[PATCH v5 03/16] crypto/hash-gcrypt: Implement new hash API

["Cédric Le Goater" <clg@redhat.com>]

From: Alejandro Zeise <alejandro.zeise@seagate.com>

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>
[ clg: - Dropped qcrypto_hash_supports() in qcrypto_gcrypt_hash_new()
       - Reworked qcrypto_gcrypt_hash_finalize()
       - Handled gcry_md_open() errors in qcrypto_gcrypt_hash_new()
       - Checkpatch fixes ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 crypto/hash-gcrypt.c | 79 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/crypto/hash-gcrypt.c b/crypto/hash-gcrypt.c
index 0973cc0d93c1..cb2cb37f25ed 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(QCryptoHashAlgo alg,
     return -1;
 }
 
+static
+QCryptoHash *qcrypto_gcrypt_hash_new(QCryptoHashAlgo alg, Error **errp)
+{
+    QCryptoHash *hash;
+    int ret;
+
+    hash = g_new(QCryptoHash, 1);
+    hash->alg = alg;
+    hash->opaque = g_new(gcry_md_hd_t, 1);
+
+    ret = gcry_md_open((gcry_md_hd_t *) hash->opaque,
+                       qcrypto_hash_alg_map[alg], 0);
+    if (ret < 0) {
+        error_setg(errp,
+                   "Unable to initialize hash algorithm: %s",
+                   gcry_strerror(ret));
+        g_free(hash->opaque);
+        g_free(hash);
+        return NULL;
+    }
+    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;
+    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, "Unable to get hash length");
+        return -1;
+    }
+
+    *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 0;
+}
 
 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,
 };
-- 
2.46.2