Date:   Fri, 7 Jan 2022 21:46:17 +0800
From:   Chen Yu <yu.c.chen@intel.com>
To:     Dan Carpenter <dan.carpenter@oracle.com>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        Len Brown <lenb@kernel.org>, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] ACPI: pfr_telemetry: Fix info leak in pfrt_log_ioctl()
Message-ID: <20220107134617.GA895400@chenyu-desktop>
References: <20220107073407.GG22086@kili>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220107073407.GG22086@kili>
Precedence: bulk

On Fri, Jan 07, 2022 at 10:34:07AM +0300, Dan Carpenter wrote:
> The "data_info" struct is copied to the user.  It has a 4 byte struct
> hole after the last struct member so we need to memset that to avoid
> copying uninitialized stack data to the user.
> 
> Fixes: b0013e037a8b ("ACPI: Introduce Platform Firmware Runtime Telemetry driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> When you're adding a new driver to the kernel then please use the new
> driver's prefix instead of just the subsystem prefix.
> 
>  Bad: ACPI: Introduce Platform Firmware Runtime Telemetry driver
> Good: ACPI / pfr_telemetry: Introduce Platform Firmware Runtime Telemetry driver
> 
Thanks for pointing this out.
> Otherwise it's just up to me to guess what prefix you wanted.
> 
>  drivers/acpi/pfr_telemetry.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/acpi/pfr_telemetry.c b/drivers/acpi/pfr_telemetry.c
> index da50dd80192c..9abf350bd7a5 100644
> --- a/drivers/acpi/pfr_telemetry.c
> +++ b/drivers/acpi/pfr_telemetry.c
> @@ -83,6 +83,7 @@ static int get_pfrt_log_data_info(struct pfrt_log_data_info *data_info,
>  	union acpi_object *out_obj, in_obj, in_buf;
>  	int ret = -EBUSY;
>  
> +	memset(data_info, 0, sizeof(*data_info));
Just one minor question, how about moving above before:
data_info->status = out_obj->package.elements[LOG_STATUS_IDX].integer.value;
after the sanity check of the _DSM result?

thanks,
Chenyu 
>  	memset(&in_obj, 0, sizeof(in_obj));
>  	memset(&in_buf, 0, sizeof(in_buf));
>  	in_obj.type = ACPI_TYPE_PACKAGE;