1 files changed, 76 insertions, 0 deletions
diff --git a/crypto/x509-utils.c b/crypto/x509-utils.c
new file mode 100644
index 0000000000..6e157af76b
--- /dev/null
+++ b/crypto/x509-utils.c
@@ -0,0 +1,76 @@
+/*
+ * 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.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "crypto/x509-utils.h"
+#include <gnutls/gnutls.h>
+#include <gnutls/crypto.h>
+#include <gnutls/x509.h>
+
+static const int qcrypto_to_gnutls_hash_alg_map[QCRYPTO_HASH_ALG__MAX] = {
+    [QCRYPTO_HASH_ALG_MD5] = GNUTLS_DIG_MD5,
+    [QCRYPTO_HASH_ALG_SHA1] = GNUTLS_DIG_SHA1,
+    [QCRYPTO_HASH_ALG_SHA224] = GNUTLS_DIG_SHA224,
+    [QCRYPTO_HASH_ALG_SHA256] = GNUTLS_DIG_SHA256,
+    [QCRYPTO_HASH_ALG_SHA384] = GNUTLS_DIG_SHA384,
+    [QCRYPTO_HASH_ALG_SHA512] = GNUTLS_DIG_SHA512,
+    [QCRYPTO_HASH_ALG_RIPEMD160] = GNUTLS_DIG_RMD160,
+};
+
+int qcrypto_get_x509_cert_fingerprint(uint8_t *cert, size_t size,
+                                      QCryptoHashAlgorithm alg,
+                                      uint8_t *result,
+                                      size_t *resultlen,
+                                      Error **errp)
+{
+    int ret = -1;
+    int hlen;
+    gnutls_x509_crt_t crt;
+    gnutls_datum_t datum = {.data = cert, .size = size};
+
+    if (alg >= G_N_ELEMENTS(qcrypto_to_gnutls_hash_alg_map)) {
+        error_setg(errp, "Unknown hash algorithm");
+        return -1;
+    }
+
+    if (result == NULL) {
+        error_setg(errp, "No valid buffer given");
+        return -1;
+    }
+
+    gnutls_x509_crt_init(&crt);
+
+    if (gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM) != 0) {
+        error_setg(errp, "Failed to import certificate");
+        goto cleanup;
+    }
+
+    hlen = gnutls_hash_get_len(qcrypto_to_gnutls_hash_alg_map[alg]);
+    if (*resultlen < hlen) {
+        error_setg(errp,
+                   "Result buffer size %zu is smaller than hash %d",
+                   *resultlen, hlen);
+        goto cleanup;
+    }
+
+    if (gnutls_x509_crt_get_fingerprint(crt,
+                                        qcrypto_to_gnutls_hash_alg_map[alg],
+                                        result, resultlen) != 0) {
+        error_setg(errp, "Failed to get fingerprint from certificate");
+        goto cleanup;
+    }
+
+    ret = 0;
+
+ cleanup:
+    gnutls_x509_crt_deinit(crt);
+    return ret;
+}