"restricted" folder/files in OS X El Capitan

After upgrading from OS X Yosemite to OS X El Capitan Developer Preview, I tried to edit /System/Library/LaunchDaemons/ssh.plist to change the default SSH port to a custom one. This is the process I've been using for a couple of years.

The problem is that El Capitan doesn't allow me to change anything in this folder (not even with "sudo"). The folder and its files are marked as "restricted" when I list the contents with "ls -lO". The same folder listing in previous versions of OS X does not show "restricted".

Is this something new to OS X El Capitan? How can I edit files/folders that are "restricted"?

---

I found out this is due to a new feature introduced in El Capitan called "SIP" (System Intregrity Protection).

Read more here: https://forums.developer.apple.com/thread/4731?q=SIP

Unfortunately, no one suggested a way of editing "restricted" files/folders without actually disabling SIP.

You can also temporarily disable SIP the following way

1. reboot
2. as soon as you hear the "Mac sound" on the grey screen, press Cmd+R to enter Recovery mode
3. Open Utilities->Terminal
4. Run the command csrutil disable
5. Reboot, you'll land in the normal OS with SIP disabled
6. do all the changes you'd like to do
7. Reboot again
8. as soon as you hear the "Mac sound" on the grey screen, press Cmd+R to enter Recovery mode
9. Enable SIP with csrutil enable
10. Reboot again
11. done

Until 10.11 unprotects certain files in /System/Library or allows you to do it yourself, the only way without disabling SIP would be to make a different service by coping the file somewhere else, like:

sudo cp /System/Library/LaunchDaemons/ssh.plist /Library/LaunchDaemons/ssh.plist

And then instead of using the Sharing panel in System Preferences, you would manage the service yourself:

sudo launchctl unload /Library/LaunchDaemons/ssh.plist
sudo launchctl load -w /Library/LaunchDaemons/ssh.plist

I would suggest you try adding whatever arguments you need to a plist in /Library/Preferences/. For example, in my case I needed to make a slight alteration to mDNSResponder to add the AlwaysAppendSearchDomains flag. As suggested by "bwells" on the Apple developer forums, I just had to do

sudo launchctl unload /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
sudo defaults write /Library/Preferences/com.apple.mDNSResponder.plist AlwaysAppendSearchDomains -bool YES
sudo launchctl load /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist

This is a much cleaner approach and persists across reboots and should also survive an upgrade (at least during the betas my manual changes after disabling SIP were overwritten). Note, as far as I know this is new to El Capitan.

You can also leave SIP enabled while disabling the filesystem management. Reboot in recovery mode and run:

csrutil enable --without fs

This will allow you to change permissions as needed.

1. Just boot into "Recovery" mode by pressing "CMD+R" while rebooting.
2. Open Terminal
3. Your disk will be mounted in /Volumes/Macintosh HD
4. Delete files via "rm" : you have absolute control in that terminal.

I use carbon copy cloner to make clonable backups... and have several in rotation.

According to mike at bombich "SIP only applies to the volume you're currently booted from, so [one can] boot from the backup volume to delete [files]".

I did use johannes' answer (recovery drive, csrutil enable/disable), but that requires reboot —> recovery drive —> turn sip off —> reboot —> delete crap —> reboot —> recovery drive —> turn sip back on —> reboot ... four reboots.

But booting from a clone and seeing the original drive as a secondary drive would allow you to delete problematic files in two reboots... yes?

You can "by pass" the SIP protection by modifying permissions on file via Finder app for the system group.

modifying permissions

It worked fine for me even after reboot, i'm running

ProductName: Mac OS X ProductVersion: 10.11 BuildVersion: 15A284