[Qemu-devel] [PATCH v2 06/11] qcow2: implement crypto amend options

[Maxim Levitsky <mlevitsk@redhat.com>]

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 block/qcow2.c | 77 +++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 62 insertions(+), 15 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index 0618a63793..26f83aeb44 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -172,6 +172,25 @@ static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset,
     return ret;
 }
 
+static QCryptoBlockCreateOptions*
+qcow2_extract_crypto_create_opts(QemuOpts *opts, const char *fmt, Error **errp)
+{
+    QDict *cryptoopts_qdict;
+    QCryptoBlockCreateOptions *cryptoopts;
+    QDict *opts_qdict;
+
+    /* Extract "encrypt." options into a qdict */
+    opts_qdict = qemu_opts_to_qdict(opts, NULL);
+    qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt.");
+    qobject_unref(opts_qdict);
+
+    /* Build QCryptoBlockCreateOptions object from qdict */
+    qdict_put_str(cryptoopts_qdict, "format", "luks");
+    cryptoopts = block_crypto_create_opts_init(cryptoopts_qdict, errp);
+    qobject_unref(cryptoopts_qdict);
+    return cryptoopts;
+}
+
 
 /* 
  * read qcow2 extension and fill bs
@@ -4365,20 +4384,10 @@ static ssize_t qcow2_measure_crypto_hdr_write_func(QCryptoBlock *block,
 static bool qcow2_measure_luks_headerlen(QemuOpts *opts, size_t *len,
                                          Error **errp)
 {
-    QDict *opts_qdict;
-    QDict *cryptoopts_qdict;
     QCryptoBlockCreateOptions *cryptoopts;
     QCryptoBlock *crypto;
 
-    /* Extract "encrypt." options into a qdict */
-    opts_qdict = qemu_opts_to_qdict(opts, NULL);
-    qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt.");
-    qobject_unref(opts_qdict);
-
-    /* Build QCryptoBlockCreateOptions object from qdict */
-    qdict_put_str(cryptoopts_qdict, "format", "luks");
-    cryptoopts = block_crypto_create_opts_init(cryptoopts_qdict, errp);
-    qobject_unref(cryptoopts_qdict);
+    cryptoopts = qcow2_extract_crypto_create_opts(opts, "luks", errp);
     if (!cryptoopts) {
         return false;
     }
@@ -4755,6 +4764,7 @@ typedef enum Qcow2AmendOperation {
      * invocation from an operation change */
     QCOW2_NO_OPERATION = 0,
 
+    QCOW2_UPDATING_ENCRYPTION,
     QCOW2_CHANGING_REFCOUNT_ORDER,
     QCOW2_DOWNGRADING,
 } Qcow2AmendOperation;
@@ -4839,6 +4849,7 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
     int ret;
     QemuOptDesc *desc = opts->list->desc;
     Qcow2AmendHelperCBInfo helper_cb_info;
+    bool encryption_update = false;
 
     while (desc && desc->name) {
         if (!qemu_opt_find(opts, desc->name)) {
@@ -4887,9 +4898,22 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
                 return -ENOTSUP;
             }
         } else if (g_str_has_prefix(desc->name, "encrypt.")) {
-            error_setg(errp,
-                       "Changing the encryption parameters is not supported");
-            return -ENOTSUP;
+
+            if (!s->crypto) {
+                error_setg(errp,
+                           "Can't amend encryption options - encryption not present");
+                return -EINVAL;
+
+            }
+
+            if (s->crypt_method_header != QCOW_CRYPT_LUKS) {
+                error_setg(errp,
+                           "Only LUKS encryption options can be amended");
+                return -ENOTSUP;
+            }
+
+            encryption_update = true;
+
         } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) {
             cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE,
                                              cluster_size);
@@ -4939,7 +4963,8 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
         .original_status_cb = status_cb,
         .original_cb_opaque = cb_opaque,
         .total_operations = (new_version < old_version)
-                          + (s->refcount_bits != refcount_bits)
+                          + (s->refcount_bits != refcount_bits) +
+                          (encryption_update == true)
     };
 
     /* Upgrade first (some features may require compat=1.1) */
@@ -4953,6 +4978,28 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
         }
     }
 
+    if (encryption_update) {
+        QCryptoBlockCreateOptions *cryptoopts;
+
+        cryptoopts = qcow2_extract_crypto_create_opts(opts, "luks", errp);
+        if (!cryptoopts) {
+            return -EINVAL;
+        }
+
+        helper_cb_info.current_operation = QCOW2_UPDATING_ENCRYPTION;
+
+        ret = qcrypto_block_amend_options(s->crypto,
+                                          qcow2_crypto_hdr_read_func,
+                                          qcow2_crypto_hdr_write_func,
+                                          bs,
+                                          cryptoopts,
+                                          force,
+                                          errp);
+        if (ret < 0) {
+            return ret;
+        }
+    }
+
     if (s->refcount_bits != refcount_bits) {
         int refcount_order = ctz32(refcount_bits);
 
-- 
2.17.2