[libvirt] [PATCH v2 0/4] Fix remote dispatch code trying to allocate 0-sized return buffers

This happens because of the switch to glib whose method g_malloc0 actually correctly returns NULL on size 0 which doesn't make sense to do. The outcome of that is that because virAllocN always returns 0, the dispatch code never fails allocation and passes the NULL pointer to the server-side public API which actually checks that and fails. https://bugzilla.redhat.com/show_bug.cgi?id=1772842 Since v1: - reworked the original patch 3/3 (now 4/4) by introducing a virCheckNonNull-style macro which checks whether the caller-provided array isn't by any chance NULL while the declared size of this array is a positive int (Dan's suggestion) -> apart from the single scenario check (NULL && n > 0), the other combinations are allowed for the legacy APIs letting the server-side handle this - added patch 3/4 when I realized one of the legacy APIs which didn't have the dispatch code autogenerated needed adjustment too - I deliberately didn't touch the APIs using typed params, as half of them are setters and the other half is supposed to be called twice, so we already have various NULL checks in place - there were a few legacy APIs that already had some protection in the remote dispatch code, so I didn't touch the client side for those, IMO we can always treat those on case-by-case basis if a similar issue arises than risk breaking one third of libvirt now :P Erik Skultety (4): rpc: gendispatch: Fix a couple of places adding trailing spaces rpc: gendispatch: Add a check for zero size client-side buffers remote: Add a check for zero sized client-side buffers libvirt-<module>: Check caller-provided buffers to be NULL with size > 0 src/internal.h | 13 +++++++++++++ src/libvirt-domain-snapshot.c | 4 ++-- src/libvirt-domain.c | 21 ++++++--------------- src/libvirt-host.c | 2 +- src/libvirt-interface.c | 4 ++-- src/libvirt-network.c | 4 ++-- src/libvirt-nodedev.c | 4 ++-- src/libvirt-nwfilter.c | 2 +- src/libvirt-secret.c | 2 +- src/libvirt-storage.c | 6 +++--- src/remote/remote_daemon_dispatch.c | 6 ++++++ src/rpc/gendispatch.pl | 12 ++++++++++-- 12 files changed, 49 insertions(+), 31 deletions(-) -- 2.23.0