For several of our clients, we provide an FTP server on a linux server, with the files hosted on a windows 2008r2 server and authentication being handled by active directory through proftpd-ldpap.
The windows share are automatically mounted on access with autofs in a /srv/ftp subfolder, and users are jailed in yet another level of subdirectory using proftpd.
I hit a bit of a wall recently with this setup, as everything seemed to be in order, autofs mounted the directory, proftpd allowed login with ldap auth, but for some reason I couldn’t write anything.
If I pointed proftpd at a local directory however, write was fine.
I finally found out that proftpd was trying to use “chmod” on every write, and with SMB < 3, it failed, resulting in a “permission denied” error and nothing whatsoever in the logs.
I fixed it by mounting the CIFS share with the “noperm” option:
homes -fstype=cifs,rw,credentials=/etc/cifscredentials,gid=nogroup,uid=proftpd,vers=2.1,noperm ://SERVER/SHARE\$/SFTP