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

libaokun
2024-05-15T08:56:33Z

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(-)

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2.39.2