Re: [PATCH] mtd: cfi: Annotate struct cfi_private with __counted_by

Gustavo A. R. Silva
2023-09-15T20:47:29Z

On 9/15/23 14:12, Kees Cook 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 checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> As found with Coccinelle[1], add __counted_by for struct cfi_private.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: Vignesh Raghavendra <vigneshr@ti.com>
> Cc: linux-mtd@lists.infradead.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
--
Gustavo

> ---
> include/linux/mtd/cfi.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/mtd/cfi.h b/include/linux/mtd/cfi.h
> index d88bb56c18e2..947410faf9e2 100644
> --- a/include/linux/mtd/cfi.h
> +++ b/include/linux/mtd/cfi.h
> @@ -287,7 +287,7 @@ struct cfi_private {
> unsigned long chipshift; /* Because they're of the same type */
> const char *im_name; /* inter_module name for cmdset_setup */
> unsigned long quirks;
> - struct flchip chips[]; /* per-chip data structure for each chip */
> + struct flchip chips[] __counted_by(numchips); /* per-chip data structure for each chip */
> };
>
> uint32_t cfi_build_cmd_addr(uint32_t cmd_ofs,