1 files changed, 105 insertions, 0 deletions
diff --git a/dom/security/SRICheck.h b/dom/security/SRICheck.h
new file mode 100644
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+++ b/dom/security/SRICheck.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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_dom_SRICheck_h
+#define mozilla_dom_SRICheck_h
+
+#include "nsTString.h"
+#include "nsStringFwd.h"
+#include "nsCOMPtr.h"
+#include "nsICryptoHash.h"
+
+class nsIChannel;
+class nsIConsoleReportCollector;
+
+namespace mozilla::dom {
+
+class SRIMetadata;
+
+class SRICheck final {
+ public:
+  static const uint32_t MAX_METADATA_LENGTH = 24 * 1024;
+  static const uint32_t MAX_METADATA_TOKENS = 512;
+
+  /**
+   * Parse the multiple hashes specified in the integrity attribute and
+   * return the strongest supported hash.
+   */
+  static nsresult IntegrityMetadata(const nsAString& aMetadataList,
+                                    const nsACString& aSourceFileURI,
+                                    nsIConsoleReportCollector* aReporter,
+                                    SRIMetadata* outMetadata);
+};
+
+// The SRICheckDataVerifier can be used in 2 different mode:
+//
+// 1. The streaming mode involves reading bytes from an input, and to use
+//    the |Update| function to stream new bytes, and to use the |Verify|
+//    function to check the hash of the content with the hash provided by
+//    the metadata.
+//
+//    Optionally, one can serialize the verified hash with |ExportDataSummary|,
+//    in a buffer in order to rely on the second mode the next time.
+//
+// 2. The pre-computed mode, involves reading a hash with |ImportDataSummary|,
+//    which got exported by the SRICheckDataVerifier and potentially cached, and
+//    then use the |Verify| function to check against the hash provided by the
+//    metadata.
+class SRICheckDataVerifier final {
+ public:
+  SRICheckDataVerifier(const SRIMetadata& aMetadata,
+                       const nsACString& aSourceFileURI,
+                       nsIConsoleReportCollector* aReporter);
+
+  // Append the following bytes to the content used to compute the hash. Once
+  // all bytes are streamed, use the Verify function to check the integrity.
+  nsresult Update(uint32_t aStringLen, const uint8_t* aString);
+
+  // Verify that the computed hash corresponds to the metadata.
+  nsresult Verify(const SRIMetadata& aMetadata, nsIChannel* aChannel,
+                  const nsACString& aSourceFileURI,
+                  nsIConsoleReportCollector* aReporter);
+
+  bool IsComplete() const { return mComplete; }
+
+  // Report the length of the computed hash and its type, such that we can
+  // reserve the space for encoding it in a vector.
+  uint32_t DataSummaryLength();
+  static uint32_t EmptyDataSummaryLength();
+
+  // Write the computed hash and its type in a pre-allocated buffer.
+  nsresult ExportDataSummary(uint32_t aDataLen, uint8_t* aData);
+  static nsresult ExportEmptyDataSummary(uint32_t aDataLen, uint8_t* aData);
+
+  // Report the length of the computed hash and its type, such that we can
+  // skip these data while reading a buffer.
+  static nsresult DataSummaryLength(uint32_t aDataLen, const uint8_t* aData,
+                                    uint32_t* length);
+
+  // Extract the computed hash and its type, such that we can |Verify| if it
+  // matches the metadata. The buffer should be at least the same size or
+  // larger than the value returned by |DataSummaryLength|.
+  nsresult ImportDataSummary(uint32_t aDataLen, const uint8_t* aData);
+
+ private:
+  nsCOMPtr<nsICryptoHash> mCryptoHash;
+  nsAutoCString mComputedHash;
+  size_t mBytesHashed;
+  uint32_t mHashLength;
+  int8_t mHashType;
+  bool mInvalidMetadata;
+  bool mComplete;
+
+  nsresult EnsureCryptoHash();
+  nsresult Finish();
+  nsresult VerifyHash(const SRIMetadata& aMetadata, uint32_t aHashIndex,
+                      const nsACString& aSourceFileURI,
+                      nsIConsoleReportCollector* aReporter);
+};
+
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_SRICheck_h