[PATCH xserver] was: Re: Two long-standing server bugs

[Thomas Klausner]

On Sun, Sep 01, 2013 at 01:37:31PM -0400, der Mouse wrote:
> The first is that CreateCursor (Xlib call XCreatePixmapCursor) with a
> non-bitmap source pixmap and a None mask is, as I read it, supposed to
> error out with BadMatch, but doesn't.  This is the one I fixed.
> 
> The second is that pixmap cursors created with a None mask get
> extended, in some cases, to the right with additional pixels in the
> background colour, usually to a multiple of 32 pixels.  I don't know
> exactly when this happens; in my experience it correlates (almost?)
> perfectly with using video hardware that's behind a PCI bus, though I
> feel reasonably sure that it's more a question of which ddx device code
> is in use.  This is not, strictly, contrary to the spec, since cursors
> "may be transformed arbitrarily to meet display limitations", but,
> since it works correctly (in the cases I've seen) when the client
> specifies a mask pixmap full of 1s, there clearly is no actual need to
> mangle cursors specified with a mask of None this way.  So I think
> calling it a bug is fair.  This is the one I kinda-sorta fixed.
> 
> Here are my patches.  Pathnames are based on NetBSD's /usr/xsrc; I
> trust people here can adapt as necessary. :-)  Anyone is welcome to
> pick these up, either to be fed back into the main tree or for private
> use, as desired.  (In case an explicit statement to this effect is
> helpful, I release any intellectual property rights I may have in these
> patches into the public domain.)
> 
> First, the `missing BadMatch' bug.
> 
> --- a/external/mit/xorg-server/dist/dix/dispatch.c
> +++ b/external/mit/xorg-server/dist/dix/dispatch.c
> @@ -2863,9 +2863,10 @@ ProcCreateCursor (ClientPtr client)
>      }
>      else if (  src->drawable.width != msk->drawable.width
>  	    || src->drawable.height != msk->drawable.height
> -	    || src->drawable.depth != 1
>  	    || msk->drawable.depth != 1)
>  	return (BadMatch);
> +    if (src->drawable.depth != 1)
> +	return (BadMatch);
>  
>      width = src->drawable.width;
>      height = src->drawable.height;

I've adapted this patch to the current xserver git sources, attached.
Please review.
 Thomas
-------------- next part --------------
>From 8057fc810fb2815ea4c069ac9c1bc77709afb778 Mon Sep 17 00:00:00 2001
From: Thomas Klausner <wiz at NetBSD.org>
Date: Tue, 3 Sep 2013 09:44:18 +0200
Subject: [PATCH:xserver] Fix bug in cursor handling.

CreateCursor (Xlib call XCreatePixmapCursor) with a non-bitmap
source pixmap and a None mask is supposed to error out with BadMatch,
but didn't.

>From der Mouse <mouse at Rodents-Montreal.ORG>

Signed-off-by: Thomas Klausner <wiz at NetBSD.org>
---
 dix/dispatch.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/dix/dispatch.c b/dix/dispatch.c
index 51d0de2..ae3b97b 100644
--- a/dix/dispatch.c
+++ b/dix/dispatch.c
@@ -2874,9 +2874,12 @@ ProcCreateCursor(ClientPtr client)
     }
     else if (src->drawable.width != msk->drawable.width
              || src->drawable.height != msk->drawable.height
-             || src->drawable.depth != 1 || msk->drawable.depth != 1)
+             || msk->drawable.depth != 1)
         return BadMatch;
 
+    if (src->drawable.depth != 1)
+        return (BadMatch);
+
     width = src->drawable.width;
     height = src->drawable.height;
 
-- 
1.8.4