From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH 18/22] gpio: acpi: fix string overflow for large pin numbers Date: Fri, 14 Jul 2017 15:52:20 +0300 Message-ID: <1500036740.29303.7.camel@linux.intel.com> References: <20170714120720.906842-1-arnd@arndb.de> <20170714120720.906842-19-arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: Received: from mga09.intel.com ([134.134.136.24]:20992 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753124AbdGNMwi (ORCPT ); Fri, 14 Jul 2017 08:52:38 -0400 In-Reply-To: <20170714120720.906842-19-arnd@arndb.de> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Arnd Bergmann , linux-kernel@vger.kernel.org, Mika Westerberg , Linus Walleij Cc: Greg Kroah-Hartman , Linus Torvalds , Guenter Roeck , akpm@linux-foundation.org, netdev@vger.kernel.org, "David S . Miller" , "James E . J . Bottomley" , "Martin K . Petersen" , linux-scsi@vger.kernel.org, x86@kernel.org, Hans de Goede , "Rafael J. Wysocki" , Wei Yongjun , linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org On Fri, 2017-07-14 at 14:07 +0200, Arnd Bergmann wrote: > gcc-7 notices that the pin_table is an array of 16-bit numbers, > but we assume it can be printed as a two-character hexadecimal > string: > > drivers/gpio/gpiolib-acpi.c: In function > 'acpi_gpiochip_request_interrupt': > drivers/gpio/gpiolib-acpi.c:206:24: warning: '%02X' directive writing > between 2 and 4 bytes into a region of size 3 [-Wformat-overflow=] >    sprintf(ev_name, "_%c%02X", >                         ^~~~ > drivers/gpio/gpiolib-acpi.c:206:20: note: directive argument in the > range [0, 65535] >    sprintf(ev_name, "_%c%02X", >                     ^~~~~~~~~ > drivers/gpio/gpiolib-acpi.c:206:3: note: 'sprintf' output between 5 > and 7 bytes into a destination of size 5 >    sprintf(ev_name, "_%c%02X", >    ^~~~~~~~~~~~~~~~~~~~~~~~~~~ >     agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L', >     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >     pin); >     ~~~~ This is obviously a false positive warning. Here we have int pin = u16 pin_table[0] <= 255 (implying >= 0). I see few options how to make it more clear 1) your proposal; 2) use "%02hhX" instead; 3) use if (ret >= 0 && ret <= 255) condition. I would choose one of the 2-3. In case gcc will complain about 3), file a bug to gcc crazy warning. > > This can't be right, so this changes it to truncate the number to > an 8-bit pin number. > > Fixes: 0d1c28a449c6 ("gpiolib-acpi: Add ACPI5 event model support to > gpio.") > Signed-off-by: Arnd Bergmann > --- >  drivers/gpio/gpiolib-acpi.c | 2 +- >  1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c > index c9b42dd12dfa..c3faea724af8 100644 > --- a/drivers/gpio/gpiolib-acpi.c > +++ b/drivers/gpio/gpiolib-acpi.c > @@ -205,7 +205,7 @@ static acpi_status > acpi_gpiochip_request_interrupt(struct acpi_resource *ares, >   char ev_name[5]; >   sprintf(ev_name, "_%c%02X", >   agpio->triggering == ACPI_EDGE_SENSITIVE ? > 'E' : 'L', > - pin); > + (u8)pin); >   if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, > &evt_handle))) >   handler = acpi_gpio_irq_handler; >   } -- Andy Shevchenko Intel Finland Oy