summaryrefslogtreecommitdiffstats
path: root/image/ImageCacheKey.cpp
blob: 59777ad19a4eab9a67cdde2a017cb4aecfdea4b6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */

#include "ImageCacheKey.h"

#include <utility>

#include "mozilla/AntiTrackingUtils.h"
#include "mozilla/HashFunctions.h"
#include "mozilla/StorageAccess.h"
#include "mozilla/StoragePrincipalHelper.h"
#include "mozilla/Unused.h"
#include "mozilla/dom/Document.h"
#include "mozilla/dom/File.h"
#include "mozilla/dom/ServiceWorkerManager.h"
#include "mozilla/StaticPrefs_privacy.h"
#include "mozilla/StorageAccess.h"
#include "nsContentUtils.h"
#include "nsHashKeys.h"
#include "nsLayoutUtils.h"
#include "nsPrintfCString.h"
#include "nsString.h"

namespace mozilla {

using namespace dom;

namespace image {

ImageCacheKey::ImageCacheKey(nsIURI* aURI, CORSMode aCORSMode,
                             const OriginAttributes& aAttrs,
                             Document* aDocument)
    : mURI(aURI),
      mOriginAttributes(aAttrs),
      mControlledDocument(GetSpecialCaseDocumentToken(aDocument)),
      mIsolationKey(GetIsolationKey(aDocument, aURI)),
      mCORSMode(aCORSMode) {}

ImageCacheKey::ImageCacheKey(const ImageCacheKey& aOther)
    : mURI(aOther.mURI),
      mOriginAttributes(aOther.mOriginAttributes),
      mControlledDocument(aOther.mControlledDocument),
      mIsolationKey(aOther.mIsolationKey),
      mHash(aOther.mHash),
      mCORSMode(aOther.mCORSMode) {}

ImageCacheKey::ImageCacheKey(ImageCacheKey&& aOther)
    : mURI(std::move(aOther.mURI)),
      mOriginAttributes(aOther.mOriginAttributes),
      mControlledDocument(aOther.mControlledDocument),
      mIsolationKey(aOther.mIsolationKey),
      mHash(aOther.mHash),
      mCORSMode(aOther.mCORSMode) {}

bool ImageCacheKey::operator==(const ImageCacheKey& aOther) const {
  // Don't share the image cache between a controlled document and anything
  // else.
  if (mControlledDocument != aOther.mControlledDocument) {
    return false;
  }
  // Don't share the image cache between two top-level documents of different
  // base domains.
  if (!mIsolationKey.Equals(aOther.mIsolationKey,
                            nsCaseInsensitiveCStringComparator)) {
    return false;
  }
  // The origin attributes always have to match.
  if (mOriginAttributes != aOther.mOriginAttributes) {
    return false;
  }

  if (mCORSMode != aOther.mCORSMode) {
    return false;
  }

  // For non-blob URIs, compare the URIs.
  bool equals = false;
  nsresult rv = mURI->Equals(aOther.mURI, &equals);
  return NS_SUCCEEDED(rv) && equals;
}

void ImageCacheKey::EnsureHash() const {
  MOZ_ASSERT(mHash.isNothing());
  PLDHashNumber hash = 0;

  // Since we frequently call Hash() several times in a row on the same
  // ImageCacheKey, as an optimization we compute our hash once and store it.

  nsPrintfCString ptr("%p", mControlledDocument);
  nsAutoCString suffix;
  mOriginAttributes.CreateSuffix(suffix);

  nsAutoCString spec;
  Unused << mURI->GetSpec(spec);
  hash = HashString(spec);

  hash = AddToHash(hash, HashString(suffix), HashString(mIsolationKey),
                   HashString(ptr));
  mHash.emplace(hash);
}

/* static */
void* ImageCacheKey::GetSpecialCaseDocumentToken(Document* aDocument) {
  // Cookie-averse documents can never have storage granted to them.  Since they
  // may not have inner windows, they would require special handling below, so
  // just bail out early here.
  if (!aDocument || aDocument->IsCookieAverse()) {
    return nullptr;
  }

  // For controlled documents, we cast the pointer into a void* to avoid
  // dereferencing it (since we only use it for comparisons).
  RefPtr<ServiceWorkerManager> swm = ServiceWorkerManager::GetInstance();
  if (swm && aDocument->GetController().isSome()) {
    return aDocument;
  }

  return nullptr;
}

/* static */
nsCString ImageCacheKey::GetIsolationKey(Document* aDocument, nsIURI* aURI) {
  if (!aDocument || !aDocument->GetInnerWindow()) {
    return ""_ns;
  }

  // Network-state isolation
  if (StaticPrefs::privacy_partition_network_state()) {
    OriginAttributes oa;
    StoragePrincipalHelper::GetOriginAttributesForNetworkState(aDocument, oa);

    nsAutoCString suffix;
    oa.CreateSuffix(suffix);

    return std::move(suffix);
  }

  // If the window is 3rd party resource, let's see if first-party storage
  // access is granted for this image.
  if (AntiTrackingUtils::IsThirdPartyWindow(aDocument->GetInnerWindow(),
                                            nullptr)) {
    uint32_t rejectedReason = 0;
    Unused << rejectedReason;
    return ShouldAllowAccessFor(aDocument->GetInnerWindow(), aURI,
                                &rejectedReason)
               ? ""_ns
               : aDocument->GetBaseDomain();
  }

  // Another scenario is if this image is a 3rd party resource loaded by a
  // first party context. In this case, we should check if the nsIChannel has
  // been marked as tracking resource, but we don't have the channel yet at
  // this point.  The best approach here is to be conservative: if we are sure
  // that the permission is granted, let's return 0. Otherwise, let's make a
  // unique image cache per the top-level document eTLD+1.
  if (!ApproximateAllowAccessForWithoutChannel(aDocument->GetInnerWindow(),
                                               aURI)) {
    // If we are here, the image is a 3rd-party resource loaded by a first-party
    // context. We can just use the document's base domain as the key because it
    // should be the same as the top-level document's base domain.
    return aDocument
        ->GetBaseDomain();  // because we don't have anything better!
  }

  return ""_ns;
}

}  // namespace image
}  // namespace mozilla