[Qemu-devel] [PULL 057/100] block: remove all encryption handling APIs

[Kevin Wolf <kwolf@redhat.com>]

From: "Daniel P. Berrange" <berrange@redhat.com>

Now that all encryption keys must be provided upfront via
the QCryptoSecret API and associated block driver properties
there is no need for any explicit encryption handling APIs
in the block layer. Encryption can be handled transparently
within the block driver. We only retain an API for querying
whether an image is encrypted or not, since that is a
potentially useful piece of metadata to report to the user.

Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-18-berrange@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block.c                   | 77 +----------------------------------------------
 block/crypto.c            |  1 -
 block/qapi.c              |  2 +-
 block/qcow.c              |  8 ++++-
 block/qcow2.c             |  1 -
 blockdev.c                | 37 ++---------------------
 hmp-commands.hx           |  2 ++
 include/block/block.h     |  3 --
 include/block/block_int.h |  1 -
 include/qapi/error.h      |  1 -
 qapi/block-core.json      | 37 ++---------------------
 qapi/common.json          |  5 +--
 12 files changed, 16 insertions(+), 159 deletions(-)

diff --git a/block.c b/block.c
index 6943962..edfa6b7 100644
--- a/block.c
+++ b/block.c
@@ -2573,15 +2573,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
         goto close_and_fail;
     }
 
-    if (!bdrv_key_required(bs)) {
-        bdrv_parent_cb_change_media(bs, true);
-    } else if (!runstate_check(RUN_STATE_PRELAUNCH)
-               && !runstate_check(RUN_STATE_INMIGRATE)
-               && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */
-        error_setg(errp,
-                   "Guest must be stopped for opening of encrypted image");
-        goto close_and_fail;
-    }
+    bdrv_parent_cb_change_media(bs, true);
 
     QDECREF(options);
 
@@ -3072,7 +3064,6 @@ static void bdrv_close(BlockDriverState *bs)
         bs->backing_format[0] = '\0';
         bs->total_sectors = 0;
         bs->encrypted = false;
-        bs->valid_key = false;
         bs->sg = false;
         QDECREF(bs->options);
         QDECREF(bs->explicit_options);
@@ -3502,72 +3493,6 @@ bool bdrv_is_encrypted(BlockDriverState *bs)
     return bs->encrypted;
 }
 
-bool bdrv_key_required(BlockDriverState *bs)
-{
-    BdrvChild *backing = bs->backing;
-
-    if (backing && backing->bs->encrypted && !backing->bs->valid_key) {
-        return true;
-    }
-    return (bs->encrypted && !bs->valid_key);
-}
-
-int bdrv_set_key(BlockDriverState *bs, const char *key)
-{
-    int ret;
-    if (bs->backing && bs->backing->bs->encrypted) {
-        ret = bdrv_set_key(bs->backing->bs, key);
-        if (ret < 0)
-            return ret;
-        if (!bs->encrypted)
-            return 0;
-    }
-    if (!bs->encrypted) {
-        return -EINVAL;
-    } else if (!bs->drv || !bs->drv->bdrv_set_key) {
-        return -ENOMEDIUM;
-    }
-    ret = bs->drv->bdrv_set_key(bs, key);
-    if (ret < 0) {
-        bs->valid_key = false;
-    } else if (!bs->valid_key) {
-        /* call the change callback now, we skipped it on open */
-        bs->valid_key = true;
-        bdrv_parent_cb_change_media(bs, true);
-    }
-    return ret;
-}
-
-/*
- * Provide an encryption key for @bs.
- * If @key is non-null:
- *     If @bs is not encrypted, fail.
- *     Else if the key is invalid, fail.
- *     Else set @bs's key to @key, replacing the existing key, if any.
- * If @key is null:
- *     If @bs is encrypted and still lacks a key, fail.
- *     Else do nothing.
- * On failure, store an error object through @errp if non-null.
- */
-void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp)
-{
-    if (key) {
-        if (!bdrv_is_encrypted(bs)) {
-            error_setg(errp, "Node '%s' is not encrypted",
-                      bdrv_get_device_or_node_name(bs));
-        } else if (bdrv_set_key(bs, key) < 0) {
-            error_setg(errp, QERR_INVALID_PASSWORD);
-        }
-    } else {
-        if (bdrv_key_required(bs)) {
-            error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED,
-                      "'%s' (%s) is encrypted",
-                      bdrv_get_device_or_node_name(bs),
-                      bdrv_get_encrypted_filename(bs));
-        }
-    }
-}
-
 const char *bdrv_get_format_name(BlockDriverState *bs)
 {
     return bs->drv ? bs->drv->format_name : NULL;
diff --git a/block/crypto.c b/block/crypto.c
index da4be74..3ad4b20 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -308,7 +308,6 @@ static int block_crypto_open_generic(QCryptoBlockFormat format,
     }
 
