On Wed, Mar 30, 2022 at 10:11:39AM +0000, David Laight wrote: > From: Xu Yilun > > Sent: 30 March 2022 07:51 > > > > On Tue, Mar 29, 2022 at 06:07:26PM +0200, Michael Walle wrote: > > > More and more drivers will check for bad characters in the hwmon name > > > and all are using the same code snippet. Consolidate that code by adding > > > a new hwmon_sanitize_name() function. > > > > > > Signed-off-by: Michael Walle <michael@xxxxxxxx> > > > --- > > > Documentation/hwmon/hwmon-kernel-api.rst | 9 ++++- > > > drivers/hwmon/hwmon.c | 49 ++++++++++++++++++++++++ > > > include/linux/hwmon.h | 3 ++ > > > 3 files changed, 60 insertions(+), 1 deletion(-) > > > > > > diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst > > > index c41eb6108103..12f4a9bcef04 100644 > > > --- a/Documentation/hwmon/hwmon-kernel-api.rst > > > +++ b/Documentation/hwmon/hwmon-kernel-api.rst > > > @@ -50,6 +50,10 @@ register/unregister functions:: > > > > > > void devm_hwmon_device_unregister(struct device *dev); > > > > > > + char *hwmon_sanitize_name(const char *name); > > > + > > > + char *devm_hwmon_sanitize_name(struct device *dev, const char *name); > > > + > > > hwmon_device_register_with_groups registers a hardware monitoring device. > > > The first parameter of this function is a pointer to the parent device. > > > The name parameter is a pointer to the hwmon device name. The registration > > > @@ -93,7 +97,10 @@ removal would be too late. > > > > > > All supported hwmon device registration functions only accept valid device > > > names. Device names including invalid characters (whitespace, '*', or '-') > > > -will be rejected. The 'name' parameter is mandatory. > > > +will be rejected. The 'name' parameter is mandatory. Before calling a > > > +register function you should either use hwmon_sanitize_name or > > > +devm_hwmon_sanitize_name to replace any invalid characters with an > > > > I suggest to duplicate the name and replace ... > > You are now going to get code that passed in NULL when the kmalloc() fails. > If 'sanitizing' the name is the correct thing to do then sanitize it > when the copy is made into the allocated structure. Then the driver is unaware of the name change, which makes more confusing. > (I'm assuming that the 'const char *name' parameter doesn't have to > be persistent - that would be another bug just waiting to happen.) The hwmon core does require a persistent "name" parameter now. No name copy is made when hwmon dev register. > > Seems really pointless to be do a kmalloc() just to pass a string > into a function. Maybe we should not force a kmalloc() when the sanitizing is needed, let the driver decide whether to duplicate the string or not. Thanks, Yilun > > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales)
