Re: [Qemu-devel] [PATCH 08/13] qcrypto: add the plumbing for encryption management

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Aug 14, 2019 at 11:22:14PM +0300, Maxim Levitsky wrote:
> This adds qcrypto_block_manage_encryption, which
>  is thin wrapper around manage_encryption of the crypto driver
>  which is also added
> 
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
>  crypto/block.c         | 29 +++++++++++++++++++++++++++++
>  crypto/blockpriv.h     |  9 +++++++++
>  include/crypto/block.h | 27 +++++++++++++++++++++++++++
>  3 files changed, 65 insertions(+)
> 
> diff --git a/crypto/block.c b/crypto/block.c
> index ee96759f7d..5916e49aba 100644
> --- a/crypto/block.c
> +++ b/crypto/block.c
> @@ -20,6 +20,7 @@
>  
>  #include "qemu/osdep.h"
>  #include "qapi/error.h"
> +
>  #include "blockpriv.h"
>  #include "block-qcow.h"
>  #include "block-luks.h"
> @@ -282,6 +283,34 @@ void qcrypto_block_free(QCryptoBlock *block)
>  }
>  
>  
> +int qcrypto_block_setup_encryption(QCryptoBlock *block,
> +                                   QCryptoBlockReadFunc readfunc,
> +                                   QCryptoBlockWriteFunc writefunc,
> +                                   void *opaque,
> +                                   enum BlkSetupEncryptionAction action,
> +                                   QCryptoEncryptionSetupOptions *options,
> +                                   bool force,
> +                                   Error **errp)
> +{
> +    if (!block->driver->setup_encryption) {
> +        error_setg(errp,
> +                "Crypto format %s doesn't support management of encryption keys",
> +                QCryptoBlockFormat_str(block->format));
> +        return -1;
> +    }
> +
> +    return block->driver->setup_encryption(block,
> +                                           readfunc,
> +                                           writefunc,
> +                                           opaque,
> +                                           action,
> +                                           options,
> +                                           force,
> +                                           errp);
> +}
> +
> +
> +
>  typedef int (*QCryptoCipherEncDecFunc)(QCryptoCipher *cipher,
>                                          const void *in,
>                                          void *out,
> diff --git a/crypto/blockpriv.h b/crypto/blockpriv.h
> index 71c59cb542..804965dca3 100644
> --- a/crypto/blockpriv.h
> +++ b/crypto/blockpriv.h
> @@ -81,6 +81,15 @@ struct QCryptoBlockDriver {
>  
>      bool (*has_format)(const uint8_t *buf,
>                         size_t buflen);
> +
> +    int (*setup_encryption)(QCryptoBlock *block,
> +                            QCryptoBlockReadFunc readfunc,
> +                            QCryptoBlockWriteFunc writefunc,
> +                            void *opaque,
> +                            enum BlkSetupEncryptionAction action,
> +                            QCryptoEncryptionSetupOptions *options,
> +                            bool force,
> +                            Error **errp);
>  };
>  
>  
> diff --git a/include/crypto/block.h b/include/crypto/block.h
> index fe12899831..60d46e3efc 100644
> --- a/include/crypto/block.h
> +++ b/include/crypto/block.h
> @@ -23,6 +23,7 @@
>  
>  #include "crypto/cipher.h"
>  #include "crypto/ivgen.h"
> +#include "block/block.h"
>  
>  typedef struct QCryptoBlock QCryptoBlock;
>  
> @@ -268,4 +269,30 @@ uint64_t qcrypto_block_get_sector_size(QCryptoBlock *block);
>   */
>  void qcrypto_block_free(QCryptoBlock *block);
>  
> +
> +/**
> + * qcrypto_block_setup_encryption:
> + * @block: the block encryption object
> + *
> + * @readfunc: callback for reading data from the volume header
> + * @writefunc: callback for writing data to the volume header
> + * @opaque: data to pass to @readfunc and @writefunc
> + * @action: tell the driver the setup action (add/erase currently)
> + * @options: driver specific options, that specify
> + *           what encryption settings to manage
> + * @force: hint for the driver to allow unsafe operation
> + * @errp: error pointer
> + *
> + * Adds/Erases a new encryption key using @options

I'd prefer to see separate APIs for add + erase instead
of overloading. It'll lead to a clearer API from callers
POV to see exactly which parameters are for each action.

> + *
> + */
> +int qcrypto_block_setup_encryption(QCryptoBlock *block,
> +                                   QCryptoBlockReadFunc readfunc,
> +                                   QCryptoBlockWriteFunc writefunc,
> +                                   void *opaque,
> +                                   enum BlkSetupEncryptionAction action,
> +                                   QCryptoEncryptionSetupOptions *options,
> +                                   bool force,
> +                                   Error **errp);
> +

Regards,
Daniel
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