#include "tls-cipher-stdname.c"
+#ifdef MACRO_PREDEF
+void
+options_tls(void)
+{
+# ifdef EXPERIMENTAL_TLS_RESUME
+builtin_macro_create_var(US"_RESUME_DECODE", RESUME_DECODE_STRING );
+# endif
+}
+#else
+
+
/* GnuTLS 2 vs 3
GnuTLS 3 only:
} exim_gnutls_state_st;
static const exim_gnutls_state_st exim_gnutls_state_init = {
- .session = NULL,
- .x509_cred = NULL,
- .priority_cache = NULL,
- .verify_requirement = VERIFY_NONE,
+ /* all elements not explicitly intialised here get 0/NULL/FALSE */
.fd_in = -1,
.fd_out = -1,
- .peer_cert_verified = FALSE,
- .peer_dane_verified = FALSE,
- .trigger_sni_changes =FALSE,
- .have_set_peerdn = FALSE,
- .host = NULL,
- .peercert = NULL,
- .peerdn = NULL,
- .ciphersuite = NULL,
- .received_sni = NULL,
-
- .tls_certificate = NULL,
- .tls_privatekey = NULL,
- .tls_sni = NULL,
- .tls_verify_certificates = NULL,
- .tls_crl = NULL,
- .tls_require_ciphers =NULL,
-
- .exp_tls_certificate = NULL,
- .exp_tls_privatekey = NULL,
- .exp_tls_verify_certificates = NULL,
- .exp_tls_crl = NULL,
- .exp_tls_require_ciphers = NULL,
- .exp_tls_verify_cert_hostnames = NULL,
-#ifndef DISABLE_EVENT
- .event_action = NULL,
-#endif
- .tlsp = NULL,
-
- .xfer_buffer = NULL,
- .xfer_buffer_lwm = 0,
- .xfer_buffer_hwm = 0,
- .xfer_eof = FALSE,
- .xfer_error = FALSE,
};
/* Not only do we have our own APIs which don't pass around state, assuming
static gnutls_dh_params_t dh_server_params = NULL;
-/* No idea how this value was chosen; preserving it. Default is 3600. */
-
-static const int ssl_session_timeout = 200;
+static int ssl_session_timeout = 3600; /* One hour */
static const uschar * const exim_default_gnutls_priority = US"NORMAL";
static BOOL gnutls_buggy_ocsp = FALSE;
#endif
+#ifdef EXPERIMENTAL_TLS_RESUME
+static gnutls_datum_t server_sessticket_key;
+#endif
/* ------------------------------------------------------------------------ */
/* macros */
+/* Daemon one-time initialisation */
+void
+tls_daemon_init(void)
+{
+#ifdef EXPERIMENTAL_TLS_RESUME
+/* We are dependent on the GnuTLS implementation of the Session Ticket
+encryption; both the strength and the key rotation period. We hope that
+the strength at least matches that of the ciphersuite (but GnuTLS does not
+document this). */
+
+static BOOL once = FALSE;
+if (once) return;
+once = TRUE;
+gnutls_session_ticket_key_generate(&server_sessticket_key); /* >= 2.10.0 */
+if (f.running_in_test_harness) ssl_session_timeout = 6;
+#endif
+}
+
/* ------------------------------------------------------------------------ */
/* Static functions */
static void
extract_exim_vars_from_tls_state(exim_gnutls_state_st * state)
{
-gnutls_cipher_algorithm_t cipher;
#ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING
int old_pool;
int rc;
tlsp->active.sock = state->fd_out;
tlsp->active.tls_ctx = state;
-cipher = gnutls_cipher_get(state->session);
-/* returns size in "bytes" */
-tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8;
-
-tlsp->cipher = state->ciphersuite;
-
DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite);
tlsp->certificate_verified = state->peer_cert_verified;
if ((rc = gnutls_priority_set(state->session, state->priority_cache)))
return tls_error_gnu(US"gnutls_priority_set", rc, host, errstr);
+/* This also sets the server ticket expiration time to the same, and
+the STEK rotation time to 3x. */
+
gnutls_db_set_cache_expiration(state->session, ssl_session_timeout);
/* Reduce security in favour of increased compatibility, if the admin
*/
static int
-peer_status(exim_gnutls_state_st *state, uschar ** errstr)
+peer_status(exim_gnutls_state_st * state, uschar ** errstr)
{
-const gnutls_datum_t *cert_list;
