From a27f3e06be07cd3719f8c42092de3ebfc9202923 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 9 Apr 2012 21:03:50 +0200 Subject: cred: copy_process() should clear child->replacement_session_keyring 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(+) diff --git a/kernel/cred.c b/kernel/cred.c index 174fa84eca30..3a55ea4fa983 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -385,6 +385,8 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags) struct cred *new; int ret; + p->replacement_session_keyring = NULL; + if ( #ifdef CONFIG_KEYS !p->cred->thread_keyring && -- cgit v1.2.3