Re: [PATCH v2] powerpc/powernv: Restrict OPAL symbol map to only be readable by root

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, May 03, 2019 at 06:27:18PM +1000, Andrew Donnellan wrote:
> On 3/5/19 5:59 pm, Greg KH wrote:>> -static BIN_ATTR_RO(symbol_map, 0);
> > > +static struct bin_attribute symbol_map_attr = {
> > > +	.attr = {.name = "symbol_map", .mode = 0400},
> > > +	.read = symbol_map_read
> > > +};
> > 
> > There's no real need to rename the structure, right?  Why not just keep
> > the bin_attr_symbol_map name?  That would make this patch even smaller.
> 
> No real need but it's locally more consistent with the rest of the PPC code.
> (Though perhaps the other cases should use the BIN_ATTR macro...)
> 
> Given this is for stable I'm happy to change that if the smaller patch is
> more acceptable.

stable doesn't care, and if this is more consistent, that's fine with
me, I didn't see the larger picture here, just providing unsolicited
patch review :)

> > >   static void opal_export_symmap(void)
> > >   {
> > > @@ -698,10 +701,10 @@ static void opal_export_symmap(void)
> > >   		return;
> > >   	/* Setup attributes */
> > > -	bin_attr_symbol_map.private = __va(be64_to_cpu(syms[0]));
> > > -	bin_attr_symbol_map.size = be64_to_cpu(syms[1]);
> > > +	symbol_map_attr.private = __va(be64_to_cpu(syms[0]));
> > > +	symbol_map_attr.size = be64_to_cpu(syms[1]);
> > > -	rc = sysfs_create_bin_file(opal_kobj, &bin_attr_symbol_map);
> > > +	rc = sysfs_create_bin_file(opal_kobj, &symbol_map_attr);
> > 
> > Meta-comment, odds are you are racing userspace when you create this
> > sysfs file, why not add it to the device's default attributes so the
> > driver core creates it for you at the correct time?
> 
> I was not previously aware of default attributes...
> 
> Are we actually racing against userspace in a subsys initcall?

You can be, if you subsys is a module :)

thanks,

greg k-h