WasmModuleBackend.h

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/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_contentanalysis_wasmmodulebackend_h

#define mozilla_contentanalysis_wasmmodulebackend_h

#include "ContentAnalysisBackend.h"

#include "MainThreadUtils.h"

#include "js/TypeDecls.h"

#include "nsCOMPtr.h"

#include "nsTArray.h"

namespace content_analysis::sdk {

class ContentAnalysisRequest;

}  // namespace content_analysis::sdk

namespace mozilla::contentanalysis {

// keep in sync with EXTENSION_ID in ContentAnalysisWasmRunner.sys.mjs

const auto kWasmModuleExtensionId = u"dlp-wasm-provider@mozilla.org"_ns;

// Backend that produces verdicts from an in-process WebAssembly DLP module.

//

// The module is loaded and executed by SpiderMonkey's wasm engine through a JS

// runner (nsIContentAnalysisWasmRunner).  This backend serializes the request

// to the canonical content_analysis SDK protobuf, hands the bytes to the

// runner, and converts the response back.  The module is read from the

// extension named by kWasmModuleExtensionId.

class WasmModuleBackend final : public ContentAnalysisBackend {

 public:

  WasmModuleBackend() = default;

  WasmModuleBackend(const WasmModuleBackend&) = delete;

  WasmModuleBackend& operator=(const WasmModuleBackend&) = delete;

  nsresult EnsureReady() override;

  nsresult Analyze(nsCOMPtr<nsIContentAnalysisRequest> aRequest,

                   bool aAutoAcknowledge) override;

  nsresult Acknowledge(

      nsCOMPtr<nsIContentAnalysisAcknowledgement> aAcknowledgement,

      const nsACString& aRequestToken) override;

  void CancelUserAction(const nsACString& aUserActionId) override;

  RefPtr<DiagnosticInfoPromise> GetDiagnosticInfo() override;

  void Shutdown() override;

 protected:

  ~WasmModuleBackend() override = default;

 private:

  // Feed the module's verdict back into ContentAnalysis.

  void HandleWasmResponse(JSContext* aCx, JS::Handle<JS::Value> aValue,

                          const nsACString& aUserActionId,

                          bool aAutoAcknowledge);

  // Hand the request/content/rules to the wasm runner and wire its promise

  // back into ContentAnalysis.

  nsresult InvokeRunner(const nsTArray<uint8_t>& aRequestBytes,

                        const nsTArray<uint8_t>& aContentBytes,

                        const nsTArray<RefPtr<nsIContentAnalysisRule>>& aRules,

                        const nsACString& aUserActionId, bool aAutoAcknowledge);

  // Number of Analyze() calls made so far, for GetDiagnosticInfo.

  int64_t mRequestCount MOZ_GUARDED_BY(sMainThreadCapability) = 0;

  // Whether the module most recently ran successfully. Updated whenever an

  // analyze() call to the runner settles.

  bool mConnectedToAgent MOZ_GUARDED_BY(sMainThreadCapability) = false;

  // Whether the most recent analyze() failure was because the module's

  // extension is not signed.

  bool mFailedSignatureVerification MOZ_GUARDED_BY(sMainThreadCapability) =

      false;

};

}  // namespace mozilla::contentanalysis

#endif  // mozilla_contentanalysis_wasmmodulebackend_h