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Diffstat (limited to 'daemon/tls.h')
| -rw-r--r-- | daemon/tls.h | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/daemon/tls.h b/daemon/tls.h new file mode 100644 index 0000000..2eb776c --- /dev/null +++ b/daemon/tls.h @@ -0,0 +1,224 @@ +/* Copyright (C) 2016 American Civil Liberties Union (ACLU) + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#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/map.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_t; +struct tls_client_ctx_t; +struct tls_credentials { + int count; + char *tls_cert; + char *tls_key; + gnutls_certificate_credentials_t credentials; + time_t valid_until; + char *ephemeral_servicename; +}; + +struct tls_client_paramlist_entry { + array_t(const char *) ca_files; + array_t(const char *) hostnames; + array_t(const char *) pins; + gnutls_certificate_credentials_t credentials; + gnutls_datum_t session_data; + uint32_t refs; +}; + +struct worker_ctx; +struct qr_task; + +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); + +typedef enum tls_client_param { + TLS_CLIENT_PARAM_NONE = 0, + TLS_CLIENT_PARAM_PIN, + TLS_CLIENT_PARAM_HOSTNAME, + TLS_CLIENT_PARAM_CA, +} tls_client_param_t; + +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_t { + /* + * Since pointer to tls_ctx_t 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_t { + /* + * Since pointer to tls_client_ctx_t 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_client_paramlist_entry *params; +}; + +/*! Create an empty TLS context in query context */ +struct tls_ctx_t* tls_new(struct worker_ctx *worker); + +/*! Close a TLS context (call gnutls_bye()) */ +void tls_close(struct tls_common_ctx *ctx); + +/*! Release a TLS context */ +void tls_free(struct tls_ctx_t* 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); + +/*! Find TLS parameters for given address. Attempt opportunistic upgrade for port 53 to 853, + * if the address is configured with a working DoT on port 853. + */ +struct tls_client_paramlist_entry *tls_client_try_upgrade(map_t *tls_client_paramlist, + const struct sockaddr *addr); + +/*! Clear (remove) TLS parameters for given address. */ +int tls_client_params_clear(map_t *tls_client_paramlist, const char *addr, uint16_t port); + +/*! Set TLS authentication parameters for given address. + * Note: hostnames must be imported before ca files, + * otherwise ca files will not be imported at all. + */ +int tls_client_params_set(map_t *tls_client_paramlist, + const char *addr, uint16_t port, + const char *param, tls_client_param_t param_type); + +/*! Free TLS authentication parameters. */ +int tls_client_params_free(map_t *tls_client_paramlist); + +/*! Allocate new client TLS context */ +struct tls_client_ctx_t *tls_client_ctx_new(struct tls_client_paramlist_entry *entry, + struct worker_ctx *worker); + +/*! Free client TLS context */ +void tls_client_ctx_free(struct tls_client_ctx_t *ctx); + +int tls_client_connect_start(struct tls_client_ctx_t *client_ctx, + struct session *session, + tls_handshake_cb handshake_cb); + +int tls_client_ctx_set_session(struct tls_client_ctx_t *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); + |