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

Message

Baokun Li April 24, 2024, 3:39 a.m. UTC

From: Baokun Li <[e-mail]>

Hello everyone!

Recently we found some bugs while doing tests on cachefiles ondemand mode,
and this patchset is a fix for some of those issues. 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.

Thanks,
Baokun

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 anon 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          | 199 +++++++++++++++++++++---------
 include/trace/events/cachefiles.h |   8 +-
 4 files changed, 158 insertions(+), 57 deletions(-)