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/beb7281055dbf0ed4d041022a67c6c5cfd126f25
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@redhat.com>
---
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
--
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On Tue, Nov 13, 2018 at 11:36:57AM +0000, Daniel P. Berrangé wrote: > 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/beb7281055dbf0ed4d041022a67c6c5cfd126f25 > > 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@redhat.com> > --- Reviewed-by: Erik Skultety <eskultet@redhat.com> -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
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