From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120411231031.614375136@linuxfoundation.org> Date: Wed, 11 Apr 2012 16:11:36 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Oleg Nesterov , David Howells Subject: [ 78/78] cred: copy_process() should clear child->replacement_session_keyring In-Reply-To: <20120411231102.GA6404@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Nesterov commit 79549c6dfda0603dba9a70a53467ce62d9335c33 upstream. keyctl_session_to_parent(task) sets ->replacement_session_keyring, it should be processed and cleared by key_replace_session_keyring(). However, this task can fork before it notices TIF_NOTIFY_RESUME and the new child gets the bogus ->replacement_session_keyring copied by dup_task_struct(). This is obviously wrong and, if nothing else, this leads to put_cred(already_freed_cred). change copy_creds() to clear this member. If copy_process() fails before this point the wrong ->replacement_session_keyring doesn't matter, exit_creds() won't be called. Signed-off-by: Oleg Nesterov Acked-by: David Howells Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- kernel/cred.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/cred.c +++ b/kernel/cred.c @@ -385,6 +385,8 @@ int copy_creds(struct task_struct *p, un struct cred *new; int ret; + p->replacement_session_keyring = NULL; + if ( #ifdef CONFIG_KEYS !p->cred->thread_keyring &&