Verified Commit c5250895 authored by Pier Angelo Vendrame's avatar Pier Angelo Vendrame 🎃 Committed by ma1
Browse files

Bug 41901: Hardcode normalized FontSubstitutes. 

Windows has a system to set font aliases through the registry.
This allows some customization that could be used as a fingerprinting
vector.
Moreover, this mechanism is used by Windows itself, and different SKUs
might have different default FontSubstitutes.
parent 6891a997

gfx/thebes/StandardFonts-win10.inc

+65 −0
Original line number Diff line number Diff line
@@ -199,3 +199,68 @@ static const char* kLangPackFonts[] = { 
//  "Rockwell Nova",  // Pan-European Supplemental Fonts - EXCLUDED

//  "Verdana Pro",  // Pan-European Supplemental Fonts - EXCLUDED

};



struct FontSubstitute {

  const char *substituteName;

  const char *actualFontName;

};



static const FontSubstitute kFontSubstitutes[] = {

  // Common substitutions

  {"Arabic Transparent", "Arial"},

  {"Arabic Transparent Bold", "Arial Bold"},

  {"Arial Baltic", "Arial"},

  {"Arial CE", "Arial"},

  {"Arial CYR", "Arial"},

  {"Arial Greek", "Arial"},

  {"Arial TUR", "Arial"},

  {"Courier New Baltic", "Courier New"},

  {"Courier New CE", "Courier New"},

  {"Courier New CYR", "Courier New"},

  {"Courier New Greek", "Courier New"},

  {"Courier New TUR", "Courier New"},

  {"Helv", "MS Sans Serif"},

  {"Helvetica", "Arial"},

  {"MS Shell Dlg 2", "Tahoma"},

  {"Tahoma Armenian", "Tahoma"},

  {"Times", "Times New Roman"},

  {"Times New Roman Baltic", "Times New Roman"},

  {"Times New Roman CE", "Times New Roman"},

  {"Times New Roman CYR", "Times New Roman"},

  {"Times New Roman Greek", "Times New Roman"},

  {"Times New Roman TUR", "Times New Roman"},

  {"Tms Rmn", "MS Serif"},

  // Common, except Japanese (which uses MS UI Gothic, instead)

  {"MS Shell Dlg", "Microsoft Sans Serif"},

  // Arabic

  {"Arial (Arabic)", "Arial"},

  {"Courier New (Arabic)", "Courier New"},

  {"Times New Roman (Arabic)", "Times New Roman"},

  // Cyrillic + Greek

  {"Courier", "Courier New"},

  // Greek

  {"Fixedsys Greek", "Fixedsys"},

  {"MS Serif Greek", "MS Serif"},

  {"MS Sans Serif Greek", "MS Sans Serif"},

  {"Small Fonts Greek", "Small Fonts"},

  {"System Greek", "System"},

  // Hebrew

  {"Arial (Hebrew)", "Arial"},

  {"Courier New (Hebrew)", "Courier New"},

  {"David Transparent", "David"},

  {"Fixed Miriam Transparent", "Miriam Fixed"},

  {"Miriam Transparent", "Miriam"},

  {"Rod Transparent", "Rod"},

  {"Times New Roman (Hebrew)", "Times New Roman"},

  // Japanese

  {"標準明朝", "ＭＳ 明朝"},

  {"標準ゴシック", "ＭＳ ゴシック"},

  {"ゴシック", "ＭＳ ゴシック"},

  {"ｺﾞｼｯｸ", "ＭＳ ゴシック"},

  {"ｸｰﾘｴ", "Courier"},

  {"ﾀｲﾑｽﾞﾛﾏﾝ", "Times New Roman"},

  {"ﾍﾙﾍﾞﾁｶ", "Arial"},

  // Simplified Chinese

  {"FangSong_GB2312", "FangSong"},

  {"KaiTi_GB2312", "KaiTi"},

};

gfx/thebes/gfxDWriteFontList.cpp

+49 −28
Original line number Diff line number Diff line
@@ -1923,6 +1923,20 @@ static void RemoveCharsetFromFontSubstitute(nsACString& aName) { 
#define MAX_VALUE_DATA 512



nsresult gfxDWriteFontList::GetFontSubstitutes() {

  if (nsContentUtils::ShouldResistFingerprinting(

          "Ignore any fingerprintable user font customization and normalize "

          "font substitutes across different Windows SKUs.",

          RFPTarget::Unknown)) {

    for (const FontSubstitute& fs : kFontSubstitutes) {

      nsAutoCString substituteName(fs.substituteName);

      nsAutoCString actualFontName(fs.actualFontName);

      BuildKeyNameFromFontName(substituteName);

