Гарантию безопасности дает среда исполнения. Компилятор также важен.

# checksec -pl 1
# checksec -d /bin
# checksec -k
# paxtest  blackhat
Mode: blackhat 
Linux fw1 2.6.34-hardened-r6 #1 SMP Mon Oct 4 02:32:46 CEST 2010 x86_64 Intel(R) Xeon(R) CPU E5520 @ 2.27GHz GenuineIntel GNU/Linux 
Executable anonymous mapping             : Killed 
Executable bss                           : Killed 
Executable data                          : Killed 
Executable heap                          : Killed 
Executable stack                         : Killed 
Executable shared library bss            : Killed 
Executable shared library data           : Killed 
Executable anonymous mapping (mprotect)  : Killed 
Executable bss (mprotect)                : Killed 
Executable data (mprotect)               : Killed 
Executable heap (mprotect)               : Killed 
Executable stack (mprotect)              : Killed 
Executable shared library bss (mprotect) : Killed 
Executable shared library data (mprotect): Killed 
Writable text segments                   : Killed 
Anonymous mapping randomisation test     : 29 bits (guessed) 
Heap randomisation test (ET_EXEC)        : 35 bits (guessed) 
Heap randomisation test (PIE)            : 35 bits (guessed) 
Main executable randomisation (ET_EXEC)  : 27 bits (guessed) 
Main executable randomisation (PIE)      : 27 bits (guessed) 
Shared library randomisation test        : 29 bits (guessed) 
Stack randomisation test (SEGMEXEC)      : 35 bits (guessed) 
Stack randomisation test (PAGEEXEC)      : 35 bits (guessed) 
Return to function (strcpy)              : paxtest: return address contains a NULL byte. 
Return to function (memcpy)              : Vulnerable 
Return to function (strcpy, PIE)         : paxtest: return address contains a NULL byte. 
Return to function (memcpy, PIE)         : Vulnerable