crypto: Introduce x509 utils

An utility function for getting fingerprint from X.509 certificate
has been introduced. Implementation only provided using gnutls.

Signed-off-by: Dorjoy Chowdhury <dorjoychy111@gmail.com>
[DB: fixed missing gnutls_x509_crt_deinit in success path]
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

include/crypto/x509-utils.h

@@ -0,0 +1,22 @@
+/*
+ * X.509 certificate related helpers
+ *
+ * Copyright (c) 2024 Dorjoy Chowdhury <dorjoychy111@gmail.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version.  See the COPYING file in the
+ * top-level directory.
+ */
+
+#ifndef QCRYPTO_X509_UTILS_H
+#define QCRYPTO_X509_UTILS_H
+
+#include "crypto/hash.h"
+
+int qcrypto_get_x509_cert_fingerprint(uint8_t *cert, size_t size,
+                                      QCryptoHashAlgorithm hash,
+                                      uint8_t *result,
+                                      size_t *resultlen,
+                                      Error **errp);
+
+#endif