From: Maximilian Luz <luzmaximilian@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: Hans de Goede <hdegoede@redhat.com>,
Mark Gross <markgross@kernel.org>,
platform-driver-x86@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] platform/surface: Split memcpy() of struct ssam_event flexible array
Date: Tue, 27 Sep 2022 13:17:33 +0200 [thread overview]
Message-ID: <93a51c6f-40f4-1808-dbd6-4cd57bbaa3ed@gmail.com> (raw)
In-Reply-To: <20220927004011.1942739-1-keescook@chromium.org>
On 9/27/22 02:40, Kees Cook wrote:
> To work around a misbehavior of the compiler's ability to see into
> composite flexible array structs (as detailed in the coming memcpy()
> hardening series[1]), split the memcpy() of the header and the payload
> so no false positive run-time overflow warning will be generated.
>
> [1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org
>
> Cc: Maximilian Luz <luzmaximilian@gmail.com>
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: Mark Gross <markgross@kernel.org>
> Cc: platform-driver-x86@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
Thanks!
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Regards,
Max
> ---
> drivers/platform/surface/surface_acpi_notify.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/platform/surface/surface_acpi_notify.c b/drivers/platform/surface/surface_acpi_notify.c
> index 44e317970557..50500e562963 100644
> --- a/drivers/platform/surface/surface_acpi_notify.c
> +++ b/drivers/platform/surface/surface_acpi_notify.c
> @@ -355,7 +355,8 @@ static u32 san_evt_bat_nf(struct ssam_event_notifier *nf,
> INIT_DELAYED_WORK(&work->work, san_evt_bat_workfn);
> work->dev = d->dev;
>
> - memcpy(&work->event, event, sizeof(struct ssam_event) + event->length);
> + work->event = *event;
> + memcpy(work->event.data, event->data, event->length);
>
> queue_delayed_work(san_wq, &work->work, delay);
> return SSAM_NOTIF_HANDLED;
next prev parent reply other threads:[~2022-09-27 11:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-27 0:40 [PATCH] platform/surface: Split memcpy() of struct ssam_event flexible array Kees Cook
2022-09-27 1:12 ` Gustavo A. R. Silva
2022-09-27 11:17 ` Maximilian Luz [this message]
2022-09-27 13:15 ` Hans de Goede
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