On Tue, 11 May 2010 14:12:52 -0400, Adam Jackson <[email protected]> wrote:
> I just want it to not trivially crash my server. I could care less > about correctness for this. How about this? From 50be5e8ff00e734506d2bb0c25054d7648f0cf1e Mon Sep 17 00:00:00 2001 From: Keith Packard <[email protected]> Date: Fri, 21 May 2010 09:01:43 -0700 Subject: [PATCH] Don't let alpha maps recurse in fb. Bug 23581. Recursive alpha maps (where one picture's alpha map is set to a picture with an external alpha map) would be all fine and dandy, except for the case where the client constructs a loop. Detecting this case when setting the alpha map values would be difficult as any time an alpha map is set, the server would have to check for the looping case. Instead, a far simpler fix is to simply disallow recursive alpha maps in the rendering code, the Render spec is ambiguous in this area and allows us to to ignore the recursive case. Signed-off-by: Keith Packard <[email protected]> --- fb/fbpict.c | 24 ++++++++++++++++++------ 1 files changed, 18 insertions(+), 6 deletions(-) diff --git a/fb/fbpict.c b/fb/fbpict.c index 896d33e..18a5204 100644 --- a/fb/fbpict.c +++ b/fb/fbpict.c @@ -332,8 +332,11 @@ create_bits_picture (PicturePtr pict, return image; } +static pixman_image_t * +image_from_pict_internal (PicturePtr pict, Bool has_clip, int *xoff, int *yoff, Bool is_alpha_map); + static void -set_image_properties (pixman_image_t *image, PicturePtr pict, Bool has_clip, int *xoff, int *yoff) +set_image_properties (pixman_image_t *image, PicturePtr pict, Bool has_clip, int *xoff, int *yoff, Bool is_alpha_map) { pixman_repeat_t repeat; pixman_filter_t filter; @@ -382,10 +385,13 @@ set_image_properties (pixman_image_t *image, PicturePtr pict, Bool has_clip, int pixman_image_set_repeat (image, repeat); - if (pict->alphaMap) + /* Fetch alpha map unless 'pict' is being used + * as the alpha map for this operation + */ + if (pict->alphaMap && !is_alpha_map) { int alpha_xoff, alpha_yoff; - pixman_image_t *alpha_map = image_from_pict (pict->alphaMap, FALSE, &alpha_xoff, &alpha_yoff); + pixman_image_t *alpha_map = image_from_pict_internal (pict->alphaMap, FALSE, &alpha_xoff, &alpha_yoff, TRUE); pixman_image_set_alpha_map ( image, alpha_map, pict->alphaOrigin.x, pict->alphaOrigin.y); @@ -417,8 +423,8 @@ set_image_properties (pixman_image_t *image, PicturePtr pict, Bool has_clip, int pixman_image_set_source_clipping (image, TRUE); } -pixman_image_t * -image_from_pict (PicturePtr pict, Bool has_clip, int *xoff, int *yoff) +static pixman_image_t * +image_from_pict_internal (PicturePtr pict, Bool has_clip, int *xoff, int *yoff, Bool is_alpha_map) { pixman_image_t *image = NULL; @@ -452,11 +458,17 @@ image_from_pict (PicturePtr pict, Bool has_clip, int *xoff, int *yoff) } if (image) - set_image_properties (image, pict, has_clip, xoff, yoff); + set_image_properties (image, pict, has_clip, xoff, yoff, is_alpha_map); return image; } +pixman_image_t * +image_from_pict (PicturePtr pict, Bool has_clip, int *xoff, int *yoff) +{ + return image_from_pict_internal (pict, has_clip, xoff, yoff, FALSE); +} + void free_pixman_pict (PicturePtr pict, pixman_image_t *image) { -- 1.7.1 > > - ajax Non-text part: application/pgp-signature -- [email protected]
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