Re: [PATCH v4 1/5] crypto: mxs-dcp: Add support for hardware-bound keys

[Herbert Xu]

On Tue, Oct 24, 2023 at 06:20:15PM +0200, David Gstir wrote:
> DCP is capable of performing AES with two hardware-bound keys:
> 
> - The one-time programmable (OTP) key which is burnt via on-chip fuses
> - The unique key (UK) which is derived from the OTP key
> 
> In addition to the two hardware-bound keys, DCP also supports
> storing keys in 4 dedicated key slots within its secure memory area
> (internal SRAM).
> 
> These keys are not stored in main memory and are therefore
> not directly accessible by the operating system. To use them
> for AES operations, a one-byte key reference has to supplied
> with the DCP operation descriptor in the control register.
> 
> This adds support for using any of these 6 keys through the crypto API
> via their key reference after they have been set up. The main purpose
> is to add support for DCP-backed trusted keys. Other use cases are
> possible too (see similar existing paes implementations), but these
> should carefully be evaluated as e.g. enabling AF_ALG will give
> userspace full access to use keys. In scenarios with untrustworthy
> userspace, this will enable en-/decryption oracles.
> 
> Co-developed-by: Richard Weinberger <richard@xxxxxx>
> Signed-off-by: Richard Weinberger <richard@xxxxxx>
> Co-developed-by: David Oberhollenzer <david.oberhollenzer@xxxxxxxxxxxxx>
> Signed-off-by: David Oberhollenzer <david.oberhollenzer@xxxxxxxxxxxxx>
> Signed-off-by: David Gstir <david@xxxxxxxxxxxxx>
> ---
>  drivers/crypto/mxs-dcp.c | 104 ++++++++++++++++++++++++++++++++++-----
>  include/soc/fsl/dcp.h    |  17 +++++++
>  2 files changed, 110 insertions(+), 11 deletions(-)
>  create mode 100644 include/soc/fsl/dcp.h

Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
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