[Spice-commits] src/spice-widget.c

Frediano Ziglio fziglio at kemper.freedesktop.org
Mon Jun 13 09:20:10 UTC 2016

 src/spice-widget.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

New commits:
commit 99f357d6a544717547c75304ffc33608a6b07d07
Author: Frediano Ziglio <fziglio at redhat.com>
Date:   Tue Jun 7 12:43:07 2016 +0100

    widget: Do not mix function linkage
    This prevents a possible crash on windows 32 bit.
    The linkage of UnhookWindowsHookEx is WINAPI which is __stdcall while
    callback for g_clear_pointer is C. This could cause stack pointer
    corruption depending on compiler flags.
    On __stdcall linkage function change the stack pointer while returning
    from a function removing the parameters. On C linkage function leave
    the stack pointer unchanged. So if the compiler call a __stdcall
    function as a C function it expect the stack pointer to be unchanged
    causing the pointer to be inconsistent by an offset.
    Signed-off-by: Frediano Ziglio <fziglio at redhat.com>

diff --git a/src/spice-widget.c b/src/spice-widget.c
index b5936bc..c528614 100644
--- a/src/spice-widget.c
+++ b/src/spice-widget.c
@@ -827,7 +827,11 @@ static void try_keyboard_ungrab(SpiceDisplay *display)
     SPICE_DEBUG("ungrab keyboard");
 #ifdef G_OS_WIN32
-    g_clear_pointer(&d->keyboard_hook, UnhookWindowsHookEx);
+    // do not use g_clear_pointer as Windows API have different linkage
+    if (d->keyboard_hook) {
+        UnhookWindowsHookEx(d->keyboard_hook);
+        d->keyboard_hook = NULL;
+    }
     d->keyboard_grab_active = false;
     g_signal_emit(widget, signals[SPICE_DISPLAY_KEYBOARD_GRAB], 0, false);

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