fix(agent): reject unsafe mandate numeric fields

services/agent/src/mandate.test.ts

@@ -93,6 +93,56 @@ test("bidFromAppraisal clamps to mandate maxBid", () => {
   assert.equal(escrow, usdcToStroops(40));
 });
 
+test("createSessionMandate rejects unsafe numeric fields", () => {
+  const p = baseParams();
+  assert.throws(
+    () => createSessionMandate({ ...p, basePriceUsdc: Number.NaN }),
+    (error: unknown) => error instanceof MandateError && error.message === "invalid mandate basePriceUsdc",
+  );
+  assert.throws(
+    () => createSessionMandate({ ...p, commitDeadline: p.commitDeadline + 0.5 }),
+    (error: unknown) => error instanceof MandateError && error.message === "invalid mandate commitDeadline",
+  );
+  assert.throws(
+    () => createSessionMandate({ ...p, roundId: 1.5 }),
+    (error: unknown) => error instanceof MandateError && error.message === "invalid mandate roundId",
+  );
+});
+
+test("verifySessionMandate rejects a signed mandate with unsafe fields", () => {
+  const p = baseParams();
+  const { mandate } = createSessionMandate(p);
+  const { signature: _signature, ...payload } = mandate;
+  const malformed = {
+    ...payload,
+    basePriceUsdc: Number.MAX_SAFE_INTEGER + 1,
+    signature: Keypair.fromSecret(p.principalSecret)
+      .sign(mandateDigest({ ...payload, basePriceUsdc: Number.MAX_SAFE_INTEGER + 1 }))
+      .toString("base64"),
+  };
+  assert.throws(
+    () => verifySessionMandate(malformed, { clock: p.clock }),
+    (error: unknown) => error instanceof MandateError && error.message === "invalid mandate basePriceUsdc",
+  );
+});
+
+test("verifySessionMandate rejects malformed stroop strings", () => {
+  const p = baseParams();
+  const { mandate } = createSessionMandate(p);
+  const { signature: _signature, ...payload } = mandate;
+  const malformedPayload = { ...payload, maxBidStroops: "1.5" };
+  const malformed = {
+    ...malformedPayload,
+    signature: Keypair.fromSecret(p.principalSecret)
+      .sign(mandateDigest(malformedPayload))
+      .toString("base64"),
+  };
+  assert.throws(
+    () => verifySessionMandate(malformed, { clock: p.clock }),
+    (error: unknown) => error instanceof MandateError && error.message === "invalid mandate maxBidStroops",
+  );
+});
+
 test("verifySessionMandate rejects when issuedAt > expiresAt", () => {
   const p = baseParams();
   const { mandate } = createSessionMandate(p);

services/agent/src/mandate.ts

@@ -49,6 +49,32 @@ export interface SessionMandate extends SessionMandatePayload {
 export class MandateError extends Error {}
 export class MandateCapError extends MandateError {}
 
+function invalidNumericField(field: string): never {
+  throw new MandateError(`invalid mandate ${field}`);
+}
+
+function assertSafeMandateInteger(value: number, field: string, minimum = 0): void {
+  if (!Number.isSafeInteger(value) || value < minimum) invalidNumericField(field);
+}
+
+function assertMandateIntegerString(value: string, field: string, minimum = 0n): void {
+  if (!/^(0|[1-9]\d*)$/.test(value)) invalidNumericField(field);
+  const parsed = BigInt(value);
+  if (parsed < minimum) invalidNumericField(field);
+}
+
+function validateMandateNumbers(payload: SessionMandatePayload): void {
+  assertSafeMandateInteger(payload.basePriceUsdc, "basePriceUsdc");
+  assertSafeMandateInteger(payload.commitDeadline, "commitDeadline");
+  assertSafeMandateInteger(payload.issuedAt, "issuedAt");
+  assertSafeMandateInteger(payload.expiresAt, "expiresAt");
+  assertMandateIntegerString(payload.roundId, "roundId", 1n);
+  assertMandateIntegerString(payload.maxBidStroops, "maxBidStroops");
+  assertMandateIntegerString(payload.maxEscrowStroops, "maxEscrowStroops");
+  assertMandateIntegerString(payload.maxAppraisalSpendStroops, "maxAppraisalSpendStroops");
+  assertMandateIntegerString(payload.appraisalPriceStroops, "appraisalPriceStroops");
+}
+
 function validateMandateTimestampOrdering(payload: SessionMandatePayload): void {
   if (payload.issuedAt > payload.expiresAt) {
     throw new MandateError("issuedAt must be <= expiresAt");
@@ -134,6 +160,7 @@ export function createSessionMandate(params: CreateMandateParams): {
     issuedAt: now,
     expiresAt: now + (params.ttlSeconds ?? 3600),
   };
+  validateMandateNumbers(payload);
   validateMandateTimestampOrdering(payload);
   const sig = principal.sign(mandateDigest(payload));
   return {
@@ -158,6 +185,7 @@ export function verifySessionMandate(
   );
   if (!ok) throw new MandateError("invalid mandate signature");
 
+  validateMandateNumbers(payload);
   validateMandateTimestampOrdering(payload);
 
   const now = opts?.now ?? (opts?.clock ?? systemClock).nowSeconds();