Re: [PATCH RFC 0/9] ALSA: Don't embed struct devices

[Takashi Iwai <tiwai@suse.de>]

On Wed, 16 Aug 2023 18:02:43 +0200,
Takashi Iwai wrote:
> 
> Hi,
> 
> this is another set of patches to attempt papering over the UAF
> problems that are seen when the delayed kobject release is enabled, as
> initially reported by Curtis:
>   https://lore.kernel.org/r/20230801171928.1460120-1-cujomalainey@chromium.org
> 
> There was a previous patch set with a different approach (using the
> device refcount dependencies), but this is a sort of step-back to the
> old way.
>   https://lore.kernel.org/r/20230807135207.17708-1-tiwai@suse.de
> 
> After discussions and evaluations, we agreed that decoupling the
> struct device from each sound component object is the safest (and
> easiest) way as of now.  For applying the changes more consistently, I
> introduced a new helper for the struct device allocation and
> initialization, and applied all components.
> 
> A couple of more changes for card_dev refcount managed aren't included
> in this patch set, though.  They might be good to have, but this patch
> set should suffice for the currently seen UAF problems.
> 
> For a long-term solution, we may restructure the device management,
> then the struct devices may be embedded again in each object.  But,
> it'll need lots of other changes and cleanups, a big TODO.
> 
> The latest patches are found in topic/dev-split branch of sound.git
> tree.
> 
> 
> Takashi
> 
> ===
> 
> Takashi Iwai (9):
>   ALSA: core: Introduce snd_device_alloc()
>   ALSA: control: Don't embed ctl_dev
>   ALSA: pcm: Don't embed device
>   ALSA: hwdep: Don't embed device
>   ALSA: rawmidi: Don't embed device
>   ALSA: compress: Don't embed device
>   ALSA: timer: Create device with snd_device_alloc()
>   ALSA: seq: Create device with snd_device_alloc()
>   ALSA: core: Drop snd_device_initialize()

Although the patch set was sent as RFC, I merged them now for 6.6 with
Acks, as there is no further plan to change.


thanks,

Takashi