+gnutls_session_t session = state->session;
+const gnutls_datum_t * cert_list;
int old_pool, rc;
unsigned int cert_list_size = 0;
gnutls_protocol_t protocol;
gnutls_mac_algorithm_t mac;
gnutls_certificate_type_t ct;
gnutls_x509_crt_t crt;
-uschar *dn_buf;
+uschar * dn_buf;
size_t sz;
if (state->have_set_peerdn)
state->peerdn = NULL;
/* tls_cipher */
-cipher = gnutls_cipher_get(state->session);
-protocol = gnutls_protocol_get_version(state->session);
-mac = gnutls_mac_get(state->session);
-kx = protocol < GNUTLS_TLS1_3 ? gnutls_kx_get(state->session) : 0;
+cipher = gnutls_cipher_get(session);
+protocol = gnutls_protocol_get_version(session);
+mac = gnutls_mac_get(session);
+kx =
+#ifdef GNUTLS_TLS1_3
+ protocol >= GNUTLS_TLS1_3 ? 0 :
+#endif
+ gnutls_kx_get(session);
old_pool = store_pool;
{
+ tls_support * tlsp = state->tlsp;
store_pool = POOL_PERM;
#ifdef SUPPORT_GNUTLS_SESS_DESC
{
gstring * g = NULL;
- uschar * s = US gnutls_session_get_desc(state->session), c;
+ uschar * s = US gnutls_session_get_desc(session), c;
/* Nikos M suggests we use this by preference. It returns like:
(TLS1.3)-(ECDHE-SECP256R1)-(RSA-PSS-RSAE-SHA256)-(AES-256-GCM)
/* debug_printf("peer_status: ciphersuite %s\n", state->ciphersuite); */
- state->tlsp->cipher = state->ciphersuite;
- state->tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8;
+ tlsp->cipher = state->ciphersuite;
+ tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8;
- state->tlsp->cipher_stdname = cipher_stdname_kcm(kx, cipher, mac);
+ tlsp->cipher_stdname = cipher_stdname_kcm(kx, cipher, mac);
}
store_pool = old_pool;
/* tls_peerdn */
-cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size);
+cert_list = gnutls_certificate_get_peers(session, &cert_list_size);
if (!cert_list || cert_list_size == 0)
{
return OK;
}
-if ((ct = gnutls_certificate_type_get(state->session)) != GNUTLS_CRT_X509)
+if ((ct = gnutls_certificate_type_get(session)) != GNUTLS_CRT_X509)
{
const uschar * ctn = US gnutls_certificate_type_get_name(ct);
DEBUG(D_tls)
int rc;
uint verify;
-if (state->verify_requirement == VERIFY_NONE)
- return TRUE;
-
DEBUG(D_tls) debug_printf("TLS: checking peer certificate\n");
*errstr = NULL;
+rc = peer_status(state, errstr);
-if ((rc = peer_status(state, errstr)) != OK || !state->peerdn)
+if (state->verify_requirement == VERIFY_NONE)
+ return TRUE;
+
+if (rc != OK || !state->peerdn)
{
verify = GNUTLS_CERT_INVALID;
*errstr = US"certificate not supplied";
static void
post_handshake_debug(exim_gnutls_state_st * state)
{
-debug_printf("gnutls_handshake was successful\n");
#ifdef SUPPORT_GNUTLS_SESS_DESC
debug_printf("%s\n", gnutls_session_get_desc(state->session));
#endif
#ifdef SUPPORT_GNUTLS_KEYLOG
+# ifdef GNUTLS_TLS1_3
if (gnutls_protocol_get_version(state->session) < GNUTLS_TLS1_3)
+#else
+if (TRUE)
+#endif
{
gnutls_datum_t c, s;
gstring * gc, * gs;
#endif
}
+
+#ifdef EXPERIMENTAL_TLS_RESUME
+static int
+tls_server_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when,
+ unsigned incoming, const gnutls_datum_t * msg)
+{
+DEBUG(D_tls) debug_printf("newticket cb\n");
+tls_in.resumption |= RESUME_CLIENT_REQUESTED;
+return 0;
+}
+
+static void
+tls_server_resume_prehandshake(exim_gnutls_state_st * state)
+{
+/* Should the server offer session resumption? */
+tls_in.resumption = RESUME_SUPPORTED;
+if (verify_check_host(&tls_resumption_hosts) == OK)
+ {
+ int rc;
+ /* GnuTLS appears to not do ticket overlap, but does emit a fresh ticket when
+ an offered resumption is unacceptable. We lose one resumption per ticket
+ lifetime, and sessions cannot be indefinitely re-used. There seems to be no
+ way (3.6.7) of changing the default number of 2 TLS1.3 tickets issued, but at
