Recently, I was configuring samba on my machine.. I wanted people to copy files to my machine but don’t want them to delete/modify the existing ones. Searched for a bit and found that adding:
create mode = 555
to the /etc/samba/smb.conf file and restarting the samba services makes the files to be created in read and execute mode. (Thus preventing anybody from modifying the files). So, others can copy files to my machine but will not be able to modify/delete them.