[OpenBIOS] [patch 6/6] Prevent dereferencing page zero and complain about invalid handles

[Blue Swirl]

On Fri, Aug 21, 2009 at 12:16 AM, Igor
Kovalenko<igor.v.kovalenko at gmail.com> wrote:
> Index: openbios-devel/forth/device/package.fs
> ===================================================================
> --- openbios-devel.orig/forth/device/package.fs
> +++ openbios-devel/forth/device/package.fs
> @@ -59,10 +59,15 @@
>
>  : find-method ( method-str method-len phandle -- false | xt true )
>   \ should we search the private wordlist too? I don't think so...
> -  >dn.methods @ find-wordlist if
> -    true
> +  ?dup if
> +    >dn.methods @ find-wordlist if
> +      true
> +    else
> +      2drop false
> +    then
>   else
> -    2drop false
> +      cr ." find-method: " type ."  : NULL phandle" cr
> +      false
>   then
>  ;
>
> @@ -75,10 +80,18 @@
>
>
>  : $call-method  ( ... method-str method-len ihandle -- ??? )
> -  dup >r >in.device-node @ find-method if
> -    r> call-package
> +  \ check if my-self exists; if not, there is nothing to call from
> +
> +  ?dup if
> +    dup >r >in.device-node @ find-method if
> +      r> call-package
> +    else
> +      cr ." $call-method: instance method not found" cr
> +      -821 throw
> +    then
>   else
> -    -21 throw
> +    cr ." $call-method: " type ."  : NULL ihandle" cr
> +    -f21 throw
>   then
>  ;

Can we find out the caller in these cases? The error messages are not
very useful to the user. They also happen on Sparc32.