linux-kernel - Re: [Xen-devel] [PATCH v2 1/2] xen/PVH: Set up GS segment for stack canary

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 14 May 2018 06:50:52 -0600
From:   "Jan Beulich" <JBeulich@...e.com>
To:     "Boris Ostrovsky" <boris.ostrovsky@...cle.com>
Cc:     "xen-devel" <xen-devel@...ts.xenproject.org>,
        "Juergen Gross" <jgross@...e.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [Xen-devel] [PATCH v2 1/2] xen/PVH: Set up GS segment for
 stack canary

>>> On 09.05.18 at 22:33, <boris.ostrovsky@...cle.com> wrote:
> @@ -64,6 +67,17 @@ ENTRY(pvh_start_xen)
>  	mov %eax,%es
>  	mov %eax,%ss
>  
> +	/* Set base address in stack canary descriptor. */
> +	movl _pa(gdt_start),%eax
> +	movl $_pa(canary),%ecx
> +	movw %cx, (PVH_GDT_ENTRY_CANARY * 8) + 0(%eax)
> +	shrl $16, %ecx
> +	movb %cl, (PVH_GDT_ENTRY_CANARY * 8) + 2(%eax)
> +	movb %ch, (PVH_GDT_ENTRY_CANARY * 8) + 5(%eax)

Is this meaningful / correct for the 64-bit case? I'd rather expect you to
write the GS base address MSR there.

Jan