third_party/blink/common/security/address_space_feature.cc

/*
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#include "third_party/blink/public/common/security/address_space_feature.h"

#include <tuple>

namespace blink {
namespace {

using AddressSpace = network::mojom::IPAddressSpace;
using Feature = mojom::WebFeature;

// A key in |kFeatureMap|.
//
// Mirrors the arguments to |AddressSpaceFeature()| except for |fetch_type|.
struct FeatureKey {
  AddressSpace client_address_space;
  bool client_is_secure_context;
  AddressSpace response_address_space;
};

// FeatureKey instances are comparable for equality.
bool operator==(const FeatureKey& lhs, const FeatureKey& rhs) {
  return std::tie(lhs.client_address_space, lhs.client_is_secure_context,
                  lhs.response_address_space) ==
         std::tie(rhs.client_address_space, rhs.client_is_secure_context,
                  rhs.response_address_space);
}

// An entry in |kFeatureMap|.
//
// A single key maps to features for all |fetch_type| values. We could instead
// have two maps, one for subresources and one for navigations, but they would
// have the exact same set of keys. Hence it is simpler to have a single map.
struct FeatureEntry {
  // The key to this entry.
  FeatureKey key;

  // The corresponding feature for |kSubresource| fetch types.
  Feature subresource_feature;

  // The corresponding feature for |kNavigation| fetch types.
  Feature navigation_feature;
};

constexpr bool kNonSecureContext = false;
constexpr bool kSecureContext = true;

constexpr struct FeatureEntry kFeatureMap[] = {
    {
        {AddressSpace::kPrivate, kNonSecureContext, AddressSpace::kLocal},
        Feature::kAddressSpacePrivateNonSecureContextEmbeddedLocal,
        Feature::kAddressSpacePrivateNonSecureContextNavigatedToLocal,
    },
    {
        {AddressSpace::kPrivate, kSecureContext, AddressSpace::kLocal},
        Feature::kAddressSpacePrivateSecureContextEmbeddedLocal,
        Feature::kAddressSpacePrivateSecureContextNavigatedToLocal,
    },
    {
        {AddressSpace::kPublic, kNonSecureContext, AddressSpace::kLocal},
        Feature::kAddressSpacePublicNonSecureContextEmbeddedLocal,
        Feature::kAddressSpacePublicNonSecureContextNavigatedToLocal,
    },
    {
        {AddressSpace::kPublic, kSecureContext, AddressSpace::kLocal},
        Feature::kAddressSpacePublicSecureContextEmbeddedLocal,
        Feature::kAddressSpacePublicSecureContextNavigatedToLocal,
    },
    {
        {AddressSpace::kPublic, kNonSecureContext, AddressSpace::kPrivate},
        Feature::kAddressSpacePublicNonSecureContextEmbeddedPrivate,
        Feature::kAddressSpacePublicNonSecureContextNavigatedToPrivate,
    },
    {
        {AddressSpace::kPublic, kSecureContext, AddressSpace::kPrivate},
        Feature::kAddressSpacePublicSecureContextEmbeddedPrivate,
        Feature::kAddressSpacePublicSecureContextNavigatedToPrivate,
    },
    {
        {AddressSpace::kUnknown, kNonSecureContext, AddressSpace::kLocal},
        Feature::kAddressSpaceUnknownNonSecureContextEmbeddedLocal,
        Feature::kAddressSpaceUnknownNonSecureContextNavigatedToLocal,
    },
    {
        {AddressSpace::kUnknown, kSecureContext, AddressSpace::kLocal},
        Feature::kAddressSpaceUnknownSecureContextEmbeddedLocal,
        Feature::kAddressSpaceUnknownSecureContextNavigatedToLocal,
    },
    {
        {AddressSpace::kUnknown, kNonSecureContext, AddressSpace::kPrivate},
        Feature::kAddressSpaceUnknownNonSecureContextEmbeddedPrivate,
        Feature::kAddressSpaceUnknownNonSecureContextNavigatedToPrivate,
    },
    {
        {AddressSpace::kUnknown, kSecureContext, AddressSpace::kPrivate},
        Feature::kAddressSpaceUnknownSecureContextEmbeddedPrivate,
        Feature::kAddressSpaceUnknownSecureContextNavigatedToPrivate,
    },
};

// Attempts to find an entry matching |key| in |kFeatureMap|.
// Returns a pointer to the entry if successful, nullptr otherwise.
const FeatureEntry* FindFeatureEntry(const FeatureKey& key) {
  for (const FeatureEntry& entry : kFeatureMap) {
    if (key == entry.key) {
      return &entry;
    }
  }
  return nullptr;
}

}  // namespace

std::optional<Feature> AddressSpaceFeature(
    FetchType fetch_type,
    AddressSpace client_address_space,
    bool client_is_secure_context,
    AddressSpace response_address_space) {
  FeatureKey key;
  key.client_address_space = client_address_space;
  key.client_is_secure_context = client_is_secure_context;
  key.response_address_space = response_address_space;

  const FeatureEntry* entry = FindFeatureEntry(key);
  if (!entry) {
    return std::nullopt;
  }

  switch (fetch_type) {
    case FetchType::kSubresource:
      return entry->subresource_feature;
    case FetchType::kNavigation:
      return entry->navigation_feature;
  }
}

}  // namespace blink