diff options
authorPeter Hutterer <>2009-10-01 10:03:42 +1000
committerPeter Hutterer <>2009-10-01 16:00:41 +1000
commit622fc98fd08aba98369e6933c3ab8c9ff85385d5 (patch)
parent758ab55d2defc78d0169fd61a7036eb9f889e9e7 (diff)
render: Fix crash in RenderAddGlyphs (#23645)
This patch fixes two bugs: size is calculated as glyph height * padded_width. If the client submits garbage, this may get above INT_MAX, resulting in a negative size if size is unsigned. The sanity checks don't trigger for negative sizes and the server goes and writes into random memory locations. If the client submits glyphs with a width or height 0, the destination pixmap is NULL, causing a null-pointer dereference. Since there's nothing to composite if the width/height is 0, we might as well skip the whole thing anyway. Tested with Xvfb, Xephyr and Xorg. X.Org Bug 23645 <> Signed-off-by: Peter Hutterer <> Reviewed-by: Keith Packard <>
1 files changed, 5 insertions, 1 deletions
diff --git a/render/render.c b/render/render.c
index a3067665e..a32d797a7 100644
--- a/render/render.c
+++ b/render/render.c
@@ -1043,7 +1043,7 @@ ProcRenderAddGlyphs (ClientPtr client)
CARD32 *gids;
xGlyphInfo *gi;
CARD8 *bits;
- int size;
+ unsigned int size;
int err;
int i, screen;
PicturePtr pSrc = NULL, pDst = NULL;
@@ -1131,6 +1131,10 @@ ProcRenderAddGlyphs (ClientPtr client)
ScreenPtr pScreen;
int error;
+ /* Skip work if it's invisibly small anyway */
+ if (!width || !height)
+ break;
pScreen = screenInfo.screens[screen];
pSrcPix = GetScratchPixmapHeader (pScreen,
width, height,