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

On Fri, Jul 14, 2017 at 9:18 PM, Andy Shevchenko
[off-list ref] wrote:

On Fri, Jul 14, 2017 at 3:07 PM, Arnd Bergmann [off-list ref] wrote:

quoted

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