      BuildKeyNameFromFontName(actualFontName);

      AddSubstitute(substituteName, actualFontName);

    }

    return NS_OK;

  }



  HKEY hKey;

  DWORD i, rv, lenAlias, lenActual, valueType;

  WCHAR aliasName[MAX_VALUE_NAME];
@@ -1957,15 +1971,24 @@ nsresult gfxDWriteFontList::GetFontSubstitutes() { 
    BuildKeyNameFromFontName(substituteName);

    RemoveCharsetFromFontSubstitute(actualFontName);

    BuildKeyNameFromFontName(actualFontName);

    AddSubstitute(substituteName, actualFontName);

  }



  return NS_OK;

}



void gfxDWriteFontList::AddSubstitute(const nsCString& substituteName,

                                      const nsCString& actualFontName) {

  if (SharedFontList()) {

      // Skip substitution if the original font is available, unless the option

      // to apply substitutions unconditionally is enabled.

    // Skip substitution if the original font is available, unless the

    // option to apply substitutions unconditionally is enabled.

    if (!StaticPrefs::gfx_windows_font_substitutes_always_AtStartup()) {

        // Font substitutions are recorded for the canonical family names; we

        // don't need FindFamily to consider localized aliases when searching.

      // Font substitutions are recorded for the canonical family names;

      // we don't need FindFamily to consider localized aliases when

      // searching.

      if (SharedFontList()->FindFamily(substituteName,

                                       /*aPrimaryNameOnly*/ true)) {

          continue;

        return;

      }

    }

    if (SharedFontList()->FindFamily(actualFontName,
@@ -1989,8 +2012,6 @@ nsresult gfxDWriteFontList::GetFontSubstitutes() { 
    }

  }

}

  return NS_OK;

}



struct FontSubstitution {

  const char* aliasName;

gfx/thebes/gfxDWriteFontList.h

+3 −0
Original line number Diff line number Diff line
@@ -466,6 +466,9 @@ class gfxDWriteFontList final : public gfxPlatformFontList { 
      const nsTArray<nsCString>* aForceClassicFams = nullptr)

      MOZ_REQUIRES(mLock);



  void AddSubstitute(const nsCString& substituteName,

                     const nsCString& actualFontName);



#ifdef MOZ_BUNDLED_FONTS

  already_AddRefed<IDWriteFontCollection> CreateBundledFontsCollection(

      IDWriteFactory* aFactory);

gfx/thebes/gfxGDIFontList.cpp

+28 −0
Original line number Diff line number Diff line
@@ -31,6 +31,10 @@ 
#include "mozilla/StaticPrefs_gfx.h"

#include "mozilla/Telemetry.h"



#include "nsContentUtils.h"



#include "StandardFonts-win10.inc"



#include <usp10.h>



using namespace mozilla;
@@ -50,6 +54,10 @@ static __inline void BuildKeyNameFromFontName(nsAString& aName) { 
  if (aName.Length() >= LF_FACESIZE) aName.Truncate(LF_FACESIZE - 1);

  ToLowerCase(aName);

}

static __inline void BuildKeyNameFromFontName(nsACString& aName) {

  if (aName.Length() >= LF_FACESIZE) aName.Truncate(LF_FACESIZE - 1);

  ToLowerCase(aName);

}



// Implementation of gfxPlatformFontList for Win32 GDI,

// using GDI font enumeration APIs to get the list of fonts
@@ -529,6 +537,26 @@ static void RemoveCharsetFromFontSubstitute(nsAString& aName) { 
#define MAX_VALUE_DATA 512



nsresult gfxGDIFontList::GetFontSubstitutes() {

  if (nsContentUtils::ShouldResistFingerprinting(

          "Ignore any fingerprintable user font customization and normalize "

          "font substitutes across different Windows SKUs.",

          RFPTarget::Unknown)) {

    for (const FontSubstitute& fs : kFontSubstitutes) {

      nsAutoCString substituteName(fs.substituteName);

      nsAutoCString actualFontName(fs.actualFontName);

      BuildKeyNameFromFontName(substituteName);

      BuildKeyNameFromFontName(actualFontName);

      gfxFontFamily* ff;

      if (!actualFontName.IsEmpty() &&

          (ff = mFontFamilies.GetWeak(actualFontName))) {

        mFontSubstitutes.InsertOrUpdate(substituteName, RefPtr{ff});

      } else {

        mNonExistingFonts.AppendElement(substituteName);

      }

    }

    return NS_OK;

  }



  HKEY hKey;

  DWORD i, rv, lenAlias, lenActual, valueType;

  WCHAR aliasName[MAX_VALUE_NAME];