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-rw-r--r--lib/secrets.c214
1 files changed, 214 insertions, 0 deletions
diff --git a/lib/secrets.c b/lib/secrets.c
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+++ b/lib/secrets.c
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+/*
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>
+ *
+ */
+
+/* TLS 1.3 secret key derivation handling.
+ */
+
+#include <config.h>
+#include "crypto-api.h"
+#include "fips.h"
+#include "gnutls_int.h"
+#include "secrets.h"
+
+/* HKDF-Extract(0,0) or HKDF-Extract(0, PSK) */
+int _tls13_init_secret(gnutls_session_t session, const uint8_t *psk, size_t psk_size)
+{
+ session->key.proto.tls13.temp_secret_size = session->security_parameters.prf->output_size;
+
+ return _tls13_init_secret2(session->security_parameters.prf,
+ psk, psk_size,
+ session->key.proto.tls13.temp_secret);
+}
+
+int _tls13_init_secret2(const mac_entry_st *prf,
+ const uint8_t *psk, size_t psk_size,
+ void *out)
+{
+ char buf[128];
+
+ if (unlikely(prf == NULL))
+ return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+ /* when no PSK, use the zero-value */
+ if (psk == NULL) {
+ psk_size = prf->output_size;
+ if (unlikely(psk_size >= sizeof(buf)))
+ return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+ memset(buf, 0, psk_size);
+ psk = (uint8_t*) buf;
+ }
+
+ return gnutls_hmac_fast(prf->id,
+ "", 0,
+ psk, psk_size,
+ out);
+}
+
+/* HKDF-Extract(Prev-Secret, key) */
+int _tls13_update_secret(gnutls_session_t session, const uint8_t *key, size_t key_size)
+{
+ gnutls_datum_t _key;
+ gnutls_datum_t salt;
+ int ret;
+
+ _key.data = (void *)key;
+ _key.size = key_size;
+ salt.data = (void *)session->key.proto.tls13.temp_secret;
+ salt.size = session->key.proto.tls13.temp_secret_size;
+
+ ret = _gnutls_hkdf_extract(session->security_parameters.prf->id,
+ &_key, &salt,
+ session->key.proto.tls13.temp_secret);
+ if (ret < 0)
+ _gnutls_switch_fips_state(GNUTLS_FIPS140_OP_ERROR);
+ else
+ _gnutls_switch_fips_state(GNUTLS_FIPS140_OP_APPROVED);
+
+ return ret;
+}
+
+/* Derive-Secret(Secret, Label, Messages) */
+int _tls13_derive_secret2(const mac_entry_st *prf,
+ const char *label, unsigned label_size,
+ const uint8_t *tbh, size_t tbh_size,
+ const uint8_t secret[MAX_HASH_SIZE],
+ void *out)
+{
+ uint8_t digest[MAX_HASH_SIZE];
+ int ret;
+ unsigned digest_size;
+
+ if (unlikely(prf == NULL))
+ return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+ if (unlikely(label_size >= sizeof(digest)))
+ return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
+
+ digest_size = prf->output_size;
+ ret = gnutls_hash_fast((gnutls_digest_algorithm_t) prf->id,
+ tbh, tbh_size, digest);
+ if (ret < 0)
+ return gnutls_assert_val(ret);
+
+ return _tls13_expand_secret2(prf, label, label_size, digest, digest_size, secret, digest_size, out);
+}
+
+/* Derive-Secret(Secret, Label, Messages) */
+int _tls13_derive_secret(gnutls_session_t session,
+ const char *label, unsigned label_size,
+ const uint8_t *tbh, size_t tbh_size,
+ const uint8_t secret[MAX_HASH_SIZE],
+ void *out)
+{
+ if (unlikely(session->security_parameters.prf == NULL))
+ return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+ return _tls13_derive_secret2(session->security_parameters.prf, label, label_size, tbh, tbh_size,
+ secret,
+ out);
+}
+
+/* HKDF-Expand-Label(Secret, Label, HashValue, Length) */
+int _tls13_expand_secret2(const mac_entry_st *prf,
+ const char *label, unsigned label_size,
+ const uint8_t *msg, size_t msg_size,
+ const uint8_t secret[MAX_HASH_SIZE],
+ unsigned out_size,
+ void *out)
+{
+ uint8_t tmp[256] = "tls13 ";
+ gnutls_buffer_st str;
+ gnutls_datum_t key;
+ gnutls_datum_t info;
+ int ret;
+
+ if (unlikely(label_size >= sizeof(tmp)-6))
+ return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
+
+ _gnutls_buffer_init(&str);
+
+ ret = _gnutls_buffer_append_prefix(&str, 16, out_size);
+ if (ret < 0) {
+ gnutls_assert();
+ goto cleanup;
+ }
+
+ memcpy(&tmp[6], label, label_size);
+ ret = _gnutls_buffer_append_data_prefix(&str, 8, tmp, label_size+6);
+ if (ret < 0) {
+ gnutls_assert();
+ goto cleanup;
+ }
+
+ ret = _gnutls_buffer_append_data_prefix(&str, 8, msg, msg_size);
+ if (ret < 0) {
+ gnutls_assert();
+ goto cleanup;
+ }
+
+ key.data = (void *)secret;
+ key.size =_gnutls_mac_get_algo_len(mac_to_entry(prf->id));
+ info.data = str.data;
+ info.size = str.length;
+
+ ret = _gnutls_hkdf_expand(prf->id, &key, &info, out, out_size);
+ if (ret < 0) {
+ _gnutls_switch_fips_state(GNUTLS_FIPS140_OP_ERROR);
+ gnutls_assert();
+ goto cleanup;
+ } else {
+ _gnutls_switch_fips_state(GNUTLS_FIPS140_OP_APPROVED);
+ }
+
+#if 0
+ _gnutls_hard_log("INT: hkdf label: %d,%s\n",
+ out_size,
+ _gnutls_bin2hex(str.data, str.length,
+ (char*)tmp, sizeof(tmp), NULL));
+ _gnutls_hard_log("INT: secret expanded for '%.*s': %d,%s\n",
+ (int)label_size, label, out_size,
+ _gnutls_bin2hex(out, out_size,
+ (char*)tmp, sizeof(tmp), NULL));
+#endif
+
+ ret = 0;
+ cleanup:
+ _gnutls_buffer_clear(&str);
+ return ret;
+}
+
+int _tls13_expand_secret(gnutls_session_t session,
+ const char *label, unsigned label_size,
+ const uint8_t *msg, size_t msg_size,
+ const uint8_t secret[MAX_HASH_SIZE],
+ unsigned out_size,
+ void *out)
+{
+ if (unlikely(session->security_parameters.prf == NULL))
+ return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+ return _tls13_expand_secret2(session->security_parameters.prf,
+ label, label_size,
+ msg, msg_size, secret,
+ out_size, out);
+}
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-08 18:14:15 +0000