[PATCH 0/3] ksmbd: fix three named stream bugs

[DaeMyung Kang]

Hi Namjae,

This series fixes three independent named stream bugs:

  1. A read at or beyond the end of a non-empty stream returns
     STATUS_INVALID_PARAMETER instead of STATUS_END_OF_FILE.
  2. Opening an existing stream with different letter case keeps the
     client's spelling in the handle. Later writes and removal can
     target a different xattr from the one that was opened.
  3. A write-only FILE_OPEN_IF on an existing stream can replace its
     value with an empty xattr when the value-length lookup fails with
     -EACCES.

The series applies to ksmbd-for-next at 5d2b1ab54e9a ("ksmbd: fix
named stream write and EOF handling"). Each fix is in a separate
patch, with its own Fixes tag and stable Cc.

I built the resulting kernel with CONFIG_SMB_SERVER=y and tested it
through SMB2.1 in a QEMU guest. Reads at and past stream EOF returned
STATUS_END_OF_FILE. A stream created as Foo was read, modified and
removed through foo, with one named stream in the listing. On a 0222
file, a write-only user opening an existing stream with FILE_OPEN_IF
received STATUS_ACCESS_DENIED and the original value remained intact;
without patch 3, the same sequence emptied the stream. The same user
could still create a new stream.

Patch 2 has a minor textual conflict in linux-next with the VFS tree's
const mnt_idmap conversion. The resolution keeps both the const
qualifier and the new actual_name argument.

Concurrent creation of case-variant stream names remains a separate
issue.

DaeMyung Kang (3):
  ksmbd: return end of file for reads past a named stream's data
  ksmbd: use the existing xattr name for a named stream
  ksmbd: preserve unreadable named streams on open

 fs/smb/server/smb2pdu.c | 10 ++++++----
 fs/smb/server/vfs.c     | 17 +++++++++++++----
 fs/smb/server/vfs.h     |  2 +-
 3 files changed, 20 insertions(+), 9 deletions(-)

-- 
2.43.0