Commit 79549c6d authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds

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: <stable@vger.kernel.org>
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 923e9a13
......@@ -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 &&
......
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