Libguestfs - Mar 2020 - [PATCH v2v v3 0/2] rhv-upload: Validate UUIDs and check they don't exist already

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

The validation helps us fail early and with a sensible error message.  The NIL
UUID is not valid for oVirt, but other than that there is no other logic in
there merely because the UUID types are a matter of the generator and they are
just forwarded in this partucular case.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
---
 v2v/output_rhv_upload.ml | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/v2v/output_rhv_upload.ml b/v2v/output_rhv_upload.ml
index 9e60d8c73150..e833569318b3 100644
--- a/v2v/output_rhv_upload.ml
+++ b/v2v/output_rhv_upload.ml
@@ -49,6 +49,16 @@ after their uploads (if you do, you must supply one for each
disk):
   -oo rhv-disk-uuid=UUID          Disk UUID
 ")
 
+let is_nonnil_uuid uuid +  let nil_uuid =
"00000000-0000-0000-0000-000000000000" in
+  let rex_uuid = lazy (
+    let hex = "[a-fA-F0-9]" in
+    let str = sprintf "^%s{8}-%s{4}-%s{4}-%s{4}-%s{12}$" hex hex hex
hex hex in
+    PCRE.compile str
+  ) in
+  if uuid = nil_uuid then false
+  else PCRE.matches (Lazy.force rex_uuid) uuid
+
 let parse_output_options options    let rhv_cafile = ref None in
   let rhv_cluster = ref None in
@@ -71,6 +81,8 @@ let parse_output_options options      |
"rhv-verifypeer", "" -> rhv_verifypeer := true
     | "rhv-verifypeer", v -> rhv_verifypeer := bool_of_string v
     | "rhv-disk-uuid", v ->
+       if not (is_nonnil_uuid v) then
+         error (f_"-o rhv-upload: invalid UUID for -oo
rhv-disk-uuid");
        rhv_disk_uuids := Some (v :: (Option.default [] !rhv_disk_uuids))
     | k, _ ->
        error (f_"-o rhv-upload: unknown output option ‘-oo %s’") k
-- 
2.25.1

This makes the code fail with a sensible error message instead of cryptic error
from ovirtsdk.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
---
 v2v/output_rhv_upload.ml   |  6 ++++++
 v2v/rhv-upload-precheck.py | 10 ++++++++++
 2 files changed, 16 insertions(+)

diff --git a/v2v/output_rhv_upload.ml b/v2v/output_rhv_upload.ml
index e833569318b3..c9fce5b95ec6 100644
--- a/v2v/output_rhv_upload.ml
+++ b/v2v/output_rhv_upload.ml
@@ -262,6 +262,12 @@ object
     error_unless_output_alloc_sparse output_alloc;
 
     (* Python code prechecks. *)
+    let json_params = match rhv_options.rhv_disk_uuids with
+    | None -> json_params
+    | Some uuids ->
+        let ids = List.map (fun uuid -> JSON.String uuid) uuids in
+        ("rhv_disk_uuids", JSON.List ids) :: json_params
+    in
     let precheck_fn = tmpdir // "v2vprecheck.json" in
     let fd = Unix.openfile precheck_fn [O_WRONLY; O_CREAT] 0o600 in
     if Python_script.run_command ~stdout_fd:fd
diff --git a/v2v/rhv-upload-precheck.py b/v2v/rhv-upload-precheck.py
index ec3fcf4e5c20..0daa485e073b 100644
--- a/v2v/rhv-upload-precheck.py
+++ b/v2v/rhv-upload-precheck.py
@@ -97,6 +97,16 @@ if cpu.architecture == types.Architecture.UNDEFINED:
     raise RuntimeError("The cluster ‘%s’ has an unknown architecture"
%
                        (params['rhv_cluster']))
 
+# Find if any disk already exists with specified UUID.
+disks_service = system_service.disks_service()
+
+for uuid in params.get('rhv_disk_uuids', []):
+    try:
+        disk_service = disks_service.disk_service(uuid).get()
+        raise RuntimeError("Disk with the UUID '%s' already
exists" % uuid)
+    except sdk.NotFoundError:
+        pass
+
 # Otherwise everything is OK, print a JSON with the results.
 results = {
     "rhv_storagedomain_uuid": storage_domain.id,
-- 
2.25.1

