VISULOX 4 Documentation

Security information about vlxsu and vlxchown (SUID bit)


During VISULOX installation the following binaries are set with SUID:

-r-sr-xr-x 1 root vlx 18760 Sep 17 14:14 ./lib/platform/vlxchown -r-sr-xr-x 1 root vlx 38007 Sep 17 14:14 ./lib/platform/vlxsu


On request and NDA, amitego will provide the source code of these tools for security reviews.




vlxchown

vlxchown is used to chown files and/or directories to another vlx* user.

Usage

vlxchown USER PATH [PATH...]


Command line arguments


USER

Unix user matching vlx* in group vlx

PATH

Path to a file/directory. The ownership

of those files is transferred to USER:vlx


Security

  • Environment variable VLX_HOME must be set.

  • Only vlx:vlx can call vlxchown.

  • vlxchown must be owned by root:vlx, and setuid.

  • Ownership is only transferred between members of the vlx group and from ttaserv.

vlxsu

setuid program to start specific apps as given user.


Usage

  vlxsu [options] <user> <cmd> [<args>...]


Command line arguments


 <user>

 Name of the user of the target persona

 <cmd>

 Name of the command to run as persona <user>

 <args>

 One or more optional arguments to pass to the program

Optional arguments (args)

-h | -help | --help

Show usage and exit

-config

Show current vlxsu configuration (my_commands) and exit

-debug

Sset debug mode on

-x

Delete all files in home directory of <user>


Security

  • Only vlx:vlx can call vlxsu.

  • vlxsu must be owned by root:vlx, and setuid.

  • The <user> must match a user prefix in my_commands.

  • The <command> must match an entry in my_commands.

  • Both PATH and LD_LIBRARY_PATH are preset.

  • The environment of the target user is restricted.


SETUID

See the 2008 paper "Revising Setuid Demystified" at: http://code.google.com/p/change-process-identity/

In particular, the change of persona fails if the resulting persona is not the target persona.