X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/f1fed05bfbcf83b7d504ea68d136c4a923d070ea..1b76ad22a23e704c1d931937953d44c9b206c867:/src/src/tls-gnu.c diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index 3a45999aa..1430f2f3c 100644 --- a/src/src/tls-gnu.c +++ b/src/src/tls-gnu.c @@ -2,7 +2,7 @@ * Exim - an Internet mail transport agent * *************************************************/ -/* Copyright (c) University of Cambridge 1995 - 2017 */ +/* Copyright (c) University of Cambridge 1995 - 2018 */ /* See the file NOTICE for conditions of use and distribution. */ /* Copyright (c) Phil Pennock 2012 */ @@ -66,13 +66,17 @@ require current GnuTLS, then we'll drop support for the ancient libraries). #if GNUTLS_VERSION_NUMBER >= 0x030506 && !defined(DISABLE_OCSP) # define SUPPORT_SRV_OCSP_STACK #endif -#if GNUTLS_VERSION_NUMBER >= 0x030000 && defined(EXPERIMENTAL_DANE) -# define SUPPORT_DANE -# define DANESSL_USAGE_DANE_TA 2 -# define DANESSL_USAGE_DANE_EE 3 -#endif -#if GNUTLS_VERSION_NUMBER < 0x999999 && defined(EXPERIMENTAL_DANE) -# define GNUTLS_BROKEN_DANE_VALIDATION + +#ifdef SUPPORT_DANE +# if GNUTLS_VERSION_NUMBER >= 0x030000 +# define DANESSL_USAGE_DANE_TA 2 +# define DANESSL_USAGE_DANE_EE 3 +# else +# error GnuTLS version too early for DANE +# endif +# if GNUTLS_VERSION_NUMBER < 0x999999 +# define GNUTLS_BROKEN_DANE_VALIDATION +# endif #endif #ifndef DISABLE_OCSP @@ -120,8 +124,8 @@ typedef struct exim_gnutls_state { BOOL peer_dane_verified; BOOL trigger_sni_changes; BOOL have_set_peerdn; - const struct host_item *host; - gnutls_x509_crt_t peercert; + const struct host_item *host; /* NULL if server */ + gnutls_x509_crt_t peercert; uschar *peerdn; uschar *ciphersuite; uschar *received_sni; @@ -152,8 +156,8 @@ typedef struct exim_gnutls_state { uschar *xfer_buffer; int xfer_buffer_lwm; int xfer_buffer_hwm; - int xfer_eof; - int xfer_error; + BOOL xfer_eof; /*XXX never gets set! */ + BOOL xfer_error; } exim_gnutls_state_st; static const exim_gnutls_state_st exim_gnutls_state_init = { @@ -194,8 +198,8 @@ static const exim_gnutls_state_st exim_gnutls_state_init = { .xfer_buffer = NULL, .xfer_buffer_lwm = 0, .xfer_buffer_hwm = 0, - .xfer_eof = 0, - .xfer_error = 0, + .xfer_eof = FALSE, + .xfer_error = FALSE, }; /* Not only do we have our own APIs which don't pass around state, assuming @@ -209,7 +213,7 @@ second connection. XXX But see gnutls_session_get_ptr() */ -static exim_gnutls_state_st state_server, state_client; +static exim_gnutls_state_st state_server; /* dh_params are initialised once within the lifetime of a process using TLS; if we used TLS in a long-lived daemon, we'd have to reconsider this. But we @@ -444,7 +448,8 @@ gnutls_datum_t channel; #endif tls_support * tlsp = state->tlsp; -tlsp->active = state->fd_out; +tlsp->active.sock = state->fd_out; +tlsp->active.tls_ctx = state; cipher = gnutls_cipher_get(state->session); /* returns size in "bytes" */ @@ -786,7 +791,7 @@ if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, goto err; where = US"configuring cert"; -now = 0; +now = 1; if ( (rc = gnutls_x509_crt_set_version(cert, 3)) || (rc = gnutls_x509_crt_set_serial(cert, &now, sizeof(now))) || (rc = gnutls_x509_crt_set_activation_time(cert, now = time(NULL))) @@ -1258,6 +1263,7 @@ tls_init( const uschar *crl, const uschar *require_ciphers, exim_gnutls_state_st **caller_state, + tls_support * tlsp, uschar ** errstr) { exim_gnutls_state_st *state; @@ -1306,9 +1312,15 @@ if (!exim_gnutls_base_init_done) if (host) { - state = &state_client; + /* For client-side sessions we allocate a context. This lets us run + several in parallel. */ + int old_pool = store_pool; + store_pool = POOL_PERM; + state = store_get(sizeof(exim_gnutls_state_st)); + store_pool = old_pool; + memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); - state->tlsp = &tls_out; + state->tlsp = tlsp; DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); rc = gnutls_init(&state->session, GNUTLS_CLIENT); } @@ -1316,7 +1328,7 @@ else { state = &state_server; memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); - state->tlsp = &tls_in; + state->tlsp = tlsp; DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); rc = gnutls_init(&state->session, GNUTLS_SERVER); } @@ -1586,6 +1598,7 @@ uint verify; if (state->verify_requirement == VERIFY_NONE) return TRUE; +DEBUG(D_tls) debug_printf("TLS: checking peer certificate\n"); *errstr = NULL; if ((rc = peer_status(state, errstr)) != OK) @@ -1613,11 +1626,10 @@ else # ifdef GNUTLS_BROKEN_DANE_VALIDATION /* Split the TLSA records into two sets, TA and EE selectors. Run the dane-verification separately so that we know which selector verified; - then we know whether to do CA-chain-verification and name-verification - (needed for TA but not EE). */ + then we know whether to do name-verification (needed for TA but not EE). */ if (usage == ((1<session), - r, 0, + r, 0, # ifdef GNUTLS_BROKEN_DANE_VALIDATION usage == (1 << DANESSL_USAGE_DANE_EE) ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, @@ -1696,20 +1708,31 @@ else *errstr = US str.data; /* don't bother to free */ goto badcert; } - state->peer_dane_verified = TRUE; # ifdef GNUTLS_BROKEN_DANE_VALIDATION /* If a TA-mode TLSA record was used for verification we must additionally - verify the CA chain and the cert name. For EE-mode, skip it. */ + verify the cert name (but not the CA chain). For EE-mode, skip it. */ if (usage & (1 << DANESSL_USAGE_DANE_EE)) # endif { - state->peer_cert_verified = TRUE; + state->peer_dane_verified = state->peer_cert_verified = TRUE; goto goodcert; } +# ifdef GNUTLS_BROKEN_DANE_VALIDATION + /* Assume that the name on the A-record is the one that should be matching + the cert. An alternate view is that the domain part of the email address + is also permissible. */ + + if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, + CS state->host->name)) + { + state->peer_dane_verified = state->peer_cert_verified = TRUE; + goto goodcert; + } +# endif } -#endif +#endif /*SUPPORT_DANE*/ rc = gnutls_certificate_verify_peers2(state->session, &verify); } @@ -1735,23 +1758,23 @@ if (rc < 0 || verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) else { - if (state->exp_tls_verify_cert_hostnames) + /* Client side, check the server's certificate name versus the name on the + A-record for the connection we made. What to do for server side - what name + to use for client? We document that there is no such checking for server + side. */ + + if ( state->exp_tls_verify_cert_hostnames + && !gnutls_x509_crt_check_hostname(state->tlsp->peercert, + CS state->exp_tls_verify_cert_hostnames) + ) { - int sep = 0; - const uschar * list = state->exp_tls_verify_cert_hostnames; - uschar * name; - while ((name = string_nextinlist(&list, &sep, NULL, 0))) - if (gnutls_x509_crt_check_hostname(state->tlsp->peercert, CS name)) - break; - if (!name) - { - DEBUG(D_tls) - debug_printf("TLS certificate verification failed: cert name mismatch\n"); - if (state->verify_requirement >= VERIFY_REQUIRED) - goto badcert; - return TRUE; - } + DEBUG(D_tls) + debug_printf("TLS certificate verification failed: cert name mismatch\n"); + if (state->verify_requirement >= VERIFY_REQUIRED) + goto badcert; + return TRUE; } + state->peer_cert_verified = TRUE; DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", state->peerdn ? state->peerdn : US""); @@ -1763,7 +1786,8 @@ goodcert: #ifdef SUPPORT_DANE tlsa_prob: - *errstr = string_sprintf("TLSA record problem: %s", dane_strerror(rc)); + *errstr = string_sprintf("TLSA record problem: %s", + rc == DANE_E_REQUESTED_DATA_NOT_AVAILABLE ? "none usable" : dane_strerror(rc)); #endif badcert: @@ -1916,12 +1940,10 @@ int rc; uschar * yield; exim_gnutls_state_st * state = gnutls_session_get_ptr(session); -cert_list = gnutls_certificate_get_peers(session, &cert_list_size); -if (cert_list) +if ((cert_list = gnutls_certificate_get_peers(session, &cert_list_size))) while (cert_list_size--) { - rc = import_cert(&cert_list[cert_list_size], &crt); - if (rc != GNUTLS_E_SUCCESS) + if ((rc = import_cert(&cert_list[cert_list_size], &crt)) != GNUTLS_E_SUCCESS) { DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", cert_list_size, gnutls_strerror(rc)); @@ -1978,7 +2000,7 @@ int rc; exim_gnutls_state_st * state = NULL; /* Check for previous activation */ -if (tls_in.active >= 0) +if (tls_in.active.sock >= 0) { tls_error(US"STARTTLS received after TLS started", "", NULL, errstr); smtp_printf("554 Already in TLS\r\n", FALSE); @@ -1992,7 +2014,7 @@ DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, NULL, tls_verify_certificates, tls_crl, - require_ciphers, &state, errstr)) != OK) return rc; + require_ciphers, &state, &tls_in, errstr)) != OK) return rc; /* If this is a host for which certificate verification is mandatory or optional, set up appropriately. */ @@ -2047,7 +2069,10 @@ if (!state->tlsp->on_connect) } /* Now negotiate the TLS session. We put our own timer on it, since it seems -that the GnuTLS library doesn't. */ +that the GnuTLS library doesn't. +From 3.1.0 there is gnutls_handshake_set_timeout() - but it requires you +to set (and clear down afterwards) up a pull-timeout callback function that does +a select, so we're no better off unless avoiding signals becomes an issue. */ gnutls_transport_set_ptr2(state->session, (gnutls_transport_ptr_t)(long) fileno(smtp_in), @@ -2137,7 +2162,7 @@ static void tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state, smtp_transport_options_block * ob) { -if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK) +if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK) { state->exp_tls_verify_cert_hostnames = #ifdef SUPPORT_I18N @@ -2182,7 +2207,7 @@ dane_data_len = store_get(i * sizeof(int)); for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS), i = 0; rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) - ) if (rr->type == T_TLSA) + ) if (rr->type == T_TLSA && rr->size > 3) { const uschar * p = rr->data; uint8_t usage = p[0], sel = p[1], type = p[2]; @@ -2231,7 +2256,7 @@ return TRUE; Arguments: fd the fd of the connection - host connected host (for messages) + host connected host (for messages and option-tests) addr the first address (not used) tb transport (always smtp) tlsa_dnsa non-NULL, either request or require dane for this host, and @@ -2239,38 +2264,56 @@ Arguments: Which implies cert must be requested and supplied, dane verify must pass, and cert verify irrelevant (incl. hostnames), and (caller handled) require_tls + tlsp record details of channel configuration errstr error string pointer -Returns: OK/DEFER/FAIL (because using common functions), - but for a client, DEFER and FAIL have the same meaning +Returns: Pointer to TLS session context, or NULL on error */ -int +void * tls_client_start(int fd, host_item *host, address_item *addr ARG_UNUSED, transport_instance * tb, -#ifdef EXPERIMENTAL_DANE +#ifdef SUPPORT_DANE dns_answer * tlsa_dnsa, #endif - uschar ** errstr) + tls_support * tlsp, uschar ** errstr) { -smtp_transport_options_block *ob = - (smtp_transport_options_block *)tb->options_block; +smtp_transport_options_block *ob = tb + ? (smtp_transport_options_block *)tb->options_block + : &smtp_transport_option_defaults; int rc; exim_gnutls_state_st * state = NULL; +uschar *cipher_list = NULL; + #ifndef DISABLE_OCSP BOOL require_ocsp = - verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; + verify_check_given_host(CUSS &ob->hosts_require_ocsp, host) == OK; BOOL request_ocsp = require_ocsp ? TRUE - : verify_check_given_host(&ob->hosts_request_ocsp, host) == OK; + : verify_check_given_host(CUSS &ob->hosts_request_ocsp, host) == OK; #endif DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); -if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, +#ifdef SUPPORT_DANE +if (tlsa_dnsa && ob->dane_require_tls_ciphers) + { + /* not using expand_check_tlsvar because not yet in state */ + if (!expand_check(ob->dane_require_tls_ciphers, US"dane_require_tls_ciphers", + &cipher_list, errstr)) + return NULL; + cipher_list = cipher_list && *cipher_list + ? ob->dane_require_tls_ciphers : ob->tls_require_ciphers; + } +#endif + +if (!cipher_list) + cipher_list = ob->tls_require_ciphers; + +if (tls_init(host, ob->tls_certificate, ob->tls_privatekey, ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, - ob->tls_require_ciphers, &state, errstr)) != OK) - return rc; + cipher_list, &state, tlsp, errstr) != OK) + return NULL; { int dh_min_bits = ob->tls_dh_min_bits; @@ -2307,7 +2350,7 @@ else && !ob->tls_verify_hosts && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) ) - || verify_check_given_host(&ob->tls_verify_hosts, host) == OK + || verify_check_given_host(CUSS &ob->tls_verify_hosts, host) == OK ) { tls_client_setup_hostname_checks(host, state, ob); @@ -2316,7 +2359,7 @@ else state->verify_requirement = VERIFY_REQUIRED; gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); } -else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK) +else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK) { tls_client_setup_hostname_checks(host, state, ob); DEBUG(D_tls) @@ -2339,14 +2382,16 @@ if (request_ocsp) DEBUG(D_tls) debug_printf("TLS: will request OCSP stapling\n"); if ((rc = gnutls_ocsp_status_request_enable_client(state->session, NULL, 0, NULL)) != OK) - return tls_error(US"cert-status-req", - gnutls_strerror(rc), state->host, errstr); - tls_out.ocsp = OCSP_NOT_RESP; + { + tls_error(US"cert-status-req", gnutls_strerror(rc), state->host, errstr); + return NULL; + } + tlsp->ocsp = OCSP_NOT_RESP; } #endif #ifndef DISABLE_EVENT -if (tb->event_action) +if (tb && tb->event_action) { state->event_action = tb->event_action; gnutls_session_set_ptr(state->session, state); @@ -2369,20 +2414,26 @@ while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); alarm(0); if (rc != GNUTLS_E_SUCCESS) + { if (sigalrm_seen) { gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_USER_CANCELED); - return tls_error(US"gnutls_handshake", "timed out", state->host, errstr); + tls_error(US"gnutls_handshake", "timed out", state->host, errstr); } else - return tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host, errstr); + tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host, errstr); + return NULL; + } DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); /* Verify late */ if (!verify_certificate(state, errstr)) - return tls_error(US"certificate verification failed", *errstr, state->host, errstr); + { + tls_error(US"certificate verification failed", *errstr, state->host, errstr); + return NULL; + } #ifndef DISABLE_OCSP if (require_ocsp) @@ -2407,24 +2458,25 @@ if (require_ocsp) if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) { - tls_out.ocsp = OCSP_FAILED; - return tls_error(US"certificate status check failed", NULL, state->host, errstr); + tlsp->ocsp = OCSP_FAILED; + tls_error(US"certificate status check failed", NULL, state->host, errstr); + return NULL; } DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); - tls_out.ocsp = OCSP_VFIED; + tlsp->ocsp = OCSP_VFIED; } #endif /* Figure out peer DN, and if authenticated, etc. */ -if ((rc = peer_status(state, errstr)) != OK) - return rc; +if (peer_status(state, errstr) != OK) + return NULL; /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ extract_exim_vars_from_tls_state(state); -return OK; +return state; } @@ -2438,35 +2490,39 @@ return OK; daemon, to shut down the TLS library, without actually doing a shutdown (which would tamper with the TLS session in the parent process). -Arguments: TRUE if gnutls_bye is to be called +Arguments: + ct_ctx client context pointer, or NULL for the one global server context + shutdown 1 if TLS close-alert is to be sent, + 2 if also response to be waited for + Returns: nothing */ void -tls_close(BOOL is_server, BOOL shutdown) +tls_close(void * ct_ctx, int shutdown) { -exim_gnutls_state_st *state = is_server ? &state_server : &state_client; +exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; -if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ +if (!state->tlsp || state->tlsp->active.sock < 0) return; /* TLS was not active */ if (shutdown) { - DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); - gnutls_bye(state->session, GNUTLS_SHUT_WR); + DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS%s\n", + shutdown > 1 ? " (with