From: Oleg Nesterov Date: Mon, 9 Apr 2012 19:03:50 +0000 (+0200) Subject: cred: copy_process() should clear child->replacement_session_keyring X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=79549c6dfda0603dba9a70a53467ce62d9335c33;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git cred: copy_process() should clear child->replacement_session_keyring 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. Cc: Signed-off-by: Oleg Nesterov Acked-by: David Howells Signed-off-by: Linus Torvalds --- diff --git a/kernel/cred.c b/kernel/cred.c index 97b36eeca4c9..e70683d9ec32 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -386,6 +386,8 @@ 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 &&