When no server name is provided in the URI, modern versions of libxml2 will set the port to '-1'. This is a change from behaviour with earlier versions which set it to 0. Libvirt expects the port to be 0 in these cases and as a result we get a bug when connecting to URIs which lack a server name: $ virsh -c test+ssh:///default list error: failed to connect to the hypervisor error: Cannot recv data: Bad port '-1': Connection reset by peer This libxml2 change was attempting to fix another bug identified by libvirt where it didn't roundtrip URIs correctly in: https://github.com/GNOME/libxml2/commit/beb7281055dbf0ed4d041022a67c6c5cf... Essentially libxml2 was not expecting apps to look at the URI port field when the server name is not provided. This was a reasonable assumption, but none the less libvirt did look at it :-) The fix is to ensure we explicitly set port to 0 when server name is not present, avoiding undefined behaviour for the port field in libxml2. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- src/util/viruri.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/src/util/viruri.c b/src/util/viruri.c index d4b793f439..c8811f64c6 100644 --- a/src/util/viruri.c +++ b/src/util/viruri.c @@ -171,7 +171,16 @@ virURIParse(const char *uri) goto error; if (VIR_STRDUP(ret->server, xmluri->server) < 0) goto error; - ret->port = xmluri->port; + /* xmluri->port value is not defined if server was + * not given. Modern versions libxml2 fill port + * differently to old versions in this case, so + * don't rely on it. eg libxml2 git commit: + * beb7281055dbf0ed4d041022a67c6c5cfd126f25 + */ + if (!ret->server || STREQ(ret->server, "")) + ret->port = 0; + else + ret->port = xmluri->port; if (VIR_STRDUP(ret->path, xmluri->path) < 0) goto error; #ifdef HAVE_XMLURI_QUERY_RAW -- 2.19.1