svn commit: r358993 - head/lib/libssp

[Kyle Evans]

Author: kevans
Date: Sat Mar 14 15:15:27 2020
New Revision: 358993
URL: https://svnweb.freebsd.org/changeset/base/358993

Log:
  libssp: don't compile with -fstack-protector*
  
  This similarly matches what we do in libc; compiling libssp with
  -fstack-protector* is actively harmful.  For instance, if the canary ctor
  ends up with a stack protector then it will trivially trigger a false
  positive as the canary's being initialized.
  
  This was noted by the reporter as irc/ircd-hybrid started crashing at start
  after our libssp was MFC'd to stable/11, as its build will explicitly link
  in libssp. On FreeBSD, this isn't necessary as SSP bits are included in
  libc, but it should absolutely not trigger runtime breakage -- it does mean
  that the canary will get initialized twice, but as this is happening early
  on in application startup it should just be redundant work.
  
  Reported by:	Tod McQuillin <devin at sevenlayer.studio>
  MFC after:	3 days

Modified:
  head/lib/libssp/Makefile

Modified: head/lib/libssp/Makefile
==============================================================================
--- head/lib/libssp/Makefile	Sat Mar 14 14:04:55 2020	(r358992)
+++ head/lib/libssp/Makefile	Sat Mar 14 15:15:27 2020	(r358993)
@@ -17,4 +17,8 @@ SRCS=		stack_protector.c fortify_stubs.c
 
 CFLAGS.fortify_stubs.c=	-Wno-unused-parameter
 
+# Stack protection on libssp symbols should be considered harmful, as we may
+# be talking about, for example, the guard setup constructor.
+SSP_CFLAGS:=
+
 .include <bsd.lib.mk>