X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/b66fecb428871a3eb274d9370671f1eaf8c5ccec..be427508c032dc0d47036eb5fea0139e0c63e9e5:/src/src/tls-gnu.c diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index fe048ba62..f64b0ae68 100644 --- a/src/src/tls-gnu.c +++ b/src/src/tls-gnu.c @@ -76,6 +76,9 @@ 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 >= 0x030603 +# define SUPPORT_GNUTLS_EXT_RAW_PARSE +#endif #ifdef SUPPORT_DANE # if GNUTLS_VERSION_NUMBER >= 0x030000 @@ -89,6 +92,12 @@ require current GnuTLS, then we'll drop support for the ancient libraries). # endif #endif +#ifdef EXPERIMENTAL_TLS_RESUME +# if GNUTLS_VERSION_NUMBER < 0x030603 +# error GNUTLS version too early for session-resumption +# endif +#endif + #ifndef DISABLE_OCSP # include #endif @@ -99,6 +108,17 @@ require current GnuTLS, then we'll drop support for the ancient libraries). #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: @@ -174,45 +194,9 @@ typedef struct exim_gnutls_state { } 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 @@ -234,9 +218,7 @@ don't want to repeat this. */ 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 = 7200; /* Two hours */ static const uschar * const exim_default_gnutls_priority = US"NORMAL"; @@ -246,8 +228,12 @@ static BOOL exim_gnutls_base_init_done = FALSE; #ifndef DISABLE_OCSP static BOOL gnutls_buggy_ocsp = FALSE; +static BOOL exim_testharness_disable_ocsp_validity_check = FALSE; #endif +#ifdef EXPERIMENTAL_TLS_RESUME +static gnutls_datum_t server_sessticket_key; +#endif /* ------------------------------------------------------------------------ */ /* macros */ @@ -256,8 +242,10 @@ static BOOL gnutls_buggy_ocsp = FALSE; /* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup the library logging; a value less than 0 disables the calls to set up logging -callbacks. Possibly GNuTLS also looks for an environment variable -"GNUTLS_DEBUG_LEVEL". */ +callbacks. GNuTLS also looks for an environment variable - except not for +setuid binaries, making it useless - "GNUTLS_DEBUG_LEVEL". +Allegedly the testscript line "GNUTLS_DEBUG_LEVEL=9 sudo exim ..." would work, +but the env var must be added to /etc/sudoers too. */ #ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL # define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 #endif @@ -303,13 +291,36 @@ static void exim_gnutls_logger_cb(int level, const char *message); static int exim_sni_handling_cb(gnutls_session_t session); -#ifndef DISABLE_OCSP +#if !defined(DISABLE_OCSP) static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, gnutls_datum_t * ocsp_response); #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); +#endif +/* 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 */ @@ -461,7 +472,6 @@ Argument: 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; @@ -472,12 +482,6 @@ tls_support * tlsp = state->tlsp; 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; @@ -653,7 +657,7 @@ if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) } m.size = statbuf.st_size; - if (!(m.data = malloc(m.size))) + if (!(m.data = store_malloc(m.size))) { fclose(fp); return tls_error_sys(US"malloc failed", errno, NULL, errstr); @@ -662,13 +666,13 @@ if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) { saved_errno = errno; fclose(fp); - free(m.data); + store_free(m.data); return tls_error_sys(US"fread failed", saved_errno, NULL, errstr); } fclose(fp); rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); - free(m.data); + store_free(m.data); if (rc) return tls_error_gnu(US"gnutls_dh_params_import_pkcs3", rc, host, errstr); DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); @@ -741,25 +745,25 @@ if (rc < 0) return tls_error_gnu(US"gnutls_dh_params_export_pkcs3(NULL) sizing", rc, host, errstr); m.size = sz; - if (!(m.data = malloc(m.size))) + if (!