[LTP] [PATCH v3] ldt.h: Add workaround for x86_64

[Ricardo B. Marlière]

On Tue May 20, 2025 at 8:29 AM -03, Ricardo B. Marlière wrote:
> From: Ricardo B. Marlière <rbm@suse.com>
>
> The commit be0aaca2f742 ("syscalls/modify_ldt: Add lapi/ldt.h") left behind
> an important factor of modify_ldt(): the kernel intentionally casts the
> return value to unsigned int. This was handled in
> testcases/cve/cve-2015-3290.c but was removed. Add it back to the relevant
> file.
>
> Reported-by: Martin Doucha <mdoucha@suse.cz>
> Reviewed-by: Martin Doucha <mdoucha@suse.cz>
> Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
> ---
> Changes in v3:
> - EDITME: describe what is new in this series revision.
> - EDITME: use bulletpoints and terse descriptions.
> - Link to v2: https://lore.kernel.org/r/20250512-fixes-modify_ldt-v2-1-eaef5577e44e@suse.com

Changes in v3:
- Moved the `(rval == -1 && errno == EINVAL)` check into safe_modify_ldt.