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If a non-NBD client connects to qemu-nbd, we would end up with a SIGSEGV in nbd_client_put() because we were trying to unregister the client's association to the export, even though we skipped inserting the client into that list. Easy trigger in two terminals: $ qemu-nbd -p 30001 --format=raw file $ nmap 127.0.0.1 -p 30001 nmap claims that it thinks it connected to a pago-services1 server (which probably means nmap could be updated to learn the NBD protocol and give a more accurate diagnosis of the open port - but that's not our problem), then terminates immediately, so our call to nbd_negotiate() fails. The fix is to reorder nbd_co_client_start() to ensure that all initialization occurs before we ever try talking to a client in nbd_negotiate(), so that the teardown sequence on negotiation failure doesn't fault while dereferencing a half-initialized object. While debugging this, I also noticed that nbd_update_server_watch() called by nbd_client_closed() was still adding a channel to accept the next client, even when the state was no longer RUNNING. That is fixed by making nbd_can_accept() pay attention to the current state. Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1451614 Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20170527030421.28366-1-eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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| .. | ||
| client.c | ||
| common.c | ||
| Makefile.objs | ||
| nbd-internal.h | ||
| server.c | ||