My stab v3 at fixing this: https://bugzilla.redhat.com/show_bug.cgi?id=1789279 It took me quite some time to go through the whole rfc 4122 just to realize we do not need to do anything with the versions. v3: - Do the check in precheck - Fix for Lazy evaluation of regexp UUID v2: - https://www.redhat.com/archives/libguestfs/2020-January/msg00221.html - Use EEXIST instead of EINVAL - Put the colliding UUID into the error - Do not evaluate the PCRE needlessly multiple times v1: https://www.redhat.com/archives/libguestfs/2020-January/msg00184.html Martin Kletzander (2): rhv-upload: Validate UUIDs passed to -oo rhv-disk-uuid (RHBZ#1789279) rhv-upload: Check that rhv-disk-uuid is not already taken (RHBZ#1789279) v2v/output_rhv_upload.ml | 18 ++++++++++++++++++ v2v/rhv-upload-precheck.py | 10 ++++++++++ 2 files changed, 28 insertions(+) -- 2.25.1