On a Thursday in 2021, Peter Krempa wrote:
Commit 95f8e3237e5486f487324c6 which introduced XML schema validation for snapshot XMLs always asserted the validation for the XML generated by 'virsh snapshot-create-as' on the basis that it's libvirt-generated, thus valid.
This unfortunately isn't true as users can influence certain bits of the XML such as the disk image path which must be a full path. Thus if a user tries to invoke virsh as:
$ virsh snapshot-create-as upstream --diskspec vda,file=relative.qcow2 error: XML document failed to validate against schema: Unable to validate doc against /path/to/domainsnapshot.rng Extra element disks in interleave Element domainsnapshot failed to validate content
They get a rather useless error from the libxml2 RNG validator.
With this fix applied, we get to the XML parser in libvirtd which has a more reasonable error:
$ virsh snapshot-create-as upstream --diskspec vda,file=relative.qcow2 error: XML error: disk snapshot image path 'relative.qcow2' must be absolute
Instead users can force validation of the XML generated by 'virsh snapshot-create-as' by passing the '--validate' flag.
Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- docs/manpages/virsh.rst | 4 +++- tools/virsh-snapshot.c | 8 +++++++- 2 files changed, 10 insertions(+), 2 deletions(-)
Reviewed-by: Ján Tomko <jtomko@redhat.com> Jano