X-Git-Url: https://vcs.fsf.org/?p=exim.git;a=blobdiff_plain;f=src%2Fsrc%2Ftls-gnu.c;h=b0b67d820824b214ff53df7fb22b9483270e115e;hp=5a37fae563348fb448bb517ec711a80073a7bca9;hb=4466248715466b6f251454283642b74de65e9d9a;hpb=2519e60d2f6124589a6a5b922dd9ae6bcb6f6588 diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index 5a37fae56..b0b67d820 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 - 2012 */ +/* Copyright (c) University of Cambridge 1995 - 2014 */ /* See the file NOTICE for conditions of use and distribution. */ /* Copyright (c) Phil Pennock 2012 */ @@ -43,6 +43,9 @@ require current GnuTLS, then we'll drop support for the ancient libraries). #if GNUTLS_VERSION_NUMBER >= 0x020c00 # include #endif +#ifdef EXPERIMENTAL_OCSP +# include +#endif /* GnuTLS 2 vs 3 @@ -71,19 +74,20 @@ Not handled here: global tls_channelbinding_b64. */ typedef struct exim_gnutls_state { - gnutls_session_t session; + gnutls_session_t session; gnutls_certificate_credentials_t x509_cred; - gnutls_priority_t priority_cache; + gnutls_priority_t priority_cache; enum peer_verify_requirement verify_requirement; - int fd_in; - int fd_out; - BOOL peer_cert_verified; - BOOL trigger_sni_changes; - BOOL have_set_peerdn; + int fd_in; + int fd_out; + BOOL peer_cert_verified; + BOOL trigger_sni_changes; + BOOL have_set_peerdn; const struct host_item *host; - uschar *peerdn; - uschar *ciphersuite; - uschar *received_sni; + gnutls_x509_crt_t peercert; + uschar *peerdn; + uschar *ciphersuite; + uschar *received_sni; const uschar *tls_certificate; const uschar *tls_privatekey; @@ -97,6 +101,7 @@ typedef struct exim_gnutls_state { uschar *exp_tls_verify_certificates; uschar *exp_tls_crl; uschar *exp_tls_require_ciphers; + uschar *exp_tls_ocsp_file; tls_support *tlsp; /* set in tls_init() */ @@ -111,7 +116,7 @@ static const exim_gnutls_state_st exim_gnutls_state_init = { NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, FALSE, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, - NULL, NULL, NULL, NULL, NULL, NULL, + NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 0, 0, 0, 0, }; @@ -199,6 +204,10 @@ static void exim_gnutls_logger_cb(int level, const char *message); static int exim_sni_handling_cb(gnutls_session_t session); +#ifdef EXPERIMENTAL_OCSP +static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, + gnutls_datum_t * ocsp_response); +#endif @@ -285,12 +294,34 @@ tls_error(when, msg, state->host); * Set various Exim expansion vars * *************************************************/ +#define exim_gnutls_cert_err(Label) do { \ + if (rc != GNUTLS_E_SUCCESS) { \ + DEBUG(D_tls) debug_printf("TLS: cert problem: %s: %s\n", (Label), gnutls_strerror(rc)); \ + return rc; } } while (0) + +static int +import_cert(const gnutls_datum * cert, gnutls_x509_crt_t * crtp) +{ +int rc; + +rc = gnutls_x509_crt_init(crtp); +exim_gnutls_cert_err(US"gnutls_x509_crt_init (crt)"); + +rc = gnutls_x509_crt_import(*crtp, cert, GNUTLS_X509_FMT_DER); +exim_gnutls_cert_err(US"failed to import certificate [gnutls_x509_crt_import(cert)]"); + +return rc; +} + +#undef exim_gnutls_cert_err + + /* We set various Exim global variables from the state, once a session has been established. With TLS callouts, may need to change this to stack variables, or just re-call it with the server state after client callout has finished. -Make sure anything set here is inset in tls_getc(). +Make sure anything set here is unset in tls_getc(). Sets: tls_active fd @@ -298,15 +329,17 @@ Sets: tls_certificate_verified bool indicator tls_channelbinding_b64 for some SASL mechanisms tls_cipher a string + tls_peercert pointer to library internal tls_peerdn a string tls_sni a (UTF-8) string + tls_ourcert pointer to library internal Argument: state the relevant exim_gnutls_state_st * */ static void -extract_exim_vars_from_tls_state(exim_gnutls_state_st *state, BOOL is_server) +extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) { gnutls_cipher_algorithm_t