[all-commits] [llvm/llvm-project] 64de00: [sanitizer] Improve FreeBSD ASLR detection

[Ed Maste via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 64de0064f315f57044294879d9ff4eacb454d45b
      https://github.com/llvm/llvm-project/commit/64de0064f315f57044294879d9ff4eacb454d45b
  Author: Ed Maste <emaste at FreeBSD.org>
  Date:   2022-01-18 (Tue, 18 Jan 2022)

  Changed paths:
    M compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp

  Log Message:
  -----------
  [sanitizer] Improve FreeBSD ASLR detection

The kern.elf64.aslr.pie_enable and kern.elf32.aslr.pie_enable sysctls
control the default setting for PIE binary address randomization, but
it is possible to enable or disable ASLR on a per-process basis.  So,
use procctl(2) to query whether ASLR is enabled.

(Note that with ASLR enabled but sysctl kern.elf64.aslr.pie_enable=0
a PIE binary will in effect have randomization disabled, and would be
functional with msan.  This is not intended as as a user-facing control
though; proccontrol(1) should be used to disable aslr for the process.)

Reviewed By: devnexen

Differential Revision: https://reviews.llvm.org/D117521