[libvirt] [PATCH 11/14] qemu: command: Add support for qcow2 + luks

[Peter Krempa]

The old qcow2 encryption format was buggy, so the new approach is to use
luks inside qcow2. As it turns out, it didn't require that many changes.

It was necessary to fix the command line formatter to stop mangling the
format when secrets are present and specify the encryption format and
secret in correct format.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
You can easily create a qcow2+luks disk image by:

qemu-img create --object secret,id=sec0,data=asdf -f qcow2 \
    -o encrypt.format=luks,encrypt.key-secret=sec0 luks.qcow2 10M

 src/qemu/qemu_command.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 6a13714eae..c1225591b3 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -1525,6 +1525,7 @@ qemuBuildDriveSourceStr(virDomainDiskDefPtr disk,
     qemuDomainSecretInfoPtr encinfo = NULL;
     virJSONValuePtr srcprops = NULL;
     char *source = NULL;
+    bool rawluks = false;
     int ret = -1;

     if (srcpriv) {
@@ -1598,14 +1599,21 @@ qemuBuildDriveSourceStr(virDomainDiskDefPtr disk,
     }
     virBufferAddLit(buf, ",");

-    if (encinfo)
-        virQEMUBuildLuksOpts(buf, &disk->src->encryption->encinfo,
-                             encinfo->s.aes.alias);
+    if (encinfo) {
+        if (disk->src->format == VIR_STORAGE_FILE_RAW) {
+            virBufferAsprintf(buf, "key-secret=%s,", encinfo->s.aes.alias);
+            rawluks = true;
+        } else if (disk->src->format == VIR_STORAGE_FILE_QCOW2 &&
+                   disk->src->encryption->format == VIR_STORAGE_ENCRYPTION_FORMAT_LUKS) {
+            virBufferAddLit(buf, "encrypt.format=luks,");
+            virBufferAsprintf(buf, "encrypt.key-secret=%s,", encinfo->s.aes.alias);
+        }
+    }

     if (disk->src->format > 0 &&
         disk->src->type != VIR_STORAGE_TYPE_DIR) {
         const char *qemuformat = virStorageFileFormatTypeToString(disk->src->format);
-        if (qemuDomainDiskHasEncryptionSecret(disk->src))
+        if (rawluks)
             qemuformat = "luks";
         virBufferAsprintf(buf, "format=%s,", qemuformat);
     }
-- 
2.16.2