Re: [PATCH v4 0/2] MR7064: ntdll: Check for invalid %gs value in 32-bit code on WoW64.

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about dlls/ntdll/unix/signal_x86_64.c:
> -
> -
> -
> - Check for fault caused by invalid %gs value (some copy protection schemes mess with it).
> -
> -
> - */
>
> +static inline BOOL check_invalid_gs( ucontext_t *sigcontext, CONTEXT *context )
> +{
> - const BYTE *instr = (const BYTE *)context->Rip;
> - TEB *teb = get_current_teb();
> - WORD system_gs = ds64_sel;
> - ULONG_PTR cur_gs = 0;
> -
>
> +#ifdef __linux__
> - if (syscall_flags & SYSCALL_HAVE_WRFSGSBASE)
> -
>    __asm__ volatile ("rdgsbase %0" : "=r" (cur_gs));
> - else
> -
>    cur_gs = arch_prctl( ARCH_GET_GS, teb );

ARCH_GET_GS yields value by writing to pointer. The return value is just error status.

```suggestion:-0+0
        arch_prctl( ARCH_GET_GS, &cur_gs );
```