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

[Eric Blake]

On 01/10/2014 12:19 PM, Jiri Denemark wrote:
> 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

s/void/avoid/

> 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 at redhat.com>
> ---
>  src/rpc/virnetserverclient.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)

ACK.  Definitely worth having in 1.2.1.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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