[dpdk-dev] [PATCH] cryptodev: formalize key wrap method in API
Akhil Goyal
gakhil at marvell.com
Tue Apr 6 10:08:05 CEST 2021
> Hi Akhil
>
> From: Akhil Goyal
> > Hi Matan,
> >
> > > The Key Wrap approach is used by applications in order to protect keys
> > > located in untrusted storage or transmitted over untrusted
> > > communications networks. The constructions are typically built from
> > > standard primitives such as block ciphers and cryptographic hash
> > > functions.
> > >
> > > The Key Wrap method and its parameters are a secret between the keys
> > > provider and the device, means that the device is preconfigured for
> > > this method using very secured way.
> > >
> > > The key wrap method may change the key length and layout.
> > >
> > > Add a description for the cipher transformation key to allow wrapped
> > > key to be forwarded by the same API.
> > >
> > > Signed-off-by: Matan Azrad <matan at nvidia.com>
> > > ---
> >
> > How will the driver gets notified whether the key is wrapped or not?
> > The driver would expect the keys are as per the capabilities exposed.
> > If it does not check as per the capabilities, how will it identify a bad Key len
> and
> > the wrapped key length?
>
> As I wrote, the device is preconfigured to the key wrapping mode in very
> secured way.
> No one knows this secret except the device and the key provider (outside the
> crypto lib and dpdk application).
> The driver may know something but not necessarily.
> If the device validation to the key is failed, the driver will return an error to
> the app.
>
Shouldn't this be a capability/feature flag whether it can be supported by the underlying
Driver or not?
I am not saying that the driver should know the details of the wrapping mode.
But it can be asked, whether it support this wrapping mode or not?
>
> > > lib/librte_cryptodev/rte_crypto_sym.h | 7 +++++++
> > > 1 file changed, 7 insertions(+)
> > >
> > > diff --git a/lib/librte_cryptodev/rte_crypto_sym.h
> > > b/lib/librte_cryptodev/rte_crypto_sym.h
> > > index 5973e31..6aca2c7 100644
> > > --- a/lib/librte_cryptodev/rte_crypto_sym.h
> > > +++ b/lib/librte_cryptodev/rte_crypto_sym.h
> > > @@ -200,6 +200,13 @@ struct rte_crypto_cipher_xform {
> > > uint16_t length; /**< key length in bytes */
> > > } key;
> > > /**< Cipher key
> > > + * The original key data may be provided wrapped (encrypted)
> > > + using
> > > a key
> > > + * wrap algorithm such as AES key wrap (from rfc3394) or other.
> > > + In
> > > such
> > > + * case, the wrapping details is a secret between the key provider and
> > > + * the device. Such key wrapping may increase the length of the
> > > provided
> > > + * key beyond the advertised supported key size. Hence it is the
> > > + * responsibility of the driver/device to validate the length of the
> > > + * provided key.
> > > *
> > > * For the RTE_CRYPTO_CIPHER_AES_F8 mode of operation, key.data
> > > will
> > > * point to a concatenation of the AES encryption key followed
> > > by a
> > > --
> > > 1.8.3.1
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