[TYPO3-english] FE BE Login problems caused by permissions

[Vlatko Šurlan]

I've just spent a few hours trying to debug login problems on one 
installation. This installation was 4.5.2 and configured with rsaauth and 
saltedpasswords and worked fine until I upgraded. The problem turned out 
to be permissions on typo3temp/sessions* folders. Currently my working 
permissions are:

drwxrws--- 2 www-data www-data 4.0K May 21 06:00 
sessions337c8b9205f88d1a265d6705e76d8947

The ones that didn't work was some strange combination like: drwx-ws-wx 
and the authentication code was failing on one of the session calls.

Just a few keywords for those having same issues:
login failing, login failure, felogin failing, belogin failing