response-wait)" : ""); + + alarm(2); + gnutls_bye(state->session, shutdown > 1 ? GNUTLS_SHUT_RDWR : GNUTLS_SHUT_WR); + alarm(0); } gnutls_deinit(state->session); gnutls_certificate_free_credentials(state->x509_cred); -state->tlsp->active = -1; +state->tlsp->active.sock = -1; +state->tlsp->active.tls_ctx = NULL; +if (state->xfer_buffer) store_free(state->xfer_buffer); memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); - -if ((state_server.session == NULL) && (state_client.session == NULL)) - { - gnutls_global_deinit(); - exim_gnutls_base_init_done = FALSE; - } } @@ -2485,17 +2541,25 @@ sigalrm_seen = FALSE; if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); inbytes = gnutls_record_recv(state->session, state->xfer_buffer, MIN(ssl_xfer_buffer_size, lim)); -alarm(0); +if (smtp_receive_timeout > 0) alarm(0); + +if (had_command_timeout) /* set by signal handler */ + smtp_command_timeout_exit(); /* does not return */ +if (had_command_sigterm) + smtp_command_sigterm_exit(); +if (had_data_timeout) + smtp_data_timeout_exit(); +if (had_data_sigint) + smtp_data_sigint_exit(); -/* Timeouts do not get this far; see command_timeout_handler(). - A zero-byte return appears to mean that the TLS session has been - closed down, not that the socket itself has been closed down. Revert to - non-TLS handling. */ +/* Timeouts do not get this far. A zero-byte return appears to mean that the +TLS session has been closed down, not that the socket itself has been closed +down. Revert to non-TLS handling. */ if (sigalrm_seen) { DEBUG(D_tls) debug_printf("Got tls read timeout\n"); - state->xfer_error = 1; + state->xfer_error = TRUE; return FALSE; } @@ -2515,7 +2579,8 @@ else if (inbytes == 0) gnutls_certificate_free_credentials(state->x509_cred); state->session = NULL; - state->tlsp->active = -1; + state->tlsp->active.sock = -1; + state->tlsp->active.tls_ctx = NULL; state->tlsp->bits = 0; state->tlsp->certificate_verified = FALSE; tls_channelbinding_b64 = NULL; @@ -2530,8 +2595,9 @@ else if (inbytes == 0) else if (inbytes < 0) { +debug_printf("%s: err from gnutls_record_recv(\n", __FUNCTION__); record_io_error(state, (int) inbytes, US"recv", NULL); - state->xfer_error = 1; + state->xfer_error = TRUE; return FALSE; } #ifndef DISABLE_DKIM @@ -2624,17 +2690,18 @@ return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm then the caller must feed DKIM. Arguments: + ct_ctx client context pointer, or NULL for the one global server context buff buffer of data len size of buffer Returns: the number of bytes read - -1 after a failed read + -1 after a failed read, including EOF */ int -tls_read(BOOL is_server, uschar *buff, size_t len) +tls_read(void * ct_ctx, uschar *buff, size_t len) { -exim_gnutls_state_st *state = is_server ? &state_server : &state_client; +exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; ssize_t inbytes; if (len > INT_MAX) @@ -2656,7 +2723,11 @@ if (inbytes == 0) { DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); } -else record_io_error(state, (int)inbytes, US"recv", NULL); +else +{ +debug_printf("%s: err from gnutls_record_recv(\n", __FUNCTION__); +record_io_error(state, (int)inbytes, US"recv", NULL); +} return -1; } @@ -2670,7 +2741,7 @@ return -1; /* Arguments: - is_server channel specifier + ct_ctx client context pointer, or NULL for the one global server context buff buffer of data len number of bytes more more data expected soon @@ -2680,11 +2751,11 @@ Returns: the number of bytes after a successful write, */ int -tls_write(BOOL is_server, const uschar *buff, size_t len, BOOL more) +tls_write(void * ct_ctx, const uschar * buff, size_t len, BOOL more) { ssize_t outbytes; size_t left = len; -exim_gnutls_state_st *state = is_server ? &state_server : &state_client; +exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; #ifdef SUPPORT_CORK static BOOL corked = FALSE; @@ -2703,6 +2774,7 @@ while (left > 0) DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); if (outbytes < 0) { + DEBUG(D_tls) debug_printf("%s: gnutls_record_send err\n", __FUNCTION__); record_io_error(state, outbytes, US"send", NULL); return -1; }