Re: [patch 2/3] i4l: silence compiler warnings for array access in Eicon DIVA ISDN driver

[David Miller <davem@davemloft.net>]

From: akpm@linux-foundation.org
Date: Thu, 11 Mar 2010 14:07:24 -0800

> From: Ian Munsie <imunsie@au.ibm.com>
> 
> When compiling this driver, the compiler throws the following warnings:
> 
> drivers/isdn/hardware/eicon/message.c:8426: warning: array subscript is above array bounds
> drivers/isdn/hardware/eicon/message.c:8427: warning: array subscript is above array bounds
> drivers/isdn/hardware/eicon/message.c:8434: warning: array subscript is above array bounds
> drivers/isdn/hardware/eicon/message.c:8435: warning: array subscript is above array bounds
> drivers/isdn/hardware/eicon/message.c:8436: warning: array subscript is above array bounds
> drivers/isdn/hardware/eicon/message.c:8447: warning: array subscript is above array bounds
> 
> This arises from the particular semantics the driver is using to write to
> the nlc array (static byte[256]).  The array has a length in byte 0
> followed by a T30_INFO struct starting at byte 1.
> 
> The T30_INFO struct has a number of variable length strings after the
> station_id entry, which cannot be explicitly defined in the struct and the
> driver accesses them with an array index to station_id beyond the length
> of station_id.
> 
> This patch merely changes the semantics that the driver uses to access the
> entries after the station_id entry to use the original 256 byte nlc array
> taking the offset and length of the station_id entry to calculate where to
> write in the array, thereby silencing the warning.
> 
> Signed-off-by: Ian Munsie <imunsie@au.ibm.com>
> Cc: Armin Schindler <mac@melware.de>
> Cc: Karsten Keil <isdn@linux-pingi.de>
> Cc: Stoyan Gaydarov <sgayda2@uiuc.edu>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Applied.