Re: [PATCH v5 3/3] block/rbd: Add support for layered encryption

[Ilya Dryomov]

On Sun, Jan 15, 2023 at 1:40 PM Or Ozeri <oro@il.ibm.com> wrote:
>
> Starting from ceph Reef, RBD has built-in support for layered encryption,
> where each ancestor image (in a cloned image setting) can be possibly
> encrypted using a unique passphrase.
>
> A new function, rbd_encryption_load2, was added to librbd API.
> This new function supports an array of passphrases (via "spec" structs).
>
> This commit extends the qemu rbd driver API to use this new librbd API,
> in order to support this new layered encryption feature.
>
> Signed-off-by: Or Ozeri <oro@il.ibm.com>
> ---
>  block/rbd.c          | 154 ++++++++++++++++++++++++++++++++++++++++++-
>  qapi/block-core.json |  11 +++-
>  2 files changed, 163 insertions(+), 2 deletions(-)
>
> diff --git a/block/rbd.c b/block/rbd.c
> index b929378871..c8418a8057 100644
> --- a/block/rbd.c
> +++ b/block/rbd.c
> @@ -71,6 +71,16 @@ static const char rbd_luks2_header_verification[
>      'L', 'U', 'K', 'S', 0xBA, 0xBE, 0, 2
>  };
>
> +static const char rbd_layered_luks_header_verification[
> +        RBD_ENCRYPTION_LUKS_HEADER_VERIFICATION_LEN] = {
> +    'R', 'B', 'D', 'L', 0xBA, 0xBE, 0, 1
> +};
> +
> +static const char rbd_layered_luks2_header_verification[
> +        RBD_ENCRYPTION_LUKS_HEADER_VERIFICATION_LEN] = {
> +    'R', 'B', 'D', 'L', 0xBA, 0xBE, 0, 2
> +};
> +
>  typedef enum {
>      RBD_AIO_READ,
>      RBD_AIO_WRITE,
> @@ -537,6 +547,129 @@ static int qemu_rbd_encryption_load(rbd_image_t image,
>
>      return 0;
>  }
> +
> +#ifdef LIBRBD_SUPPORTS_ENCRYPTION_LOAD2
> +static int qemu_rbd_encryption_load2(rbd_image_t image,
> +                                     RbdEncryptionOptions *encrypt,
> +                                     Error **errp)
> +{
> +    int r = 0;
> +    int encrypt_count = 1;
> +    int i;
> +    RbdEncryptionOptions *curr_encrypt;
> +    rbd_encryption_spec_t *specs;
> +    rbd_encryption_luks1_format_options_t *luks_opts;
> +    rbd_encryption_luks2_format_options_t *luks2_opts;
> +    rbd_encryption_luks_format_options_t *luks_any_opts;
> +
> +    /* count encryption options */
> +    for (curr_encrypt = encrypt; curr_encrypt->parent;
> +         curr_encrypt = curr_encrypt->parent) {
> +        ++encrypt_count;
> +    }

This seems a bit weird because it doesn't follow the usual counting
pattern.  I had to stop and re-read it to make sure there is nothing
funny going on.  I'd make it:

    for (curr_encrypt = encrypt->parent; curr_encrypt;
         curr_encrypt = curr_encrypt->parent) {

> +
> +    specs = g_new0(rbd_encryption_spec_t, encrypt_count);
> +
> +    curr_encrypt = encrypt;
> +    for (i = 0; i < encrypt_count; ++i) {
> +        switch (curr_encrypt->format) {
> +            case RBD_IMAGE_ENCRYPTION_FORMAT_LUKS: {
> +                specs[i].format = RBD_ENCRYPTION_FORMAT_LUKS1;
> +
> +                luks_opts = g_new0(rbd_encryption_luks1_format_options_t, 1);
> +                specs[i].opts = luks_opts;
> +                specs[i].opts_size = sizeof(*luks_opts);
> +
> +                r = qemu_rbd_convert_luks_options(
> +                        qapi_RbdEncryptionOptionsLUKS_base(
> +                                &curr_encrypt->u.luks),
> +                        (char **)&luks_opts->passphrase,
> +                        &luks_opts->passphrase_size,
> +                        errp);
> +                break;
> +            }
> +            case RBD_IMAGE_ENCRYPTION_FORMAT_LUKS2: {
> +                specs[i].format = RBD_ENCRYPTION_FORMAT_LUKS2;
> +
> +                luks2_opts = g_new0(rbd_encryption_luks2_format_options_t, 
> 1);
> +                specs[i].opts = luks2_opts;
> +                specs[i].opts_size = sizeof(*luks2_opts);
> +
> +                r = qemu_rbd_convert_luks_options(
> +                        qapi_RbdEncryptionOptionsLUKS2_base(
> +                                &curr_encrypt->u.luks2),
> +                        (char **)&luks2_opts->passphrase,
> +                        &luks2_opts->passphrase_size,
> +                        errp);
> +                break;
> +            }
> +            case RBD_IMAGE_ENCRYPTION_FORMAT_LUKS_ANY: {
> +                specs[i].format = RBD_ENCRYPTION_FORMAT_LUKS;
> +
> +                luks_any_opts = g_new0(rbd_encryption_luks_format_options_t, 
> 1);
> +                specs[i].opts = luks_any_opts;
> +                specs[i].opts_size = sizeof(*luks_any_opts);
> +
> +                r = qemu_rbd_convert_luks_options(
> +                        qapi_RbdEncryptionOptionsLUKSAny_base(
> +                                &curr_encrypt->u.luks_any),
> +                        (char **)&luks_any_opts->passphrase,
> +                        &luks_any_opts->passphrase_size,
> +                        errp);
> +                break;
> +            }
> +

The blank line before the default case is still there.

Thanks,

                Ilya