1 files changed, 235 insertions, 0 deletions
diff --git a/daemon/tls.h b/daemon/tls.h
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+/* Copyright (C) 2016 American Civil Liberties Union (ACLU)
+ * Copyright (C) CZ.NIC, z.s.p.o
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#pragma once
+
+#include <uv.h>
+#include <gnutls/gnutls.h>
+#include <libknot/packet/pkt.h>
+#include "lib/defines.h"
+#include "lib/generic/array.h"
+#include "lib/generic/trie.h"
+#include "lib/utils.h"
+
+#define MAX_TLS_PADDING KR_EDNS_PAYLOAD
+#define TLS_MAX_UNCORK_RETRIES 100
+
+/* rfc 5476, 7.3 - handshake Protocol overview
+ * https://tools.ietf.org/html/rfc5246#page-33
+ * Message flow for a full handshake (only mandatory messages)
+ * ClientHello           -------->
+                                        ServerHello
+                         <--------      ServerHelloDone
+   ClientKeyExchange
+   Finished              -------->
+                         <--------      Finished
+ *
+ * See also https://blog.cloudflare.com/keyless-ssl-the-nitty-gritty-technical-details/
+ * So it takes 2 RTT.
+ * As we use session tickets, there are additional messages, add one RTT mode.
+ */
+ #define TLS_MAX_HANDSHAKE_TIME (KR_CONN_RTT_MAX * 3)
+
+/** Transport session (opaque). */
+struct session;
+
+struct tls_ctx;
+struct tls_client_ctx;
+struct tls_credentials {
+	int count;
+	char *tls_cert;
+	char *tls_key;
+	gnutls_certificate_credentials_t credentials;
+	time_t valid_until;
+	char *ephemeral_servicename;
+};
+
+
+#define TLS_SHA256_RAW_LEN 32 /* gnutls_hash_get_len(GNUTLS_DIG_SHA256) */
+/** Required buffer length for pin_sha256, including the zero terminator. */
+#define TLS_SHA256_BASE64_BUFLEN (((TLS_SHA256_RAW_LEN * 8 + 4) / 6) + 3 + 1)
+
+#if GNUTLS_VERSION_NUMBER >= 0x030400
+	#define TLS_CAN_USE_PINS 1
+#else
+	#define TLS_CAN_USE_PINS 0
+#endif
+
+
+/** TLS authentication parameters for a single address-port pair. */
+typedef struct {
+	uint32_t refs; /**< Reference count; consider TLS sessions in progress. */
+	bool insecure; /**< Use no authentication. */
+	const char *hostname; /**< Server name for SNI and certificate check, lowercased.  */
+	array_t(const char *) ca_files; /**< Paths to certificate files; not really used. */
+	array_t(const uint8_t *) pins; /**< Certificate pins as raw unterminated strings.*/
+	gnutls_certificate_credentials_t credentials; /**< CA creds. in gnutls format.  */
+	gnutls_datum_t session_data; /**< Session-resumption data gets stored here.    */
+} tls_client_param_t;
+/** Holds configuration for TLS authentication for all potential servers.
+ * Special case: NULL pointer also means empty. */
+typedef trie_t tls_client_params_t;
+
+/** Get a pointer-to-pointer to TLS auth params.
+ * If it didn't exist, it returns NULL (if !do_insert) or pointer to NULL. */
+tls_client_param_t ** tls_client_param_getptr(tls_client_params_t **params,
+				const struct sockaddr *addr, bool do_insert);
+
+/** Get a pointer to TLS auth params or NULL. */
+static inline tls_client_param_t *
+	tls_client_param_get(tls_client_params_t *params, const struct sockaddr *addr)
+{
+	tls_client_param_t **pe = tls_client_param_getptr(&params, addr, false);
+	return pe ? *pe : NULL;
+}
+
+/** Allocate and initialize the structure (with ->ref = 1). */
+tls_client_param_t * tls_client_param_new();
+/** Reference-counted free(); any inside data is freed alongside. */
+void tls_client_param_unref(tls_client_param_t *entry);
+
+int tls_client_param_remove(tls_client_params_t *params, const struct sockaddr *addr);
+/** Free TLS authentication parameters. */
+void tls_client_params_free(tls_client_params_t *params);
+
+
+struct worker_ctx;
+struct qr_task;
+struct network;
+struct engine;
+
+typedef enum tls_client_hs_state {
+	TLS_HS_NOT_STARTED = 0,
+	TLS_HS_IN_PROGRESS,
+	TLS_HS_DONE,
+	TLS_HS_CLOSING,
+	TLS_HS_LAST
+} tls_hs_state_t;
+
+typedef int (*tls_handshake_cb) (struct session *session, int status);
+
+
+struct tls_common_ctx {
+	bool client_side;
+	gnutls_session_t tls_session;
+	tls_hs_state_t handshake_state;
+	struct session *session;
+	/* for reading from the network */
+	const uint8_t *buf;
+	ssize_t nread;
+	ssize_t consumed;
