RE: [PATCH 06/10] security: fix documentation for the path_chmod hook

Edwin Zimmerman
2019-02-07T14:10:02Z

On Thursday, February 07, 2019 8:50 AM Al Viro wrote:
> On Thu, Feb 07, 2019 at 03:44:54PM +0300, Denis Efremov wrote:
> > The path_chmod hook was changed in the commit
> > "switch security_path_chmod() to struct path *" (cdcf116d44e7).
> > The argument @mnt was removed from the hook, @dentry was changed
> > to @path. This patch updates the documentation accordingly.
> >
> > Signed-off-by: Denis Efremov <efremov@ispras.ru>
> > ---
> > include/linux/lsm_hooks.h | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> > index cb93972257be..5d6428d0027b 100644
> > --- a/include/linux/lsm_hooks.h
> > +++ b/include/linux/lsm_hooks.h
> > @@ -304,8 +304,7 @@
> > * Return 0 if permission is granted.
> > * @path_chmod:
> > * Check for permission to change DAC's permission of a file or directory.
> > - * @dentry contains the dentry structure.
> > - * @mnt contains the vfsmnt structure.
> > + * @path contains the path structure.
>
> May I politely inquire about the value of these comments? How much information
> is provided by refering to an argument as "the dentry structure" or "the path
> structure", especially when there's nothing immediately above that would introduce
> either. "Type of 'dentry' argument is somehow related to struct dentry,
> try and guess what the value might be - we don't care, we just need every
> argument commented"?
>
> Who needs that crap in the first place?

The comments fill a valuable place to folks like me who are new to the linux security modules.
In my spare time, I'm writing a new LSM specifically geared for parental controls uses, and the
comments in lsm_hooks.h have helped me out more than once. Perhaps the comments could
be inproved by changing them to something like this:
"@[arg] contains the [type] structure, defined in linux/[?].h"