UidBind software module restricts the call to bind() function to specific uid/gid as defined in a configfs tree. It offers a straightforward solution to control socket communication permissions efficiently.
UidBind is a straightforward software module that enables calls to bind() function only to uid/gid defined in a configfs tree. Let's take an example to understand its functionality. Suppose Admin Joe has loaded the uidbind module, and User Sam (with uid 1017) tries bind() on port 8081, but it fails, showing an error message "Can't grab 0.0.0.0:8081 with bind: Operation not permitted." Then, Admin Joe goes to /config/uidbind and makes some changes to allow the binding of the port. After the changes, User Sam tries again, and now it works, and they both are happy.
In addition to this, Admin Joe can assign a port to multiple users with different IP addresses. For instance, Admin Joe has two IPv4 addresses configured on his server (192.168.1.2 and 192.168.1.3) and wants to assign port 8082 to two different users, Tom (uid 1017) and Rob (uid 1026). To achieve this, Admin Joe makes some changes to the directory structure and assigns port to each user accordingly.
However, Admin Joe can also restrict users from binding on certain IP addresses and ports. For instance, if Admin Joe is paranoid and knows that Rob needs only port 8082 on UDP, he can change the permission settings accordingly.
Furthermore, Admin Joe can also allow bind() on a port to a specific group rather than individual users. To demonstrate this, Admin Joe allows bind() on port 8083 to all members of group "binders" (gid 1717).
Lastly, Admin Joe can limit the binding of a port to a specific user and a specific process. For example, he can allow only python scripts owned by User Dom to bind on port 8017.
Overall, UidBind is a useful software module for managing port binding and access control. Its simple yet powerful functionality enables the control and restriction of access to ports by various users and processes.
Version 0.4: N/A