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Groups > linux.kernel > #1687621

Re: [PATCH 17/22] platform/x86: alienware-wmi: fix format string overflow warning

From Arnd Bergmann <arnd@arndb.de>
Newsgroups linux.kernel
Subject Re: [PATCH 17/22] platform/x86: alienware-wmi: fix format string overflow warning
Date 2017-07-14 21:40 +0200
Message-ID <u3eBr-7TO-5@gated-at.bofh.it> (permalink)
References <u37zX-3en-5@gated-at.bofh.it> <u37JF-3iP-35@gated-at.bofh.it> <u3ei6-7Mf-17@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Fri, Jul 14, 2017 at 9:18 PM, Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Fri, Jul 14, 2017 at 3:07 PM, Arnd Bergmann <arnd@arndb.de> wrote:
>> gcc points out a possible format string overflow for a large value of 'zone':
>>
>> drivers/platform/x86/alienware-wmi.c: In function 'alienware_wmi_init':
>> drivers/platform/x86/alienware-wmi.c:461:24: error: '%02X' directive writing between 2 and 8 bytes into a region of size 6 [-Werror=format-overflow=]
>>    sprintf(buffer, "zone%02X", i);
>>                         ^~~~
>> drivers/platform/x86/alienware-wmi.c:461:19: note: directive argument in the range [0, 2147483646]
>>    sprintf(buffer, "zone%02X", i);
>>                    ^~~~~~~~~~
>> drivers/platform/x86/alienware-wmi.c:461:3: note: 'sprintf' output between 7 and 13 bytes into a destination of size 10
>>
>> While the zone should never be that large, it's easy to make the
>> buffer a few bytes longer so gcc can prove this to be safe.
>
> Please, be a bit smarter on such fixes.
>
> Here we need to convert
>
> int i;
>
> to
>
> u8 i;

That was my first impulse, but then I decided not to change the
idiomatic 'int i' for the index variable to 'u8' as that would be
less idiomatic.

> I will take it after addressing above.
>
> P.S. You may do this change across the file.

How about changing it to 'u8 zone'?

     Arnd

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Thread

[PATCH 00/22] gcc-7 -Wformat-* warnings Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:10 +0200
  [PATCH 01/22] kbuild: disable -Wformat-truncation warnings by default Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:10 +0200
  [PATCH 02/22] scsi: megaraid: fix format-overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:10 +0200
  [PATCH 07/22] scsi: gdth: increase the procfs event buffer size Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
  [PATCH 18/22] gpio: acpi: fix string overflow for large pin numbers Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 18/22] gpio: acpi: fix string overflow for large pin  numbers Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2017-07-14 15:00 +0200
      Re: [PATCH 18/22] gpio: acpi: fix string overflow for large pin numbers Arnd Bergmann <arnd@arndb.de> - 2017-07-14 22:00 +0200
  [PATCH 03/22] scsi: mpt3sas: fix format overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
  [PATCH 11/22] net: thunder_bgx: avoid format string overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 11/22] net: thunder_bgx: avoid format string overflow  warning Robin Murphy <robin.murphy@arm.com> - 2017-07-14 14:40 +0200
    Re: [PATCH 11/22] net: thunder_bgx: avoid format string overflow  warning David Miller <davem@davemloft.net> - 2017-07-14 18:10 +0200
  [PATCH 10/22] bnx2x: fix format overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 10/22] bnx2x: fix format overflow warning David Miller <davem@davemloft.net> - 2017-07-14 18:10 +0200
  [PATCH 21/22] fscache: fix fscache_objlist_show format processing Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
  [PATCH 14/22] [media] usbvision-i2c: fix format overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 14/22] [media] usbvision-i2c: fix format overflow warning Hans Verkuil <hverkuil@xs4all.nl> - 2017-07-17 15:00 +0200
      Re: [PATCH 14/22] [media] usbvision-i2c: fix format overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-17 15:00 +0200
        Re: [PATCH 14/22] [media] usbvision-i2c: fix format overflow warning Hans Verkuil <hverkuil@xs4all.nl> - 2017-07-17 15:00 +0200
  [PATCH 04/22] scsi: fusion: fix string overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    RE: [PATCH 04/22] scsi: fusion: fix string overflow warning David Laight <David.Laight@ACULAB.COM> - 2017-07-17 11:20 +0200
      Re: [PATCH 04/22] scsi: fusion: fix string overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-17 14:10 +0200
  [PATCH 15/22] hwmon: applesmc: fix format string overflow Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 15/22] hwmon: applesmc: fix format string overflow Guenter Roeck <linux@roeck-us.net> - 2017-07-14 16:10 +0200
  [PATCH 12/22] vmxnet3: avoid format strint overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 12/22] vmxnet3: avoid format strint overflow warning David Miller <davem@davemloft.net> - 2017-07-14 18:10 +0200
  [PATCH 17/22] platform/x86: alienware-wmi: fix format string overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    RE: [PATCH 17/22] platform/x86: alienware-wmi: fix format string  overflow warning <Mario.Limonciello@dell.com> - 2017-07-14 20:40 +0200
    Re: [PATCH 17/22] platform/x86: alienware-wmi: fix format string  overflow warning Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-07-14 21:20 +0200
      Re: [PATCH 17/22] platform/x86: alienware-wmi: fix format string  overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 21:40 +0200
        Re: [PATCH 17/22] platform/x86: alienware-wmi: fix format string  overflow warning Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-07-14 21:50 +0200
  [PATCH 05/22] scsi: gdth: avoid buffer overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
  [PATCH 09/22] net: niu: fix format string overflow warning: Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 09/22] net: niu: fix format string overflow warning: David Miller <davem@davemloft.net> - 2017-07-14 18:10 +0200
  [PATCH 08/22] isdn: divert: fix sprintf buffer overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 08/22] isdn: divert: fix sprintf buffer overflow warning David Miller <davem@davemloft.net> - 2017-07-14 18:10 +0200
  [PATCH 16/22] x86: intel-mid: fix a format string overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
  [PATCH 06/22] scsi: fnic: fix format string overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
  [PATCH 22/22] IB/mlx4: fix sprintf format warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 22/22] IB/mlx4: fix sprintf format warning Leon Romanovsky <leon@kernel.org> - 2017-07-14 15:50 +0200
  [PATCH 20/22] sound: pci: avoid string overflow warnings Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 20/22] sound: pci: avoid string overflow warnings Takashi Iwai <tiwai@suse.de> - 2017-07-14 14:30 +0200
  [PATCH 13/22] liquidio: fix possible eeprom format string overflow Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200
    Re: [PATCH 13/22] liquidio: fix possible eeprom format string  overflow David Miller <davem@davemloft.net> - 2017-07-14 18:10 +0200
  [PATCH 19/22] block: DAC960: shut up format-overflow warning Arnd Bergmann <arnd@arndb.de> - 2017-07-14 14:20 +0200

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