ksmbd: let the owner read and change the DACL when no ACE names it

smb_check_perm_dacl() refuses the owner when neither its DACL lookup nor
the POSIX ACL fallback matches. The owner then cannot read or replace
the DACL over SMB. MS-DTYP 2.5.3.2 grants the owner READ_CONTROL and
WRITE_DAC unless an OWNER RIGHTS ACE applies.

An empty DACL allows the owner's explicit requests for these rights but
refuses MAXIMUM_ALLOWED. smb2_open() uses that check for the maximal
access reply (MS-SMB2 3.3.5.9.5), so even a READ_CONTROL open fails when
it asks for that reply.

Grant the owner's implicit rights on both paths, for explicit requests
and MAXIMUM_ALLOWED, unless an OWNER RIGHTS ACE applies.

Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Cc: stable@vger.kernel.org
Signed-off-by: Ian Bridges <icb@fastmail.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

0 files changed, 0 insertions, 0 deletions