"Ctrl-Alt-Del to login" important for security?

[Scott James Remnant]

On Thu, 2006-03-02 at 01:01 +0000, Pete Ryland wrote:

> Just wanted to make the point in case it wasn't known that the reason
> Ctrl-Alt-Del is special is because on the PC it triggers a hardware
> interrupt when pressed, which only the kernel is privvy to (as with SysReq
> too btw).
> 
That's true, if I recall correctly the Windows kernel traps that and
itself takes care of bringing up the login dialog.

Obviously here in the Real World we don't like to put things like X and
gdm into the kernel <g>

So a typical implementation could be:

- modify /etc/inittab, change the "ca:" line to run a dbus helper (or
  other IPC trick) to send a message on the bus
- make gdm listen for that, and not show the login dialog until it
  appears

The obvious flaw here is that you've now reduced the security from "only
the kernel can" to "anyone who can get root can"


Also hasn't recent Windows abandoned this trick anyway, I'm sure XP just
lets you click your username when it boots.

Scott
-- 
Scott James Remnant
scott at ubuntu.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 191 bytes
Desc: This is a digitally signed message part
Url : https://lists.ubuntu.com/archives/sounder/attachments/20060302/9c4714c3/attachment.pgp