"Couldn't we set up a mode where any content owned by a user, or downloaded by a user, was flagged as not executable. This means no scripts, downloaded binaries, downloaded libraries, java or perl programs etc. would be able to be executed by the logged in user. All files in any directory writeable by the user would be implicitly non-executable.
The only allowed executable content would be that which was owned by the system (ie. no one running a web browser or application that downloads runnable binaries would be able to execute them)
The system could be set into two modes, "programmer" mode, where these restrictions were removed, and "user" mode where the desktop becomes safer for web browsers, which would be the default mode for most "normal" users.
All I got to say is:
Its in there!
SELinux confined users can do this. Setup an account as a staff_u or user_u user and turn off the allow_user_exec_content/allow_staff_exec
xguest_u gets this by default.
Steps to try this out.
# semanage login -a -s staff_u -rs0-s0:c0.c1023 USERNAME
# setsebool -P allow_staff_exec_content 0
Now login to USERNAME.
> id -Z
getsebool -a | grep staff
allow_staff_exec_content --> off
> ls -lZ ~/virus
-rwxrwxr-x. dwalsh dwalsh staff_u:object_r:user_home_t:s0 /home/devel/dwalsh/virus
bash: /home/devel/dwalsh/virus: Permission denied
# setenforce 0
Hey wait a minute, this is not Windows!!!