(m.data = store_malloc(m.size))) return tls_error_sys(US"memory allocation failed", errno, NULL, errstr); /* this will return a size 1 less than the allocation size above */ if ((rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, m.data, &sz))) { - free(m.data); + store_free(m.data); return tls_error_gnu(US"gnutls_dh_params_export_pkcs3() real", rc, host, errstr); } m.size = sz; /* shrink by 1, probably */ if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) { - free(m.data); + store_free(m.data); return tls_error_sys(US"TLS cache write D-H params failed", errno, NULL, errstr); } - free(m.data); + store_free(m.data); if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) return tls_error_sys(US"TLS cache write D-H params final newline failed", errno, NULL, errstr); @@ -873,6 +877,82 @@ return -rc; } +#ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE +/* Make a note that we saw a status-request */ +static int +tls_server_clienthello_ext(void * ctx, unsigned tls_id, + const unsigned char *data, unsigned size) +{ +/* https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml */ +if (tls_id == 5) /* status_request */ + { + DEBUG(D_tls) debug_printf("Seen status_request extension\n"); + tls_in.ocsp = OCSP_NOT_RESP; + } +return 0; +} + +/* Callback for client-hello, on server, if we think we might serve stapled-OCSP */ +static int +tls_server_clienthello_cb(gnutls_session_t session, unsigned int htype, + unsigned when, unsigned int incoming, const gnutls_datum_t * msg) +{ +/* Call fn for each extension seen. 3.6.3 onwards */ +return gnutls_ext_raw_parse(NULL, tls_server_clienthello_ext, msg, + GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO); +} +#endif + +/* Callback for certificate-status, on server. We sent stapled OCSP. */ +static int +tls_server_certstatus_cb(gnutls_session_t session, unsigned int htype, + unsigned when, unsigned int incoming, const gnutls_datum_t * msg) +{ +DEBUG(D_tls) debug_printf("Sending certificate-status\n"); +#ifdef SUPPORT_SRV_OCSP_STACK +tls_in.ocsp = exim_testharness_disable_ocsp_validity_check + ? OCSP_VFY_NOT_TRIED : OCSP_VFIED; /* We know that GnuTLS verifies responses */ +#else +tls_in.ocsp = OCSP_VFY_NOT_TRIED; +#endif +return 0; +} + +/* Callback for handshake messages, on server */ +static int +tls_server_hook_cb(gnutls_session_t sess, u_int htype, unsigned when, + unsigned incoming, const gnutls_datum_t * msg) +{ +switch (htype) + { +#ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE + case GNUTLS_HANDSHAKE_CLIENT_HELLO: + return tls_server_clienthello_cb(sess, htype, when, incoming, msg); +#endif + case GNUTLS_HANDSHAKE_CERTIFICATE_STATUS: + return tls_server_certstatus_cb(sess, htype, when, incoming, msg); +#ifdef EXPERIMENTAL_TLS_RESUME + case GNUTLS_HANDSHAKE_NEW_SESSION_TICKET: + return tls_server_ticket_cb(sess, htype, when, incoming, msg); +#endif + default: + return 0; + } +} + + +static void +tls_server_testharness_ocsp_fiddle(void) +{ +extern char ** environ; +if (environ) for (uschar ** p = USS environ; *p; p++) + if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0) + { + DEBUG(D_tls) debug_printf("Permitting known bad OCSP response\n"); + exim_testharness_disable_ocsp_validity_check = TRUE; + } +} + /************************************************* * Variables re-expanded post-SNI * *************************************************/ @@ -1007,12 +1087,13 @@ if (state->exp_tls_certificate && *state->exp_tls_certificate) else { int gnutls_cert_index = -rc; - DEBUG(D_tls) debug_printf("TLS: cert/key %s registered\n", cfile); + DEBUG(D_tls) debug_printf("TLS: cert/key %d %s registered\n", gnutls_cert_index, cfile); /* Set the OCSP stapling server info */ #ifndef DISABLE_OCSP if (tls_ocsp_file) + { if (gnutls_buggy_ocsp) { DEBUG(D_tls) @@ -1020,37 +1101,53 @@ if (state->exp_tls_certificate && *state->exp_tls_certificate) } else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0))) { - /* Use the full callback method for stapling just to get - observability. More efficient would be to read the file once only, - if it never changed (due to SNI). Would need restart on file update, - or watch datestamp. */ + DEBUG(D_tls) debug_printf("OCSP response file = %s\n", ofile); + +# ifdef SUPPORT_GNUTLS_EXT_RAW_PARSE + if (f.running_in_test_harness) tls_server_testharness_ocsp_fiddle(); -# ifdef SUPPORT_SRV_OCSP_STACK + if (!exim_testharness_disable_ocsp_validity_check) + { + if ((rc = gnutls_certificate_set_ocsp_status_request_file2( + state->x509_cred, CCS ofile, gnutls_cert_index, + GNUTLS_X509_FMT_DER)) < 0) + return tls_error_gnu( + US"gnutls_certificate_set_ocsp_status_request_file2", + rc, host, errstr); + + /* Arrange callbacks for OCSP request observability */ + + gnutls_handshake_set_hook_function(state->session, + GNUTLS_HANDSHAKE_ANY, GNUTLS_HOOK_POST, tls_server_hook_cb); + } + else +# elif defined(SUPPORT_SRV_OCSP_STACK) if ((rc = gnutls_certificate_set_ocsp_status_request_function2( - state->x509_cred, gnutls_cert_index, - server_ocsp_stapling_cb, ofile))) - return tls_error_gnu( + state->x509_cred, gnutls_cert_index, + server_ocsp_stapling_cb, ofile))) + return tls_error_gnu( US"gnutls_certificate_set_ocsp_status_request_function2", rc, host, errstr); -# else - if (cnt++ > 0) + else +# endif { - DEBUG(D_tls) - debug_printf("oops; multiple OCSP files not supported\n"); - break; + if (cnt++ > 0) + { + DEBUG(D_tls) + debug_printf("oops; multiple OCSP files not supported\n"); + break; + } + gnutls_certificate_set_ocsp_status_request_function( + state->x509_cred, server_ocsp_stapling_cb, ofile); } - gnutls_certificate_set_ocsp_status_request_function( - state->x509_cred, server_ocsp_stapling_cb, ofile); -# endif - - DEBUG(D_tls) debug_printf("OCSP response file = %s\n", ofile); } else DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n"); -#endif + } +#endif /* DISABLE_OCSP */ } } - else + else /* client */ { if (0 < (rc = tls_add_certfile(state, host, state->exp_tls_certificate, state->exp_tls_privatekey, errstr))) @@ -1148,6 +1245,14 @@ else #endif gnutls_certificate_set_x509_trust_file(state->x509_cred, CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); + +#ifdef SUPPORT_CA_DIR + /* Mimic the behaviour with OpenSSL of not advertising a usable-cert list + when using the directory-of-certs config model. */ + + if ((statbuf.st_mode & S_IFMT) == S_IFDIR) + gnutls_certificate_send_x509_rdn_sequence(state->session, 1); +#endif } if (cert_count < 0) @@ -1329,7 +1434,7 @@ if (host) several in parallel. */ int old_pool = store_pool; store_pool = POOL_PERM; - state = store_get(sizeof(exim_gnutls_state_st)); + state = store_get(sizeof(exim_gnutls_state_st), FALSE); store_pool = old_pool; memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); @@ -1421,6 +1526,9 @@ if ((rc = gnutls_priority_init(&state->priority_cache, CCS p, &errpos))) 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 @@ -1490,9 +1598,10 @@ Returns: OK/DEFER/FAIL */ 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; @@ -1501,7 +1610,7 @@ gnutls_kx_algorithm_t kx; 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) @@ -1511,14 +1620,48 @@ state->have_set_peerdn = TRUE; 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 = gnutls_kx_get(state->session); +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(session), c; + + /* Nikos M suggests we use this by preference. It returns like: + (TLS1.3)-(ECDHE-SECP256R1)-(RSA-PSS-RSAE-SHA256)-(AES-256-GCM) + + For partial back-compat, put a colon after the TLS version, replace the + )-( grouping with __, replace in-group - with _ and append the :keysize. */ + + /* debug_printf("peer_status: gnutls_session_get_desc %s\n", s); */ + + for (s++; (c = *s) && c != ')'; s++) g = string_catn(g, s, 1); + g = string_catn(g, US":", 1); + if (*s) s++; /* now on _ between groups */ + while ((c = *s)) + { + for (*++s && ++s; (c = *s) && c != ')'; s++) g = string_catn(g, c == '-' ? US"_" : s, 1); + /* now on ) closing group */ + if ((c = *s) && *++s == '-') g = string_catn(g, US"__", 2); + /* now on _ between groups */ + } + g = string_catn(g, US":", 1); + g = string_cat(g, string_sprintf("%d", (int) gnutls_cipher_get_key_size(cipher) * 8)); + state->ciphersuite = string_from_gstring(g); + } +#else state->ciphersuite = string_sprintf("%s:%s:%d", gnutls_protocol_get_name(protocol), gnutls_cipher_suite_get_name(kx, cipher, mac), @@ -1529,14 +1672,19 @@ old_pool = store_pool; releases did return "TLS 1.0"; play it safe, just in case. */ for (uschar * p = state->ciphersuite; *p; p++) if (isspace(*p)) *p = '-'; - state->tlsp->cipher = state->ciphersuite; +#endif + +/* debug_printf("peer_status: ciphersuite %s\n", state->ciphersuite); */ + + 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) { @@ -1548,7 +1696,7 @@ 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) @@ -1583,7 +1731,7 @@ if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) exim_gnutls_peer_err(US"getting size for cert DN failed"); return FAIL; /* should not happen */ } -dn_buf = store_get_perm(sz); +dn_buf = store_get_perm(sz, TRUE); /* tainted */ rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); @@ -1620,13 +1768,14 @@ verify_certificate(exim_gnutls_state_st * state, uschar ** errstr) 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"; @@ -1662,8 +1811,8 @@ else for(nrec = 0; state->dane_data_len[nrec]; ) nrec++; nrec++; - dd = store_get(nrec * sizeof(uschar *)); - ddl = store_get(nrec * sizeof(int)); + dd = store_get(nrec * sizeof(uschar *), FALSE); + ddl = store_get(nrec * sizeof(int), FALSE); nrec--; if ((rc = dane_state_init(&s, 0))) @@ -1891,13 +2040,12 @@ uschar * dummy_errstr; rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); if (rc != GNUTLS_E_SUCCESS) { - DEBUG(D_tls) { + DEBUG(D_tls) if (rc == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) debug_printf("TLS: no SNI presented in handshake.\n"); else debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", gnutls_strerror(rc), rc); - } return 0; } @@ -1910,7 +2058,7 @@ if (sni_type != GNUTLS_NAME_DNS) /* We now have a UTF-8 string in sni_name */ old_pool = store_pool; store_pool = POOL_PERM; -state->received_sni = string_copyn(US sni_name, data_len); +state->received_sni = string_copy_taint(US sni_name, TRUE); store_pool = old_pool; /* We set this one now so that variable expansions below will work */ @@ -1937,7 +2085,7 @@ return 0; -#ifndef DISABLE_OCSP +#if !defined(DISABLE_OCSP) static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, @@ -2022,6 +2170,94 @@ for (unsigned i = d->size; i > 0; i--, s++) return g; } +static void +post_handshake_debug(exim_gnutls_state_st * state) +{ +#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; + /* we only want the client random and the master secret */ + gnutls_session_get_random(state->session, &c, &s); + gnutls_session_get_master_secret(state->session, &s); + gc = ddump(&c); + gs = ddump(&s); + debug_printf("CLIENT_RANDOM %.*s %.*s\n", (int)gc->ptr, gc->s, (int)gs->ptr, gs->s); + } +else + debug_printf("To get keying info for TLS1.3 is hard:\n" + " set environment variable SSLKEYLOGFILE to a filename writable by uid exim\n" + " add SSLKEYLOGFILE to keep_environment in the exim config\n" + " run exim as root\n" + " if using sudo, add SSLKEYLOGFILE to env_keep in /etc/sudoers\n"); +#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_ANY, GNUTLS_HOOK_POST, tls_server_hook_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 */ @@ -2069,6 +2305,10 @@ if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, 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. */ @@ -2168,24 +2408,11 @@ if (rc != GNUTLS_E_SUCCESS) return FAIL; } -DEBUG(D_tls) - { - debug_printf("gnutls_handshake was successful\n"); -#ifdef SUPPORT_GNUTLS_SESS_DESC - debug_printf("%s\n", gnutls_session_get_desc(state->session)); +#ifdef EXPERIMENTAL_TLS_RESUME +tls_server_resume_posthandshake(state); #endif -#ifdef SUPPORT_GNUTLS_KEYLOG - { - gnutls_datum_t c, s; - gstring * gc, * gs; - gnutls_session_get_random(state->session, &c, &s); - gnutls_session_get_master_secret(state->session, &s); - gc = ddump(&c); - gs = ddump(&s); - debug_printf("CLIENT_RANDOM %.*s %.