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[2001:1c00:c1e:bf00:d69d:5353:dba5:ee81]) by smtp.gmail.com with ESMTPSA id 2-20020a170906318200b0078116c361d9sm814628ejy.10.2022.09.27.06.15.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 27 Sep 2022 06:15:31 -0700 (PDT) Message-ID: <62b2133e-05ec-1a09-8214-b2b847c0e97e@redhat.com> Date: Tue, 27 Sep 2022 15:15:30 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.1 Subject: Re: [PATCH] platform/surface: Split memcpy() of struct ssam_event flexible array To: Kees Cook , Maximilian Luz Cc: Mark Gross , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org References: <20220927004011.1942739-1-keescook@chromium.org> From: Hans de Goede In-Reply-To: <20220927004011.1942739-1-keescook@chromium.org> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org Hi, 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 > Cc: Hans de Goede > Cc: Mark Gross > Cc: platform-driver-x86@vger.kernel.org > Signed-off-by: Kees Cook Thank you for your patch, I've applied this patch to my review-hans branch: https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans Note it will show up in my review-hans branch once I've pushed my local branch there, which might take a while. Once I've run some tests on this branch the patches there will be added to the platform-drivers-x86/for-next branch and eventually will be included in the pdx86 pull-request to Linus for the next merge-window. Regards, Hans > --- > 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;