apparmor: update how unconfined is handled

ns->unconfined is being used read side without locking, nor rcu but is
being updated when a namespace is removed. This works for the root ns
which is never removed but has a race window and can cause failures when
children namespaces are removed.

Also ns and ns->unconfined have a circular refcounting dependency that
is problematic and must be broken. Currently this is done incorrectly
when the namespace is destroyed.

Fix this by forward referencing unconfined via the replacedby infrastructure
instead of directly updating the ns->unconfined pointer.

Remove the circular refcount dependency by making the ns and its unconfined
profile share the same refcount.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
This commit is contained in:
John Johansen
2013-07-10 21:08:43 -07:00
parent 77b071b340
commit fa2ac468db
3 changed files with 67 additions and 83 deletions

View File

@@ -434,7 +434,7 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm)
new_profile = aa_get_profile(profile);
goto x_clear;
} else if (perms.xindex & AA_X_UNCONFINED) {
new_profile = aa_get_profile(ns->unconfined);
new_profile = aa_get_newest_profile(ns->unconfined);
info = "ux fallback";
} else {
error = -ENOENT;