fix(agent): Check subnet canister ranges

packages/agent/src/canisterStatus/index.ts

@@ -87,8 +87,8 @@ export const request = async (options: {
         const response = await agent.readState(canisterId, {
           paths: [encodedPaths[index]],
         });
-        const cert = new Certificate(response, agent);
-        const verified = await cert.verify();
+        const cert = new Certificate(response.certificate, agent.fetchRootKey());
+        const verified = await cert.verify(canisterId);
         if (!verified) {
           throw new Error(
             'There was a problem certifying the response data. Please verify your connection to the mainnet, or be sure to call fetchRootKey on your agent if you are developing locally',

packages/agent/src/certificate.test.ts

@@ -3,9 +3,12 @@
  * an instance of ArrayBuffer).
  * @jest-environment node
  */
+import { fromHexString } from '@dfinity/candid';
 import * as cbor from './cbor';
 import * as Cert from './certificate';
 import { fromHex, toHex } from './utils/buffer';
+import { Principal } from '@dfinity/principal';
+import { verify } from 'crypto';
 
 function label(str: string): ArrayBuffer {
   return new TextEncoder().encode(str);
@@ -15,6 +18,13 @@ function pruned(str: string): ArrayBuffer {
   return fromHex(str);
 }
 
+// Root public key for the IC main net, encoded as hex
+const IC_ROOT_KEY =
+  '308182301d060d2b0601040182dc7c0503010201060c2b0601040182dc7c05030201036100814' +
+  'c0e6ec71fab583b08bd81373c255c3c371b2e84863c98a4f1e08b74235d14fb5d9c0cd546d968' +
+  '5f913a0c0b2cc5341583bf4b4392e467db96d65b9bb4cb717112f8472e0d5a4d14505ffd7484' +
+  'b01291091c5f87b98883463f98091a0baaae';
+
 test('hash tree', async () => {
   const cborEncode = fromHex(
     '8301830183024161830183018302417882034568656c6c6f810083024179820345776f726c64' +
@@ -124,3 +134,38 @@ test('lookup', () => {
   expect(toText(Cert.lookup_path([fromText('d')], tree))).toEqual('morning');
   expect(Cert.lookup_path([fromText('e')], tree)).toEqual(undefined);
 });
+
+// The sample certificate for testing delegation is extracted from the response used in agent-rs tests, where they were taken
+// from an interaction with the IC mainnet.
+const SAMPLE_CERT: string =
+  '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';
+
+test('delegation works for canisters within the subnet range', async () => {
+  const canisterId = Principal.fromText('ivg37-qiaaa-aaaab-aaaga-cai');
+  const cert = new Cert.Certificate(fromHex(SAMPLE_CERT), Promise.resolve(fromHex(IC_ROOT_KEY)));
+  const result = await cert.verify(canisterId);
+  expect(result).toEqual(true);
+});
+
+test('delegation check fails for canisters outside of the subnet range', async () => {
+  // Use a different principal than the happy path, which isn't in the delegation ranges.
+  const canisterId = Principal.fromText('ryjl3-tyaaa-aaaaa-aaaba-cai');
+  const cert = new Cert.Certificate(fromHex(SAMPLE_CERT), Promise.resolve(fromHex(IC_ROOT_KEY)));
+  // This is a bit crufty; verify returns a boolean, but can also indicate verification errors
+  // by throwing exceptions
+  try {
+    const result = await cert.verify(canisterId);
+    expect(result).toEqual(false);
+  } catch (e) {}
+});
+
+// The only situation in which one can read state of the IC management canister
+// is when the user calls provisional_create_canister_with_cycles. In this case,
+// we shouldn't check the delegations.
+test('delegation check succeeds for the management canister', async () => {
+  const cert = new Cert.Certificate(fromHex(SAMPLE_CERT), Promise.resolve(fromHex(IC_ROOT_KEY)));
+  // This is a bit crufty; verify returns a boolean, but can also indicate verification errors
+  // by throwing exceptions
+  const result = await cert.verify(Principal.managementCanister());
+  expect(result).toEqual(true);
+});

packages/agent/src/certificate.ts

@@ -1,9 +1,9 @@
-import { Agent, getDefaultAgent, ReadStateResponse } from './agent';
 import * as cbor from './cbor';
 import { AgentError } from './errors';
 import { hash } from './request_id';
 import { blsVerify } from './utils/bls';
 import { concat, fromHex, toHex } from './utils/buffer';
+import { Principal } from '@dfinity/principal';
 
