[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [RFC PATCH 4/4] net: slirp: allow CFI with libslirp >= 4.7
From: |
Samuel Thibault |
Subject: |
Re: [RFC PATCH 4/4] net: slirp: allow CFI with libslirp >= 4.7 |
Date: |
Wed, 27 Apr 2022 01:19:47 +0200 |
User-agent: |
NeoMutt/20170609 (1.8.3) |
Paolo Bonzini, le mar. 12 avril 2022 14:13:37 +0200, a ecrit:
> slirp 4.7 introduces a new CFI-friendly timer callback that does
> not pass function pointers within libslirp as callbacks for timers.
> Check the version number and, if it is new enough, allow using CFI
> even with a system libslirp.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
> ---
> meson.build | 24 ++++++++++++------------
> 1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/meson.build b/meson.build
> index 861de93c4f..92a83580a3 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -2485,21 +2485,21 @@ if have_system
> slirp = declare_dependency(link_with: libslirp,
> dependencies: slirp_deps,
> include_directories: slirp_inc)
> + else
> + # slirp <4.7 is incompatible with CFI support in QEMU. This is because
> + # it passes function pointers within libslirp as callbacks for timers.
> + # When using a system-wide shared libslirp, the type information for the
> + # callback is missing and the timer call produces a false positive with
> CFI.
> + #
> + # Now that slirp_opt has been defined, check if the selected slirp is
> compatible
> + # with control-flow integrity.
> + if get_option('cfi') and slirp.found() and
> slirp.version().version_compare('<4.7')
> + error('Control-Flow Integrity is not compatible with system-wide
> slirp.' \
> + + ' Please configure with --enable-slirp=git or upgrade to
> libslirp 4.7')
> + endif
> endif
> endif
>
> -# For CFI, we need to compile slirp as a static library together with qemu.
> -# This is because we register slirp functions as callbacks for QEMU Timers.
> -# When using a system-wide shared libslirp, the type information for the
> -# callback is missing and the timer call produces a false positive with CFI.
> -#
> -# Now that slirp_opt has been defined, check if the selected slirp is
> compatible
> -# with control-flow integrity.
> -if get_option('cfi') and slirp_opt == 'system'
> - error('Control-Flow Integrity is not compatible with system-wide slirp.' \
> - + ' Please configure with --enable-slirp=git')
> -endif
> -
> fdt = not_found
> if have_system
> fdt_opt = get_option('fdt')
> --
> 2.35.1
>
--
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.