Re: [PATCH] gdb/dwarf2read.c: Sanity check DW_AT_sibling values.

[Will Newton <will.newton@linaro.org>]

On 4 November 2013 15:57, Tom Tromey <tromey@redhat.com> wrote:
>>>>>> "Will" == Will Newton <will.newton@linaro.org> writes:
>
> Will> When reading objects with corrupt debug information it is possible that
> Will> the sibling chain can form a loop, which leads to an infinite loop and
> Will> memory exhaustion.
>
> Will> Avoid this situation by disregarding and DW_AT_sibling values that point
> Will> to a lower address than the current entry.
>
> Thanks for doing this.
>
> Will> +       const gdb_byte *sibling_ptr = buffer + dwarf2_get_ref_die_offset (&attr).sect_off;
>
> This line is too long, it should be split somewhere.

Thanks, I'll fix these.

> Will> +       if (sibling_ptr < info_ptr)
> Will> +         complaint (&symfile_complaints,
> Will> +                    _("DW_AT_sibling points backwards"));
>
> I wonder whether the check should be "<=".

I'm not sure. It looks to me that info_ptr at this point will point to
the next attribute/DIE which could be a valid sibling?

-- 
Will Newton
Toolchain Working Group, Linaro