widget/windows/UrlmonHeaderOnlyUtils.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 https://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_UrlmonHeaderOnlyUtils_h
   8 #define mozilla_UrlmonHeaderOnlyUtils_h
   9
  10 #include "mozilla/ShellHeaderOnlyUtils.h"
  11
  12 namespace mozilla {
  13
  14 /**
  15  * We used to validate a uri with SHParseDisplayName to mitigate the Windows
  16  * bug (Bug 394974).  However, Bug 1573051 revealed an issue that a fragment,
  17  * a string following a hash mark (#), is dropped when we extract a string
  18  * from PIDL.  This is the intended behavior of Windows.
  19  *
  20  * To deal with the fragment issue as well as keeping our mitigation, we
  21  * decided to use CreateUri to validate a uri string, but we also keep using
  22  * SHParseDisplayName as a pre-check.  This is because there are several
  23  * cases where CreateUri succeeds while SHParseDisplayName fails such as
  24  * a non-existent file: uri.
  25  *
  26  * To minimize the impact of introducing CreateUri into the validation logic,
  27  * we try to mimic the logic of windows_storage!IUriToPidl (ieframe!IUriToPidl
  28  * in Win7) which is executed behind SHParseDisplayName.
  29  * What IUriToPidl does is:
  30  *   1) If a given uri has a fragment, removes a fragment.
  31  *   2) Takes an absolute uri if it's available in the given uri, otherwise
  32  *      takes a raw uri.
  33  *
  34  * As we need to get a full uri including a fragment, this function does 2).
  35  */
  36 inline LauncherResult<_bstr_t> UrlmonValidateUri(const wchar_t* aUri) {
  37   LauncherResult<UniqueAbsolutePidl> pidlResult = ShellParseDisplayName(aUri);
  38   if (pidlResult.isErr()) {
  39     return pidlResult.propagateErr();
  40   }
  41
  42   // The value of |flags| is the same value as used in ieframe!_EnsureIUri in
  43   // Win7, which is called behind SHParseDisplayName.  In Win10, on the other
  44   // hand, an flag 0x03000000 is also passed to CreateUri, but we don't
  45   // specify it because it's undocumented and unknown.
  46   constexpr DWORD flags =
  47       Uri_CREATE_NO_DECODE_EXTRA_INFO | Uri_CREATE_CANONICALIZE |
  48       Uri_CREATE_CRACK_UNKNOWN_SCHEMES | Uri_CREATE_PRE_PROCESS_HTML_URI |
  49       Uri_CREATE_IE_SETTINGS;
  50   RefPtr<IUri> uri;
  51   HRESULT hr;
  52   SAFECALL_URLMON_FUNC(CreateUri, aUri, flags, 0, getter_AddRefs(uri));
  53   if (FAILED(hr)) {
  54     return LAUNCHER_ERROR_FROM_HRESULT(hr);
  55   }
  56
  57   _bstr_t bstrUri;
  58
  59   hr = uri->GetAbsoluteUri(bstrUri.GetAddress());
  60   if (FAILED(hr)) {
  61     return LAUNCHER_ERROR_FROM_HRESULT(hr);
  62   }
  63
  64   if (hr == S_FALSE) {
  65     hr = uri->GetRawUri(bstrUri.GetAddress());
  66     if (FAILED(hr)) {
  67       return LAUNCHER_ERROR_FROM_HRESULT(hr);
  68     }
  69   }
  70
  71   return bstrUri;
  72 }
  73
  74 }  // namespace mozilla
  75
  76 #endif  // mozilla_UrlmonHeaderOnlyUtils_h