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Xext: dynamically allocate the PanoramiXDepths[j].vids array 

Control flow is:
   PanoramiXMaybeAddDepth() allocates an array size 240 (pDepth->numVisuals)
   PanoramiXMaybeAddVisual() finds up to 270 matches (pScreen->numVisuals)
   and writes those into the previously allocated array.

This caused invalid reads/writes followed by eventually a double-free abort.

Reproduced with xorg-integration-tests server test
XineramaTest.ScreenCrossing/* (and a bunch of others).

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Keith Packard <keithp@keithp.com>
This commit is contained in:
Peter Hutterer 2018-07-18 13:22:43 +10:00
parent 1c7f34e99f
commit 93cafb0828
1 changed files with 4 additions and 5 deletions
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9
Xext/panoramiX.c
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@ -751,11 +751,7 @@ PanoramiXMaybeAddDepth(DepthPtr pDepth)
PanoramiXNumDepths, sizeof(DepthRec));
PanoramiXDepths[j].depth = pDepth->depth;
PanoramiXDepths[j].numVids = 0;
/* XXX suboptimal, should grow these dynamically */
if (pDepth->numVids)
PanoramiXDepths[j].vids = xallocarray(pDepth->numVids, sizeof(VisualID));
else
PanoramiXDepths[j].vids = NULL;
PanoramiXDepths[j].vids = NULL;
}
static void
@ -796,6 +792,9 @@ PanoramiXMaybeAddVisual(VisualPtr pVisual)
for (k = 0; k < PanoramiXNumDepths; k++) {
if (PanoramiXDepths[k].depth == pVisual->nplanes) {
PanoramiXDepths[k].vids = reallocarray(PanoramiXDepths[k].vids,
PanoramiXDepths[k].numVids + 1,
sizeof(VisualID));
PanoramiXDepths[k].vids[PanoramiXDepths[k].numVids] = pVisual->vid;
PanoramiXDepths[k].numVids++;
break;