Re: [PATCH net v3] ptp: ocp: Fix board ID over-read

[Vadim Fedorenko <vadim.fedorenko@linux.dev>]

On 04.08.2026 22:07, Ahmad Byagowi wrote:
> The EEPROM board ID is a fixed 13-byte field and is not guaranteed to
> contain a NUL terminator. Passing it directly to
> devlink_info_version_fixed_put() treats it as a C string and may read
> beyond the field.
> 
> Format at most OCP_BOARD_ID_LEN bytes into the existing local buffer
> before reporting the ID. Use a precision limit because the snprintf()
> output size alone does not bound the source string scan.
> 
> Fixes: 0cfcdd1ebcfe ("ptp: ocp: add nvmem interface for accessing eeprom")
> Cc: stable@vger.kernel.org
> Signed-off-by: Ahmad Byagowi <ahmadexp@gmail.com>
> ---
> Changes since RFC v2:
> - Split the safety fix from the net-next feature series and target net.
> - Use the short Fixes hash.
> - Reuse the existing devlink info buffer and bound the source scan with
>    string precision.
> - Limit the change to the board ID over-read.
> 
> RFC v2:
> https://lore.kernel.org/r/20260803205011.1249-5-ahmadexp@gmail.com/
> 
>   drivers/ptp/ptp_ocp.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
> index 35e911f1ad78c..3d26ec1f7b9ec 100644
> --- a/drivers/ptp/ptp_ocp.c
> +++ b/drivers/ptp/ptp_ocp.c
> @@ -2177,9 +2177,11 @@ ptp_ocp_devlink_info_get(struct devlink *devlink, struct devlink_info_req *req,
>   	if (err)
>   		return err;
>   
> +	snprintf(buf, sizeof(buf), "%.*s", OCP_BOARD_ID_LEN,
> +		 (const char *)bp->board_id);
>   	err = devlink_info_version_fixed_put(req,
>   			DEVLINK_INFO_VERSION_GENERIC_BOARD_ID,
> -			bp->board_id);
> +			buf);
>   	if (err)
>   		return err;
>   
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>