cipher; #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING @@ -314,18 +347,19 @@ int old_pool; int rc; gnutls_datum_t channel; #endif +tls_support * tlsp = state->tlsp; -state->tlsp->active = state->fd_out; +tlsp->active = state->fd_out; cipher = gnutls_cipher_get(state->session); /* returns size in "bytes" */ -state->tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; +tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; -state->tlsp->cipher = state->ciphersuite; +tlsp->cipher = state->ciphersuite; DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); -state->tlsp->certificate_verified = state->peer_cert_verified; +tlsp->certificate_verified = state->peer_cert_verified; /* note that tls_channelbinding_b64 is not saved to the spool file, since it's only available for use for authenticators while this TLS session is running. */ @@ -346,8 +380,17 @@ if (rc) { } #endif -state->tlsp->peerdn = state->peerdn; -state->tlsp->sni = state->received_sni; +/* peercert is set in peer_status() */ +tlsp->peerdn = state->peerdn; +tlsp->sni = state->received_sni; + +/* record our certificate */ + { + const gnutls_datum * cert = gnutls_certificate_get_ours(state->session); + gnutls_x509_crt_t crt; + + tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; + } } @@ -658,7 +701,7 @@ uschar *saved_tls_crl = NULL; int cert_count; /* We check for tls_sni *before* expansion. */ -if (!state->host) +if (!host) /* server */ { if (!state->received_sni) { @@ -700,7 +743,7 @@ if (!expand_check_tlsvar(tls_certificate)) if ((state->exp_tls_certificate == NULL) || (*state->exp_tls_certificate == '\0')) { - if (state->host == NULL) + if (!host) return tls_error(US"no TLS server certificate is specified", NULL, NULL); else DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); @@ -745,6 +788,30 @@ if (state->exp_tls_certificate && *state->exp_tls_certificate) DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); } /* tls_certificate */ + +/* Set the OCSP stapling server info */ + +#ifdef EXPERIMENTAL_OCSP +if ( !host /* server */ + && tls_ocsp_file + ) + { + if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", + &state->exp_tls_ocsp_file)) + return DEFER; + + /* 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. */ + + gnutls_certificate_set_ocsp_status_request_function(state->x509_cred, + server_ocsp_stapling_cb, state->exp_tls_ocsp_file); + + DEBUG(D_tls) debug_printf("Set OCSP response file %s\n", &state->exp_tls_ocsp_file); + } +#endif + + /* Set the trusted CAs file if one is provided, and then add the CRL if one is provided. Experiment shows that, if the certificate file is empty, an unhelpful error message is provided. However, if we just refrain from setting anything up @@ -1072,7 +1139,6 @@ return OK; - /************************************************* * Extract peer information * *************************************************/ @@ -1178,11 +1244,11 @@ if (ct != GNUTLS_CRT_X509) if (state->verify_requirement == VERIFY_REQUIRED) { return tls_error((Label), gnutls_strerror(rc), state->host); } \ return OK; } } while (0) -rc = gnutls_x509_crt_init(&crt); -exim_gnutls_peer_err(US"gnutls_x509_crt_init (crt)"); +rc = import_cert(&cert_list[0], &crt); +exim_gnutls_peer_err(US"cert 0"); + +state->tlsp->peercert = state->peercert = crt; -rc = gnutls_x509_crt_import(crt, &cert_list[0], GNUTLS_X509_FMT_DER); -exim_gnutls_peer_err(US"failed to import certificate [gnutls_x509_crt_import(cert 0)]"); sz = 0; rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) @@ -1193,6 +1259,7 @@ if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) dn_buf = store_get_perm(sz); 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)]"); + state->peerdn = dn_buf; return OK; @@ -1228,25 +1295,23 @@ unsigned int verify; *error = NULL; -rc = peer_status(state); -if (rc != OK) +if ((rc = peer_status(state)) != OK) { verify = GNUTLS_CERT_INVALID; - *error = "not supplied"; + *error = "certificate not supplied"; } else - { rc = gnutls_certificate_verify_peers2(state->session, &verify); - } /* Handle the result of verification. INVALID seems to be set as well as REVOKED, but leave the test for both. */ -if ((rc < 0) || (verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0) +if (rc < 0 || verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) { state->peer_cert_verified = FALSE; - if (*error == NULL) - *error = ((verify & GNUTLS_CERT_REVOKED) != 0) ? "revoked" : "invalid"; + if (!