dom/security/SRIMetadata.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_SRIMetadata_h
   8 #define mozilla_dom_SRIMetadata_h
   9
  10 #include "nsTArray.h"
  11 #include "nsString.h"
  12 #include "SRICheck.h"
  13
  14 namespace mozilla::dom {
  15
  16 class SRIMetadata final {
  17   friend class SRICheck;
  18
  19  public:
  20   static const uint32_t MAX_ALTERNATE_HASHES = 256;
  21   static const int8_t UNKNOWN_ALGORITHM = -1;
  22
  23   /**
  24    * Create an empty metadata object.
  25    */
  26   SRIMetadata() : mAlgorithmType(UNKNOWN_ALGORITHM), mEmpty(true) {}
  27
  28   /**
  29    * Split a string token into the components of an SRI metadata
  30    * attribute.
  31    */
  32   explicit SRIMetadata(const nsACString& aToken);
  33
  34   /**
  35    * Returns true when this object's hash algorithm is weaker than the
  36    * other object's hash algorithm.
  37    */
  38   bool operator<(const SRIMetadata& aOther) const;
  39
  40   /**
  41    * Not implemented. Should not be used.
  42    */
  43   bool operator>(const SRIMetadata& aOther) const;
  44
  45   /**
  46    * Add another metadata's hash to this one.
  47    */
  48   SRIMetadata& operator+=(const SRIMetadata& aOther);
  49
  50   /**
  51    * Returns true when the two metadata use the same hash algorithm.
  52    */
  53   bool operator==(const SRIMetadata& aOther) const;
  54
  55   bool IsEmpty() const { return mEmpty; }
  56   bool IsMalformed() const { return mHashes.IsEmpty() || mAlgorithm.IsEmpty(); }
  57   bool IsAlgorithmSupported() const {
  58     return mAlgorithmType != UNKNOWN_ALGORITHM;
  59   }
  60   bool IsValid() const { return !IsMalformed() && IsAlgorithmSupported(); }
  61
  62   uint32_t HashCount() const { return mHashes.Length(); }
  63   void GetHash(uint32_t aIndex, nsCString* outHash) const;
  64   void GetAlgorithm(nsCString* outAlg) const { *outAlg = mAlgorithm; }
  65   void GetHashType(int8_t* outType, uint32_t* outLength) const;
  66
  67   const nsString& GetIntegrityString() const { return mIntegrityString; }
  68
  69   // Return true if:
  70   // - this integrity metadata is empty, or
  71   // - the other integrity metadata has the same hash algorithm and also the
  72   // same set of values otherwise, return false.
  73   //
  74   // This method simply checks if the other integrity metadata is identical to
  75   // this one (if it exists), so that a load that has been checked against that
  76   // other integrity metadata implies that the current integrity metadata is
  77   // also satisfied.
  78   bool CanTrustBeDelegatedTo(const SRIMetadata& aOther) const;
  79
  80  private:
  81   CopyableTArray<nsCString> mHashes;
  82   nsString mIntegrityString;
  83   nsCString mAlgorithm;
  84   int8_t mAlgorithmType;
  85   bool mEmpty;
  86 };
  87
  88 }  // namespace mozilla::dom
  89
  90 #endif  // mozilla_dom_SRIMetadata_h