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server: refactor HTTP signature validation

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This commit is contained in:
Johann150 2023-06-26 22:02:27 +02:00
parent 9289b0e8ed
commit 597de07465
Signed by untrusted user: Johann150
GPG key ID: 9EE6577A2A06F8F1
3 changed files with 89 additions and 120 deletions
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53
packages/backend/src/queue/processors/inbox.ts
View file

@ -1,6 +1,5 @@
import { URL } from 'node:url';
import Bull from 'bull';
import httpSignature from '@peertube/http-signature';
import { perform } from '@/remote/activitypub/perform.js';
import Logger from '@/services/logger.js';
import { registerOrFetchInstanceDoc } from '@/services/register-or-fetch-instance-doc.js';
@ -11,17 +10,18 @@ import { getApId } from '@/remote/activitypub/type.js';
import { fetchInstanceMetadata } from '@/services/fetch-instance-metadata.js';
import { Resolver } from '@/remote/activitypub/resolver.js';
import { LdSignature } from '@/remote/activitypub/misc/ld-signature.js';
import { getAuthUser } from '@/remote/activitypub/misc/auth-user.js';
import { StatusError } from '@/misc/fetch.js';
import { AuthUser, getAuthUser } from '@/remote/activitypub/misc/auth-user.js';
import { InboxJobData } from '@/queue/types.js';
import { shouldBlockInstance } from '@/misc/should-block-instance.js';
import { verifyHttpSignature } from '@/remote/http-signature.js';
const logger = new Logger('inbox');
// ユーザーのinboxにアクティビティが届いた時の処理
// Processing when an activity arrives in the user's inbox
export default async (job: Bull.Job<InboxJobData>): Promise<string> => {
const signature = job.data.signature; // HTTP-signature
const activity = job.data.activity;
const resolver = new Resolver();
//#region Log
const info = Object.assign({}, activity) as any;
@ -29,46 +29,12 @@ export default async (job: Bull.Job<InboxJobData>): Promise<string> => {
logger.debug(JSON.stringify(info, null, 2));
//#endregion
const keyIdLower = signature.keyId.toLowerCase();
if (keyIdLower.startsWith('acct:')) {
return `Old keyId is no longer supported. ${keyIdLower}`;
}
const host = extractDbHost(keyIdLower)
// Stop if the host is blocked.
if (await shouldBlockInstance(host)) {
return `Blocked request: ${host}`;
}
const resolver = new Resolver();
let authUser;
try {
authUser = await getAuthUser(signature.keyId, getApId(activity.actor), resolver);
} catch (e) {
if (e instanceof StatusError) {
if (e.isClientError) {
return `skip: Ignored deleted actors on both ends ${activity.actor} - ${e.statusCode}`;
} else {
throw new Error(`Error in actor ${activity.actor} - ${e.statusCode || e}`);
}
}
}
if (authUser == null) {
// Key not found? Unacceptable!
return 'skip: failed to resolve user';
} else {
// Found key!
}
// verify the HTTP Signature
const httpSignatureValidated = httpSignature.verifySignature(signature, authUser.key.keyPem);
const validated = await verifyHttpSignature(signature, resolver, getApId(activity.actor));
let authUser = validated.authUser;
// The signature must be valid.
// The signature must also match the actor otherwise anyone could sign any activity.
if (!httpSignatureValidated || authUser.user.uri !== activity.actor) {
if (validated.status !== 'valid' || validated.authUser.user.uri !== activity.actor) {
// Last resort: LD-Signature
if (activity.signature) {
if (activity.signature.type !== 'RsaSignature2017') {
@ -107,6 +73,11 @@ export default async (job: Bull.Job<InboxJobData>): Promise<string> => {
}
}
// authUser cannot be null at this point:
// either it was already not null because the HTTP signature was valid
// or, if the LD signature was not verified, this function will already have returned.
authUser = authUser as AuthUser;
// Verify that the actor's host is not blocked
const signerHost = extractDbHost(authUser.user.uri!);
if (await shouldBlockInstance(signerHost)) {

