[PATCH 0/2] topic: meson: add more compiler hardening flags

["Daniel P. Berrangé" <berrange@redhat.com>]

This brings more compiler hardening flags to the default QEMU
build process. The proposed flags have already been adopted by
default in the kernel build process. At some point it is hoped
that distros might enable them globally, as they've done in
the past with things like _FORTIFY_SOURCE. Meanwhile they are
easy things to enable in QEMU which have negligible cost and
clear benefits to hardening. Considering QEMU shows no signs
of stoppping the flow of guest triggerable CVEs, investing in
hardening is worthwhile. See the respective commit messages
for details

I also tested enabling -ftrapv, to change signed integer
overflow from wrapping, to trapping instead. This exposed a
bug in the string-input-visitor which overflows when parsing
ranges, and exposed the test-int128 code as (harmlessly)
overflowing during its testing. Both can be fixed, but I'm
not entirely sure whether -ftrapv is viable or not. I was
wondering about TCG and whether it has a need to intentionally
allow integer overflow for any of its instruction emulation
requirements ?  "make check" passes qtest but that's not
sufficiently broad to make me comfortable. Thus I've not
included an -ftrapv patch here.

Daniel P. Berrangé (2):
  meson: mitigate against ROP exploits with -fzero-call-used-regs
  meson: mitigate against use of uninitialize stack for exploits

 meson.build | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

-- 
2.41.0