Re: [PATCH] i2c: amd-asf: Validate firmware-reported length

[Andi Shyti]

Hi Paritosh,

On Fri, Jun 12, 2026 at 10:18:15AM +0000, Paritosh Potukuchi wrote:
> The firmware may sometimes return a length greater than the
> allocated buffer size, which can lead to out-of-bounds access
> and a kernel panic.

How often does it happen? Should it be considered a fix?

Shyam, any comments on this?

> Currently, the driver does not validate the length read from
> firmware.
> 
> Add a check to ensure the firmware-reported length stays within
> the bounds of the data buffer.
> 
> Fix indentation issues reported by checkpatch.

I'm going to remove this comment here as I'm going to take only
this patch and it's a meaningless information to leave in the log
history.

> Signed-off-by: Paritosh Potukuchi <paritosh.potukuchi@xxxxxxx>
> ---
>  drivers/i2c/busses/i2c-amd-asf-plat.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-amd-asf-plat.c b/drivers/i2c/busses/i2c-amd-asf-plat.c
> index ca45f0f23321..e1699da838c2 100644
> --- a/drivers/i2c/busses/i2c-amd-asf-plat.c
> +++ b/drivers/i2c/busses/i2c-amd-asf-plat.c
> @@ -90,6 +90,9 @@ static void amd_asf_process_target(struct work_struct *work)
>  		outb_p(reg, ASFDATABNKSEL);
>  		cmd = inb_p(ASFINDEX);
>  		len = inb_p(ASFDATARWPTR);
> +		if (len > ASF_BLOCK_MAX_BYTES)
> +			return;
> +

Your patch makes sense to me. I'd just like a blank line before
the 'if' statement. No need to resend it; I'll add it while
applying the patch unless you disagree.

Besides that, the patch is not properly formatted. It is missing:

1. Versioning: this should have been "[PATCH v2] ...".

2. Changelog: for a single patch, it should be added below
   the '---' line, after your Signed-off-by. You added
   "Fix indentation issues..." as a sort of changelog, but
   it is in the wrong place and it is not clear that it is
   a changelog.

3. Please don't send a new version as a reply to the previous
   one. From a maintainer's point of view, that makes it more
   difficult to track and apply.

That said, I believe this is your first patch, and that's
perfectly fine. Welcome to the community :-)

Unless there are further comments, I'll apply your patch to
i2c/i2c-for-7.2.

Thanks,
Andi