72
packages/backend/src/server/activitypub/fetch-signature.ts → packages/backend/src/remote/http-signature.ts
View file

@ -1,14 +1,12 @@
import httpSignature from '@peertube/http-signature';
import { extractDbHost } from '@/misc/convert-host.js';
import { shouldBlockInstance } from '@/misc/should-block-instance.js';
import { authUserFromKeyId, getAuthUser } from '@/remote/activitypub/misc/auth-user.js';
import { getApId, isActor } from '@/remote/activitypub/type.js';
import { StatusError } from '@/misc/fetch.js';
import { Resolver } from '@/remote/activitypub/resolver.js';
import { createPerson } from '@/remote/activitypub/models/person.js';
import config from '@/config/index.js';
export type SignatureValidationResult = 'missing' | 'invalid' | 'rejected' | 'valid' | 'always';
import { URL } from 'node:url';
import { extractDbHost } from "@/misc/convert-host.js";
import { shouldBlockInstance } from "@/misc/should-block-instance.js";
import httpSignature from "@peertube/http-signature";
import { Resolver } from "./activitypub/resolver.js";
import { StatusError } from "@/misc/fetch.js";
import { AuthUser, authUserFromKeyId, getAuthUser } from "./activitypub/misc/auth-user.js";
import { ApObject, getApId, isActor } from "./activitypub/type.js";
import { createPerson } from "./activitypub/models/person.js";
async function resolveKeyId(keyId: string, resolver: Resolver): Promise<AuthUser | null> {
// Do we already know that keyId?
@ -38,42 +36,36 @@ async function resolveKeyId(keyId: string, resolver: Resolver): Promise<AuthUser
return null;
}
export async function validateFetchSignature(req: IncomingMessage): Promise<SignatureValidationResult> {
let signature;
if (config.allowUnsignedFetches === true)
return 'always';
try {
signature = httpSignature.parseRequest(req);
} catch (e) {
// TypeScript has wrong typings for Error, meaning I can't extract `name`.
// No typings for @peertube/http-signature's Errors either.
// This means we have to report it as missing instead of invalid in cases
// where the structure is incorrect.
return 'missing';
}
export type SignatureValidationResult = {
status: 'missing' | 'invalid' | 'rejected';
authUser: AuthUser | null;
} | {
status: 'valid';
authUser: AuthUser;
};
export async function verifyHttpSignature(signature: httpSignature.IParsedSignature, resolver: Resolver, actor?: ApObject): Promise<SignatureValidationResult> {
// This old `keyId` format is no longer supported.
const keyIdLower = signature.keyId.toLowerCase();
if (keyIdLower.startsWith('acct:'))
return 'invalid';
if (keyIdLower.startsWith('acct:')) return { status: 'invalid', authUser: null };
const host = extractDbHost(keyIdLower);
// Reject if the host is blocked.
if (await shouldBlockInstance(host))
return 'rejected';
if (await shouldBlockInstance(host)) return { status: 'rejected', authUser: null };
const resolver = new Resolver();
let authUser;
let authUser = null;
try {
authUser = await resolveKeyId(signature.keyId, resolver);
if (actor != null) {
authUser = await getAuthUser(signature.keyId, getApId(actor), resolver);
} else {
authUser = await resolveKeyId(signature.keyId, resolver);
}
} catch (e) {
if (e instanceof StatusError) {
if (e.isClientError) {
// Actor is deleted.
return 'rejected';
return { status: 'rejected', authUser };
} else {
throw new Error(`Error in signature ${signature} - ${e.statusCode || e}`);
}
@ -82,20 +74,22 @@ export async function validateFetchSignature(req: IncomingMessage): Promise<Sign
if (authUser == null) {
// Key not found? Unacceptable!
return 'invalid';
return { status: 'invalid', authUser };
} else {
// Found key!
}
// Make sure the resolved user matches the keyId host.
if (authUser.user.host !== host)
return 'rejected';
if (authUser.user.host !== host) return { status: 'rejected', authUser };
// Verify the HTTP Signature
const httpSignatureValidated = httpSignature.verifySignature(signature, authUser.key.keyPem);
if (httpSignatureValidated === true)
return 'valid';
return {
status: 'valid',
authUser,
};
// Otherwise, fail.
return 'invalid';
return { status: 'invalid', authUser };
}

