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SubjectRe: [PATCH][next] staging: greybus: Add __counted_by for struct apr_rx_buf and use struct_size()
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On 10/9/23 4:52 PM, Gustavo A. R. Silva wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> While there, use struct_size() helper, instead of the open-coded
> version, to calculate the size for the allocation of the whole
> flexible structure, including of course, the flexible-array member.
>
> This code was found with the help of Coccinelle, and audited and
> fixed manually.

Looks good to me, and I like the use of struct_size().

Reviewed-by: Alex Elder <elder@linaro.org>

>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
> drivers/staging/greybus/raw.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/greybus/raw.c b/drivers/staging/greybus/raw.c
> index a00978c8e1d2..b9c6eff7cdc1 100644
> --- a/drivers/staging/greybus/raw.c
> +++ b/drivers/staging/greybus/raw.c
> @@ -29,7 +29,7 @@ struct gb_raw {
> struct raw_data {
> struct list_head entry;
> u32 len;
> - u8 data[];
> + u8 data[] __counted_by(len);
> };
>
> static const struct class raw_class = {
> @@ -73,7 +73,7 @@ static int receive_data(struct gb_raw *raw, u32 len, u8 *data)
> goto exit;
> }
>
> - raw_data = kmalloc(sizeof(*raw_data) + len, GFP_KERNEL);
> + raw_data = kmalloc(struct_size(raw_data, data, len), GFP_KERNEL);
> if (!raw_data) {
> retval = -ENOMEM;
> goto exit;

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