xorg-x11-server/xserver-1.9-reset-root-null.patch

60 lines
2.2 KiB
Diff

From d25c74c843b83e7c6acbeb52d4807559c83f98cb Mon Sep 17 00:00:00 2001
From: Dave Airlie <airlied@linux.ie>
Date: Mon, 16 Aug 2010 12:16:48 +1000
Subject: [PATCH] dix: reset pScreen->root to NULL when root window is deleted.
We were seeing a crash in the FreeAllResources codepath,
running valgrind revealed this,
==12536== Invalid read of size 4
==12536== at 0x810BCAB: DeliverPropertyEvent (rrproperty.c:33)
==12536== by 0x80958A4: TraverseTree (window.c:227)
==12536== by 0x809593E: WalkTree (window.c:255)
==12536== by 0x810BC66: RRDeliverPropertyEvent (rrproperty.c:53)
==12536== by 0x810BD5D: RRDeleteProperty.clone.0 (rrproperty.c:76)
==12536== by 0x810BD98: RRDeleteAllOutputProperties (rrproperty.c:88)
==12536== by 0x810A36E: RROutputDestroyResource (rroutput.c:407)
==12536== by 0x808DF4E: FreeClientResources (resource.c:859)
==12536== by 0x808E005: FreeAllResources (resource.c:876)
==12536== by 0x8062300: main (main.c:305)
==12536== Address 0x46ba8ac is 4 bytes inside a block of size 164 free'd
==12536== at 0x40057F6: free (vg_replace_malloc.c:325)
==12536== by 0x8087F1F: _dixFreeObjectWithPrivates (privates.c:357)
==12536== by 0x809832A: DeleteWindow (window.c:926)
==12536== by 0x808DF4E: FreeClientResources (resource.c:859)
==12536== by 0x808E005: FreeAllResources (resource.c:876)
==12536== by 0x8062300: main (main.c:305)
Its a use after free on the root window, since we have already deleted it
at this point. This patch checks if the window we are destroying is the root
window and resets the pointer to NULL if it is.
Signed-off-by: Dave Airlie <airlied@redhat.com>
---
dix/window.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/dix/window.c b/dix/window.c
index 4a47dd5..33ef943 100644
--- a/dix/window.c
+++ b/dix/window.c
@@ -895,10 +895,15 @@ DeleteWindow(pointer value, XID wid)
WindowPtr pParent;
WindowPtr pWin = (WindowPtr)value;
xEvent event;
+ ScreenPtr pScreen;
+
+ pScreen = pWin->drawable.pScreen;
UnmapWindow(pWin, FALSE);
CrushTree(pWin);
+ if (pWin == pScreen->root)
+ pScreen->root = NULL;
pParent = pWin->parent;
if (wid && pParent && SubStrSend(pWin, pParent))
--
1.7.2.1