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Linux: Fixed a use-after-free in XWindowSystem::findDisplays()

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ed 2020-11-03 17:07:38 +00:00
parent 8070fa0ec4
commit 09ecc0ebef
1 changed files with 44 additions and 30 deletions
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74
modules/juce_gui_basics/native/x11/juce_linux_XWindowSystem.cpp
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@ -2168,24 +2168,39 @@ ModifierKeys XWindowSystem::getNativeRealtimeModifiers() const
return ModifierKeys::currentModifiers;
}
static bool hasWorkAreaData (const XWindowSystemUtilities::GetXProperty& prop)
{
return prop.success
&& prop.actualType == XA_CARDINAL
&& prop.actualFormat == 32
&& prop.numItems == 4
&& prop.data != nullptr;
}
static Rectangle<int> getWorkArea (const XWindowSystemUtilities::GetXProperty& prop)
{
if (hasWorkAreaData (prop))
{
auto* positionData = prop.data;
std::array<long, 4> position;
for (auto& p : position)
{
memcpy (&p, positionData, sizeof (long));
positionData += sizeof (long);
}
return { (int) position[0], (int) position[1],
(int) position[2], (int) position[3] };
}
return {};
}
Array<Displays::Display> XWindowSystem::findDisplays (float masterScale) const
{
Array<Displays::Display> displays;
Atom hints = XWindowSystemUtilities::Atoms::getIfExists (display, "_NET_WORKAREA");
auto getWorkAreaPropertyData = [&] (int screenNum) -> unsigned char*
{
if (hints != None)
{
XWindowSystemUtilities::GetXProperty prop (X11Symbols::getInstance()->xRootWindow (display, screenNum), hints, 0, 4, false, XA_CARDINAL);
if (prop.success && prop.actualType == XA_CARDINAL && prop.actualFormat == 32 && prop.numItems == 4)
return prop.data;
}
return nullptr;
};
auto workAreaHints = XWindowSystemUtilities::Atoms::getIfExists (display, "_NET_WORKAREA");
#if JUCE_USE_XRANDR
{
@ -2198,11 +2213,13 @@ Array<Displays::Display> XWindowSystem::findDisplays (float masterScale) const
for (int i = 0; i < numMonitors; ++i)
{
if (getWorkAreaPropertyData (i) == nullptr)
auto rootWindow = X11Symbols::getInstance()->xRootWindow (display, i);
XWindowSystemUtilities::GetXProperty prop (rootWindow, workAreaHints, 0, 4, false, XA_CARDINAL);
if (! hasWorkAreaData (prop))
continue;
if (auto* screens = X11Symbols::getInstance()->xRRGetScreenResources (display,
X11Symbols::getInstance()->xRootWindow (display, i)))
if (auto* screens = X11Symbols::getInstance()->xRRGetScreenResources (display, rootWindow))
{
for (int j = 0; j < screens->noutput; ++j)
{
@ -2286,25 +2303,22 @@ Array<Displays::Display> XWindowSystem::findDisplays (float masterScale) const
if (displays.isEmpty())
#endif
{
if (hints != None)
if (workAreaHints != None)
{
auto numMonitors = X11Symbols::getInstance()->xScreenCount (display);
for (int i = 0; i < numMonitors; ++i)
{
if (auto* positionData = getWorkAreaPropertyData (i))
XWindowSystemUtilities::GetXProperty prop (X11Symbols::getInstance()->xRootWindow (display, i),
workAreaHints, 0, 4, false, XA_CARDINAL);
auto workArea = getWorkArea (prop);
if (! workArea.isEmpty())
{
std::array<long, 4> position;
for (auto& p : position)
{
memcpy (&p, positionData, sizeof (long));
positionData += sizeof (long);
}
Displays::Display d;
d.totalArea = { (int) position[0], (int) position[1],
(int) position[2], (int) position[3] };
d.totalArea = workArea;
d.isMain = displays.isEmpty();
d.scale = masterScale;
d.dpi = DisplayHelpers::getDisplayDPI (display, i);