tinyapps.org / blog

Bluetooth Internet Sharing with Snow Leopard, Treo 755P, and Missing Sync #

It's easy to connect your Treo 755P to the Internet via Bluetooth thanks to Missing Sync for Palm OS. Just open "Internet Sharing Assistant" under Missing Sync's Help menu and follow the few simple steps for configuring the Treo. No need for enabling "Share my Internet connection with other Bluetooth devices" in System Preferences > Bluetooth > Advanced... or "Internet Sharing" in System Preferences > Sharing. The only caveat is that you may have to setuid on pppd (sudo chmod u+s /usr/sbin/pppd) to resolve Error: PPP Timeout (0x1231) when connecting. Be aware of the risk involved with setuid:
chmod u+s /usr/sbin/pppd

What this does is make pppd run with root privileges even if the binary is run by an ordinary user. This allows a normal user to run pppd with the necessary privileges to set up the network interfaces and the kernel routing table.

Programs that run 'set uid root' are potential security holes and you should be extremely cautious about making programs 'suid root'. A number of programs (including pppd) have been carefully written to minimize the danger of running suid root, so you should be safe with this one, (but no guarantees).

(from the Linux PPP HOWTO)
Once more:
Programs that use this bit must be carefully designed to be immune to buffer overrun attacks. Successful buffer overrun attacks on vulnerable applications allow the attacker to execute arbitrary code under the rights of the process being exploited. In the event a vulnerable process uses the setuid bit to run as root, the code will be executed with root privileges, in effect giving the attacker root access to the system on which the vulnerable process is running.

(from Wikipedia)
Tested under Missing Sync for Palm OS 6.0.6 and OS X 10.6.8. Additional keywords: reverse DUN, tethering.

/palm | Nov 08, 2011

Subscribe or visit the archives