     bs->encrypted = true;
-    bs->valid_key = true;
 
     ret = 0;
  cleanup:
diff --git a/block/qapi.c b/block/qapi.c
index 0a41d59..080eb8f 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -45,7 +45,7 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
     info->ro                     = bs->read_only;
     info->drv                    = g_strdup(bs->drv->format_name);
     info->encrypted              = bs->encrypted;
-    info->encryption_key_missing = bdrv_key_required(bs);
+    info->encryption_key_missing = false;
 
     info->cache = g_new(BlockdevCacheInfo, 1);
     *info->cache = (BlockdevCacheInfo) {
diff --git a/block/qcow.c b/block/qcow.c
index db0c5a9..8a24930 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -220,7 +220,13 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
             goto fail;
         }
         bs->encrypted = true;
-        bs->valid_key = true;
+    } else {
+        if (encryptfmt) {
+            error_setg(errp, "No encryption in image header, but options "
+                       "specified format '%s'", encryptfmt);
+            ret = -EINVAL;
+            goto fail;
+        }
     }
     s->cluster_bits = header.cluster_bits;
     s->cluster_size = 1 << s->cluster_bits;
diff --git a/block/qcow2.c b/block/qcow2.c
index 7d1c5a3..2dd5d51 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1171,7 +1171,6 @@ static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,
         }
 
         bs->encrypted = true;
-        bs->valid_key = true;
     }
 
     s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
diff --git a/blockdev.c b/blockdev.c
index e2016b6..92c5991 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -593,10 +593,6 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
 
         bs->detect_zeroes = detect_zeroes;
 
-        if (bdrv_key_required(bs)) {
-            autostart = 0;
-        }
-
         block_acct_setup(blk_get_stats(blk), account_invalid, account_failed);
 
         if (!parse_stats_intervals(blk_get_stats(blk), interval_list, errp)) {
@@ -2265,24 +2261,8 @@ void qmp_block_passwd(bool has_device, const char *device,
                       bool has_node_name, const char *node_name,
                       const char *password, Error **errp)
 {
-    Error *local_err = NULL;
-    BlockDriverState *bs;
-    AioContext *aio_context;
-
-    bs = bdrv_lookup_bs(has_device ? device : NULL,
-                        has_node_name ? node_name : NULL,
-                        &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-        return;
-    }
-
-    aio_context = bdrv_get_aio_context(bs);
-    aio_context_acquire(aio_context);
-
-    bdrv_add_key(bs, password, errp);
-
-    aio_context_release(aio_context);
+    error_setg(errp,
+               "Setting block passwords directly is no longer supported");
 }
 
 /*
@@ -2591,12 +2571,6 @@ void qmp_blockdev_change_medium(bool has_device, const char *device,
         goto fail;
     }
 
-    bdrv_add_key(medium_bs, NULL, &err);
-    if (err) {
-        error_propagate(errp, err);
-        goto fail;
-    }
-
     rc = do_open_tray(has_device ? device : NULL,
                       has_id ? id : NULL,
                       false, &err);
@@ -3866,13 +3840,6 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
 
     QTAILQ_INSERT_TAIL(&monitor_bdrv_states, bs, monitor_list);
 
-    if (bs && bdrv_key_required(bs)) {
-        QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
-        bdrv_unref(bs);
-        error_setg(errp, "blockdev-add doesn't support encrypted devices");
-        goto fail;
-    }
-
 fail:
     visit_free(v);
 }
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 275ccdf..75f8bac 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1646,6 +1646,8 @@ STEXI
 @item block_passwd @var{device} @var{password}
 @findex block_passwd
 Set the encrypted device @var{device} password to @var{password}
+
+This command is now obsolete and will always return an error since 2.10
 ETEXI
 
     {
diff --git a/include/block/block.h b/include/block/block.h
index 4a27252..2d637d1 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -464,9 +464,6 @@ BlockDriverState *bdrv_next(BdrvNextIterator *it);
 
