	});
	36	});
	37
	38	describe("anti-wrapping structural checks", () => {
	39	it("runs before signature verification", () => {
	40	const coverage = SRC.indexOf("assertSignatureCoversAssertion(xml)");
	41	const verify = SRC.indexOf("if (!verifySamlSignature(xml, idpCertPem))");
	42	expect(coverage).toBeGreaterThan(-1);
	43	expect(verify).toBeGreaterThan(-1);
	44	// A rewritten-but-validly-signed document must not reach attribute
	45	// extraction just because SignedInfo checks out.
	46	expect(coverage).toBeLessThan(verify);
	47	});
	48
	49	it("rejects multiple Assertions", () => {
	50	expect(SRC).toContain("assertionIds.length > 1");
	51	expect(SRC).toContain("signature-wrapping attempt");
	52	});
	53
	54	it("rejects a Reference that covers neither the Response nor the Assertion", () => {
	55	expect(SRC).toContain("referenced !== assertionIds[0] && referenced !== responseId");
	56	});
	57
	58	it("rejects a response with no Assertion at all", () => {
	59	expect(SRC).toContain("assertionIds.length === 0");
	60	});
	61	});
	62
	63	describe("signature algorithm selection", () => {
	64	it("reads Algorithm from SignatureMethod, not the first match in the doc", () => {
	65	// The old regex /Algorithm="([^"]+)"/ matched CanonicalizationMethod,
	66	// which appears first in a normal response — so the real algorithm was
	67	// never read and it silently fell back to SHA1.
	68	expect(SRC).toContain("SignatureMethod[^>]*\\bAlgorithm=");
	69	expect(SRC).not.toMatch(/const algMatch = xml\.match\(\/Algorithm=/);
	70	});
	71
	72	it("refuses an unrecognised algorithm instead of defaulting to SHA1", () => {
	73	expect(SRC).toContain("unrecognised SignatureMethod");
	74	});
	75	});
	76
	77	describe("the incompleteness is documented, not hidden", () => {
	78	it("verifySamlSignature is marked as not proving assertion integrity", () => {
	79	// Whoever reads this next must not mistake it for full XML-DSig.
	80	expect(SRC).toContain("INCOMPLETE BY DESIGN");
	81	});
	82	});