Re: [PATCH v4 03/15] crypto/hash-gcrypt: Implement new hash API

[Daniel P . Berrangé]

On Wed, Aug 07, 2024 at 07:51:10PM +0000, Alejandro Zeise wrote:
> Implements the new hashing API in the gcrypt hash driver.
> Supports creating/destroying a context, updating the context
> with input data and obtaining an output hash.
> 
> Signed-off-by: Alejandro Zeise <alejandro.zeise@seagate.com>
> ---
>  crypto/hash-gcrypt.c | 79 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 79 insertions(+)
> 
> diff --git a/crypto/hash-gcrypt.c b/crypto/hash-gcrypt.c
> index 829e48258d..e05511cafa 100644
> --- a/crypto/hash-gcrypt.c
> +++ b/crypto/hash-gcrypt.c
> @@ -1,6 +1,7 @@
>  /*
>   * QEMU Crypto hash algorithms
>   *
> + * Copyright (c) 2024 Seagate Technology LLC and/or its Affiliates
>   * Copyright (c) 2016 Red Hat, Inc.
>   *
>   * This library is free software; you can redistribute it and/or
> @@ -110,7 +111,85 @@ qcrypto_gcrypt_hash_bytesv(QCryptoHashAlgorithm alg,
>      return -1;
>  }
>  
> +static
> +QCryptoHash *qcrypto_gcrypt_hash_new(QCryptoHashAlgorithm alg, Error **errp)
> +{
> +    QCryptoHash *hash = NULL;
> +
> +    if (!qcrypto_hash_supports(alg)) {
> +        error_setg(errp,
> +                   "Unknown hash algorithm %d",
> +                   alg);
> +    } else {
> +        hash = g_new(QCryptoHash, 1);
> +        hash->alg = alg;
> +        hash->opaque = g_new(gcry_md_hd_t, 1);
> +
> +        gcry_md_open((gcry_md_hd_t *) hash->opaque, 
> qcrypto_hash_alg_map[alg], 0);
> +    }
> +
> +    return hash;
> +}
> +
> +static
> +void qcrypto_gcrypt_hash_free(QCryptoHash *hash)
> +{
> +    gcry_md_hd_t *ctx = hash->opaque;
> +
> +    if (ctx) {
> +        gcry_md_close(*ctx);
> +        g_free(ctx);
> +    }
> +
> +    g_free(hash);
> +}
> +
> +
> +static
> +int qcrypto_gcrypt_hash_update(QCryptoHash *hash,
> +                               const struct iovec *iov,
> +                               size_t niov,
> +                               Error **errp)
> +{
> +    gcry_md_hd_t *ctx = hash->opaque;
> +
> +    for (int i = 0; i < niov; i++) {
> +        gcry_md_write(*ctx, iov[i].iov_base, iov[i].iov_len);
> +    }
> +
> +    return 0;
> +}
> +
> +static
> +int qcrypto_gcrypt_hash_finalize(QCryptoHash *hash,
> +                                 uint8_t **result,
> +                                 size_t *result_len,
> +                                 Error **errp)
> +{
> +    unsigned char *digest;
> +    int ret = 0;
> +    gcry_md_hd_t *ctx = hash->opaque;
> +
> +    *result_len = gcry_md_get_algo_dlen(qcrypto_hash_alg_map[hash->alg]);
> +    if (*result_len == 0) {
> +        error_setg(errp, "%s",
> +                   "Unable to get hash length");
> +        ret = -1;

Same note about doing an immediate 'return -1' in error paths,
to avoid extra else clauses.

> +    } else {
> +        *result = g_new(uint8_t, *result_len);
> +
> +        /* Digest is freed by gcry_md_close(), copy it */
> +        digest = gcry_md_read(*ctx, 0);
> +        memcpy(*result, digest, *result_len);
> +    }
> +
> +    return ret;
> +}
>  
>  QCryptoHashDriver qcrypto_hash_lib_driver = {
>      .hash_bytesv = qcrypto_gcrypt_hash_bytesv,
> +    .hash_new      = qcrypto_gcrypt_hash_new,
> +    .hash_update   = qcrypto_gcrypt_hash_update,
> +    .hash_finalize = qcrypto_gcrypt_hash_finalize,
> +    .hash_free     = qcrypto_gcrypt_hash_free,
>  };
> -- 
> 2.34.1
> 

With regards,
Daniel
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