Add SMB2_0_INFO_SECURITY request support

[principis]

This PR implements support for the SMB2 QUERY_INFO request with InfoType SMB2_0_INFO_SECURITY.

I chose the OWNER_SECURITY_INFORMATION, GROUP_SECURITY_INFORMATION and DACL_SECURITY_INFORMATION security attributes, since this is what pysmb queries for and is everything I need. I'm not sure if more is necessary at this time.

Let me know if any changes are necessary!

Edit: force push to fix typo

[hirochachacha]

Hi, thank you for the huge work! I didn't check it in detail yet, but here is my initial review.
Also, please consider implementing SetSecurity feature in the same PR, so that we can add test as well.

[hirochachacha]

same as above. we should define ACE(ACL?) type on the top package instead of internal package.

[principis]

I refactored the way ACE's are decoded. Let me know if you agree with this approach!
An other option is renaming the internal ACE struct and just copy everything to the external ACE.

[principis]

Also, please consider implementing SetSecurity feature in the same PR, so that we can add test as well.

I started implementing setSecurity on this branch. It sadly doesn't work (the server responds with STATUS_INVALID_INFO_CLASS), and I can't find the problem easily.

Implementing setSecurity in an abstract way is also incredibly difficult. My current implementation (if it would work) isn't very useful.

I'd like to omit it from this PR. My time is unfortunately limited, and if it's something I need in the future, I'll be happy to open a PR.

I'll add some tests to check if the returned FileSecurityInfo is well formed.

[hirochachacha]

Thanks, give me some time to review and think. I will revisit this on this weekend.

[principis]

Take your time, thanks!

I've added a Security method on Share type, since that seemed necessary. Not sure if the other methods are still useful, but I'll let you decide! :)

[hirochachacha]

Hi, sorry for the delay. I did some investigation and I concluded that current Security/SetSecurity design doesn't work well because sacl and dacl require different permissions. Instead, I want to split its functionalities into 6 pieces.

func (f *File) GetDacl() (*ACL, error)
func (f *File) SetDacl(acl *ACL) error

func (f *File) GetSacl() (*ACL, error)
func (f *File) SetSacl(acl *ACL) error

func (f *File) GetOwner() (user, group *SID, err error)
func (f *File) SetOwner(user, group *SID) error

I rethought about exposing SID on the top package for convenience of encoding of SID.
So, I want to introduce helper functions for SID

func MustSID(s string) *SID
func ParseSID(s string) (*SID, error)

we also need to add constants like SecurityDescriptor's control flags, AceType, AccessMask.
because of current usage of dot import on the package, it will incur collisions. so we need to do refactoring.

There're a lot things to solve this issue. I made a draft on top of your work, but I need more time for investigations and tests.

[principis]

Sounds good! Let me know if you want me to help with something.