[fjarlq]

No, root can still run chmod, because its superuser privileges override the new restrictive directory perms. That was my point.

Maybe the original problem was actually "chmod a-rwx /bin/chmod" ... That would mean even the superuser couldn't execute /bin/chmod anymore, so you'd have to do something more creative to reset the executable bit on /bin/chmod. Like compile a C program that calls the chmod system call, or:

  mv /bin/chmod /bin/chmod.orig
  cp -p /bin/ls /bin/chmod
  cp /bin/chmod.orig /bin/chmod

[pantalaimon]

> Like compile a C program that calls the chmod system call

The compiler wouldn't be executable anymore either

[claviola]

Yes, it would. Like he said, you can still run it unless you specifically removed its permissions.