#xhost

[ammohitchaprana]

www.xHost.live is way better than Vercel.

[ushf]

Old X access notes

In following the recent Fedora25 discussion about whether Wayland is ready for primetime I noticed a suggestion about working around a gparted bug by allowing access to X server for root. It does not seem like a nice idea from a security perspective. To be fair/clear it was just proposed as a work-around to an immediate problem.

I realized I had forgotten what the SI string means, so went to track it down. Essentially it is

$ xhost access control enabled, only authorized clients can connect SI:localuser:trappist SI:localuser:gnome-initial-setup SI:localuser:gdm SI:localuser:root

The SI part stands for "System Interpreted" which the man pages specify as being one of the limited number of types

IPv6 IPv6 literal addresses hostname Network host name localuser Local connection user id localgroup Local connection group id

There is a caution that

If your system supports this method and you use it, be warned that some programs that proxy connections and are setuid or setgid may get authenticated as the uid or gid of the proxy process. For instance, some versions of ssh will be authenticated as the user root, no matter what user is running the ssh client, so on systems with such software, adding access for localuser:root may allow wider access than intended to the X display.

[laurentschneider]

Untrusted X11 forwarding

I wrote a while ago about my security concerns regarding xhost + xterm -display mypc:0

Way back then, I suggested ssh tunnel. SSH is pretty easy to set up, by enabling the X11Forwarding option.

In OpenSSH 3.8 release note, 2004, there was a new default . ssh(1) now uses untrusted cookies for X11-Forwarding In the man ssh_config page, it’s still documented as being the default ForwardX11Trusted…

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[knoffhoff]

How to change the color of the Firefox navigation bar.

To change the color of the navigation bar (address bar and search bar) of Firefox use the following commands in Linux:

# go to the firefox profile directory cd ~/.mozilla/firefox/*/ # create a directory chrome mkdir chrome # create the file userChrome.css echo "#nav-bar { background-color: #a0a0a0 !important }" >> chrome/userChrome.css

Why I need it

I run several Firefox windows for different Linux users on the same graphical desktop. I do this because I have an internet connection provided by my company and a mobile internet connection. Each Firefox instance uses another internet connection. Since I do not like the personas for Firefox, I use different background colors to distinguish the Firefox windows.

You can add another user (e.g. user "internet") to your X11 desktop with the following command:

xhost +SI:localuser:internet