Jose Carlos Luna Duran writes: > In my opinion the drop of privs in bash was mostly a "help" measure > for poorly written setuid programs executing system() calls. I don't > think is the role of bash to do this ...
True, but it is a slight help and I'm in favour of keeping it. > Correct me if I'm wrong, but even in that case there is another "help" > measure that has been implemented at least in linux kernels > 3.1: > http://lxr.free-electrons.com/source/kernel/sys.c?v=3.1#L628 For permanent dropping of privilege I suggest calling setgid() and setuid() to the desired values *twice* (and ignore the return code). Then try to reset to the original values (should fail; ignore return code). Then test that the real and effective values are the same and are the ones you want - that's the result that indicates success in this case. And exit() if failed. That's the simple usage guide - David Wagner has written at length on the technicalities.
