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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 predictab

by ptx 6mo ago

> 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/ https://wiki.netbsd.org/security/kaslr/

keysersoze33 6mo ago
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-security-from-grsecurity-member.56298/ https://forums.freebsd.org/threads/truth-about-linux-4-6-sec...
- pixl97 6mo ago
  Security is an onion, honestly you want both layers to be as hard as possible.
ktm5j 6mo ago
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/ https://FreeBSD.org/" BUG_REPORT_URL="https://bugs.FreeBSD.org/ https://bugs.FreeBSD.org/" [kmiles@peter ~]$ sysctl kern.elf64.aslr.enable kern.elf64.aslr.enable: 1
- savant2 6mo ago
  This knob isn't KASLR, it just enables ASLR for ELF binaries.