instead of passing sids for the owner and group, create a security
descriptor and pass that back. this way we can add all the security
information that was queried in the daemon and pass a fully formed
security descriptor back to the kernel.
notice: irp_mj_query_security provides a pointer to the buffer that
suppose to hold the security descriptor. that memory is valid only
in the context of the process doing the security irp. we can't use
this pointer in then upcall entry and try to write the security
descriptor directly there as we process the downcall. that leads
to kernel oops.
thus we have to first allocate memory to hold the security descriptor
then copy bytes passed to us from the daemon. then do another copy
with the context of the security irp.
this commit does NOT have correct windows to nfs4 acl mappings but
rather has the wrapper functions defined for mapping them.
cthon tests still work with these mappings.
Basic handling of owner and group security query (no dacl).
Added new upcall for NFS41_ACL_QUERY (driver and daemon code).
Daemon, upon getting NFS41_ACL_QUERY first places a getattr that has
owner, group attribute request. We currently don't cache them!!!
Then, we parse nfs4name format (ie user@domain or group@domain)
into user and domain. We currently ignore domain part!!!
Then, we assume that whatever we are mapping is "known" locally
(ie LookupAccountName() api which retrieves a SID for a given name).
Mapping from name to SID can only be done in the userland. We then
copy the bytes via the upcall pipe to the kernel. If the received
user or group cant be mapped via LookupAccoundName(), we create a
well known null SID as the reply.
Kernel creates a security descriptor in the absolute-format and adds
owner and group sids to it. Important: RtlSetOwner/Group functions only
work with absolute-format security descriptor, however the reply to the
user needs to be in the self-relative format.
The way security query works is that it passes us a buffer to be filled
with the security context. However the user doesn't know how big the
buffer should be so, the user is allowed to pass a null buffer and have
the kernel return how much memory is needed. This leads to 2 security
queries => 2 NFS41_ACL_QUERY upcalls => 2 getattr rpcs... It should be
improved.
TODO:
- need to add caching of owner/group attributes for a file?
- need to add calls to LDAP for more general mapping?
- need to cache reply of the ACL if supplied length is 0?
