1 files changed, 119 insertions, 0 deletions
diff --git a/dom/security/SRICheck.h b/dom/security/SRICheck.h
new file mode 100644
index 000000000..82929fe36
--- /dev/null
+++ b/dom/security/SRICheck.h
@@ -0,0 +1,119 @@
+/* -*- 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 "nsCOMPtr.h"
+#include "nsICryptoHash.h"
+
+class nsIChannel;
+class nsIUnicharStreamLoader;
+class nsIConsoleReportCollector;
+
+namespace mozilla {
+namespace 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);
+
+  /**
+   * Process the integrity attribute of the element.  A result of false
+   * must prevent the resource from loading.
+   */
+  static nsresult VerifyIntegrity(const SRIMetadata& aMetadata,
+                                  nsIUnicharStreamLoader* aLoader,
+                                  const nsAString& aString,
+                                  const nsACString& aSourceFileURI,
+                                  nsIConsoleReportCollector* aReporter);
+};
+
+// 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 dom
+} // namespace mozilla
+
+#endif // mozilla_dom_SRICheck_h