linux-kernel - Re: [patch 06/15] sysfs: dont call notify

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Message-Id: <E1JtGfH-0008Bv-MI@pomaz-ex.szeredi.hu>
Date:	Tue, 06 May 2008 08:28:39 +0200
From:	Miklos Szeredi <miklos@...redi.hu>
To:	gregkh@...e.de
CC:	miklos@...redi.hu, akpm@...ux-foundation.org, hch@...radead.org,
	viro@...IV.linux.org.uk, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Subject: Re: [patch 06/15] sysfs: dont call notify_change

> > sysfs_chmod_file() calls notify_change() to change the permission bits
> > on a sysfs file.  Replace with explicit call to sysfs_setattr() and
> > fsnotify_change().
> > 
> > This is equivalent, except that security_inode_setattr() is not
> > called.  This function is called by drivers, so the security checks do
> > not make any sense.
> 
> Are you sure?  As a user, you can chmod the sysfs file and it will
> stick,

Right, but that's not sysfs_chmod_file() but sys_chmod(), which calls
notify_change(), which calls security_inode_setattr().

sysfs_chmod_file() is just called by a couple of drivers to change the
file mode during operation, it's never called by user action directly.

Miklos
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