82
packages/backend/src/server/activitypub.ts
View file

@ -20,8 +20,11 @@ import Outbox from './activitypub/outbox.js';
import Followers from './activitypub/followers.js';
import Following from './activitypub/following.js';
import Featured from './activitypub/featured.js';
import { SignatureValidationResult, validateFetchSignature } from './activitypub/fetch-signature.js';
import { isInstanceActor } from '@/services/instance-actor.js';
import { getUser } from './api/common/getters.js';
import config from '@/config/index.js';
import { verifyHttpSignature } from '@/remote/http-signature.js';
import { Resolver } from '@/remote/activitypub/resolver.js';
// Init router
const router = new Router();
@ -62,30 +65,33 @@ export function setResponseType(ctx: Router.RouterContext): void {
}
async function handleSignature(ctx: Router.RouterContext): Promise<boolean> {
const result = await validateFetchSignature(ctx.req);
switch (result) {
if (config.allowUnsignedFetches) {
// Fetch signature verification is disabled.
case 'always':
ctx.set('Cache-Control', 'public, max-age=180');
return true;
// Fetch signature verification succeeded.
case 'valid':
ctx.set('Cache-Control', 'no-store');
return true;
case 'missing':
case 'invalid':
// This would leak information on blocks. Only use for debugging.
// ctx.status = 400;
// break;
// eslint-disable-next-line no-fallthrough
case 'rejected':
default:
ctx.status = 403;
break;
}
ctx.set('Cache-Control', 'public, max-age=180');
return true;
} else {
let verified;
try {
let signature = httpSignature.parseRequest(ctx.req);
verified = await verifyHttpSignature(signature, new Resolver());
} catch (e) {
verified = { status: 'missing' };
}
ctx.set('Cache-Control', 'no-store');
return false;
switch (verified.status) {
// Fetch signature verification succeeded.
case 'valid':
ctx.set('Cache-Control', 'no-store');
return true;
case 'missing':
case 'invalid':
case 'rejected':
default:
ctx.status = 403;
ctx.set('Cache-Control', 'no-store');
return false;
}
}
}
// inbox
@ -150,31 +156,29 @@ router.get('/notes/:note/activity', async ctx => {
setResponseType(ctx);
});
async function requireHttpSignature(ctx: Router.Context, next: () => Promise<void>) {
if (!(await handleSignature(ctx))) {
return;
} else {
await next();
}
}
// outbox
router.get('/users/:user/outbox', async ctx => {
if (!(await handleSignature(ctx))) return;
return await Outbox(ctx);
});
router.get('/users/:user/outbox', requireHttpSignature, Outbox);
// followers
router.get('/users/:user/followers', async ctx => {
if (!(await handleSignature(ctx))) return;
return await Followers(ctx);
});
router.get('/users/:user/followers', requireHttpSignature, Followers);
// following
router.get('/users/:user/following', async ctx => {
if (!(await handleSignature(ctx))) return;
return await Following(ctx);
});
router.get('/users/:user/following', requireHttpSignature, Following);
// featured
router.get('/users/:user/collections/featured', async ctx => {
if (!(await handleSignature(ctx))) return;
return await Featured(ctx);
});
router.get('/users/:user/collections/featured', requireHttpSignature, Featured);
// publickey
// This does not require HTTP signatures in order for other instances
// to be able to verify our own signatures.
router.get('/users/:user/publickey', async ctx => {
const userId = ctx.params.user;