Quoting James Morris (jmorris@xxxxxxxxx):
> On Thu, 12 Nov 2009, Julia Lawall wrote:
>
> > From: Julia Lawall <julia@xxxxxxx>
> >
> > As observed by Joe Perches, sizeof of a constant string includes the
> > trailing 0. If what is wanted is to check the initial characters of
> > another string, this trailing 0 should not be taken into account. If an
> > exact match is wanted, strcmp should be used instead.
>
> > --- a/security/selinux/hooks.c
> > +++ b/security/selinux/hooks.c
> > @@ -448,7 +448,7 @@ static int sb_finish_set_opts(struct sup
> > sbsec->flags &= ~SE_SBLABELSUPP;
> >
> > /* Special handling for sysfs. Is genfs but also has setxattr handler*/
> > - if (strncmp(sb->s_type->name, "sysfs", sizeof("sysfs")) == 0)
> > + if (strncmp(sb->s_type->name, "sysfs", sizeof("sysfs") - 1) == 0)
> > sbsec->flags |= SE_SBLABELSUPP;
>
> Shouldn't this be a simple strcmp() ?
Yes I think so.
Julia seems to be arguing that if a module introduces a new fs with
name 'sysfs_foo' then this check should match that fs too (since
for sysfs, sb->s_type->name = "sysfs" which also has a trailing \0,
so for the regular sysfs her patch makes no practical difference).
-serge
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