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compositor: check viewport source rect validity

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wp_viewporter spec requires protocol errors when the viewport is outside
the buffer area.

The viewport is checked in wl_surface.commit handler as the error needs
to be delivered as a reply to the commit, not at state apply time later
(e.g. with synchronized sub-surfaces, or at render time).

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>
This commit is contained in:
Pekka Paalanen 2016-04-26 13:46:38 +03:00
parent 4826f87605
commit d9aae9c18c
1 changed files with 75 additions and 0 deletions
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75
src/compositor.c
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@ -2670,6 +2670,71 @@ weston_surface_build_buffer_matrix(const struct weston_surface *surface,
weston_matrix_scale(matrix, vp->buffer.scale, vp->buffer.scale, 1);
}
/**
* Compute a + b > c while being safe to overflows.
*/
static bool
fixed_sum_gt(wl_fixed_t a, wl_fixed_t b, wl_fixed_t c)
{
return (int64_t)a + (int64_t)b > (int64_t)c;
}
static bool
weston_surface_is_pending_viewport_source_valid(
const struct weston_surface *surface)
{
const struct weston_surface_state *pend = &surface->pending;
const struct weston_buffer_viewport *vp = &pend->buffer_viewport;
int width_from_buffer = 0;
int height_from_buffer = 0;
wl_fixed_t w;
wl_fixed_t h;
/* If viewport source rect is not set, it is always ok. */
if (vp->buffer.src_width == wl_fixed_from_int(-1))
return true;
if (pend->newly_attached) {
if (pend->buffer) {
convert_size_by_transform_scale(&width_from_buffer,
&height_from_buffer,
pend->buffer->width,
pend->buffer->height,
vp->buffer.transform,
vp->buffer.scale);
} else {
/* No buffer: viewport is irrelevant. */
return true;
}
} else {
width_from_buffer = surface->width_from_buffer;
height_from_buffer = surface->height_from_buffer;
}
assert((width_from_buffer == 0) == (height_from_buffer == 0));
assert(width_from_buffer >= 0 && height_from_buffer >= 0);
/* No buffer: viewport is irrelevant. */
if (width_from_buffer == 0 || height_from_buffer == 0)
return true;
/* overflow checks for wl_fixed_from_int() */
if (width_from_buffer > wl_fixed_to_int(INT32_MAX))
return false;
if (height_from_buffer > wl_fixed_to_int(INT32_MAX))
return false;
w = wl_fixed_from_int(width_from_buffer);
h = wl_fixed_from_int(height_from_buffer);
if (fixed_sum_gt(vp->buffer.src_x, vp->buffer.src_width, w))
return false;
if (fixed_sum_gt(vp->buffer.src_y, vp->buffer.src_height, h))
return false;
return true;
}
/* Translate pending damage in buffer co-ordinates to surface
* co-ordinates and union it with a pixman_region32_t.
* This should only be called after the buffer is attached.
@ -2809,6 +2874,16 @@ surface_commit(struct wl_client *client, struct wl_resource *resource)
struct weston_surface *surface = wl_resource_get_user_data(resource);
struct weston_subsurface *sub = weston_surface_to_subsurface(surface);
if (!weston_surface_is_pending_viewport_source_valid(surface)) {
assert(surface->viewport_resource);
wl_resource_post_error(surface->viewport_resource,
WP_VIEWPORT_ERROR_OUT_OF_BUFFER,
"wl_surface@%d has viewport source outside buffer",
wl_resource_get_id(resource));
return;
}
if (sub) {
weston_subsurface_commit(sub);
return;