lkml.org 
[lkml]   [2022]   [Jun]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] hwmon: (xgene) restrict power measurements to admin by default
On 6/3/22 08:21, D Scott Phillips wrote:
> Access to power information can be used to infer the instructions being run
> and possibly even data being processed on a cpu[1]. Restrict access to
> power information to administrator users by default. (Cf. a similar
> powercap change[2].)
>
> [1]: Lipp, Moritz, et al. "PLATYPUS: software-based power side-channel
> attacks on x86." 2021 IEEE Symposium on Security and Privacy (SP).
> IEEE, 2021.
> [2]: commit 949dd0104c49 ("powercap: restrict energy meter to root access")
>
> Fixes: ed42cfa881e1 ("hwmon: Add xgene hwmon driver")
> Signed-off-by: D Scott Phillips <scott@os.amperecomputing.com>
> Cc: stable@vger.kernel.org
> ---
> drivers/hwmon/xgene-hwmon.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hwmon/xgene-hwmon.c b/drivers/hwmon/xgene-hwmon.c
> index 5cde837bfd09..6ad1daf2d354 100644
> --- a/drivers/hwmon/xgene-hwmon.c
> +++ b/drivers/hwmon/xgene-hwmon.c
> @@ -397,9 +397,9 @@ static DEVICE_ATTR_RO(temp1_label);
> static DEVICE_ATTR_RO(temp1_input);
> static DEVICE_ATTR_RO(temp1_critical_alarm);
> static DEVICE_ATTR_RO(power1_label);
> -static DEVICE_ATTR_RO(power1_input);
> +static DEVICE_ATTR_ADMIN_RO(power1_input);
> static DEVICE_ATTR_RO(power2_label);
> -static DEVICE_ATTR_RO(power2_input);
> +static DEVICE_ATTR_ADMIN_RO(power2_input);
>
> static struct attribute *xgene_hwmon_attrs[] = {
> &dev_attr_temp1_label.attr,


NACK. The hwmon ABI expects world read access. Either find a workaround
by making the measurements less accurate, or drop the driver. Also see
commit 9049572fb145 ("hwmon: Remove amd_energy driver"), "Attribute access"
in Documentation/hwmon/sysfs-interface.rst, and [1].

Guenter


---
[1] https://patchwork.kernel.org/project/linux-hwmon/patch/20210409174852.4585-2-linux@roeck-us.net/

\
 
 \ /
  Last update: 2022-06-03 17:37    [W:0.034 / U:0.064 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site