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

James Morris
2008-02-28T01:21:18Z

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))

?

> 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.

> +#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.

> + 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.

> +#ifdef CONFIG_SECURITY
> +#define ATTR_SECURITY_LABEL 65536
> +#endif

I don't think there's any harm in always defining this.

--
James Morris
<jmorris@namei.org>