Re: [PATCH] thunderbolt: xdomain: Avoid potential stack OOB read

[Mika Westerberg]

On Mon, Dec 06, 2021 at 10:34:13PM -0800, Kees Cook wrote:
> tb_xdp_properties_changed_request() was calling tb_xdp_handle_error() with
> a struct tb_xdp_properties_changed_response on the stack, which does not
> have the "error" field present when cast to struct tb_xdp_error_response.
> This was detected when building with -Warray-bounds:
> 
> drivers/thunderbolt/xdomain.c: In function 'tb_xdomain_properties_changed':
> drivers/thunderbolt/xdomain.c:226:22: error: array subscript 'const struct tb_xdp_error_response[0]' is partly outside array bounds of 'struct tb_xdp_properties_changed_response[1]' [-Werror=array-bounds]
>   226 |         switch (error->error) {
>       |                 ~~~~~^~~~~~~
> drivers/thunderbolt/xdomain.c:448:51: note: while referencing 'res'
>   448 |         struct tb_xdp_properties_changed_response res;
>       |                                                   ^~~
> 
> Add union containing struct tb_xdp_error_response to structures passed
> to tb_xdp_handle_error(), so that the "error" field will be present.
> 
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Applied, thanks!