Messages in this thread Patch in this message | | | Date | Wed, 9 Dec 2009 18:45:27 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [patch 5/9] security: Use get_task_cred() in keyctl_session_to_parent() |
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On Thu, Dec 10, 2009 at 12:53:12AM -0000, Thomas Gleixner wrote: > Strictly this is not necessary today, but according to Paul McKenney > it's not guaranteed that irq disabled regions will prevent RCU > progress. That's a property of the current implementation. In > preempt-rt this assumption is not true anymore. > > Use get_task_cred() to make this future proof.
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> from RCU perspective.
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Cc: James Morris <jmorris@namei.org> > Cc: linux-security-module@vger.kernel.org > --- > security/keys/keyctl.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > Index: linux-2.6-tip/security/keys/keyctl.c > =================================================================== > --- linux-2.6-tip.orig/security/keys/keyctl.c > +++ linux-2.6-tip/security/keys/keyctl.c > @@ -1237,7 +1237,7 @@ long keyctl_get_security(key_serial_t ke > long keyctl_session_to_parent(void) > { > struct task_struct *me, *parent; > - const struct cred *mycred, *pcred; > + const struct cred *mycred, *pcred = NULL; > struct cred *cred, *oldcred; > key_ref_t keyring_r; > int ret; > @@ -1274,7 +1274,7 @@ long keyctl_session_to_parent(void) > /* the parent and the child must have different session keyrings or > * there's no point */ > mycred = current_cred(); > - pcred = __task_cred(parent); > + pcred = get_task_cred(parent); > if (mycred == pcred || > mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) > goto already_same; > @@ -1312,6 +1312,7 @@ long keyctl_session_to_parent(void) > set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME); > > write_unlock_irq(&tasklist_lock); > + put_cred(pcred); > if (oldcred) > put_cred(oldcred); > return 0; > @@ -1321,6 +1322,8 @@ already_same: > not_permitted: > write_unlock_irq(&tasklist_lock); > put_cred(cred); > + if (pcred) > + put_cred(pcred); > return ret; > > error_keyring: > >
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