paxtests ASLR results with recent kernels

Javier Martinez <[email protected]> Sun, 8 Mar 2026 11:05:10 +0100
Newsgroups	gmane.linux.gentoo.user
Message-ID	<[email protected]>

Hi all, I want to share this with you because I found it simply impressive:

It seems that recent kernels through .config allows to set up how many 
randomization bits shall be set to ASLR as an switchable option. Here is 
the result.

Probably you would need one MAC option to protect Writeable text 
segments and mprotect, but you could benefict of an increased ASLR 
strength. The system is a Rockpi4SE

Mode: 1
Blackhat
Kernel:
Linux cerberus 6.18.16-rsbac #1 SMP PREEMPT_RT Sat Mar  7 17:12:12 CET 
2026 aarch64 GNU/Linux

Relase information:
LSB Version:	n/a
Distributor ID:	Gentoo
Description:	Gentoo Linux
Release:	2.18
Codename:	n/a
Test results:
/usr/bin/paxtest: línea 69: 
/usr/lib64/paxtest/aarch64-unknown-linux-gnu-gcc: No existe el fichero o 
el directorio

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 randomization test     : 30 quality bits (guessed)
Heap randomization test (ET_EXEC)        : 30 quality bits (guessed)
Heap randomization test (PIE)            : 30 quality bits (guessed)
Main executable randomization (ET_EXEC)  : 26 quality bits (guessed)
Main executable randomization (PIE)      : 27 quality bits (guessed)
Shared library randomization test        : 26 quality bits (guessed)
VDSO randomization test                  : 30 quality bits (guessed)
Stack randomization test (SEGMEXEC)      : 26 quality bits (guessed)
Stack randomization test (PAGEEXEC)      : 26 quality bits (guessed)
Arg/env randomization test (SEGMEXEC)    : 18 quality bits (guessed)
Arg/env randomization test (PAGEEXEC)    : 18 quality bits (guessed)
Offset to library randomisation (ET_EXEC): 26 quality bits (guessed)
Offset to library randomisation (ET_DYN) : 26 quality bits (guessed)
Randomization under memory exhaustion @~0: 30 bits (guessed)
Randomization under memory exhaustion @0 : 30 bits (guessed)
Return to function (strcpy)              : paxtest: return address 
contains a NULL byte.
Return to function (memcpy)              : Return to function (strcpy, 
PIE)         : paxtest: return address contains a NULL byte.
Return to function (memcpy, PIE)
OpenPGP_0x57E64E0B7FC3BEDF.asc (application/pgp-keys, 3 KB)
OpenPGP_signature.asc (application/pgp-signature, 840 B)