*s\n", (int)gc->ptr, gc->s, (int)gs->ptr, gs->s); - } -#endif - } + +DEBUG(D_tls) post_handshake_debug(state); /* Verify after the fact */ @@ -2201,10 +2428,6 @@ if (!verify_certificate(state, errstr)) *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); @@ -2270,8 +2493,8 @@ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) ) if (rr->type == T_TLSA) i++; -dane_data = store_get(i * sizeof(uschar *)); -dane_data_len = store_get(i * sizeof(int)); +dane_data = store_get(i * sizeof(uschar *), FALSE); +dane_data_len = store_get(i * sizeof(int), FALSE); i = 0; for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; @@ -2279,6 +2502,7 @@ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; ) if (rr->type == T_TLSA && rr->size > 3) { const uschar * p = rr->data; +/*XXX need somehow to mark rr and its data as tainted. Doues this mean copying it? */ uint8_t usage = p[0], sel = p[1], type = p[2]; DEBUG(D_tls) @@ -2317,6 +2541,142 @@ return TRUE; +#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. We'd like to filter the retrieved session + for ticket advisory expiry, but 3.6.1 seems to give no access to that */ + + 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. */ + +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, TRUE); + + 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)); + } +} + + +/* 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 * *************************************************/ @@ -2457,6 +2817,10 @@ if (request_ocsp) } #endif +#ifdef EXPERIMENTAL_TLS_RESUME +tls_client_resume_prehandshake(state, tlsp, host, ob); +#endif + #ifndef DISABLE_EVENT if (tb && tb->event_action) { @@ -2492,24 +2856,7 @@ if (rc != GNUTLS_E_SUCCESS) return FALSE; } -DEBUG(D_tls) - { - 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 - { - gnutls_datum_t c, s; - gstring * gc, * gs; - gnutls_session_get_random(state->session, &c, &s); - gnutls_session_get_master_secret(state->session, &s); - gc = ddump(&c); - gs = ddump(&s); - debug_printf("CLIENT_RANDOM %.*s %.*s\n", (int)gc->ptr, gc->s, (int)gs->ptr, gs->s); - } -#endif - } +DEBUG(D_tls) post_handshake_debug(state); /* Verify late */ @@ -2520,7 +2867,7 @@ if (!verify_certificate(state, errstr)) } #ifndef DISABLE_OCSP -if (require_ocsp) +if (request_ocsp) { DEBUG(D_tls) { @@ -2544,17 +2891,20 @@ if (require_ocsp) { tlsp->ocsp = OCSP_FAILED; tls_error(US"certificate status check failed", NULL, state->host, errstr); - return FALSE; + if (require_ocsp) + return FALSE; + } + else + { + DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); + tlsp->ocsp = OCSP_VFIED; } - DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); - tlsp->ocsp = OCSP_VFIED; } #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 */ @@ -2587,8 +2937,9 @@ void tls_close(void * ct_ctx, int shutdown) { exim_gnutls_state_st * state = ct_ctx ? ct_ctx : &state_server; +tls_support * tlsp = state->tlsp; -if (!state->tlsp || state->tlsp->active.sock < 0) return; /* TLS was not active */ +if (!tlsp || tlsp->active.sock < 0) return; /* TLS was not active */ if (shutdown) { @@ -2600,12 +2951,26 @@ if (shutdown) ALARM_CLR(0); } +if (!ct_ctx) /* server */ + { + receive_getc = smtp_getc; + receive_getbuf = smtp_getbuf; + receive_get_cache = smtp_get_cache; + receive_ungetc = smtp_ungetc; + receive_feof = smtp_feof; + receive_ferror = smtp_ferror; + receive_smtp_buffered = smtp_buffered; + } + gnutls_deinit(state->session); gnutls_certificate_free_credentials(state->x509_cred); +tlsp->active.sock = -1; +tlsp->active.tls_ctx = NULL; +/* Leave bits, peercert, cipher, peerdn, certificate_verified set, for logging */ +tls_channelbinding_b64 = NULL; + -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)); } @@ -2655,28 +3020,7 @@ if (sigalrm_seen) else if (inbytes == 0) { DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); - - receive_getc = smtp_getc; - receive_getbuf = smtp_getbuf; - receive_get_cache = smtp_get_cache; - receive_ungetc = smtp_ungetc; - receive_feof = smtp_feof; - receive_ferror = smtp_ferror; - receive_smtp_buffered = smtp_buffered; - - gnutls_deinit(state->session); - gnutls_certificate_free_credentials(state->x509_cred); - - state->session = NULL; - state->tlsp->active.sock = -1; - state->tlsp->active.tls_ctx = NULL; - state->tlsp->bits = 0; - state->tlsp->certificate_verified = FALSE; - tls_channelbinding_b64 = NULL; - state->tlsp->cipher = NULL; - state->tlsp->peercert = NULL; - state->tlsp->peerdn = NULL; - + tls_close(NULL, TLS_NO_SHUTDOWN); return FALSE; } @@ -3052,6 +3396,7 @@ fprintf(f, "Library version: GnuTLS: Compile: %s\n" gnutls_check_version(NULL)); } +#endif /*!MACRO_PREDEF*/ /* vi: aw ai sw=2 */ /* End of tls-gnu.c */