block/qcow2: extend qemu-img amend interface with crypto options

Now that we have all the infrastructure in place,
wire it in the qcow2 driver and expose this to the user.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200608094030.670121-9-mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 62 insertions, 9 deletions

diff --git a/block/qcow2.c b/block/qcow2.c
index 389205dffd..750e9c4842 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -176,6 +176,19 @@ static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset,
     return ret;
 }
 
+static QDict*
+qcow2_extract_crypto_opts(QemuOpts *opts, const char *fmt, Error **errp)
+{
+    QDict *cryptoopts_qdict;
+    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);
+    qdict_put_str(cryptoopts_qdict, "format", fmt);
+    return cryptoopts_qdict;
+}
 
 /*
  * read qcow2 extension and fill bs
@@ -4860,16 +4873,9 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
 
     if (has_luks) {
         g_autoptr(QCryptoBlockCreateOptions) create_opts = NULL;
-        QDict *opts_qdict;
-        QDict *cryptoopts;
+        QDict *cryptoopts = qcow2_extract_crypto_opts(opts, "luks", errp);
         size_t headerlen;
 
-        opts_qdict = qemu_opts_to_qdict(opts, NULL);
-        qdict_extract_subqdict(opts_qdict, &cryptoopts, "encrypt.");
-        qobject_unref(opts_qdict);
-
-        qdict_put_str(cryptoopts, "format", "luks");
-
         create_opts = block_crypto_create_opts_init(cryptoopts, errp);
         qobject_unref(cryptoopts);
         if (!create_opts) {
@@ -5273,6 +5279,7 @@ typedef enum Qcow2AmendOperation {
     QCOW2_NO_OPERATION = 0,
 
     QCOW2_UPGRADING,
+    QCOW2_UPDATING_ENCRYPTION,
     QCOW2_CHANGING_REFCOUNT_ORDER,
     QCOW2_DOWNGRADING,
 } Qcow2AmendOperation;
@@ -5354,6 +5361,7 @@ 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)) {
@@ -5380,6 +5388,18 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
             backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
         } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) {
             backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
+        } else if (g_str_has_prefix(desc->name, "encrypt.")) {
+            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_LAZY_REFCOUNTS)) {
             lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS,
                                                lazy_refcounts);
@@ -5422,7 +5442,8 @@ 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) */
@@ -5435,6 +5456,33 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
         }
     }
 
+    if (encryption_update) {
+        QDict *amend_opts_dict;
+        QCryptoBlockAmendOptions *amend_opts;
+
+        helper_cb_info.current_operation = QCOW2_UPDATING_ENCRYPTION;
+        amend_opts_dict = qcow2_extract_crypto_opts(opts, "luks", errp);
+        if (!amend_opts_dict) {
+            return -EINVAL;
+        }
+        amend_opts = block_crypto_amend_opts_init(amend_opts_dict, errp);
+        qobject_unref(amend_opts_dict);
+        if (!amend_opts) {
+            return -EINVAL;
+        }
+        ret = qcrypto_block_amend_options(s->crypto,
+                                          qcow2_crypto_hdr_read_func,
+                                          qcow2_crypto_hdr_write_func,
+                                          bs,
+                                          amend_opts,
+                                          force,
+                                          errp);
+        qapi_free_QCryptoBlockAmendOptions(amend_opts);
+        if (ret < 0) {
+            return ret;
+        }
+    }
+
     if (s->refcount_bits != refcount_bits) {
         int refcount_order = ctz32(refcount_bits);
 
@@ -5694,6 +5742,11 @@ static QemuOptsList qcow2_amend_opts = {
     .name = "qcow2-amend-opts",
     .head = QTAILQ_HEAD_INITIALIZER(qcow2_amend_opts.head),
     .desc = {
+        BLOCK_CRYPTO_OPT_DEF_LUKS_STATE("encrypt."),
+        BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT("encrypt."),
+        BLOCK_CRYPTO_OPT_DEF_LUKS_OLD_SECRET("encrypt."),
+        BLOCK_CRYPTO_OPT_DEF_LUKS_NEW_SECRET("encrypt."),
+        BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."),
         QCOW_COMMON_OPTIONS,
         { /* end of list */ }
     }