diff options
| author | Peter Hutterer <peter.hutterer@who-t.net> | 2009-10-01 10:03:42 +1000 |
|---|---|---|
| committer | Peter Hutterer <peter.hutterer@who-t.net> | 2009-10-01 16:00:41 +1000 |
| commit | 622fc98fd08aba98369e6933c3ab8c9ff85385d5 (patch) | |
| tree | 196e12a99f6b4c8c711a289535b865d9e7a22fd8 | |
| parent | 758ab55d2defc78d0169fd61a7036eb9f889e9e7 (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 <http://bugs.freedesktop.org/show_bug.cgi?id=23645>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Keith Packard <keithp@keithp.com>
| -rw-r--r-- | render/render.c | 6 |
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, |