On Wed, Mar 11, 2020 at 03:54:33PM +0100, Martin Kletzander
wrote:
> The validation helps us fail early and with a sensible error message.  The
NIL
> UUID is not valid for oVirt, but other than that there is no other logic in
> there merely because the UUID types are a matter of the generator and they
are
> just forwarded in this partucular case.
> 
> Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
> ---
>  v2v/output_rhv_upload.ml | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/v2v/output_rhv_upload.ml b/v2v/output_rhv_upload.ml
> index 9e60d8c73150..e833569318b3 100644
> --- a/v2v/output_rhv_upload.ml
> +++ b/v2v/output_rhv_upload.ml
> @@ -49,6 +49,16 @@ after their uploads (if you do, you must supply one for
each disk):
>    -oo rhv-disk-uuid=UUID          Disk UUID
>  ")
>  
> +let is_nonnil_uuid uuid > +  let nil_uuid =
"00000000-0000-0000-0000-000000000000" in
> +  let rex_uuid = lazy (
> +    let hex = "[a-fA-F0-9]" in
> +    let str = sprintf "^%s{8}-%s{4}-%s{4}-%s{4}-%s{12}$" hex hex
hex hex hex in
> +    PCRE.compile str
> +  ) in
> +  if uuid = nil_uuid then false
> +  else PCRE.matches (Lazy.force rex_uuid) uuid
> +
>  let parse_output_options options >    let rhv_cafile = ref None in
>    let rhv_cluster = ref None in
> @@ -71,6 +81,8 @@ let parse_output_options options >      |
"rhv-verifypeer", "" -> rhv_verifypeer := true
>      | "rhv-verifypeer", v -> rhv_verifypeer := bool_of_string
v
>      | "rhv-disk-uuid", v ->
> +       if not (is_nonnil_uuid v) then
> +         error (f_"-o rhv-upload: invalid UUID for -oo
rhv-disk-uuid");
>         rhv_disk_uuids := Some (v :: (Option.default [] !rhv_disk_uuids))
>      | k, _ ->
>         error (f_"-o rhv-upload: unknown output option ‘-oo %s’")
k
> -- 
It needs to document the new option in docs/virt-v2v-output-rhv.pod

and in v2v/output_rhv_upload.ml in the print_output_options ()
function a little bit earlier in the file.

Apart from this the patch series is fine.  Personally I think I would
have jammed the two patches into one, not sure I follow why they're
separate, but that's just a style thing.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine.  Supports Linux and Windows.
http://people.redhat.com/~rjones/virt-df/

On Wed, Mar 11, 2020 at 03:54:33PM +0100, Martin Kletzander
wrote:
> The validation helps us fail early and with a sensible error message.  The
NIL
> UUID is not valid for oVirt, but other than that there is no other logic in
> there merely because the UUID types are a matter of the generator and they
are
> just forwarded in this partucular case.
> 
> Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
> ---
>  v2v/output_rhv_upload.ml | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/v2v/output_rhv_upload.ml b/v2v/output_rhv_upload.ml
> index 9e60d8c73150..e833569318b3 100644
> --- a/v2v/output_rhv_upload.ml
> +++ b/v2v/output_rhv_upload.ml
> @@ -49,6 +49,16 @@ after their uploads (if you do, you must supply one for
each disk):
>    -oo rhv-disk-uuid=UUID          Disk UUID
>  ")
>  
> +let is_nonnil_uuid uuid > +  let nil_uuid =
"00000000-0000-0000-0000-000000000000" in
> +  let rex_uuid = lazy (
> +    let hex = "[a-fA-F0-9]" in
> +    let str = sprintf "^%s{8}-%s{4}-%s{4}-%s{4}-%s{12}$" hex hex
hex hex hex in
> +    PCRE.compile str
> +  ) in
> +  if uuid = nil_uuid then false
> +  else PCRE.matches (Lazy.force rex_uuid) uuid
Actually the use of lazy here is wrong.  The regular expression
is not being created lazily at all.

You need to do something like:

let is_nonnil_uuid   let nil_uuid =
"00000000-0000-0000-0000-000000000000" in
  let rex_uuid = lazy (
    let hex = "[a-fA-F0-9]" in
    let str = sprintf "^%s{8}-%s{4}-%s{4}-%s{4}-%s{12}$" hex hex hex
hex hex in
    PCRE.compile str
  ) in
  fun uuid ->
    if uuid = nil_uuid then false
    else PCRE.matches (Lazy.force rex_uuid) uuid

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine.  Supports Linux and Windows.
http://people.redhat.com/~rjones/virt-df/