Started to learn Samba. Found: 2 version:4.5.12+dfsg-2+on Debian deb9u4 9.
Set up the minimum configuration for the user's access to the home directory:
[global] workgroup = WORKGROUP dns proxy = no log file = /var/log/samba/log.%m max log size = 1000 syslog = 0 panic action = /usr/share/samba/panic-action %d server role = standalone server passdb backend = tdbsam obey pam restrictions = yes unix password sync = yes passwd program = /usr/bin/passwd %u passwd chat = *Enter\\snew\\s*\\spassword:* %n\ *Retype\\snew\\s*\\spassword:* %n\ *password\\supdated\\ssuccessfully* . pam password change = yes map to guest = bad user usershare allow guests = yes [homes] comment = Home Directories browseable = no read only = no create mask = 0644 directory mask = 0755 valid users = %S path = /home/%S/samba
The essence of the question is: why Samba does not allow to write to the user files in the home directory (and subdirectories), if she's exposed to the right, e.g. 755? Thus, if the put rights, for example, 775 the files are written OK! That is, to allow writing to the owner, have to give write access to their group!