Updating Kernel Extensions with Radmind: Best Practices

One of the problems that I’ve run into so far using Radmind to manage Mac OS X—specifically, the Leopard to Snow Leopard transition—is that kextd helpfully starts recreating your kernel extension cache as soon as you modify anything in /System/Library/Extensions. This can be problematic when you’re updating core system files; as you update the 10.5 kernel extensions to their 10.6 counterparts, you don’t want the 10.5 version of kextd creating a cache of 10.6 kernel extensions, especially as the kernel extension cache has moved (from /System/Library/Extensions.mkext to /System/Library/Caches/com.apple.kext.caches/). So, should you handle this? My solution is to stop kextd if I know that I’m updating kernel extensions; that way, they won’t be re-created until reboot. Here’s the script:



# update_kernel_extensions: Manage the replacement of old kernel extensions.
#                           If there are updates, kill kextd and destroy the
#                           caches.



/usr/bin/grep "${KEXT_FOLDER}" "${transcript}" > "${result}"

if test -n "${result}"; then #result is non-empty
    # Disable kextd to prevent it from recreating kernel extension caches, which
    # will be re-created at startup.
    if test -n "$(/bin/launchctl list | /usr/bin/grep ${KEXTD_LAUNCHD})"; then
        #kextd is running
        /bin/launchctl unload "${SYSTEM_LAUNCHD_FOLDER}/${KEXTD_LAUNCHD}.plist"

    # Remove kernel extension cache.
    /bin/rm -rf "${KEXT_CACHE}"

rm -f "${result}"

In its present form, it only works on Snow Leopard, but I’ll be updating it to work on Leopard as well.

Google Delivers Mac Google Earth API Plugin, But at What Cost?

UPDATE: Google has released a version of Google Earth (including the plugin) without the self-updating feature.

The Mac blogs around the ‘net are all abuzz today about Google’s release of a Mac version of the Google Maps API, but I noticed something funny when I installed it.  The plug-in is a standard Mac Internet Plug-In, meaning you can install it at either /Library/Internet Plug-Ins or ~/Library/Internet Plug-Ins.  So why does the install package prompt you for administrator credentials when you choose to install it into your home folder?  The answer lives at /Library/Google.

It turns out that when you install the plugin, the installer also installs a software update component, code-named “keystone.”  It installs the following components:

  • An application bundle at /Library/Google/GoogleSoftwareUpdate/GoogleSoftwareUpdate.bundle
  • A “Ticket Store” at /Library/Google/GoogleSoftwareUpdate/TicketStore/ — does anyone know what this does?  I sure don’t.
  • A LaunchDaemon that runs as root on demand, at /Library/LaunchDaemons/com.google.keystone.daemon.plist
  • A LaunchAgent (/Library/LaunchAgents/com.google.keystone.agent.plist) that runs when you’re logged in, presumably to fire up the daemon so you can receive updates without administrative privileges.

Interestingly enough, this software component is never mentioned by Google.  It isn’t an option you can deselect in the installer.  Even worse, the plugin’s uninstall instructions don’t say a thing about it.  This means that after you follow the plugin uninstall instructions, your computer is still checking in with Google’s servers to make sure that it’s up-to-date.  I’m reluctant to call this malware, but it sure seems like spyware, doesn’t it?  At the very least the installer ought to mention something.

Be cautious when installing this plugin onto any computer where security is essential.  Any software component that runs as root, such as the updater this installer installs, is another attack vector for intruders trying to get at your data.

For what it’s worth, the API plugin does work if you only copy the stuff in /Library/Internet Plug-Ins to a computer or to your user account, so it appears that you can still use the plugin in a secure environment, you’ll just have to update it yourself and not have Google do it for you.

I’ve also mentioned this on the official Google Group.