dom/webauthn/WebAuthnManager.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_WebAuthnManager_h
   8 #define mozilla_dom_WebAuthnManager_h
   9
  10 #include "mozilla/Maybe.h"
  11 #include "mozilla/MozPromise.h"
  12 #include "mozilla/RandomNum.h"
  13 #include "mozilla/dom/AbortSignal.h"
  14 #include "mozilla/dom/PWebAuthnTransaction.h"
  15 #include "mozilla/dom/WebAuthnManagerBase.h"
  16
  17 /*
  18  * Content process manager for the WebAuthn protocol. Created on calls to the
  19  * WebAuthentication DOM object, this manager handles establishing IPC channels
  20  * for WebAuthn transactions, as well as keeping track of JS Promise objects
  21  * representing transactions in flight.
  22  *
  23  * The WebAuthn spec (https://www.w3.org/TR/webauthn/) allows for two different
  24  * types of transactions: registration and signing. When either of these is
  25  * requested via the DOM API, the following steps are executed in the
  26  * WebAuthnManager:
  27  *
  28  * - Validation of the request. Return a failed promise to js if request does
  29  *   not have correct parameters.
  30  *
  31  * - If request is valid, open a new IPC channel for running the transaction. If
  32  *   another transaction is already running in this content process, cancel it.
  33  *   Return a pending promise to js.
  34  *
  35  * - Send transaction information to parent process (by running the Start*
  36  *   functions of WebAuthnManager). Assuming another transaction is currently in
  37  *   flight in another content process, parent will handle canceling it.
  38  *
  39  * - On return of successful transaction information from parent process, turn
  40  *   information into DOM object format required by spec, and resolve promise
  41  *   (by running the Finish* functions of WebAuthnManager). On cancellation
  42  *   request from parent, reject promise with corresponding error code. Either
  43  *   outcome will also close the IPC channel.
  44  *
  45  */
  46
  47 namespace mozilla::dom {
  48
  49 class Credential;
  50
  51 class WebAuthnTransaction {
  52  public:
  53   explicit WebAuthnTransaction(const RefPtr<Promise>& aPromise)
  54       : mPromise(aPromise), mId(NextId()) {
  55     MOZ_ASSERT(mId > 0);
  56   }
  57
  58   // JS Promise representing the transaction status.
  59   RefPtr<Promise> mPromise;
  60
  61   // Unique transaction id.
  62   uint64_t mId;
  63
  64  private:
  65   // Generates a probabilistically unique ID for the new transaction. IDs are 53
  66   // bits, as they are used in javascript. We use a random value if possible,
  67   // otherwise a counter.
  68   static uint64_t NextId() {
  69     static uint64_t counter = 0;
  70     Maybe<uint64_t> rand = mozilla::RandomUint64();
  71     uint64_t id =
  72         rand.valueOr(++counter) & UINT64_C(0x1fffffffffffff);  // 2^53 - 1
  73     // The transaction ID 0 is reserved.
  74     return id ? id : 1;
  75   }
  76 };
  77
  78 class WebAuthnManager final : public WebAuthnManagerBase, public AbortFollower {
  79  public:
  80   NS_DECL_ISUPPORTS_INHERITED
  81   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(WebAuthnManager, WebAuthnManagerBase)
  82
  83   explicit WebAuthnManager(nsPIDOMWindowInner* aParent)
  84       : WebAuthnManagerBase(aParent) {}
  85
  86   already_AddRefed<Promise> MakeCredential(
  87       const PublicKeyCredentialCreationOptions& aOptions,
  88       const Optional<OwningNonNull<AbortSignal>>& aSignal, ErrorResult& aError);
  89
  90   already_AddRefed<Promise> GetAssertion(
  91       const PublicKeyCredentialRequestOptions& aOptions,
  92       const bool aConditionallyMediated,
  93       const Optional<OwningNonNull<AbortSignal>>& aSignal, ErrorResult& aError);
  94
  95   already_AddRefed<Promise> Store(const Credential& aCredential,
  96                                   ErrorResult& aError);
  97
  98   already_AddRefed<Promise> IsUVPAA(GlobalObject& aGlobal, ErrorResult& aError);
  99
 100   // WebAuthnManagerBase
 101
 102   void FinishMakeCredential(
 103       const uint64_t& aTransactionId,
 104       const WebAuthnMakeCredentialResult& aResult) override;
 105
 106   void FinishGetAssertion(const uint64_t& aTransactionId,
 107                           const WebAuthnGetAssertionResult& aResult) override;
 108
 109   void RequestAborted(const uint64_t& aTransactionId,
 110                       const nsresult& aError) override;
 111
 112   // AbortFollower
 113
 114   void RunAbortAlgorithm() override;
 115
 116  private:
 117   virtual ~WebAuthnManager();
 118
 119   // Send a Cancel message to the parent, reject the promise with the given
 120   // reason (an nsresult or JS::Handle<JS::Value>), and clear the transaction.
 121   template <typename T>
 122   void CancelTransaction(const T& aReason) {
 123     CancelParent();
 124     RejectTransaction(aReason);
 125   }
 126
 127   // Reject the promise with the given reason (an nsresult or JS::Value), and
 128   // clear the transaction.
 129   template <typename T>
 130   void RejectTransaction(const T& aReason) {
 131     if (!NS_WARN_IF(mTransaction.isNothing())) {
 132       mTransaction.ref().mPromise->MaybeReject(aReason);
 133     }
 134
 135     ClearTransaction();
 136   }
 137
 138   // Send a Cancel message to the parent.
 139   void CancelParent();
 140
 141   // Clears all information we have about the current transaction.
 142   void ClearTransaction();
 143
 144   // The current transaction, if any.
 145   Maybe<WebAuthnTransaction> mTransaction;
 146 };
 147
 148 inline void ImplCycleCollectionTraverse(
 149     nsCycleCollectionTraversalCallback& aCallback,
 150     WebAuthnTransaction& aTransaction, const char* aName, uint32_t aFlags = 0) {
 151   ImplCycleCollectionTraverse(aCallback, aTransaction.mPromise, aName, aFlags);
 152 }
 153
 154 inline void ImplCycleCollectionUnlink(WebAuthnTransaction& aTransaction) {
 155   ImplCycleCollectionUnlink(aTransaction.mPromise);
 156 }
 157
 158 }  // namespace mozilla::dom
 159
 160 #endif  // mozilla_dom_WebAuthnManager_h