Customer cannot view Opportunities on Portal

We created a Web Form for Opportunities, and set the Role Management Permissions to allow customer access to Opportunities. The problem with this is the customer can see all opportunities not only the once associated with his account.

When we select only created then they cannot see any opportunities.

Can someone help me to set this

This was solved by the following

def get_context(context):
context.read_only = 1
context.add_next_prev_links = 1

def get_list_context(context):