+ least they go out in a single packet. */
+
+ if (!(rc = gnutls_session_ticket_enable_server(state->session,
+ &server_sessticket_key)))
+ tls_in.resumption |= RESUME_SERVER_TICKET;
+ else
+ DEBUG(D_tls)
+ debug_printf("enabling session tickets: %s\n", US gnutls_strerror(rc));
+
+ /* Try to tell if we see a ticket request */
+ gnutls_handshake_set_hook_function(state->session,
+ GNUTLS_HANDSHAKE_NEW_SESSION_TICKET, GNUTLS_HOOK_POST, tls_server_ticket_cb);
+ }
+}
+
+static void
+tls_server_resume_posthandshake(exim_gnutls_state_st * state)
+{
+if (gnutls_session_resumption_requested(state->session))
+ {
+ /* This tells us the client sent a full ticket. We use a
+ callback on session-ticket request, elsewhere, to tell
+ if a client asked for a ticket. */
+
+ tls_in.resumption |= RESUME_CLIENT_SUGGESTED;
+ DEBUG(D_tls) debug_printf("client requested resumption\n");
+ }
+if (gnutls_session_is_resumed(state->session))
+ {
+ tls_in.resumption |= RESUME_USED;
+ DEBUG(D_tls) debug_printf("Session resumed\n");
+ }
+}
+#endif
/* ------------------------------------------------------------------------ */
/* Exported functions */
NULL, tls_verify_certificates, tls_crl,
require_ciphers, &state, &tls_in, errstr)) != OK) return rc;
+#ifdef EXPERIMENTAL_TLS_RESUME
+tls_server_resume_prehandshake(state);
+#endif
+
/* If this is a host for which certificate verification is mandatory or
optional, set up appropriately. */
return FAIL;
}
+#ifdef EXPERIMENTAL_TLS_RESUME
+tls_server_resume_posthandshake(state);
+#endif
+
DEBUG(D_tls) post_handshake_debug(state);
/* Verify after the fact */
*errstr);
}
-/* Figure out peer DN, and if authenticated, etc. */
-
-if ((rc = peer_status(state, NULL)) != OK) return rc;
-
/* Sets various Exim expansion variables; always safe within server */
extract_exim_vars_from_tls_state(state);
+#ifdef EXPERIMENTAL_TLS_RESUME
+/* On the client, get any stashed session for the given IP from hints db
+and apply it to the ssl-connection for attempted resumption. Although
+there is a gnutls_session_ticket_enable_client() interface it is
+documented as unnecessary (as of 3.6.7) as "session tickets are emabled
+by deafult". There seems to be no way to disable them, so even hosts not
+enabled by the transport option will be sent a ticket request. We will
+however avoid storing and retrieving session information. */
+
+static void
+tls_retrieve_session(tls_support * tlsp, gnutls_session_t session,
+ host_item * host, smtp_transport_options_block * ob)
+{
+tlsp->resumption = RESUME_SUPPORTED;
+if (verify_check_given_host(CUSS &ob->tls_resumption_hosts, host) == OK)
+ {
+ dbdata_tls_session * dt;
+ int len, rc;
+ open_db dbblock, * dbm_file;
+
+ DEBUG(D_tls)
+ debug_printf("check for resumable session for %s\n", host->address);
+ tlsp->host_resumable = TRUE;
+ tlsp->resumption |= RESUME_CLIENT_REQUESTED;
+ if ((dbm_file = dbfn_open(US"tls", O_RDONLY, &dbblock, FALSE, FALSE)))
+ {
+ /* key for the db is the IP */
+ if ((dt = dbfn_read_with_length(dbm_file, host->address, &len)))
+ if (!(rc = gnutls_session_set_data(session,
+ CUS dt->session, (size_t)len - sizeof(dbdata_tls_session))))
+ {
+ DEBUG(D_tls) debug_printf("good session\n");
+ tlsp->resumption |= RESUME_CLIENT_SUGGESTED;
+ }
+ else DEBUG(D_tls) debug_printf("setting session resumption data: %s\n",
+ US gnutls_strerror(rc));
+ dbfn_close(dbm_file);
+ }
+ }
+}
+
+
+static void
+tls_save_session(tls_support * tlsp, gnutls_session_t session, const host_item * host)
+{
+/* TLS 1.2 - we get both the callback and the direct posthandshake call,
+but this flag is not set until the second. TLS 1.3 it's the other way about.