 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
 bool bdrv_is_encrypted(BlockDriverState *bs);
-bool bdrv_key_required(BlockDriverState *bs);
-int bdrv_set_key(BlockDriverState *bs, const char *key);
-void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp);
 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
                          void *opaque);
 const char *bdrv_get_node_name(const BlockDriverState *bs);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 701508d..b9069c5 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -529,7 +529,6 @@ struct BlockDriverState {
     int open_flags; /* flags used to open the file, re-used for re-open */
     bool read_only; /* if true, the media is read only */
     bool encrypted; /* if true, the media is encrypted */
-    bool valid_key; /* if true, a valid encryption key has been set */
     bool sg;        /* if true, the device is a /dev/sg* */
     bool probed;    /* if true, format was probed rather than specified */
     bool force_share; /* if true, always allow all shared permissions */
diff --git a/include/qapi/error.h b/include/qapi/error.h
index 7e532d0..5d5e737 100644
--- a/include/qapi/error.h
+++ b/include/qapi/error.h
@@ -125,7 +125,6 @@
 typedef enum ErrorClass {
     ERROR_CLASS_GENERIC_ERROR = QAPI_ERROR_CLASS_GENERICERROR,
     ERROR_CLASS_COMMAND_NOT_FOUND = QAPI_ERROR_CLASS_COMMANDNOTFOUND,
-    ERROR_CLASS_DEVICE_ENCRYPTED = QAPI_ERROR_CLASS_DEVICEENCRYPTED,
     ERROR_CLASS_DEVICE_NOT_ACTIVE = QAPI_ERROR_CLASS_DEVICENOTACTIVE,
     ERROR_CLASS_DEVICE_NOT_FOUND = QAPI_ERROR_CLASS_DEVICENOTFOUND,
     ERROR_CLASS_KVM_MISSING_CAP = QAPI_ERROR_CLASS_KVMMISSINGCAP,
diff --git a/qapi/block-core.json b/qapi/block-core.json
index bb075c0..d04d277 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -259,8 +259,7 @@
 #
 # @encrypted: true if the backing device is encrypted
 #
-# @encryption_key_missing: true if the backing device is encrypted but an
-#                          valid encryption key is missing
+# @encryption_key_missing: Deprecated; always false
 #
 # @detect_zeroes: detect and optimize zero writes (Since 2.1)
 #
@@ -946,39 +945,7 @@
 # This command sets the password of a block device that has not been open
 # with a password and requires one.
 #
-# The two cases where this can happen are a block device is created through
-# QEMU's initial command line or a block device is changed through the legacy
-# @change interface.
-#
-# In the event that the block device is created through the initial command
-# line, the VM will start in the stopped state regardless of whether '-S' is
-# used.  The intention is for a management tool to query the block devices to
-# determine which ones are encrypted, set the passwords with this command, and
-# then start the guest with the @cont command.
-#
-# Either @device or @node-name must be set but not both.
-#
-# @device: the name of the block backend device to set the password on
-#
-# @node-name: graph node name to set the password on (Since 2.0)
-#
-# @password: the password to use for the device
-#
-# Returns: nothing on success
-#          If @device is not a valid block device, DeviceNotFound
-#          If @device is not encrypted, DeviceNotEncrypted
-#
-# Notes:  Not all block formats support encryption and some that do are not
-#         able to validate that a password is correct.  Disk corruption may
-#         occur if an invalid password is specified.
-#
-# Since: 0.14.0
-#
-# Example:
-#
-# -> { "execute": "block_passwd", "arguments": { "device": "ide0-hd0",
-#                                                "password": "12345" } }
-# <- { "return": {} }
+# This command is now obsolete and will always return an error since 2.10
 #
 ##
 { 'command': 'block_passwd', 'data': {'*device': 'str',
diff --git a/qapi/common.json b/qapi/common.json
index b626647..8355d5a 100644
--- a/qapi/common.json
+++ b/qapi/common.json
@@ -14,9 +14,6 @@
 #
 # @CommandNotFound: the requested command has not been found
 #
-# @DeviceEncrypted: the requested operation can't be fulfilled because the
-#                   selected device is encrypted
-#
 # @DeviceNotActive: a device has failed to be become active
 #
 # @DeviceNotFound: the requested device has not been found
@@ -28,7 +25,7 @@
 ##
 { 'enum': 'QapiErrorClass',
   # Keep this in sync with ErrorClass in error.h
-  'data': [ 'GenericError', 'CommandNotFound', 'DeviceEncrypted',
+  'data': [ 'GenericError', 'CommandNotFound',
             'DeviceNotActive', 'DeviceNotFound', 'KVMMissingCap' ] }
 
 ##
-- 
1.8.3.1