From: Guenter Roeck <linux@roeck-us.net>
To: Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org,
Henrik Rydberg <rydberg@bitmath.org>,
Jean Delvare <jdelvare@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
akpm@linux-foundation.org, netdev@vger.kernel.org,
"David S . Miller" <davem@davemloft.net>,
"James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
linux-scsi@vger.kernel.org, x86@kernel.org,
linux-hwmon@vger.kernel.org
Subject: Re: [PATCH 15/22] hwmon: applesmc: fix format string overflow
Date: Fri, 14 Jul 2017 07:06:54 -0700 [thread overview]
Message-ID: <f2e1e06c-3dc3-a3cd-9e93-c9e197ff4cc4@roeck-us.net> (raw)
In-Reply-To: <20170714120720.906842-16-arnd@arndb.de>
On 07/14/2017 05:07 AM, Arnd Bergmann wrote:
> gcc-7 warns that the key might exceed five bytes for lage index
> values:
>
> drivers/hwmon/applesmc.c: In function 'applesmc_show_fan_position':
> drivers/hwmon/applesmc.c:906:18: error: '%d' directive writing between 1 and 5 bytes into a region of size 4 [-Werror=format-overflow=]
> sprintf(newkey, FAN_ID_FMT, to_index(attr));
> ^~~~~~~
> drivers/hwmon/applesmc.c:906:18: note: directive argument in the range [0, 65535]
> drivers/hwmon/applesmc.c:906:2: note: 'sprintf' output between 5 and 9 bytes into a destination of size 5
>
> As the key is required to be four characters plus trailing zero,
> we know that the index has to be small here. I'm using snprintf()
> to avoid the warning. This would truncate the string instead of
> overflowing.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
I submitted a more comprehensive patch a couple of days ago. There are other similar
sprintf() calls in the driver which gcc doesn't report.
Guenter
> ---
> drivers/hwmon/applesmc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
> index 0af7fd311979..515163b9a89f 100644
> --- a/drivers/hwmon/applesmc.c
> +++ b/drivers/hwmon/applesmc.c
> @@ -903,7 +903,7 @@ static ssize_t applesmc_show_fan_position(struct device *dev,
> char newkey[5];
> u8 buffer[17];
>
> - sprintf(newkey, FAN_ID_FMT, to_index(attr));
> + snprintf(newkey, sizeof(newkey), FAN_ID_FMT, to_index(attr));
>
> ret = applesmc_read_key(newkey, buffer, 16);
> buffer[16] = 0;
>
next prev parent reply other threads:[~2017-07-14 14:06 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-14 12:06 [PATCH 00/22] gcc-7 -Wformat-* warnings Arnd Bergmann
2017-07-14 12:06 ` [PATCH 01/22] kbuild: disable -Wformat-truncation warnings by default Arnd Bergmann
2017-07-14 12:06 ` [PATCH 02/22] scsi: megaraid: fix format-overflow warning Arnd Bergmann
2017-07-14 12:06 ` [PATCH 03/22] scsi: mpt3sas: fix format overflow warning Arnd Bergmann
2017-07-14 12:06 ` [PATCH 04/22] scsi: fusion: fix string " Arnd Bergmann
2017-07-17 9:17 ` David Laight
2017-07-17 12:00 ` Arnd Bergmann
2017-07-14 12:06 ` [PATCH 05/22] scsi: gdth: avoid buffer " Arnd Bergmann
2017-07-14 12:06 ` [PATCH 06/22] scsi: fnic: fix format string " Arnd Bergmann
2017-07-14 12:06 ` [PATCH 07/22] scsi: gdth: increase the procfs event buffer size Arnd Bergmann
2017-07-14 12:07 ` [PATCH 08/22] isdn: divert: fix sprintf buffer overflow warning Arnd Bergmann
2017-07-14 16:03 ` David Miller
2017-07-14 12:07 ` [PATCH 09/22] net: niu: fix format string overflow warning: Arnd Bergmann
2017-07-14 16:03 ` David Miller
2017-07-14 12:07 ` [PATCH 10/22] bnx2x: fix format overflow warning Arnd Bergmann
2017-07-14 16:03 ` David Miller
2017-07-14 12:07 ` [PATCH 11/22] net: thunder_bgx: avoid format string " Arnd Bergmann
2017-07-14 12:33 ` Robin Murphy
2017-07-14 16:03 ` David Miller
2017-07-14 12:07 ` [PATCH 12/22] vmxnet3: avoid format strint " Arnd Bergmann
2017-07-14 16:04 ` David Miller
2017-07-14 12:07 ` [PATCH 13/22] liquidio: fix possible eeprom format string overflow Arnd Bergmann
2017-07-14 16:04 ` David Miller
2017-07-14 22:40 ` Burla, Satananda
2017-07-14 12:07 ` [PATCH 14/22] [media] usbvision-i2c: fix format overflow warning Arnd Bergmann
2017-07-17 12:53 ` Hans Verkuil
2017-07-17 12:57 ` Arnd Bergmann
2017-07-17 12:59 ` Hans Verkuil
2017-07-14 12:07 ` [PATCH 15/22] hwmon: applesmc: fix format string overflow Arnd Bergmann
2017-07-14 14:06 ` Guenter Roeck [this message]
2017-07-14 12:07 ` [PATCH 16/22] x86: intel-mid: fix a format string overflow warning Arnd Bergmann
2017-07-14 12:07 ` [PATCH 17/22] platform/x86: alienware-wmi: fix " Arnd Bergmann
2017-07-14 18:30 ` Mario.Limonciello
2017-07-14 19:18 ` Andy Shevchenko
2017-07-14 19:37 ` Arnd Bergmann
2017-07-14 19:49 ` Andy Shevchenko
2017-07-14 12:07 ` [PATCH 18/22] gpio: acpi: fix string overflow for large pin numbers Arnd Bergmann
2017-07-14 12:52 ` Andy Shevchenko
2017-07-14 19:59 ` Arnd Bergmann
2017-07-14 12:07 ` [PATCH 19/22] block: DAC960: shut up format-overflow warning Arnd Bergmann
2017-07-14 14:04 ` Jens Axboe
2017-07-14 12:07 ` [PATCH 20/22] sound: pci: avoid string overflow warnings Arnd Bergmann
2017-07-14 12:28 ` Takashi Iwai
2017-07-18 11:52 ` Arnd Bergmann
2017-07-14 12:07 ` [PATCH 21/22] fscache: fix fscache_objlist_show format processing Arnd Bergmann
2017-07-14 12:07 ` [PATCH 22/22] IB/mlx4: fix sprintf format warning Arnd Bergmann
2017-07-14 13:48 ` Leon Romanovsky
2017-07-25 1:48 ` [PATCH 00/22] gcc-7 -Wformat-* warnings Martin K. Petersen
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