Tag: UNIX

SAS Restricted Options on UNIX

In a tweet by Gordon Cox last month, I was reminded of the restricted options facility available with SAS® software on UNIX platforms. This is capability where an administrator can set mandatory SAS system options at multiple levels of granularity: globally, per-group, and/or per-user. The reason for this post is that I don’t look at the documentation for this very often and every time I do it takes me a while to track it down. I always think its going to be in the UNIX companion in the Base SAS area… but it’s not! That gets me every time. Instead it’s tucked away in the Configuration Guide for SAS 9.2 Foundation for UNIX Environments (PDF) in Chapter 2 – Restricted Options. You can find this document in the Install Center section of support.sas.com under SAS Installation Note 36467: Documentation for a SAS® 9.2 installation on UNIX.

The context of the tweet was that the restricted options facility is another mechanism whereby a default setting of the NOXCMD option for SAS platform servers could be overridden for a subset of trusted users or groups in a SAS platform installation. The NOXCMD option is discussed in an earlier post: NOXCMD: NO eXternal CoMmanDs!

A quick summary of restricted options:

  • SAS Systems Options under UNIX set by an administrator, that cannot be changed by a user
  • Processed in the order global, group, then user. The last instance of an option is the one that wins.
  • Global restrictions are read from the file !SASROOT/misc/rstropts/rsasv9.cfg
  • Group restrictions are read from the file !SASROOT/misc/rstropts/groups/<groupname>_rsasv9.cfg
  • User restrictions are read from the file !SASROOT/misc/rstropts/users/<userid>_rsasv9.cfg

On Linux (at least) I can use the command “id -gn <userid>” to find out the effective group name for a user, given their user id. For example, “id -gn sassrv” might generate “sas“.

In my SAS 9.2 installation on Linux, whilst everyone else is still constrained by the NOXCMD option, I can ensure that the SAS Enterprise Guide user Bob Baxter, who has a user id of bob, can still use operating system commands in the SAS programs he runs on the SASApp server, by creating the file /usr/local/SAS/SASFoundation/9.2/misc/rstropts/users/bob_rsasv9.cfg with the following contents:

-xcmd

Of course, this only applies to SAS processes launched and run as the requesting user. Whilst it can be used to override NOXCMD for specific users/groups using a standard workspace server, it cant be used to distinguish between different users on the same stored process server, since all users will share SAS stored process server processes running under a shared identity (like sassrv). In that situation directing the users to separate SAS application servers would be more appropriate. There is an example of this in Jim Fenton & Robert Ladd’s SAS Global Forum 2010 paper 311-2010: A Practical Approach to Securing a SAS® 9.2 Intelligence Platform Deployment

Thanks to Gordon for reminding me about the restricted options facility.

Handy SAS Usage Note for Troubleshooting UNIX Authentication

Whilst troubleshooting why LDAP based users couldn’t authenticate against a SAS Metadata Server configured for host authentication, I found this handy resource: SAS Usage Note 39891: Using PROC PERMTEST to diagnose UNIX host authentication issues in SAS® 9.2. The server in question already had correctly functioning LDAP host authentication via PAM, it was just that the SAS Metadata Server wasn’t able to authenticate the LDAP users. The usage note helped me fix the problem by leading me to the SASFoundation/SAS9.2/utilities/bin/sasauth.conf file where I found it had methods=pw instead of methods=pam (must have chosen the wrong options at install time). I actually didn’t need to run PROC PERMTEST this time but the usage note contains clear instructions on how to when required. Interestingly PROC PERMTEST doesn’t seem to appear in the Base SAS® 9.2 Procedures Guide.