[libvirt] [PATCH] Remove ssp buffer size setting

[Daniel P. Berrange]

On Fri, Jun 06, 2014 at 01:00:20PM +0200, Martin Kletzander wrote:
> On Fri, Jun 06, 2014 at 11:40:24AM +0200, Ján Tomko wrote:
> >This option only makes sense with -fstack-protector.
> >With -fstack-protector-all, even functions with buffers
> >smaller than this are protected.
> >
> >https://bugzilla.redhat.com/show_bug.cgi?id=1105456
> >---
> >m4/virt-compile-warnings.m4 | 8 --------
> >1 file changed, 8 deletions(-)
> >
> >diff --git a/m4/virt-compile-warnings.m4 b/m4/virt-compile-warnings.m4
> >index 574fbc4..ebc931d 100644
> >--- a/m4/virt-compile-warnings.m4
> >+++ b/m4/virt-compile-warnings.m4
> >@@ -171,14 +171,6 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[
> >       dnl be great overhead in adding -fstack-protector-all instead
> >       dnl wantwarn="$wantwarn -fstack-protector"
> >       wantwarn="$wantwarn -fstack-protector-all"
> >-       wantwarn="$wantwarn --param=ssp-buffer-size=4"
> 
> It would be nice to keep that line in here with the explanation that
> -fstack-protector-all does not make use of that param.
> 
> >-       dnl Even though it supports it, clang complains about
> >-       dnl use of --param=ssp-buffer-size=4 unless used with
> >-       dnl the -c arg. It doesn't like it when used with args
> >-       dnl that just link together .o files. Unfortunately
> >-       dnl we can't avoid that with automake, so we must turn
> >-       dnl off the following clang specific warning
> >-       wantwarn="$wantwarn -Wno-unused-command-line-argument"
> 
> Why do you also remove this line?
> 
> >       ;;
> >       *-*-freebsd*)
> >       dnl FreeBSD ships old gcc 4.2.1 which doesn't handle
> 
> Also, out of the context of this patch, doesn't that param need to be
> added to the freebsd version since it uses -fstack-protector only?


Ideally we should actually use  -fstack-protector-strong if we find
it supported, in preference to -fstack-protector-all. The strong
variant would still require us to set ssp-buffer-size.

Regards,
Daniel
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