Does iOS (or iPhone OS) support file operations via SMB network shares? If so, are there any documents about how to do this?
iOS does not have any APIs to work with SMB. However, SMB is currently documented by Microsoft and implementing it is not impossible (although not easy too). I've created a freeware project which contains most of what you need to handle SMB. See
https://sourceforge.net/projects/smb4ios/
It does not use Samba or any other heavy-weight libraries. Works mostly for printers, but with what's already there it's easy to add support for file handling or whatever.
I don't care about GPL stuff, you can just reuse the code without concerns for that. Just check if the NTLM library I used has the correct license for you (or implement your own NTLM).