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> It's worth noting that FreeBSD made this easier than it would be on a modern Linux kernel: FreeBSD 14.x has no KASLR (kernel addresses are fixed and predictable) and no stack canaries for integer arrays (the overflowed buffer is int32_t[]).

What about FreeBSD 15.x then? I didn't see anything in the release notes or the mitigations(7) man page about KASLR. Is it being worked on?

NetBSD apparently has it: https://wiki.netbsd.org/security/kaslr/



I don't understand this, because KASLR has been default in FreeBSD since 13.2:

[kmiles@peter ~]$ cat /etc/os-release

NAME=FreeBSD

VERSION="13.3-RELEASE-p4"

VERSION_ID="13.3"

ID=freebsd

ANSI_COLOR="0;31"

PRETTY_NAME="FreeBSD 13.3-RELEASE-p4"

CPE_NAME="cpe:/o:freebsd:freebsd:13.3"

HOME_URL="https://FreeBSD.org/"

BUG_REPORT_URL="https://bugs.FreeBSD.org/"

[kmiles@peter ~]$ sysctl kern.elf64.aslr.enable

kern.elf64.aslr.enable: 1


This knob isn't KASLR, it just enables ASLR for ELF binaries.


This is more of a Linux kernel criticism of KASLR, but perhaps it's related as to why it's not been a priority in FreeBSD (i.e. it gives a false sense of safety and rather focus on 'proper' security hardening): https://forums.freebsd.org/threads/truth-about-linux-4-6-sec...


Security is an onion, honestly you want both layers to be as hard as possible.




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