Re: [PATCH] KEYS: close race between key lookup and freeing

[David Howells <dhowells@redhat.com>]

Sasha Levin <sasha.levin@oracle.com> wrote:

> When a key is being garbage collected, it's key->user would get put before
> the ->destroy() callback is called, where the key is removed from it's
> respective tracking structures.
> 
> This leaves a key hanging in a semi-invalid state which leaves a window open
> for a different task to try an access key->user. An example is
> find_keyring_by_name() which would dereference key->user for a key that is
> in the process of being garbage collected (where key->user was freed but
> ->destroy() wasn't called yet - so it's still present in the linked list).
> 
> This would cause either a panic, or corrupt memory.
> 
> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

Applied.