On 8/27/25 1:28 PM, Daniel P. Berrangé wrote:
> On Mon, Aug 18, 2025 at 05:42:56PM -0400, Zhuoying Cai wrote:
>> Introduce new helper functions for x509 certificate, which will be used
>> by the certificate store:
>>
>> qcrypto_x509_convert_cert_der() - converts a certificate from PEM to DER
>> format
>>
>> These functions provide support for certificate format conversion.
>>
>> Signed-off-by: Zhuoying Cai <zy...@linux.ibm.com>
>> ---
>> crypto/x509-utils.c | 51 +++++++++++++++++++++++++++++++++++++
>> include/crypto/x509-utils.h | 20 +++++++++++++++
>> 2 files changed, 71 insertions(+)
>>
>> diff --git a/crypto/x509-utils.c b/crypto/x509-utils.c
>> index 6176a88653..29d5146bb2 100644
>> --- a/crypto/x509-utils.c
>> +++ b/crypto/x509-utils.c
>> @@ -81,6 +81,48 @@ int qcrypto_get_x509_cert_fingerprint(uint8_t *cert,
>> size_t size,
>> return ret;
>> }
>>
>> +int qcrypto_x509_convert_cert_der(uint8_t *cert, size_t size,
>> + uint8_t **result, size_t *resultlen,
>> + Error **errp)
>> +{
>> + int ret = -1;
>> + int rc;
>> + 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;
>> + }
>> +
>> + if (*resultlen == 0) {
>> + error_setg(errp, "Invalid buffer size");
>> + goto cleanup;
>> + }
>
> Requiring resultlen to be set as an input parameter is strange, when
> this function is allocating the buffer. It would be better if we
> ignore resultlen on input and....
>
>
>> +
>> + *result = g_malloc0(*resultlen);
>> + rc = gnutls_x509_crt_export(crt, GNUTLS_X509_FMT_DER, *result,
>> resultlen);
>
> Use 'gnutls_x509_crt_export2' instead
>
> datum.data = NULL;
> datum.size = 0;
> rc = gnutls_x509_crt_export2(crt, GNUTLS_X509_FMT_DER, &datum);
> if (rc != 0) {
> ....
> }
> *result = g_new0(uint8_t, datum.size);
> *resultlen = datum.size;
> memcpy(result, datum.data, datum.size);
> gnutls_free(datum.data);
>
Thanks for the suggestion! I'll make the change in the next version.
>> + if (rc != 0) {
>> + error_setg(errp, "Failed to convert certificate to DER format: %s",
>> + gnutls_strerror(rc));
>> + g_clear_pointer(result, g_free);
>> + goto cleanup;
>> + }
>> +
>> + ret = 0;
>> +
>> +cleanup:
>> + gnutls_x509_crt_deinit(crt);
>> + return ret;
>> +}
>> +
>> #else /* ! CONFIG_GNUTLS */
>>
>> int qcrypto_get_x509_cert_fingerprint(uint8_t *cert, size_t size,
>> @@ -93,4 +135,13 @@ int qcrypto_get_x509_cert_fingerprint(uint8_t *cert,
>> size_t size,
>> return -1;
>> }
>>
>> +int qcrypto_x509_convert_cert_der(uint8_t *cert, size_t size,
>> + uint8_t **result,
>> + size_t *resultlen,
>> + Error **errp)
>> +{
>> + error_setg(errp, "GNUTLS is required to export X.509 certificate");
>> + return -1;
>> +}
>> +
>> #endif /* ! CONFIG_GNUTLS */
>> diff --git a/include/crypto/x509-utils.h b/include/crypto/x509-utils.h
>> index 1e99661a71..4239e3e55a 100644
>> --- a/include/crypto/x509-utils.h
>> +++ b/include/crypto/x509-utils.h
>> @@ -19,4 +19,24 @@ int qcrypto_get_x509_cert_fingerprint(uint8_t *cert,
>> size_t size,
>> size_t *resultlen,
>> Error **errp);
>>
>> +/**
>> + * qcrypto_x509_convert_cert_der
>> + * @cert: pointer to the raw certificate data in PEM format
>> + * @size: size of the certificate
>> + * @result: output location for the allocated buffer for the certificate in
>> DER format
>> + (the function allocates memory which must be freed by the
>> caller)
>> + * @resultlen: pointer to the size of the buffer
>> + (will be updated with the actual size of the DER-encoded
>> certificate)
>> + * @errp: error pointer
>> + *
>> + * Convert the given @cert from PEM to DER format.
>> + *
>> + * Returns: 0 on success,
>> + * -1 on error.
>> + */
>> +int qcrypto_x509_convert_cert_der(uint8_t *cert, size_t size,
>> + uint8_t **result,
>> + size_t *resultlen,
>> + Error **errp);
>> +
>> #endif
>> --
>> 2.50.1
>>
>
> With regards,
> Daniel
