3:47 a.m.
On Mon, Mar 06, 2023 at 06:53:12 -0600, Or Ozeri wrote:
This commit enables libvirt users to use layered encryption
of RBD images, using the librbd encryption engine.
This allows opening of an encrypted cloned image
whose parent is encrypted with a possibly different encryption key.
To open such images, multiple encryption secrets are expected
to be defined under the encryption XML tag.
Signed-off-by: Or Ozeri <oro(a)il.ibm.com>
---
docs/formatstorageencryption.rst | 11 +++--
src/conf/schemas/storagecommon.rng | 4 +-
src/qemu/qemu_block.c | 23 +++++++---
src/qemu/qemu_domain.c | 14 ++++++
...k-rbd-encryption-layering.x86_64-7.2.0.err | 1 +
...rbd-encryption-layering.x86_64-latest.args | 39 ++++++++++++++++
.../disk-network-rbd-encryption-layering.xml | 40 +++++++++++++++++
tests/qemuxml2argvtest.c | 2 +
...-rbd-encryption-layering.x86_64-latest.xml | 45 +++++++++++++++++++
tests/qemuxml2xmltest.c | 1 +
10 files changed, 169 insertions(+), 11 deletions(-)
create mode 100644
tests/qemuxml2argvdata/disk-network-rbd-encryption-layering.x86_64-7.2.0.err
create mode 100644
tests/qemuxml2argvdata/disk-network-rbd-encryption-layering.x86_64-latest.args
create mode 100644 tests/qemuxml2argvdata/disk-network-rbd-encryption-layering.xml
create mode 100644
tests/qemuxml2xmloutdata/disk-network-rbd-encryption-layering.x86_64-latest.xml
[...]
diff --git a/src/qemu/qemu_block.c b/src/qemu/qemu_block.c
index f6d21d2040..e0f355874f 100644
--- a/src/qemu/qemu_block.c
+++ b/src/qemu/qemu_block.c
@@ -543,7 +543,8 @@ qemuBlockStorageSourceGetRBDProps(virStorageSource *src,
qemuDomainStorageSourcePrivate *srcPriv = QEMU_DOMAIN_STORAGE_SOURCE_PRIVATE(src);
g_autoptr(virJSONValue) servers = NULL;
virJSONValue *ret = NULL;
- g_autoptr(virJSONValue) encrypt = NULL;
+ g_autolist(virJSONValue) encrypts = NULL;
+ virJSONValue *null_encrypt = NULL;
const char *encformat = NULL;
const char *username = NULL;
g_autoptr(virJSONValue) authmodes = NULL;
[...]
@@ -579,11 +582,17 @@
qemuBlockStorageSourceGetRBDProps(virStorageSource *src,
break;
}
- if (virJSONValueObjectAdd(&encrypt,
- "s:format", encformat,
- "s:key-secret",
srcPriv->encinfo[0]->alias,
- NULL) < 0)
- return NULL;
+ for (i = src->encryption->nsecrets; i > 0; --i) {
+ virJSONValue *encrypt = NULL;
+ if (virJSONValueObjectAdd(&encrypt,
+ "s:format", encformat,
+ "s:key-secret",
srcPriv->encinfo[i-1]->alias,
+ "A:parent", encrypts ? (virJSONValue
**)&encrypts->data : &null_encrypt,
+ NULL) < 0)
+ return NULL;
+
+ encrypts = g_list_prepend(encrypts, encrypt);
+ }
}
if (virJSONValueObjectAdd(&ret,
@@ -592,7 +601,7 @@ qemuBlockStorageSourceGetRBDProps(virStorageSource *src,
"S:snapshot", src->snapshot,
"S:conf", src->configFile,
"A:server", &servers,
- "A:encrypt", &encrypt,
+ "A:encrypt", encrypts ? (virJSONValue
**)&encrypts->data : &null_encrypt,
"S:user", username,
"A:auth-client-required", &authmodes,
"S:key-secret", keysecret,
The use of the 'list' makes the code very opaque and confusing.
You declare the list as an automatic list, thus the members will be
freed, but the 'A:' formatter of virJSONValueObjectAdd actually consumes
the pointer. So you basically are creating a list, where each member in
the list is empty except for the top, as it was consumed by
virJSONValueObjectAdd.
That means you don't even need a list and it will make the code also
more clear:
You only need this:
for (i = src->encryption->nsecrets; i > 0; --i) {
g_autoptr(virJSONValue) new = NULL;
/* we consume the lower layer 'encrypt' into a new object */
if (virJSONValueObjectAdd(&new,
"s:format", encformat,
"s:key-secret",
srcPriv->encinfo[i-1]->alias,
"A:parent", &encrypt,
NULL) < 0)
return NULL;
encrypt = g_steal_pointer(&new);
}
}
You can drop all the other hunks in the function. (except for adding
size_t i).
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index ffe29dc832..e336273588 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
[...]
@@ -5210,6 +5216,14 @@
qemuDomainValidateStorageSource(virStorageSource *src,
_("librbd encryption is supported only with RBD
backed disks"));
return -1;
}
+
+ if (src->encryption->nsecrets > 1) {
+ if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_RBD_ENCRYPTION_LAYERING)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("librbd encryption layering is not
supported by this QEMU binary"));
+ return -1;
+ }
As noted in previous patch you must here validate that also the disk is
not an SD card.
+ }
break;
case VIR_STORAGE_ENCRYPTION_ENGINE_DEFAULT:
[...]
diff --git
a/tests/qemuxml2argvdata/disk-network-rbd-encryption-layering.xml
b/tests/qemuxml2argvdata/disk-network-rbd-encryption-layering.xml
new file mode 100644
index 0000000000..cbde665958
--- /dev/null
+++ b/tests/qemuxml2argvdata/disk-network-rbd-encryption-layering.xml
@@ -0,0 +1,40 @@
+<domain type='qemu'>
+ <name>encryptdisk</name>
+ <uuid>496898a6-e6ff-f7c8-5dc2-3cf410945ee9</uuid>
+ <memory unit='KiB'>1048576</memory>
+ <currentMemory unit='KiB'>524288</currentMemory>
+ <vcpu placement='static'>1</vcpu>
+ <os>
+ <type arch='x86_64' machine='pc-i440fx-2.1'>hvm</type>
+ <boot dev='hd'/>
+ </os>
+ <clock offset='utc'/>
+ <on_poweroff>destroy</on_poweroff>
+ <on_reboot>restart</on_reboot>
+ <on_crash>destroy</on_crash>
+ <devices>
+ <emulator>/usr/bin/qemu-system-x86_64</emulator>
+ <disk type='network' device='disk'>
+ <driver name='qemu' type='raw'/>
+ <source protocol='rbd' name='pool/image'>
+ <host name='mon1.example.org' port='6321'/>
+ <host name='mon2.example.org' port='6322'/>
+ <host name='mon3.example.org' port='6322'/>
+ <encryption format='luks' engine='librbd'>
+ <secret type='passphrase'
uuid='0a81f5b2-8403-7b23-c8d6-21ccc2f80fb0'/>
+ <secret type='passphrase'
uuid='0a81f5b2-8403-7b23-c8d6-21ccc2f80d6f'/>
Since the first secret is used for the current image and subsequent ones
for the parents it results in config:
"encrypt":{"format":"luks",
"key-secret":"libvirt-1-format-encryption-secret0",
"parent": { "format":"luks",
"key-secret":"libvirt-1-format-encryption-secret1" }}
You thus want to use at least 3 secrets to show the multiple layers the
documentation talks about
+ </encryption>
+ </source>
+ <target dev='vda' bus='virtio'/>
+ </disk>