Administration Reference

fs setcell

Purpose

Allows or disallows running of setuid programs from specified cells

Synopsis

fs setcell -cell <cell name>+  [-suid]  [-nosuid]  [-help]
   
fs setce -c <cell name>+  [-s]  [-n]  [-h]

Description

The fs setcell command sets whether the Cache Manager allows programs (and other executable files) from each cell named by the -cell argument to run with setuid permission. By default, the Cache Manager allows programs from its home cell to run with setuid permission, but not programs from any foreign cells. A program belongs to the same cell as the file server machine that houses the volume in which the program's binary file resides, as specified in the file server machine's /usr/afs/etc/ThisCell file. The Cache Manager determines its own home cell by reading the /usr/vice/etc/ThisCell file at initialization.

To enable programs from each specified cell to run with setuid permission, include the -suid flag. To prohibit programs from running with setuid permission, include the -nosuid flag, or omit both flags.

The fs setcell command directly alters a cell's setuid status as recorded in kernel memory, so rebooting the machine is unnecessary. However, non-default settings do not persist across reboots of the machine unless the appropriate fs setcell command appears in the machine's AFS initialization file.

To display a cell's setuid status, issue the fs getcellstatus command.

Cautions

AFS does not recognize effective UID: if a setuid program accesses AFS files and directories, it does so using the current AFS identity of the AFS user who initialized the program, not of the program's owner. Only the local file system recognizes effective UID.

Only members of the system:administrators group can turn on the setuid mode bit on an AFS file or directory.

When the setuid mode bit is turned on, the UNIX ls -l command displays the third user mode bit as an s instead of an x. However, the s does not appear on an AFS file or directory unless setuid permission is enabled for the cell in which the file resides.

Options

-cell

Names each cell for which to set setuid status. Provide the fully qualified domain name, or a shortened form that disambiguates it from the other cells listed in the local /usr/vice/etc/CellServDB file.

-suid

Allows programs from each specified cell to run with setuid privilege. Provide it or the -nosuid flag, or omit both flags to disallow programs from running with setuid privilege.

-nosuid

Prevents programs from each specified cell from running with setuid privilege. Provide it or the -suid flag, or omit both flags to disallow programs form running with setuid privilege.

-help

Prints the online help for this command. All other valid options are ignored.

Examples

The following command enables executable files from the State University cell to run with setuid privilege on the local machine:

   % fs setcell -cell stateu.edu -suid
   

Privilege Required

The issuer must be logged in as the local superuser root.

Related Information

fs getcellstatus