Specifications

Red Hat Enterprise Linux to Oracle Solaris Porting Guide

Chapter 8 Runtime Environment

Though RHEL and Oracle Solaris are UNIX-based operating systems, there are some fundamental

differences in their runtime environments. One such difference which might affect application is the

privilege models on the two systems. Oracle Solaris uses the new least privilege model, which gives a

specified process only a subset of superuser powers, not full access to all privileges.

User and Process Privileges and Permissions

Legacy UNIX systems follow a superuser-based model. Hence, either an application is designed to run

as a “normal user” and have very limited privileges or it will have to run directly as the root user and

have almost all privileges. Typically, an application ported from such legacy operating systems might

have checks for UID (0/root) to test for the availability of specific privileges. On the other hand, on

Oracle Solaris, which uses the least privilege model, a user can have some of the 50 fine-grained

privileges.

The Oracle Solaris least privilege model conveniently enables normal users to do things such as bind to

lower-numbered ports, start daemon processes, and so on. On the other hand, it also protects the

system against programs that previously ran with full root privileges because they needed very limited

access, for example, mounting a file system. Hence, setuid root binaries and daemons that run with

full root privileges on RHEL are rarely necessary under the Oracle Solaris least privilege model.

While migrating an application from RHEL to Oracle Solaris per security best practices, try running

the application as a normal least privileged user, and then add necessary privileges to the process. In

order to determine which privilege is missing for a given application, use the debugging functionality of

ppriv in the shell, for example:

User1>/usr/bin/ppriv -D $$ // Enable ppriv debugging

User1>./my_net_application arg1 //Execute the application

my_net_application[2885]: missing privilege "net_icmpaccess" (euid = 2002,

syscall = 230) for "devpolicy" needed at so_socket+0xa4

my_net_application: icmp socket: Permission denied

User1>ppriv -N $$ //Disable ppriv debugging

From this, it is now evident that the PRIV_NET_ICMPACCESS privilege is not available for UID

2002. Once granted, my_net_application will start running successfully.

The role-based access control (RBAC) facility in Oracle Solaris 11 gives you the opportunity to deliver

fine-grained security in new and modified applications. RBAC is an alternative to the all-or-nothing

security model of traditional superuser-based systems. With RBAC, an administrator can assign

privileged functions to specific user accounts (or special accounts called roles). RBAC can also be used