Re: [PATCH v2 00/12] cachefiles: some bugfixes and cleanups for ondemand requests

[Jeff Layton <jlayton@kernel.org>]

On Wed, 2024-05-15 at 16:45 +0800, libaokun@huaweicloud.com wrote:
> From: Baokun Li <libaokun1@huawei.com>
> 
> Hi all!
> 
> This is the second version of this patch series. Thank you, Jia Zhu and
> Jingbo Xu, for the feedback in the previous version.
> 
> We've been testing ondemand mode for cachefiles since January, and we're
> almost done. We hit a lot of issues during the testing period, and this
> patch set fixes some of the issues related to ondemand requests.
> The patches have passed internal testing without regression.
> 
> The following is a brief overview of the patches, see the patches for
> more details.
> 
> Patch 1-5: Holding reference counts of reqs and objects on read requests
> to avoid malicious restore leading to use-after-free.
> 
> Patch 6-10: Add some consistency checks to copen/cread/get_fd to avoid
> malicious copen/cread/close fd injections causing use-after-free or hung.
> 
> Patch 11: When cache is marked as CACHEFILES_DEAD, flush all requests,
> otherwise the kernel may be hung. since this state is irreversible, the
> daemon can read open requests but cannot copen.
> 
> Patch 12: Allow interrupting a read request being processed by killing
> the read process as a way of avoiding hung in some special cases.
> 
> Comments and questions are, as always, welcome.
> Please let me know what you think.
> 
> Thanks,
> Baokun
> 
> Changes since v1:
>   * Collect RVB from Jia Zhu and Jingbo Xu.(Thanks for your review!)
>   * Pathch 1: Add Fixes tag and enrich the commit message.
>   * Pathch 7: Add function graph comments.
>   * Pathch 8: Update commit message and comments.
>   * Pathch 9: Enriched commit msg.
> 
> Baokun Li (11):
>   cachefiles: remove request from xarry during flush requests
>   cachefiles: remove err_put_fd tag in cachefiles_ondemand_daemon_read()
>   cachefiles: fix slab-use-after-free in cachefiles_ondemand_get_fd()
>   cachefiles: fix slab-use-after-free in
>     cachefiles_ondemand_daemon_read()
>   cachefiles: add output string to cachefiles_obj_[get|put]_ondemand_fd
>   cachefiles: add consistency check for copen/cread
>   cachefiles: add spin_lock for cachefiles_ondemand_info
>   cachefiles: never get a new anonymous fd if ondemand_id is valid
>   cachefiles: defer exposing anon_fd until after copy_to_user() succeeds
>   cachefiles: flush all requests after setting CACHEFILES_DEAD
>   cachefiles: make on-demand read killable
> 
> Zizhi Wo (1):
>   cachefiles: Set object to close if ondemand_id < 0 in copen
> 
>  fs/cachefiles/daemon.c            |   3 +-
>  fs/cachefiles/internal.h          |   5 +
>  fs/cachefiles/ondemand.c          | 218 ++++++++++++++++++++++--------
>  include/trace/events/cachefiles.h |   8 +-
>  4 files changed, 177 insertions(+), 57 deletions(-)
> 

Looks like most of these are fixes inside the ondemand code, which I
don't have the greatest grasp of, so...

Acked-by: Jeff Layton <jlayton@kernel.org>