On 8/28/19 11:10 PM, John Snow wrote:
On 8/7/19 10:21 AM, Daniel Henrique Barboza wrote:
When using a non-UTF8 secret to create a volume using qemu-img, the
following error happens:
$ qemu-img create -f luks --object
secret,id=vol_1_encrypt0,file=vol_resize_pool.vol_1.secret.qzVQrI -o
key-secret=vol_1_encrypt0 /var/tmp/pool_target/vol_1 10240K
Formatting '/var/tmp/pool_target/vol_1', fmt=luks size=10485760
key-secret=vol_1_encrypt0
qemu-img: /var/tmp/pool_target/vol_1: Data from secret vol_1_encrypt0 is not
valid UTF-8
However, the created file '/var/tmp/pool_target/vol_1' is left behind in the
file system after the failure. This behavior can be observed when creating
the volume using Libvirt, via 'virsh vol-create', and then getting "volume
target path already exist" errors when trying to re-create the volume.
The volume file is created inside block_crypto_co_create_opts_luks(), in
block/crypto.c. If the bdrv_create_file() call is successful but any
succeeding step fails*, the existing 'fail' label does not take into
account the created file, leaving it behind.
This patch changes block_crypto_co_create_opts_luks() to delete
'filename' in case of failure. A failure in this point means that
the volume is now truncated/corrupted, so even if 'filename' was an
existing volume before calling qemu-img, it is now unusable. Deleting
the file it is not much worse than leaving it in the filesystem in
this scenario, and we don't have to deal with checking the file
pre-existence in the code.
* in our case, block_crypto_co_create_generic calls qcrypto_block_create,
which calls qcrypto_block_luks_create, and this function fails when
calling qcrypto_secret_lookup_as_utf8.
Reported-by: Srikanth Aithal <bssrika...@in.ibm.com>
Suggested-by: Kevin Wolf <kw...@redhat.com>
Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com>
---
block/crypto.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/block/crypto.c b/block/crypto.c
index 8237424ae6..8ffca81df6 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -30,6 +30,7 @@
#include "qapi/error.h"
#include "qemu/module.h"
#include "qemu/option.h"
+#include "qemu/cutils.h"
#include "crypto.h"
typedef struct BlockCrypto BlockCrypto;
@@ -575,6 +576,25 @@ fail:
bdrv_unref(bs);
qapi_free_QCryptoBlockCreateOptions(create_opts);
qobject_unref(cryptoopts);
+
+ /*
+ * If an error occurred, delete the file. Even if the file existed
+ * beforehand, it has been truncated and corrupted in the process.
+ */
+ if (ret) {
+ Error *local_err;
+ int r_del = bdrv_delete_file(filename, &local_err);
+ /*
+ * ENOTSUP will happen if the block driver doesn't support
+ * 'bdrv_co_delete_file'. ENOENT will happen if the file
+ * doesn't exist. Both are predictable and shouldn't be
+ * reported back to the user.
+ */
Hm, actually, didn't you use ENOENT to mean that we couldn't figure out
which driver to use?
True. In this context though I am referring to the co_routine function
that deletes the file:
-------
(file-posix.c)
static int coroutine_fn raw_co_delete_file(BlockDriverState *bs,
Error **errp)
{
struct stat st;
int ret;
if (!(stat(bs->filename, &st) == 0) || !S_ISREG(st.st_mode)) {
ret = -ENOENT;
error_setg_errno(errp, -ret, "%s is not a regular file",
bs->filename);
goto done;
}
(...)
-----
I'll make it clearer in the comment where ENOENT is coming from.
(In fact, this is a good reason to change the !drv error in patch 2 from
ENOENT to ENOMEDIUM ....)
+ if ((r_del < 0) && (r_del != -ENOTSUP) && (r_del != -ENOENT)) {
+ error_reportf_err(local_err, "%s: ", bs->filename);
+ }> + }
+
return ret;
}
