exec: Copy oldsighand->action under spin-lock

commit 5bf2fedca8 upstream.

unshare_sighand should only access oldsighand->action
while holding oldsighand->siglock, to make sure that
newsighand->action is in a consistent state.

Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: stable@vger.kernel.org
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/AM8PR10MB470871DEBD1DED081F9CC391E4389@AM8PR10MB4708.EURPRD10.PROD.OUTLOOK.COM
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Bernd Edlinger 2021-06-07 15:54:27 +02:00 committed by Greg Kroah-Hartman
parent 265b6fb780
commit 46b4b1e11e

View File

@ -1198,11 +1198,11 @@ static int unshare_sighand(struct task_struct *me)
return -ENOMEM;
refcount_set(&newsighand->count, 1);
memcpy(newsighand->action, oldsighand->action,
sizeof(newsighand->action));
write_lock_irq(&tasklist_lock);
spin_lock(&oldsighand->siglock);
memcpy(newsighand->action, oldsighand->action,
sizeof(newsighand->action));
rcu_assign_pointer(me->sighand, newsighand);
spin_unlock(&oldsighand->siglock);
write_unlock_irq(&tasklist_lock);