Re: [PATCH v2] iio: irsd200: fix -Warray-bounds bug in irsd200_trigger_handler

[Kees Cook <keescook@chromium.org>]

On Thu, Aug 10, 2023 at 11:59:10AM +0800, GONG, Ruiqi wrote:
> From: "GONG, Ruiqi" <gongruiqi1@huawei.com>
> 
> When compiling with gcc 13 with -Warray-bounds enabled:
> 
> In file included from drivers/iio/proximity/irsd200.c:15:
> In function ‘iio_push_to_buffers_with_timestamp’,
>     inlined from ‘irsd200_trigger_handler’ at drivers/iio/proximity/irsd200.c:770:2:
> ./include/linux/iio/buffer.h:42:46: error: array subscript ‘int64_t {aka long long int}[0]’
> is partly outside array bounds of ‘s16[1]’ {aka ‘short int[1]’} [-Werror=array-bounds=]
>    42 |                 ((int64_t *)data)[ts_offset] = timestamp;
>       |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
> drivers/iio/proximity/irsd200.c: In function ‘irsd200_trigger_handler’:
> drivers/iio/proximity/irsd200.c:763:13: note: object ‘buf’ of size 2
>   763 |         s16 buf = 0;
>       |             ^~~
> 
> The problem seems to be that irsd200_trigger_handler() is taking a s16
> variable as an int64_t buffer. As Jonathan suggested [1], fix it by
> extending the buffer to a two-element array of s64.
> 
> Link: https://github.com/KSPP/linux/issues/331
> Link: https://lore.kernel.org/lkml/20230809181329.46c00a5d@jic23-huawei/ [1]
> Fixes: 3db3562bc66e ("iio: Add driver for Murata IRS-D200")
> Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook