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SubjectRe: [TOMOYO #12 (2.6.28-rc2-mm1) 06/11] Common functions for TOMOYOLinux.

Serge E. Hallyn wrote:
> > I need to clarify reachability of "struct task_struct".
> >
> > A process inside a virtualized environment cannot reach "struct task_struct"
> > which belongs to outside the virtualized environment.
> >
> > A process outside virtualized environments can reach "struct task_struct"
> > which belongs to inside virtualized environments, can't it?
> To be precise, there isn't a real 'inside' and 'outside' virtualized
> environements. Rather pid namespaces are hierarchical.
So, processes which have non-topmost namespace cannot see processes which have
topmost namespace (like chroot()).
Then, it might be preferable if TOMOYO can prevent processes which have
non-topmost namespace from modifying policy information.
Do you think TOMOYO should do "current->nsproxy->pid_ns == &init_pid_ns"
checking like below one?

static bool tomoyo_is_policy_manager(void)
struct tomoyo_policy_manager_entry *ptr;
const char *exe;
const struct task_struct *task = current;
const struct tomoyo_path_info *domainname = tomoyo_domain()->domainname;
bool found = false;

if (!tomoyo_policy_loaded)
return true;
if (!tomoyo_manage_by_non_root && (task->cred->uid || task->cred->euid))
return false;
/* Don't allow modifying policy by processes not having init_pid_ns. */
if (task->nsproxy->pid_ns != &init_pid_ns)
return false;
list1_for_each_entry(ptr, &tomoyo_policy_manager_list, list) {
if (!ptr->is_deleted && ptr->is_domain
&& !tomoyo_pathcmp(domainname, ptr->manager))
return true;

> (Taking another look) it looks like In is_select_one() you're doing the
> right thing - you look up the domain of a task based on
> find_task_by_vpid() on a passed-in pid. Seems correct.
I see, thanks.

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