From 9a227a2fd642ec057a0ec70d67d5699d65553294 Mon Sep 17 00:00:00 2001 From: Marcin Wojtas Date: Fri, 22 Jan 2021 13:13:03 +0100 Subject: [PATCH] Enable PIE by default on 64-bit architectures This patch adds Position Independent Executables (PIE) flags for building OS. It allows to enable the ASLR feature based only on the sysctl knobs, without need to rebuild the image. Tests showed that no problems with stability / performance degradation were seen when using PIEs with ASLR disabled. The change is limited only for 64-bit architectures. Use bsd.opts.mk instead of the src.opts.mk in order to satisfy all build dependencies related to MK_PIE. Reviewed by: emaste, imp Obtained from: Semihalf Sponsored by: Stormshield Differential Revision: https://reviews.freebsd.org/D28328 --- share/mk/bsd.opts.mk | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/share/mk/bsd.opts.mk b/share/mk/bsd.opts.mk index 88c73cc6bfe4..9f9889d0a0f0 100644 --- a/share/mk/bsd.opts.mk +++ b/share/mk/bsd.opts.mk @@ -75,7 +75,6 @@ __DEFAULT_NO_OPTIONS = \ INIT_ALL_PATTERN \ INIT_ALL_ZERO \ INSTALL_AS_USER \ - PIE \ RETPOLINE \ STALE_STAGED @@ -85,6 +84,21 @@ __DEFAULT_DEPENDENT_OPTIONS = \ STAGING_PROG/STAGING \ STALE_STAGED/STAGING \ +# +# Default to disabling PIE on 32-bit architectures. The small address space +# means that ASLR is of limited effectiveness, and it may cause issues with +# some memory-hungry workloads. +# +.if ${MACHINE_ARCH} == "armv6" || ${MACHINE_ARCH} == "armv7" \ + || ${MACHINE_ARCH} == "i386" || ${MACHINE_ARCH} == "mips" \ + || ${MACHINE_ARCH} == "mipsel" || ${MACHINE_ARCH} == "mipselhf" \ + || ${MACHINE_ARCH} == "mipshf" || ${MACHINE_ARCH} == "mipsn32" \ + || ${MACHINE_ARCH} == "mipsn32el" || ${MACHINE_ARCH} == "powerpc" \ + || ${MACHINE_ARCH} == "powerpcspe" +__DEFAULT_NO_OPTIONS+= PIE +.else +__DEFAULT_YES_OPTIONS+=PIE +.endif .include