 /**
  * A certificate needs to be verified (using {@link Certificate.prototype.verify})
@@ -102,20 +102,19 @@ function isBufferEqual(a: ArrayBuffer, b: ArrayBuffer): boolean {
 export class Certificate {
   private readonly cert: Cert;
   private verified = false;
-  private _rootKey: ArrayBuffer | null = null;
 
-  constructor(response: ReadStateResponse, private _agent: Agent = getDefaultAgent()) {
-    this.cert = cbor.decode(new Uint8Array(response.certificate));
+  constructor(certificate: ArrayBuffer, private _rootKey: Promise<ArrayBuffer>) {
+    this.cert = cbor.decode(new Uint8Array(certificate));
   }
 
   public lookup(path: Array<ArrayBuffer | string>): ArrayBuffer | undefined {
     this.checkState();
     return lookup_path(path, this.cert.tree);
   }
 
-  public async verify(): Promise<boolean> {
+  public async verify(canisterId: Principal): Promise<boolean> {
     const rootHash = await reconstruct(this.cert.tree);
-    const derKey = await this._checkDelegation(this.cert.delegation);
+    const derKey = await this._checkDelegationAndGetKey(canisterId, this.cert.delegation);
     const sig = this.cert.signature;
     const key = extractDER(derKey);
     const msg = concat(domain_sep('ic-state-root'), rootHash);
@@ -130,28 +129,41 @@ export class Certificate {
     }
   }
 
-  private async _checkDelegation(d?: Delegation): Promise<ArrayBuffer> {
+  private async _checkDelegationAndGetKey(
+    canisterId: Principal,
+    d?: Delegation,
+  ): Promise<ArrayBuffer> {
     if (!d) {
-      if (!this._rootKey) {
-        if (this._agent.rootKey) {
-          this._rootKey = this._agent.rootKey;
-          return this._rootKey;
-        }
-
-        throw new Error(`Agent does not have a rootKey. Do you need to call 'fetchRootKey'?`);
-      }
       return this._rootKey;
     }
-    const cert: Certificate = new Certificate(d as any, this._agent);
-    if (!(await cert.verify())) {
+    const cert: Certificate = new Certificate(d.certificate, this._rootKey);
+    if (!(await cert.verify(canisterId))) {
       throw new Error('fail to verify delegation certificate');
     }
 
-    const lookup = cert.lookup(['subnet', d.subnet_id, 'public_key']);
-    if (!lookup) {
+    if (canisterId.compareTo(Principal.managementCanister()) != 'eq') {
+      const range_lookup = cert.lookup(['subnet', d.subnet_id, 'canister_ranges']);
+      if (!range_lookup) {
+        throw new Error(`Could not find canister ranges for subnet 0x${toHex(d.subnet_id)}`);
+      }
+      const ranges_arr: Array<[Uint8Array, Uint8Array]> = cbor.decode(range_lookup);
+      const ranges: Array<[Principal, Principal]> = ranges_arr.map(v => [
+        Principal.fromUint8Array(v[0]),
+        Principal.fromUint8Array(v[1]),
+      ]);
+
+      const canister_in_range = ranges.some(r => r[0].ltEq(canisterId) && r[1].gtEq(canisterId));
+      if (!canister_in_range) {
+        throw new Error(
+          `Canister ${canisterId} not in range of delegations for subnet 0x${toHex(d.subnet_id)}`,
+        );
+      }
+    }
+    const public_key_lookup = cert.lookup(['subnet', d.subnet_id, 'public_key']);
+    if (!public_key_lookup) {
       throw new Error(`Could not find subnet key for subnet 0x${toHex(d.subnet_id)}`);
     }
-    return lookup;
+    return public_key_lookup;
   }
 }
 

