On Tue, Mar 19, 2019 at 07:03:30PM -0300, 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 fixes it by adding a flag to indicate whether bdrv_create_file()
> created the file, and then unlinking it in the 'fail' label if
> necessary.
>
> * 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>
> Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com>
> ---
> block/crypto.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/block/crypto.c b/block/crypto.c
> index fd8c7cfac6..5b43424845 100644
> --- a/block/crypto.c
> +++ b/block/crypto.c
> @@ -533,6 +533,7 @@ static int coroutine_fn
> block_crypto_co_create_opts_luks(const char *filename,
> BlockDriverState *bs = NULL;
> QDict *cryptoopts;
> int64_t size;
> + bool filecreated = false;
> int ret;
>
> /* Parse options */
> @@ -554,6 +555,7 @@ static int coroutine_fn
> block_crypto_co_create_opts_luks(const char *filename,
> if (ret < 0) {
> goto fail;
> }
> + filecreated = true;
>
> bs = bdrv_open(filename, NULL, NULL,
> BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
> @@ -569,7 +571,14 @@ static int coroutine_fn
> block_crypto_co_create_opts_luks(const char *filename,
> }
>
> ret = 0;
> + goto cleanup;
> +
> fail:
> + if (filecreated) {
> + unlink(filename);
You can't do this I'm afraid.
"filename" cannot be assumed to be a local file - it can be an arbitrary
block device backend string.
Contrary to what you might expect, given the call to bdrv_create_file,
we can't actually assume this method created the file either. The above
bdrv_create_file method may have merely formatted a pre-existing volume.
To fix this requires a "bdrv_delete" callback in the BlockDriver code,
and the actual deletion would need to be done in the "qemu-img create"
code.
Regards,
Daniel
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