block: move encryption deprecation warning into qcow code

For a couple of releases we have been warning

  Encrypted images are deprecated
  Support for them will be removed in a future release.
  You can use 'qemu-img convert' to convert your image to an unencrypted one.

This warning was issued by system emulators, qemu-img, qemu-nbd
and qemu-io. Such a broad warning was issued because the original
intention was to rip out all the code for dealing with encryption
inside the QEMU block layer APIs.

The new block encryption framework used for the LUKS driver does
not rely on the unloved block layer API for encryption keys,
instead using the QOM 'secret' object type. It is thus no longer
appropriate to warn about encryption unconditionally.

When the qcow/qcow2 drivers are converted to use the new encryption
framework too, it will be practical to keep AES-CBC support present
for use in qemu-img, qemu-io & qemu-nbd to allow for interoperability
with older QEMU versions and liberation of data from existing encrypted
qcow2 files.

This change moves the warning out of the generic block code and
into the qcow/qcow2 drivers. Further, the warning is set to only
appear when running the system emulators, since qemu-img, qemu-io,
qemu-nbd are expected to support qcow2 encryption long term now that
the maint burden has been eliminated.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

8 files changed, 33 insertions, 50 deletions

diff --git a/block.c b/block.c
index b4bec4b1e6..af3584389d 100644
--- a/block.c
+++ b/block.c
@@ -289,6 +289,11 @@ static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
     return 0;
 }
 
+bool bdrv_uses_whitelist(void)
+{
+    return use_bdrv_whitelist;
+}
+
 typedef struct CreateCo {
     BlockDriver *drv;
     char *filename;
@@ -1013,13 +1018,6 @@ static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
         goto free_and_fail;
     }
 
-    if (bs->encrypted) {
-        error_report("Encrypted images are deprecated");
-        error_printf("Support for them will be removed in a future release.\n"
-                     "You can use 'qemu-img convert' to convert your image"
-                     " to an unencrypted one.\n");
-    }
-
     ret = refresh_total_sectors(bs, bs->total_sectors);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "Could not refresh total sector count");
diff --git a/block/qcow.c b/block/qcow.c
index 8ea8e5ceef..b6c2e6ec78 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -24,6 +24,7 @@
 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "qemu-common.h"
+#include "qemu/error-report.h"
 #include "block/block_int.h"
 #include "sysemu/block-backend.h"
 #include "qemu/module.h"
@@ -158,6 +159,14 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
     }
     s->crypt_method_header = header.crypt_method;
     if (s->crypt_method_header) {
+        if (bdrv_uses_whitelist() &&
+            s->crypt_method_header == QCOW_CRYPT_AES) {
+            error_report("qcow built-in AES encryption is deprecated");
+            error_printf("Support for it will be removed in a future release.\n"
+                         "You can use 'qemu-img convert' to switch to an\n"
+                         "unencrypted qcow image, or a LUKS raw image.\n");
+        }
+
         bs->encrypted = 1;
     }
     s->cluster_bits = header.cluster_bits;
diff --git a/block/qcow2.c b/block/qcow2.c
index 642802971c..73c4f6b0ba 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -965,6 +965,14 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
     }
     s->crypt_method_header = header.crypt_method;
     if (s->crypt_method_header) {
+        if (bdrv_uses_whitelist() &&
+            s->crypt_method_header == QCOW_CRYPT_AES) {
+            error_report("qcow2 built-in AES encryption is deprecated");
+            error_printf("Support for it will be removed in a future release.\n"
+                         "You can use 'qemu-img convert' to switch to an\n"
+                         "unencrypted qcow2 image, or a LUKS raw image.\n");
+        }
+
         bs->encrypted = 1;
     }
 
diff --git a/include/block/block.h b/include/block/block.h
index c236e1d813..b4b4650fd3 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -193,6 +193,7 @@ void bdrv_io_limits_update_group(BlockDriverState *bs, const char *group);
 