packages/agent/src/polling/index.ts

@@ -29,8 +29,8 @@ export async function pollForResponse(
 ): Promise<ArrayBuffer> {
   const path = [new TextEncoder().encode('request_status'), requestId];
   const state = await agent.readState(canisterId, { paths: [path] });
-  const cert = new Certificate(state, agent);
-  const verified = await cert.verify();
+  const cert = new Certificate(state.certificate, agent.fetchRootKey());
+  const verified = await cert.verify(canisterId);
   if (!verified) {
     throw new Error('Fail to verify certificate');
   }

packages/principal/src/index.test.ts

@@ -24,4 +24,21 @@ describe('Principal', () => {
   it('errors out on parsing invalid characters', () => {
     expect(() => Principal.fromText('Hello world!')).toThrow();
   });
+
+  it('compares principals correctly', () => {
+    const anonymous = Principal.anonymous();
+    const principal1 = Principal.fromText('ryjl3-tyaaa-aaaaa-aaaba-cai');
+    const principal2 = Principal.fromText('ivg37-qiaaa-aaaab-aaaga-cai');
+    for (let p of [anonymous, principal1, principal2]) {
+      expect(p.compareTo(p)).toBe('eq');
+      expect(p.ltEq(p)).toBe(true);
+      expect(p.gtEq(p)).toBe(true);
+    }
+    expect(principal1.compareTo(principal2)).toBe('lt');
+    expect(principal1.compareTo(anonymous)).toBe('lt');
+    expect(principal2.compareTo(principal1)).toBe('gt');
+    expect(principal2.compareTo(anonymous)).toBe('lt');
+    expect(anonymous.compareTo(principal1)).toBe('gt');
+    expect(anonymous.compareTo(principal2)).toBe('gt');
+  });
 });

packages/principal/src/index.ts

@@ -5,6 +5,8 @@ import { sha224 } from './utils/sha224';
 const SELF_AUTHENTICATING_SUFFIX = 2;
 const ANONYMOUS_SUFFIX = 4;
 
+const MANAGEMENT_CANISTER_PRINCIPAL_HEX_STR = 'aaaaa-aa';
+
 const fromHexString = (hexString: string) =>
   new Uint8Array((hexString.match(/.{1,2}/g) ?? []).map(byte => parseInt(byte, 16)));
 
@@ -16,6 +18,10 @@ export class Principal {
     return new this(new Uint8Array([ANONYMOUS_SUFFIX]));
   }
 
+  public static managementCanister(): Principal {
+    return this.fromHex(MANAGEMENT_CANISTER_PRINCIPAL_HEX_STR);
+  }
+
   public static selfAuthenticating(publicKey: Uint8Array): Principal {
     const sha = sha224(publicKey);
     return new this(new Uint8Array([...sha, SELF_AUTHENTICATING_SUFFIX]));
@@ -96,4 +102,25 @@ export class Principal {
   public toString(): string {
     return this.toText();
   }
+
+  public compareTo(other: Principal): 'lt' | 'eq' | 'gt' {
+    for (let i = 0; i < Math.min(this._arr.length, other._arr.length); i++) {
+      if (this._arr[i] < other._arr[i]) return 'lt';
+      else if (this._arr[i] > other._arr[i]) return 'gt';
+    }
+    // Here, at least one principal is a prefix of the other principal (they could be the same)
+    if (this._arr.length < other._arr.length) return 'lt';
+    if (this._arr.length > other._arr.length) return 'gt';
+    return 'eq';
+  }
+
+  public ltEq(other: Principal): boolean {
+    const cmp = this.compareTo(other);
+    return cmp == 'lt' || cmp == 'eq';
+  }
+
+  public gtEq(other: Principal): boolean {
+    const cmp = this.compareTo(other);
+    return cmp == 'gt' || cmp == 'eq';
+  }
 }