Allow spaces in username for LDAP users

[jochenrill]

PR #342 was only partially applied. Spaces should not be at the start
and end of a username but they can be inside.

[lafriks]

LGTM

[codecov-io]

Codecov Report

Merging #2880 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2880   +/-   ##
=======================================
  Coverage   27.05%   27.05%           
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  Files          89       89           
  Lines       17650    17650           
=======================================
  Hits         4775     4775           
  Misses      12189    12189           
  Partials      686      686

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[lunny]

Why we allow a username with a space in the middle of the word?

[jochenrill]

Because it is allowed by the specification and Microsoft uses it:
https://msdn.microsoft.com/en-us/library/aa366101(v=vs.85).aspx

[ethantkoenig]

Shouldn't we add a check for leading/trailing spaces, since those are disallowed?

[lafriks]

@ethantkoenig is right. Best solution should be just to trim spaces for entered username

[jochenrill]

Space at the begining and end are already being trimed (models/login_source.go) and triming them inside the username would be wrong. Suppose I wanted to bind to CN=Jeff Smith,OU=Sales,DC=Fabrikam,DC=COM (which is a valid Windows CN), I would like be able to configure cn=%s,OU=Sales,DC=Fabrikam,DC=COM as bind dn.

[lafriks]

No I meant only at the begining and end. If they are already trimmed than all is good

[lunny]

LGTM