KEYS: Fix bug in keyctl_session_to_parent() if parent has no session keyring

[linux-beck.git] / security / keys / keyctl.c

diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index b2b0998d6abda7759433d7032d255eb0a317c126..60924f6a52db2bbff40ddc953a50bb9d708febb5 100644 (file)
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1272,6 +1272,7 @@ long keyctl_session_to_parent(void)
        keyring_r = NULL;
 
        me = current;
+       rcu_read_lock();
        write_lock_irq(&tasklist_lock);
 
        parent = me->real_parent;
@@ -1304,7 +1305,8 @@ long keyctl_session_to_parent(void)
                goto not_permitted;
 
        /* the keyrings must have the same UID */
-       if (pcred->tgcred->session_keyring->uid != mycred->euid ||
+       if ((pcred->tgcred->session_keyring &&
+            pcred->tgcred->session_keyring->uid != mycred->euid) ||
            mycred->tgcred->session_keyring->uid != mycred->euid)
                goto not_permitted;
 
@@ -1319,6 +1321,7 @@ long keyctl_session_to_parent(void)
        set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME);
 
        write_unlock_irq(&tasklist_lock);
+       rcu_read_unlock();
        if (oldcred)
                put_cred(oldcred);
        return 0;
@@ -1327,6 +1330,7 @@ already_same:
        ret = 0;
 not_permitted:
        write_unlock_irq(&tasklist_lock);
+       rcu_read_unlock();
        put_cred(cred);
        return ret;