fix(vhd-lib): VhdFile implementation is not compatible with encrypted remote (#7045)

CHANGELOG.unreleased.md

@@ -17,6 +17,7 @@
 - [Google/GitHub Auth] Fix `Internal Server Error` (xo-server: `Cannot read properties of undefined (reading 'id')`) when logging in with Google or GitHub [Forum#7729](https://xcp-ng.org/forum/topic/7729) (PRs [#7031](https://github.com/vatesfr/xen-orchestra/pull/7031) [#7032](https://github.com/vatesfr/xen-orchestra/pull/7032))
 - [Jobs] Fix schedules not being displayed on first load [#6968](https://github.com/vatesfr/xen-orchestra/issues/6968) (PR [#7034](https://github.com/vatesfr/xen-orchestra/pull/7034))
 - [OVA Export] Fix support of disks with more than 8.2GiB of content (PR [#7047](https://github.com/vatesfr/xen-orchestra/pull/7047))
+- [Backup] Fix `VHDFile implementation is not compatible with encrypted remote` when using VHD directory with encryption (PR [#7045](https://github.com/vatesfr/xen-orchestra/pull/7045))
 
 ### Packages to release
 
@@ -34,6 +35,7 @@
 
 <!--packages-start-->
 
+- vhd-lib minor
 - xo-server patch
 - xo-server-auth-github patch
 - xo-server-auth-google patch

packages/vhd-lib/Vhd/VhdFile.js

@@ -83,9 +83,6 @@ exports.VhdFile = class VhdFile extends VhdAbstract {
   }
 
   static async open(handler, path, { flags, checkSecondFooter = true } = {}) {
-    if (handler.isEncrypted) {
-      throw new Error(`VHDFile implementation is not compatible with encrypted remote`)
-    }
     const fd = await handler.openFile(path, flags ?? 'r+')
     const vhd = new VhdFile(handler, fd)
     // openning a file for reading does not trigger EISDIR as long as we don't really read from it :
@@ -93,7 +90,13 @@ exports.VhdFile = class VhdFile extends VhdAbstract {
     // EISDIR pathname refers to a directory and the access requested
     // involved writing (that is, O_WRONLY or O_RDWR is set).
     // reading the header ensure we have a well formed file immediatly
-    await vhd.readHeaderAndFooter(checkSecondFooter)
+    try {
+      // can throw if handler is encrypted or remote is broken
+      await vhd.readHeaderAndFooter(checkSecondFooter)
+    } catch (err) {
+      await handler.closeFile(fd)
+      throw err
+    }
     return {
       dispose: () => handler.closeFile(fd),
       value: vhd,

packages/vhd-lib/openVhd.js

@@ -6,12 +6,19 @@ const { VhdFile } = require('./Vhd/VhdFile.js')
 
 exports.openVhd = async function openVhd(handler, path, opts) {
   const resolved = await resolveVhdAlias(handler, path)
-  try {
-    return await VhdFile.open(handler, resolved, opts)
-  } catch (e) {
-    if (e.code !== 'EISDIR') {
-      throw e
+
+  // VHD files can't be encrypted since we can't modify part of a file during merge
+  //
+  // Skip trying to open it if the remote is encrypted
+  if (!handler.isEncrypted) {
+    try {
+      return await VhdFile.open(handler, resolved, opts)
+    } catch (e) {
+      if (e.code !== 'EISDIR') {
+        throw e
+      }
     }
-    return await VhdDirectory.open(handler, resolved, opts)
   }
+
+  return await VhdDirectory.open(handler, resolved, opts)
 }