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Bug 779326 - GIMP Crash on Merging/flattening image ...

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... possibly due to small win32 stack

Limit the number of samples processed in one go by gimp_composite_blend()
so that we don't overflow the stack when we alloca() buffers on it.
This commit is contained in:
Ell 2017-03-08 15:01:51 -05:00
parent 44b4d0f6ab
commit 7704b6100e
1 changed files with 35 additions and 3 deletions
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38
app/operations/layer-modes/gimpoperationlayermode.c
View file

@ -35,6 +35,14 @@
#include "gimpoperationlayermode.h"
/* the maximum number of samples to process in one go. used to limit
* the size of the buffers we allocate on the stack.
*/
#define GIMP_COMPOSITE_BLEND_MAX_SAMPLES ((1 << 19) /* 0.5 MiB */ / \
16 /* bytes per pixel */ / \
2 /* max number of buffers */)
enum
{
PROP_0,
@ -1009,9 +1017,9 @@ gimp_composite_blend (GimpOperationLayerMode *layer_mode,
GimpLayerColorSpace composite_space = layer_mode->composite_space;
GimpLayerCompositeMode composite_mode = layer_mode->composite_mode;
gfloat *blend_in = in;
gfloat *blend_layer = layer;
gfloat *blend_out = out;
gfloat *blend_in;
gfloat *blend_layer;
gfloat *blend_out;
gboolean composite_needs_in_color =
composite_mode == GIMP_LAYER_COMPOSITE_SRC_OVER ||
@ -1020,6 +1028,30 @@ gimp_composite_blend (GimpOperationLayerMode *layer_mode,
const Babl *composite_to_blend_fish = NULL;
const Babl *blend_to_composite_fish = NULL;
/* make sure we don't process more than GIMP_COMPOSITE_BLEND_MAX_SAMPLES
* at a time, so that we don't overflow the stack if we allocate buffers
* on it. note that this has to be done with a nested function call,
* because alloca'd buffers remain for the duration of the stack frame.
*/
while (samples > GIMP_COMPOSITE_BLEND_MAX_SAMPLES)
{
gimp_composite_blend (layer_mode,
in, layer, mask, out,
GIMP_COMPOSITE_BLEND_MAX_SAMPLES,
blend_func);
in += 4 * GIMP_COMPOSITE_BLEND_MAX_SAMPLES;
layer += 4 * GIMP_COMPOSITE_BLEND_MAX_SAMPLES;
mask += GIMP_COMPOSITE_BLEND_MAX_SAMPLES;
out += 4 * GIMP_COMPOSITE_BLEND_MAX_SAMPLES;
samples -= GIMP_COMPOSITE_BLEND_MAX_SAMPLES;
}
blend_in = in;
blend_layer = layer;
blend_out = out;
if (blend_space != GIMP_LAYER_COLOR_SPACE_AUTO)
{
g_assert (composite_space >= 1 && composite_space < 4);