crypto: support HMAC algorithms based on glib

This patch add glib-backed HMAC algorithms support

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

crypto/hmac-glib.c

@@ -16,6 +16,126 @@
 #include "qapi/error.h"
 #include "crypto/hmac.h"
 
+/* Support for HMAC Algos has been added in GLib 2.30 */
+#if GLIB_CHECK_VERSION(2, 30, 0)
+
+static int qcrypto_hmac_alg_map[QCRYPTO_HASH_ALG__MAX] = {
+    [QCRYPTO_HASH_ALG_MD5] = G_CHECKSUM_MD5,
+    [QCRYPTO_HASH_ALG_SHA1] = G_CHECKSUM_SHA1,
+    [QCRYPTO_HASH_ALG_SHA256] = G_CHECKSUM_SHA256,
+/* Support for HMAC SHA-512 in GLib 2.42 */
+#if GLIB_CHECK_VERSION(2, 42, 0)
+    [QCRYPTO_HASH_ALG_SHA512] = G_CHECKSUM_SHA512,
+#else
+    [QCRYPTO_HASH_ALG_SHA512] = -1,
+#endif
+    [QCRYPTO_HASH_ALG_SHA224] = -1,
+    [QCRYPTO_HASH_ALG_SHA384] = -1,
+    [QCRYPTO_HASH_ALG_RIPEMD160] = -1,
+};
+
+typedef struct QCryptoHmacGlib QCryptoHmacGlib;
+struct QCryptoHmacGlib {
+    GHmac *ghmac;
+};
+
+bool qcrypto_hmac_supports(QCryptoHashAlgorithm alg)
+{
+    if (alg < G_N_ELEMENTS(qcrypto_hmac_alg_map) &&
+        qcrypto_hmac_alg_map[alg] != -1) {
+        return true;
+    }
+
+    return false;
+}
+
+QCryptoHmac *qcrypto_hmac_new(QCryptoHashAlgorithm alg,
+                              const uint8_t *key, size_t nkey,
+                              Error **errp)
+{
+    QCryptoHmac *hmac;
+    QCryptoHmacGlib *ctx;
+
+    if (!qcrypto_hmac_supports(alg)) {
+        error_setg(errp, "Unsupported hmac algorithm %s",
+                   QCryptoHashAlgorithm_lookup[alg]);
+        return NULL;
+    }
+
+    hmac = g_new0(QCryptoHmac, 1);
+    hmac->alg = alg;
+
+    ctx = g_new0(QCryptoHmacGlib, 1);
+
+    ctx->ghmac = g_hmac_new(qcrypto_hmac_alg_map[alg],
+                            (const uint8_t *)key, nkey);
+    if (!ctx->ghmac) {
+        error_setg(errp, "Cannot initialize hmac and set key");
+        goto error;
+    }
+
+    hmac->opaque = ctx;
+    return hmac;
+
+error:
+    g_free(ctx);
+    g_free(hmac);
+    return NULL;
+}
+
+void qcrypto_hmac_free(QCryptoHmac *hmac)
+{
+    QCryptoHmacGlib *ctx;
+
+    if (!hmac) {
+        return;
+    }
+
+    ctx = hmac->opaque;
+    g_hmac_unref(ctx->ghmac);
+
+    g_free(ctx);
+    g_free(hmac);
+}
+
+int qcrypto_hmac_bytesv(QCryptoHmac *hmac,
+                        const struct iovec *iov,
+                        size_t niov,
+                        uint8_t **result,
+                        size_t *resultlen,
+                        Error **errp)
+{
+    QCryptoHmacGlib *ctx;
+    int i, ret;
+
+    ctx = hmac->opaque;
+
+    for (i = 0; i < niov; i++) {
+        g_hmac_update(ctx->ghmac, iov[i].iov_base, iov[i].iov_len);
+    }
+
+    ret = g_checksum_type_get_length(qcrypto_hmac_alg_map[hmac->alg]);
+    if (ret < 0) {
+        error_setg(errp, "Unable to get hmac length");
+        return -1;
+    }
+
+    if (*resultlen == 0) {
+        *resultlen = ret;
+        *result = g_new0(uint8_t, *resultlen);
+    } else if (*resultlen != ret) {
+        error_setg(errp, "Result buffer size %zu is smaller than hmac %d",
+                   *resultlen, ret);
+        return -1;
+    }
+
+    g_hmac_get_digest(ctx->ghmac, *result, resultlen);
+
+    return 0;
+}
+
+#else
+
 bool qcrypto_hmac_supports(QCryptoHashAlgorithm alg)
 {
     return false;
@@ -42,3 +162,5 @@ int qcrypto_hmac_bytesv(QCryptoHmac *hmac,
 {
     return -1;
 }
+
+#endif