On Thu, Jan 07, 2021 at 06:51:07PM -0800, Hyunwook (Wooky) Baek wrote:
> Don't assume dest/source buffers are userspace addresses when manually
> copying data for string I/O or MOVS MMIO, as {get,put}_user() will fail
> if handed a kernel address and ultimately lead to a kernel panic.
>
> Signed-off-by: Hyunwook (Wooky) Baek <bae...@google.com>
> Acked-by: David Rientjes <rient...@google.com>
> ---
> arch/x86/kernel/sev-es.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
> index 0bd1a0fc587e..812494d216ba 100644
> --- a/arch/x86/kernel/sev-es.c
> +++ b/arch/x86/kernel/sev-es.c
> @@ -286,6 +286,12 @@ static enum es_result vc_write_mem(struct es_em_ctxt
> *ctxt,
> u16 d2;
> u8 d1;
>
> + /* If instruction ran in kernel mode and the I/O buffer is in kernel
> space */
> + if (!user_mode(ctxt->regs) && !access_ok(s, size)) {
^^^
Just by looking at this patch I know you haven't tested it before sending.
:-(
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
