Re: [libvirt] [PATCH] Don't crash if a connection closes early

https://bugzilla.redhat.com/show_bug.cgi?id=1047577 When a client closes its connection to libvirtd early during virConnectOpen, more specifically just after making REMOTE_PROC_CONNECT_SUPPORTS_FEATURE call to check if VIR_DRV_FEATURE_PROGRAM_KEEPALIVE is supported without even waiting for the result, libvirtd may crash due to a race in keep-alive initialization. Once receiving the REMOTE_PROC_CONNECT_SUPPORTS_FEATURE call, the daemon's event loop delegates it to a worker thread. In case the event loop detects EOF on the connection and calls virNetServerClientClose before the worker thread starts to handle REMOTE_PROC_CONNECT_SUPPORTS_FEATURE call, client->keepalive will be disposed by the time virNetServerClientStartKeepAlive gets called from remoteDispatchConnectSupportsFeature. Because the flow is common for both authenticated and read-only connections, even unprivileged clients may cause the daemon to crash. To void the crash, virNetServerClientStartKeepAlive needs to check if

the connection is still open before starting keep-alive protocol. Every libvirt release since 0.9.8 is affected by this bug. Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; --- src/rpc/virnetserverclient.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)