[Mesa-dev] [PATCH] glsl: Fix overflow of ImageAccess[] array.
Ilia Mirkin
imirkin at alum.mit.edu
Sun Feb 14 01:30:51 UTC 2016
On Sat, Feb 13, 2016 at 8:27 PM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> The ImageAccess array is statically sized to MAX_IMAGE_UNIFORMS:
>
> GLenum ImageAccess[MAX_IMAGE_UNIFORMS];
>
> There was no bounds checking ensuring we don't overflow. Passing in a
> shader with too many uniforms would cause writes to extend into other
> fields, such as sh->NumImages.
>
> Later linker checks already handle reporting an error when there are too
> many images, so just avoid corrupting structures here.
>
> This rearranges the logic a bit to look more like the sampler case.
>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> ---
> src/compiler/glsl/link_uniforms.cpp | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/src/compiler/glsl/link_uniforms.cpp b/src/compiler/glsl/link_uniforms.cpp
> index 7072c16..f08ca47 100644
> --- a/src/compiler/glsl/link_uniforms.cpp
> +++ b/src/compiler/glsl/link_uniforms.cpp
> @@ -649,15 +649,15 @@ private:
> current_var->data.image_write_only ? GL_WRITE_ONLY :
> GL_READ_WRITE);
>
> - for (unsigned j = 0; j < MAX2(1, uniform->array_elements); ++j)
> - prog->_LinkedShaders[shader_type]->
> - ImageAccess[this->next_image + j] = access;
> + const unsigned first = this->next_image;
>
> /* Increment the image index by 1 for non-arrays and by the
> * number of array elements for arrays.
> */
> this->next_image += MAX2(1, uniform->array_elements);
>
> + for (unsigned i = first; i < MIN2(next_image, MAX_IMAGE_UNIFORMS); i++)
It's a bit odd that you do this->next_image += foo, but then use
next_image directly... if that's the style, I guess it's OK.
> + prog->_LinkedShaders[shader_type]-> ImageAccess[i] = access;
Remove the space before ImageAccess?
With that,
Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>
> }
> }
>
> --
> 2.7.1
>
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