Re: [PATCH v5 08/29] crypto/x509-utils: Add helper functions for DIAG 320 subcode 2

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

On Mon, Aug 18, 2025 at 05:43:01PM -0400, Zhuoying Cai wrote:
> Introduce new helper functions to extract certificate metadata needed for
> DIAG 320 subcode 2:
> 
> qcrypto_x509_check_cert_times() - validates the certificate's validity period against the current time
> qcrypto_x509_get_pk_algorithm() - returns the public key algorithm used in the certificate
> qcrypto_x509_get_cert_key_id() - extracts the key ID from the certificate
> 
> These functions provide support for metadata extraction and validity checking
> for X.509 certificates.
> 
> Signed-off-by: Zhuoying Cai <zycai@linux.ibm.com>
> ---
>  crypto/x509-utils.c         | 174 ++++++++++++++++++++++++++++++++++++
>  include/crypto/x509-utils.h |  58 ++++++++++++
>  2 files changed, 232 insertions(+)
> 
> diff --git a/crypto/x509-utils.c b/crypto/x509-utils.c
> index 29d5146bb2..67b42aad1f 100644
> --- a/crypto/x509-utils.c
> +++ b/crypto/x509-utils.c
> @@ -27,6 +27,21 @@ static const int qcrypto_to_gnutls_hash_alg_map[QCRYPTO_HASH_ALGO__MAX] = {
>      [QCRYPTO_HASH_ALGO_RIPEMD160] = GNUTLS_DIG_RMD160,
>  };
>  
> +static const int gnutls_to_qcrypto_pk_alg_map[] = {
> +    [GNUTLS_PK_RSA] = QCRYPTO_PK_ALGO_RSA,
> +    [GNUTLS_PK_DSA] = QCRYPTO_PK_ALGO_DSA,
> +    [GNUTLS_PK_ECDSA] = QCRYPTO_PK_ALGO_ECDSA,
> +    [GNUTLS_PK_RSA_OAEP] = QCRYPTO_PK_ALGO_RSA_OAEP,
> +    [GNUTLS_PK_EDDSA_ED25519] = QCRYPTO_PK_ALGO_ED25519,
> +    [GNUTLS_PK_EDDSA_ED448] = QCRYPTO_PK_ALGO_ED448,
> +};
> +
> +static const int qcrypto_to_gnutls_keyid_flags_map[] = {
> +    [QCRYPTO_HASH_ALGO_SHA1] = GNUTLS_KEYID_USE_SHA1,
> +    [QCRYPTO_HASH_ALGO_SHA256] = GNUTLS_KEYID_USE_SHA256,
> +    [QCRYPTO_HASH_ALGO_SHA512] = GNUTLS_KEYID_USE_SHA512,
> +};
> +
>  int qcrypto_get_x509_cert_fingerprint(uint8_t *cert, size_t size,
>                                        QCryptoHashAlgo alg,
>                                        uint8_t *result,
> @@ -123,6 +138,143 @@ cleanup:
>      return ret;
>  }
>  

> +
> +int qcrypto_x509_get_pk_algorithm(uint8_t *cert, size_t size, Error **errp)
> +{
> +    int rc;
> +    int ret = -1;
> +    unsigned int bits;
> +    gnutls_x509_crt_t crt;
> +    gnutls_datum_t datum = {.data = cert, .size = size};
> +
> +    rc = gnutls_x509_crt_init(&crt);
> +    if (rc < 0) {
> +        error_setg(errp, "Failed to initialize certificate: %s", gnutls_strerror(rc));
> +        return ret;
> +    }
> +
> +    rc = gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM);
> +    if (rc != 0) {
> +        error_setg(errp, "Failed to import certificate: %s", gnutls_strerror(rc));
> +        goto cleanup;
> +    }
> +
> +    rc = gnutls_x509_crt_get_pk_algorithm(crt, &bits);
> +    if (rc >= G_N_ELEMENTS(gnutls_to_qcrypto_pk_alg_map)) {
> +        error_setg(errp, "Unknown public key algorithm %d", rc);
> +        goto cleanup;
> +    }
> +
> +    ret = gnutls_to_qcrypto_pk_alg_map[rc];
> +
> +cleanup:
> +    gnutls_x509_crt_deinit(crt);
> +    return ret;
> +}
> +
> +int qcrypto_x509_get_cert_key_id(uint8_t *cert, size_t size,
> +                                 QCryptoHashAlgo hash_alg,
> +                                 uint8_t **result,
> +                                 size_t *resultlen,
> +                                 Error **errp)
> +{
> +    int rc;
> +    int ret = -1;
> +    gnutls_x509_crt_t crt;
> +    gnutls_datum_t datum = {.data = cert, .size = size};
> +
> +    if (hash_alg >= G_N_ELEMENTS(qcrypto_to_gnutls_keyid_flags_map)) {

Must also check qcrypto_to_gnutls_hash_alg_map bounds.

> +        error_setg(errp, "Unknow hash algorithm %d", hash_alg);

's/Unknow/Unknown/'

> +        return ret;
> +     }
> +
> +    rc = gnutls_x509_crt_init(&crt);
> +    if (rc < 0) {
> +        error_setg(errp, "Failed to initialize certificate: %s", gnutls_strerror(rc));
> +        return ret;
> +    }
> +
> +    rc = gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM);
> +    if (rc != 0) {
> +        error_setg(errp, "Failed to import certificate: %s", gnutls_strerror(rc));
> +        goto cleanup;
> +    }
> +
> +    *resultlen = gnutls_hash_get_len(qcrypto_to_gnutls_hash_alg_map[hash_alg]);
> +    if (*resultlen == 0) {
> +        error_setg(errp, "Failed to get hash algorithn length: %s", gnutls_strerror(rc));
> +        goto cleanup;
> +    }
> +
> +    *result = g_malloc0(*resultlen);
> +    if (gnutls_x509_crt_get_key_id(crt,
> +                                   qcrypto_to_gnutls_keyid_flags_map[hash_alg],
> +                                   *result, resultlen) != 0) {
> +        error_setg(errp, "Failed to get key ID from certificate");
> +        g_clear_pointer(result, g_free);
> +        goto cleanup;
> +    }
> +
> +    ret = 0;
> +
> +cleanup:
> +    gnutls_x509_crt_deinit(crt);
> +    return ret;
> +}
> +

With regards,
Daniel
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