+	uint8_t recv_buf[16384];
+	tls_handshake_cb handshake_cb;
+	struct worker_ctx *worker;
+	size_t write_queue_size;
+};
+
+struct tls_ctx {
+	/*
+	 * Since pointer to tls_ctx needs to be casted
+	 * to  tls_ctx_common in some functions,
+	 * this field must be always at first position
+	 */
+	struct tls_common_ctx c;
+	struct tls_credentials *credentials;
+};
+
+struct tls_client_ctx {
+	/*
+	 * Since pointer to tls_client_ctx needs to be casted
+	 * to  tls_ctx_common in some functions,
+	 * this field must be always at first position
+	 */
+	struct tls_common_ctx c;
+	tls_client_param_t *params; /**< It's reference-counted. */
+};
+
+/*! Create an empty TLS context in query context */
+struct tls_ctx* tls_new(struct worker_ctx *worker);
+
+/*! Close a TLS context (call gnutls_bye()) */
+void tls_close(struct tls_common_ctx *ctx);
+
+/*! Close a TLS client context (call gnutls_bye()), storing its session data
+ * for potential resumption. */
+void tls_client_close(struct tls_client_ctx *ctx);
+
+/*! Release a TLS context */
+void tls_free(struct tls_ctx* tls);
+
+/*! Push new data to TLS context for sending */
+int tls_write(uv_write_t *req, uv_handle_t* handle, knot_pkt_t * pkt, uv_write_cb cb);
+
+/*! Unwrap incoming data from a TLS stream and pass them to TCP session.
+ * @return the number of newly-completed requests (>=0) or an error code
+ */
+ssize_t tls_process_input_data(struct session *s, const uint8_t *buf, ssize_t nread);
+
+/*! Set TLS certificate and key from files. */
+int tls_certificate_set(struct network *net, const char *tls_cert, const char *tls_key);
+
+/*! Borrow TLS credentials for context. */
+struct tls_credentials *tls_credentials_reserve(struct tls_credentials *tls_credentials);
+
+/*! Release TLS credentials for context (decrements refcount or frees). */
+int tls_credentials_release(struct tls_credentials *tls_credentials);
+
+/*! Free TLS credentials, must not be called if it holds positive refcount. */
+void tls_credentials_free(struct tls_credentials *tls_credentials);
+
+/*! Log DNS-over-TLS OOB key-pin form of current credentials:
+ * https://tools.ietf.org/html/rfc7858#appendix-A */
+void tls_credentials_log_pins(struct tls_credentials *tls_credentials);
+
+/*! Generate new ephemeral TLS credentials. */
+struct tls_credentials * tls_get_ephemeral_credentials(struct engine *engine);
+
+/*! Get TLS handshake state. */
+tls_hs_state_t tls_get_hs_state(const struct tls_common_ctx *ctx);
+
+/*! Set TLS handshake state. */
+int tls_set_hs_state(struct tls_common_ctx *ctx, tls_hs_state_t state);
+
+
+/*! Allocate new client TLS context */
+struct tls_client_ctx *tls_client_ctx_new(tls_client_param_t *entry,
+					    struct worker_ctx *worker);
+
+/*! Free client TLS context */
+void tls_client_ctx_free(struct tls_client_ctx *ctx);
+
+int tls_client_connect_start(struct tls_client_ctx *client_ctx,
+			     struct session *session,
+			     tls_handshake_cb handshake_cb);
+
+int tls_client_ctx_set_session(struct tls_client_ctx *ctx, struct session *session);
+
+
+/* Session tickets, server side.  Implementation in ./tls_session_ticket-srv.c */
+
+/*! Opaque struct used by tls_session_ticket_* functions. */
+struct tls_session_ticket_ctx;
+
+/*! Suggested maximum reasonable secret length. */
+#define TLS_SESSION_TICKET_SECRET_MAX_LEN 1024
+
+/*! Create a session ticket context and initialize it (secret gets copied inside).
+ *
+ * Passing zero-length secret implies using a random key, i.e. not synchronized
+ * between multiple instances.
+ *
+ * Beware that knowledge of the secret (if nonempty) breaks forward secrecy,
+ * so you should rotate the secret regularly and securely erase all past secrets.
+ * With TLS < 1.3 it's probably too risky to set nonempty secret.
+ */
+struct tls_session_ticket_ctx * tls_session_ticket_ctx_create(
+		uv_loop_t *loop, const char *secret, size_t secret_len);
+
+/*! Try to enable session tickets for a server session. */
+void tls_session_ticket_enable(struct tls_session_ticket_ctx *ctx, gnutls_session_t session);
+
+/*! Free all resources of the session ticket context.  NULL is accepted as well. */
+void tls_session_ticket_ctx_destroy(struct tls_session_ticket_ctx *ctx);
+