Re: [PATCH 03/11] VFS: Add security label support to *notify

Dave Quigley
2008-02-28T16:32:27Z

On Thu, 2008-02-28 at 12:20 +1100, James Morris wrote:
> On Wed, 27 Feb 2008, David P. Quigley wrote:
>
> > +int inode_setsecurity(struct inode *inode, struct iattr *attr)
> > +{
> > + const char *suffix = security_maclabel_getname()
> > + + XATTR_SECURITY_PREFIX_LEN;
> > + int error;
> > +
> > + if (!attr->ia_valid & ATTR_SECURITY_LABEL)
> > + return -EINVAL;
>
> Do you mean:
>
> if (!(attr->ia_valid & ATTR_SECURITY_LABEL))
>
> ?

Yep that is what it should be.

>
> > mode &= ~S_ISGID;
> > inode->i_mode = mode;
> > }
> > +#ifdef CONFIG_SECURITY
> > + if (ia_valid & ATTR_SECURITY_LABEL)
> > + inode_setsecurity(inode, attr);
> > +#endif
>
> You're not checking the return value of inode_setsecurity().
>
> Why not just rely on inode_setsecurity() to perform the check, then you
> can lose the #ifdefs in the core code & make it a noop for
> !CONFIG_SECURITY.

I'm not clear as to what you are suggesting here. are you saying put the
#ifdef CONFIG_SECURITY around inode_setsecurity and make the case where
CONFIG_SECURITY isn't set an empty static inline function?

>
>
> > +#ifdef CONFIG_SECURITY
> > + if (ia_valid & ATTR_SECURITY_LABEL) {
> > + char *key = (char *)security_maclabel_getname();
> > + vfs_setxattr_locked(dentry, key,
> > + attr->ia_label, attr->ia_label_len, 0);
> > + /* Avoid calling inode_setsecurity()
> > + * via inode_setattr() below
> > + */
> > + attr->ia_valid &= ~ATTR_SECURITY_LABEL;
> > + }
> > +#endif
> > +
>
> Similarly, make this a function which is compiled away for
> !CONFIG_SECURITY.

Same as above.

>
> > + if (!error) {
> > +#ifdef CONFIG_SECURITY
> > + fsnotify_change(dentry, ATTR_SECURITY_LABEL);
> > +#endif
> > fsnotify_xattr(dentry);
>
> Put the #ifdef inside fsnotify_change() and only process
> ATTR_SECURITY_LABEL if CONFIG_SECURITY.

Will do.

>
>
> > +#ifdef CONFIG_SECURITY
> > +#define ATTR_SECURITY_LABEL 65536
> > +#endif
>
> I don't think there's any harm in always defining this.
>
>