From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartosz Golaszewski Subject: [PATCH v2 1/7] gpio: mockup: improve the debugfs input sanitization Date: Tue, 30 May 2017 10:58:34 +0200 Message-ID: <1496134720-5363-2-git-send-email-brgl@bgdev.pl> References: <1496134720-5363-1-git-send-email-brgl@bgdev.pl> Return-path: Received: from mail-wm0-f49.google.com ([74.125.82.49]:33407 "EHLO mail-wm0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750998AbdE3I6s (ORCPT ); Tue, 30 May 2017 04:58:48 -0400 Received: by mail-wm0-f49.google.com with SMTP id m7so25872798wmg.0 for ; Tue, 30 May 2017 01:58:47 -0700 (PDT) In-Reply-To: <1496134720-5363-1-git-send-email-brgl@bgdev.pl> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Linus Walleij , Alexandre Courbot , Bamvor Jian Zhang Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski We're currently only checking the first character of the input to the debugfs event files, so a string like '0sdfdsf' is valid and indicates a falling edge event. Be more strict and only allow '0', '1', '0\n' & '1\n'. While we're at it: move the sanitization code before the irq_enabled check so that we indicate an error on invalid input even if nobody is waiting for events. Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpio-mockup.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c index ba8d62a..da76267 100644 --- a/drivers/gpio/gpio-mockup.c +++ b/drivers/gpio/gpio-mockup.c @@ -208,8 +208,7 @@ static ssize_t gpio_mockup_event_write(struct file *file, struct seq_file *sfile; struct gpio_desc *desc; struct gpio_chip *gc; - int val; - char buf; + int rv, val; sfile = file->private_data; priv = sfile->private; @@ -217,19 +216,15 @@ static ssize_t gpio_mockup_event_write(struct file *file, chip = priv->chip; gc = &chip->gc; + rv = kstrtoint_from_user(usr_buf, size, 0, &val); + if (rv) + return rv; + if (val != 0 && val != 1) + return -EINVAL; + if (!chip->lines[priv->offset].irq_enabled) return size; - if (copy_from_user(&buf, usr_buf, 1)) - return -EFAULT; - - if (buf == '0') - val = 0; - else if (buf == '1') - val = 1; - else - return -EINVAL; - gpiod_set_value_cansleep(desc, val); priv->chip->irq_ctx.irq = gc->irq_base + priv->offset; irq_work_queue(&priv->chip->irq_ctx.work); -- 2.9.3