Per https://lists.samba.org/archive/samba/2018-September/217904.html and https://lists.samba.org/archive/samba/2018-September/217992.html A more general change to our authentication code caused setting --authentication-file=/proc/self/fd/3 to no longer to work. A use case is eg: https://github.com/1afa/sambadav/blob/master/src/lib/SambaDAV/SMBClient/Process.php#L67
Created attachment 14991 [details] patch for 4.10 cherry-picked from master
G'Day Karolin, Please select for 4.10. (It might also be good for 4.9, I've not checked yet).
Pushed to autobuild-v4-10-test.
(In reply to Karolin Seeger from comment #3) Pushed again to autobuild-v4-10-test.
Pushed to v4-10-test. Closing out bug report. Thanks!
Fix in master was commit ac487bf4d04c9771ada1ca7eeb9dac4e5fe34185