server/middlewares/activitypub.ts

   1 import { NextFunction, Request, Response } from 'express'
   2 import { getAPId } from '@server/helpers/activitypub'
   3 import { isActorDeleteActivityValid } from '@server/helpers/custom-validators/activitypub/actor'
   4 import { ActivityDelete, ActivityPubSignature } from '../../shared'
   5 import { HttpStatusCode } from '../../shared/models/http/http-error-codes'
   6 import { logger } from '../helpers/logger'
   7 import { isHTTPSignatureVerified, isJsonLDSignatureVerified, parseHTTPSignature } from '../helpers/peertube-crypto'
   8 import { ACCEPT_HEADERS, ACTIVITY_PUB, HTTP_SIGNATURE } from '../initializers/constants'
   9 import { getOrCreateAPActor, loadActorUrlOrGetFromWebfinger } from '../lib/activitypub/actors'
  10
  11 async function checkSignature (req: Request, res: Response, next: NextFunction) {
  12   try {
  13     const httpSignatureChecked = await checkHttpSignature(req, res)
  14     if (httpSignatureChecked !== true) return
  15
  16     const actor = res.locals.signature.actor
  17
  18     // Forwarded activity
  19     const bodyActor = req.body.actor
  20     const bodyActorId = getAPId(bodyActor)
  21     if (bodyActorId && bodyActorId !== actor.url) {
  22       const jsonLDSignatureChecked = await checkJsonLDSignature(req, res)
  23       if (jsonLDSignatureChecked !== true) return
  24     }
  25
  26     return next()
  27   } catch (err) {
  28     const activity: ActivityDelete = req.body
  29     if (isActorDeleteActivityValid(activity) && activity.object === activity.actor) {
  30       logger.debug('Handling signature error on actor delete activity', { err })
  31       return res.status(HttpStatusCode.NO_CONTENT_204).end()
  32     }
  33
  34     logger.warn('Error in ActivityPub signature checker.', { err })
  35     return res.fail({
  36       status: HttpStatusCode.FORBIDDEN_403,
  37       message: 'ActivityPub signature could not be checked'
  38     })
  39   }
  40 }
  41
  42 function executeIfActivityPub (req: Request, res: Response, next: NextFunction) {
  43   const accepted = req.accepts(ACCEPT_HEADERS)
  44   if (accepted === false || ACTIVITY_PUB.POTENTIAL_ACCEPT_HEADERS.includes(accepted) === false) {
  45     // Bypass this route
  46     return next('route')
  47   }
  48
  49   logger.debug('ActivityPub request for %s.', req.url)
  50
  51   return next()
  52 }
  53
  54 // ---------------------------------------------------------------------------
  55
  56 export {
  57   checkSignature,
  58   executeIfActivityPub,
  59   checkHttpSignature
  60 }
  61
  62 // ---------------------------------------------------------------------------
  63
  64 async function checkHttpSignature (req: Request, res: Response) {
  65   // FIXME: compatibility with http-signature < v1.3
  66   const sig = req.headers[HTTP_SIGNATURE.HEADER_NAME] as string
  67   if (sig && sig.startsWith('Signature ') === true) req.headers[HTTP_SIGNATURE.HEADER_NAME] = sig.replace(/^Signature /, '')
  68
  69   let parsed: any
  70
  71   try {
  72     parsed = parseHTTPSignature(req, HTTP_SIGNATURE.CLOCK_SKEW_SECONDS)
  73   } catch (err) {
  74     logger.warn('Invalid signature because of exception in signature parser', { reqBody: req.body, err })
  75
  76     res.fail({
  77       status: HttpStatusCode.FORBIDDEN_403,
  78       message: err.message
  79     })
  80     return false
  81   }
  82
  83   const keyId = parsed.keyId
  84   if (!keyId) {
  85     res.fail({
  86       status: HttpStatusCode.FORBIDDEN_403,
  87       message: 'Invalid key ID',
  88       data: {
  89         keyId
  90       }
  91     })
  92     return false
  93   }
  94
  95   logger.debug('Checking HTTP signature of actor %s...', keyId)
  96
  97   let [ actorUrl ] = keyId.split('#')
  98   if (actorUrl.startsWith('acct:')) {
  99     actorUrl = await loadActorUrlOrGetFromWebfinger(actorUrl.replace(/^acct:/, ''))
 100   }
 101
 102   const actor = await getOrCreateAPActor(actorUrl)
 103
 104   const verified = isHTTPSignatureVerified(parsed, actor)
 105   if (verified !== true) {
 106     logger.warn('Signature from %s is invalid', actorUrl, { parsed })
 107
 108     res.fail({
 109       status: HttpStatusCode.FORBIDDEN_403,
 110       message: 'Invalid signature',
 111       data: {
 112         actorUrl
 113       }
 114     })
 115     return false
 116   }
 117
 118   res.locals.signature = { actor }
 119   return true
 120 }
 121
 122 async function checkJsonLDSignature (req: Request, res: Response) {
 123   const signatureObject: ActivityPubSignature = req.body.signature
 124
 125   if (!signatureObject || !signatureObject.creator) {
 126     res.fail({
 127       status: HttpStatusCode.FORBIDDEN_403,
 128       message: 'Object and creator signature do not match'
 129     })
 130     return false
 131   }
 132
 133   const [ creator ] = signatureObject.creator.split('#')
 134
 135   logger.debug('Checking JsonLD signature of actor %s...', creator)
 136
 137   const actor = await getOrCreateAPActor(creator)
 138   const verified = await isJsonLDSignatureVerified(actor, req.body)
 139
 140   if (verified !== true) {
 141     logger.warn('Signature not verified.', req.body)
 142
 143     res.fail({
 144       status: HttpStatusCode.FORBIDDEN_403,
 145       message: 'Signature could not be verified'
 146     })
 147     return false
 148   }
 149
 150   res.locals.signature = { actor }
 151   return true
 152 }