Re: [PATCH] dell-smbios: fix string overflow

[Darren Hart <dvhart@infradead.org>]

On Wed, Nov 08, 2017 at 01:08:39PM +0100, Arnd Bergmann wrote:
> The new sysfs code overwrites two fixed-length character arrays
> that are each one byte shorter than they need to be, to hold
> the trailing \0:
> 
> drivers/platform/x86/dell-smbios.c: In function 'build_tokens_sysfs':
> drivers/platform/x86/dell-smbios.c:494:42: error: 'sprintf' writing a terminating nul past the end of the destination [-Werror=format-overflow=]
>    sprintf(buffer_location, "%04x_location",
> drivers/platform/x86/dell-smbios.c:494:3: note: 'sprintf' output 14 bytes into a destination of size 13
> drivers/platform/x86/dell-smbios.c:506:36: error: 'sprintf' writing a terminating nul past the end of the destination [-Werror=format-overflow=]
>    sprintf(buffer_value, "%04x_value",
> drivers/platform/x86/dell-smbios.c:506:3: note: 'sprintf' output 11 bytes into a destination of size 10
> 
> This changes it to just use kasprintf(), which always gets it right.
> 
> Fixes: 33b9ca1e53b4 ("platform/x86: dell-smbios: Add a sysfs interface for SMBIOS tokens")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>


Queued, thanks Arnd.

Yes, please keep the error messages. Costs us nothing and can be useful to have.

I corrected the prefix as noted, and added the details of the gcc and reverted
patch for reproducer context.

-- 
Darren Hart
VMware Open Source Technology Center