If a user belongs to a group that has not been set in the excluded groups from sharing, he can share files

[davitol]

Steps to reproduce

1. Create a user that belongs to two groups
2. Go to admin page
3. Set one of the previous groups to be excluded from sharing
4. Login with the user created and try to share a file

Expected behaviour

Proposal:
If a user belongs to a group that has been set in the excluded groups from sharing, he should not be able to share files (most restrictive condition)

Actual behaviour

If a user belongs to a group that has not been set in the excluded groups, he can share files

Server configuration

Operating system: ubuntu 14.04

Web server: apache 2.4.7

Database: mysql

PHP version: 5.5.9

**ownCloud version: ownCloud Enterprise Edition 8.2.1. (RC2)

Updated from an older ownCloud or fresh install: Fresh install

Are you using external storage, if yes which one: no;
Are you using encryption: no
Are you using an external user-backend, if yes which one: no

Client configuration

Browser: Firefox

[davitol]

@blizzz

Another situation:
Using an Active Directory with nested groups allowed. User belongs to group1 and this group is included in group2 (nested). If group2 is added to 'Exclude groups from sharing', the user should not be able to share files, even if group1 is not included in the forbidden groups specifically

[rullzer]

Well that would be changeing behaviour and have unexpected result for people that rely on the current behaviour.

Anyway, this is a duplicate of #16346. So lets discuss there.