 void bdrv_init(void);
 void bdrv_init_with_whitelist(void);
+bool bdrv_uses_whitelist(void);
 BlockDriver *bdrv_find_protocol(const char *filename,
                                 bool allow_protocol_prefix,
                                 Error **errp);
diff --git a/tests/qemu-iotests/049.out b/tests/qemu-iotests/049.out
index a2b6703956..4673b67f37 100644
--- a/tests/qemu-iotests/049.out
+++ b/tests/qemu-iotests/049.out
@@ -187,12 +187,6 @@ qemu-img create -f qcow2 -o encryption=off TEST_DIR/t.qcow2 64M
 Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
 
 qemu-img create -f qcow2 -o encryption=on TEST_DIR/t.qcow2 64M
-qemu-img: Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
-qemu-img: Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
 Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=on cluster_size=65536 lazy_refcounts=off refcount_bits=16
 
 == Check lazy_refcounts option (only with v3) ==
diff --git a/tests/qemu-iotests/087 b/tests/qemu-iotests/087
index af44299e07..27cbebc2bc 100755
--- a/tests/qemu-iotests/087
+++ b/tests/qemu-iotests/087
@@ -45,7 +45,8 @@ function do_run_qemu()
 
 function run_qemu()
 {
-    do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qmp | _filter_qemu \
+    do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qmp \
+                          | _filter_qemu | _filter_imgfmt \
                           | sed -e 's/\("actual-size":\s*\)[0-9]\+/\1SIZE/g'
 }
 
diff --git a/tests/qemu-iotests/087.out b/tests/qemu-iotests/087.out
index d0662f95e8..055c553cdb 100644
--- a/tests/qemu-iotests/087.out
+++ b/tests/qemu-iotests/087.out
@@ -38,19 +38,14 @@ QMP_VERSION
 
 === Encrypted image ===
 
-qemu-img: Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
-qemu-img: Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 encryption=on
 Testing: -S
 QMP_VERSION
 {"return": {}}
-Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
+IMGFMT built-in AES encryption is deprecated
+Support for it will be removed in a future release.
+You can use 'qemu-img convert' to switch to an
+unencrypted IMGFMT image, or a LUKS raw image.
 {"error": {"class": "GenericError", "desc": "blockdev-add doesn't support encrypted devices"}}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN"}
@@ -58,9 +53,10 @@ You can use 'qemu-img convert' to convert your image to an unencrypted one.
 Testing:
 QMP_VERSION
 {"return": {}}
-Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
+IMGFMT built-in AES encryption is deprecated
+Support for it will be removed in a future release.
+You can use 'qemu-img convert' to switch to an
+unencrypted IMGFMT image, or a LUKS raw image.
 {"error": {"class": "GenericError", "desc": "Guest must be stopped for opening of encrypted image"}}
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN"}
@@ -68,12 +64,6 @@ You can use 'qemu-img convert' to convert your image to an unencrypted one.
 
 === Missing driver ===
 
-qemu-img: Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
-qemu-img: Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 encryption=on
 Testing: -S
 QMP_VERSION
diff --git a/tests/qemu-iotests/134.out b/tests/qemu-iotests/134.out
index a16acb81cd..6493704ecf 100644
--- a/tests/qemu-iotests/134.out
+++ b/tests/qemu-iotests/134.out
@@ -1,43 +1,25 @@
 QA output created by 134
-qemu-img: Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
-qemu-img: Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 encryption=on
 
 == reading whole image ==
-Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
 Disk image 'TEST_DIR/t.qcow2' is encrypted.
 password:
 read 134217728/134217728 bytes at offset 0
 128 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
 == rewriting whole image ==
-Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
 Disk image 'TEST_DIR/t.qcow2' is encrypted.
 password:
 wrote 134217728/134217728 bytes at offset 0
 128 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
 == verify pattern ==
-Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
 Disk image 'TEST_DIR/t.qcow2' is encrypted.
 password:
 read 134217728/134217728 bytes at offset 0
 128 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
 == verify pattern failure with wrong password ==
-Encrypted images are deprecated
-Support for them will be removed in a future release.
-You can use 'qemu-img convert' to convert your image to an unencrypted one.
 Disk image 'TEST_DIR/t.qcow2' is encrypted.
 password:
 Pattern verification failed at offset 0, 134217728 bytes