Enable GCC stack protection (aka Propolice) for userland:

- It is opt-out for now so as to give it maximum testing, but it may be
  turned opt-in for stable branches depending on the consensus.  You
  can turn it off with WITHOUT_SSP.
- WITHOUT_SSP was previously used to disable the build of GNU libssp.
  It is harmless to steal the knob as SSP symbols have been provided
  by libc for a long time, GNU libssp should not have been much used.
- SSP is disabled in a few corners such as system bootstrap programs
  (sys/boot), process bootstrap code (rtld, csu) and SSP symbols themselves.
- It should be safe to use -fstack-protector-all to build world, however
  libc will be automatically downgraded to -fstack-protector because it
  breaks rtld otherwise.
- This option is unavailable on ia64.

Enable GCC stack protection (aka Propolice) for kernel:
- It is opt-out for now so as to give it maximum testing.
- Do not compile your kernel with -fstack-protector-all, it won't work.

Submitted by:	Jeremie Le Hen <jeremie@le-hen.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/libc/Makefile b/lib/libc/Makefile
index 2caf0a1..2d97fbe 100644
--- a/lib/libc/Makefile
+++ b/lib/libc/Makefile
@@ -122,3 +122,9 @@ libkern.${MACHINE_ARCH}:: ${KMSRCS}
 
 # Disable warnings in contributed sources.
 CWARNFLAGS:=	${.IMPSRC:Ngdtoa_*.c:C/^.+$/${CWARNFLAGS}/}
+# XXX For now, we don't allow libc to be compiled with
+# -fstack-protector-all because it breaks rtld.  We may want to make a librtld
+# in the future to circumvent this.
+SSP_CFLAGS:=	${SSP_CFLAGS:S/^-fstack-protector-all$/-fstack-protector/}
+# Disable stack protection for SSP symbols.
+SSP_CFLAGS:=	${.IMPSRC:N*/stack_protector.c:C/^.+$/${SSP_CFLAGS}/}