Re: [PATCH 1/1] cred: copy_process() should clear child->replacement_session_keyring

[David Howells]

Oleg Nesterov <oleg@xxxxxxxxxx> wrote:

> 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@xxxxxxxxxxxxxxx>
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

Acked-by: David Howells <dhowells@xxxxxxxxxx>
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