Re: [PATCH v3 00/12] hw/misc/aspeed_hace: Fix SG Accumulative Hash Calculations

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

On Mon, Aug 05, 2024 at 03:50:35PM +0000, Alejandro Zeise wrote:
> The goal of this patch series is to fix accumulative hashing support in the 
> Aspeed HACE module. The issue that stemmed this patch was a failure to boot an
> OpenBMC image using the "ast2600-evb" machine. The U-boot
> 2019.04 loader failed to verify image hashes.
> 
> These incorrect image hashes given by the HACE to the U-boot guest are due to 
> an oversight in the HACE module. Previously when operating in 
> scatter-gather accumulative mode, the HACE would cache the address provided by 
> the guest which contained the source data. However, there was no deep copy, 
> so when HACE generated the digest upon the reception of the final accumulative chunk 
> the digest was incorrect, as the addresses provided had their regions overwritten
> by that time.
> 
> This fix consists of two main steps:
> * Add an accumulative hashing function to the qcrypto library
> * Modify the HACE module to use the accumulative hashing functions
> 
> All the crypto library backends (nettle, gnutls, etc.) support accumulative hashing,
> so it was trivial to create wrappers for those functions.
> 
> Changes in V3:
> * Reworked crypto hash API with comments from Daniel
>   * Creation/Deletion of contexts, updating, and finalizing
>   * Modified existing API functions to use the new 4 main core functions
>   * Added test for accumulative hashing
>   * Added afalg driver implementation
> * Fixed bug in HACE module where hash context fails to allocate,
>   causing the HACE internal state to be incorrect and segfault.
> 
> Changes in V2:
> * Fixed error checking bug in libgcrypt crypto backend of
>   accumulate_bytesv
> 
> Alejandro Zeise (12):
>   crypto: accumulative hashing API
>   crypto/hash-glib: Remove old hash API implementation
>   crypto/hash-glib: Implement new hash API
>   crypto/hash-gcrypt: Remove old hash API implementation
>   crypto/hash-gcrypt: Implement new hash API
>   crypto/hash-gnutls: Remove old hash API
>   crypto/hash-gnutls: Implement new hash API
>   crypto/hash-nettle: Remove old hash API
>   crypto/hash-nettle: Implement new hash API
>   crypto/hash-afalg: Update to new API
>   tests/unit/test-crypto-hash: accumulative hashing
>   hw/misc/aspeed_hace: Fix SG Accumulative hashing

To allow 'make check' to succeed at every individual patch, you'll need to
re-order these, and split a couple of patches, to be more or less like this:

   crypto: accumulative hashing API   (only define new driver APIs & new public APIs here)
   crypto/hash-glib: Implement new hash API
   crypto/hash-gcrypt: Implement new hash API
   crypto/hash-gnutls: Implement new hash API
   crypto/hash-nettle: Implement new hash API
   crypto/hash-afalg: Update to new API  (only add new APIs here )
   < convert old public APIs to call the new driver APIs here>
   tests/unit/test-crypto-hash: accumulative hashing
   crypto/hash-glib: Remove old hash API implementation
   crypto/hash-gcrypt: Remove old hash API implementation
   crypto/hash-gnutls: Remove old hash API
   crypto/hash-nettle: Remove old hash API
   < remove old afalg support here >
   < remove old driver APIs here >
   hw/misc/aspeed_hace: Fix SG Accumulative hashing


With regards,
Daniel
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