+Keep both calls as the session data cannot be extracted before handshake
+completes. */
+
+#ifdef GNUTLS_SFLAGS_SESSION_TICKET
+if (gnutls_session_get_flags(session) & GNUTLS_SFLAGS_SESSION_TICKET)
+ {
+ gnutls_datum_t tkt;
+ int rc;
+
+ DEBUG(D_tls) debug_printf("server offered session ticket\n");
+ tlsp->ticket_received = TRUE;
+ tlsp->resumption |= RESUME_SERVER_TICKET;
+
+ if (tlsp->host_resumable)
+ if (!(rc = gnutls_session_get_data2(session, &tkt)))
+ {
+ open_db dbblock, * dbm_file;
+ int dlen = sizeof(dbdata_tls_session) + tkt.size;
+ dbdata_tls_session * dt = store_get(dlen);
+
+ DEBUG(D_tls) debug_printf("session data size %u\n", (unsigned)tkt.size);
+ memcpy(dt->session, tkt.data, tkt.size);
+ gnutls_free(tkt.data);
+
+ if ((dbm_file = dbfn_open(US"tls", O_RDWR, &dbblock, FALSE, FALSE)))
+ {
+ /* key for the db is the IP */
+ dbfn_delete(dbm_file, host->address);
+ dbfn_write(dbm_file, host->address, dt, dlen);
+ dbfn_close(dbm_file);
+
+ DEBUG(D_tls)
+ debug_printf("wrote session db (len %u)\n", (unsigned)dlen);
+ }
+ }
+ else DEBUG(D_tls)
+ debug_printf("extract session data: %s\n", US gnutls_strerror(rc));
+ }
+#endif
+}
+
+
+/* With a TLS1.3 session, the ticket(s) are not seen until
+the first data read is attempted. And there's often two of them.
+Pick them up with this callback. We are also called for 1.2
+but we do nothing.
+*/
+static int
+tls_client_ticket_cb(gnutls_session_t sess, u_int htype, unsigned when,
+ unsigned incoming, const gnutls_datum_t * msg)
+{
+exim_gnutls_state_st * state = gnutls_session_get_ptr(sess);
+tls_support * tlsp = state->tlsp;
+
+DEBUG(D_tls) debug_printf("newticket cb\n");
+
+if (!tlsp->ticket_received)
+ tls_save_session(tlsp, sess, state->host);
+return 0;
+}
+
+
+static void
+tls_client_resume_prehandshake(exim_gnutls_state_st * state,
+ tls_support * tlsp, host_item * host,
+ smtp_transport_options_block * ob)
+{
+gnutls_session_set_ptr(state->session, state);
+gnutls_handshake_set_hook_function(state->session,
+ GNUTLS_HANDSHAKE_NEW_SESSION_TICKET, GNUTLS_HOOK_POST, tls_client_ticket_cb);
+
+tls_retrieve_session(tlsp, state->session, host, ob);
+}
+
+static void
+tls_client_resume_posthandshake(exim_gnutls_state_st * state,
+ tls_support * tlsp, host_item * host)
+{
+if (gnutls_session_is_resumed(state->session))
+ {
+ DEBUG(D_tls) debug_printf("Session resumed\n");
+ tlsp->resumption |= RESUME_USED;
+ }
+
+tls_save_session(tlsp, state->session, host);
+}
+#endif /* EXPERIMENTAL_TLS_RESUME */
+
+
/*************************************************
* Start a TLS session in a client *
*************************************************/
}
#endif
+#ifdef EXPERIMENTAL_TLS_RESUME
+tls_client_resume_prehandshake(state, tlsp, host, ob);
+#endif
+
#ifndef DISABLE_EVENT
if (tb && tb->event_action)
{
}
#endif
-/* Figure out peer DN, and if authenticated, etc. */
-
-if (peer_status(state, errstr) != OK)
- return FALSE;
+#ifdef EXPERIMENTAL_TLS_RESUME
+tls_client_resume_posthandshake(state, tlsp, host);
+#endif
/* Sets various Exim expansion variables; may need to adjust for ACL callouts */
gnutls_check_version(NULL));
}
+#endif /*!MACRO_PREDEF*/
/* vi: aw ai sw=2
*/
/* End of tls-gnu.c */
projects / exim.git / blobdiff