From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Reid Subject: Re: [PATCH v3] gpio: Remove VLA from stmpe driver Date: Thu, 29 Mar 2018 08:07:05 +0800 Message-ID: References: <20180328175957.23904-1-labbott@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180328175957.23904-1-labbott@redhat.com> Content-Language: en-AU Sender: linux-kernel-owner@vger.kernel.org To: Laura Abbott , Linus Walleij , Kees Cook , Patrice Chotard Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com List-Id: linux-gpio@vger.kernel.org On 29/03/2018 01:59, Laura Abbott wrote: > The new challenge is to remove VLAs from the kernel > (see https://lkml.org/lkml/2018/3/7/621) > > The number of GPIOs on the supported chips is fairly small > so stack allocate to a known upper bound and spit out a warning > if any new chips have more gpios. > > Signed-off-by: Laura Abbott > --- > v3: Split this off from the rest of the series since some of the > patches had been picked up. Switched to just hardcoding an upper > bound for the stack array since it's only a few extra bytes > of stack space. > --- > drivers/gpio/gpio-stmpe.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c > index f8d7d1cd8488..8d6a5a7e612d 100644 > --- a/drivers/gpio/gpio-stmpe.c > +++ b/drivers/gpio/gpio-stmpe.c > @@ -363,13 +363,15 @@ static struct irq_chip stmpe_gpio_irq_chip = { > .irq_set_type = stmpe_gpio_irq_set_type, > }; > > +#define MAX_GPIOS 24 > + > static irqreturn_t stmpe_gpio_irq(int irq, void *dev) > { > struct stmpe_gpio *stmpe_gpio = dev; > struct stmpe *stmpe = stmpe_gpio->stmpe; > u8 statmsbreg; > int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8); > - u8 status[num_banks]; > + u8 status[DIV_ROUND_UP(MAX_GPIOS, 8)]; > int ret; > int i; > > @@ -434,6 +436,11 @@ static int stmpe_gpio_probe(struct platform_device *pdev) > struct stmpe_gpio *stmpe_gpio; > int ret, irq; > > + if (stmpe->num_gpios > MAX_GPIOS) { > + dev_err(&pdev->dev, "Need to increase maximum GPIO number\n"); > + return -EINVAL; > + } > + > stmpe_gpio = kzalloc(sizeof(*stmpe_gpio), GFP_KERNEL); > if (!stmpe_gpio) > return -ENOMEM; > FWIW Reviewed-by: Phil Reid -- Regards Phil Reid