In case get_spec_node() is being called for a special node starting
with '@' it won't set *canonical_name. This can result in a crash of
xenstored due to dereferencing the uninitialized name in
fire_watches().
This is no security issue as it requires either a privileged caller or
ownership of the special node in question by an unprivileged caller
(which is questionable, as this would make the owner privileged in some
way).
Fixes: d6bb63924f ("tools/xenstore: introduce dummy nodes for special watch paths")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>