*error) + *error = verify & GNUTLS_CERT_REVOKED + ? "certificate revoked" : "certificate invalid"; DEBUG(D_tls) debug_printf("TLS certificate verification failed (%s): peerdn=%s\n", @@ -1373,6 +1438,31 @@ return 0; +#ifdef EXPERIMENTAL_OCSP + +static int +server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, + gnutls_datum_t * ocsp_response) +{ +int ret; + +tls_in.ocsp = OCSP_NOT_RESP; +if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) + { + DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", + (char *)ptr); + return GNUTLS_E_NO_CERTIFICATE_STATUS; + } + +tls_in.ocsp = OCSP_NOT_VFY; +return 0; +} + +#endif + + + + /* ------------------------------------------------------------------------ */ /* Exported functions */ @@ -1459,15 +1549,15 @@ mode, the fflush() happens when smtp_getc() is called. */ if (!state->tlsp->on_connect) { smtp_printf("220 TLS go ahead\r\n"); - fflush(smtp_out); /*XXX JGH */ + fflush(smtp_out); } /* Now negotiate the TLS session. We put our own timer on it, since it seems that the GnuTLS library doesn't. */ gnutls_transport_set_ptr2(state->session, - (gnutls_transport_ptr)fileno(smtp_in), - (gnutls_transport_ptr)fileno(smtp_out)); + (gnutls_transport_ptr)(long) fileno(smtp_in), + (gnutls_transport_ptr)(long) fileno(smtp_out)); state->fd_in = fileno(smtp_in); state->fd_out = fileno(smtp_out); @@ -1501,22 +1591,17 @@ DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); /* Verify after the fact */ -if (state->verify_requirement != VERIFY_NONE) +if ( state->verify_requirement != VERIFY_NONE + && !verify_certificate(state, &error)) { - if (!verify_certificate(state, &error)) + if (state->verify_requirement != VERIFY_OPTIONAL) { - if (state->verify_requirement == VERIFY_OPTIONAL) - { - DEBUG(D_tls) - debug_printf("TLS: continuing on only because verification was optional, after: %s\n", - error); - } - else - { - tls_error(US"certificate verification failed", error, NULL); - return FAIL; - } + tls_error(US"certificate verification failed", error, NULL); + return FAIL; } + DEBUG(D_tls) + debug_printf("TLS: continuing on only because verification was optional, after: %s\n", + error); } /* Figure out peer DN, and if authenticated, etc. */ @@ -1526,7 +1611,7 @@ if (rc != OK) return rc; /* Sets various Exim expansion variables; always safe within server */ -extract_exim_vars_from_tls_state(state, TRUE); +extract_exim_vars_from_tls_state(state); /* TLS has been set up. Adjust the input functions to read via TLS, and initialize appropriately. */ @@ -1555,14 +1640,7 @@ Arguments: fd the fd of the connection host connected host (for messages) addr the first address (not used) - certificate certificate file - privatekey private key file - sni TLS SNI to send to remote host - verify_certs file for certificate verify - verify_crl CRL for verify - require_ciphers list of allowed ciphers or NULL - dh_min_bits minimum number of bits acceptable in server's DH prime - timeout startup timeout + ob smtp transport options Returns: OK/DEFER/FAIL (because using common functions), but for a client, DEFER and FAIL have the same meaning @@ -1571,58 +1649,94 @@ Returns: OK/DEFER/FAIL (because using common functions), int tls_client_start(int fd, host_item *host, address_item *addr ARG_UNUSED, - uschar *certificate, uschar *privatekey, uschar *sni, - uschar *verify_certs, uschar *verify_crl, - uschar *require_ciphers, -#ifdef EXPERIMENTAL_OCSP - uschar *require_ocsp ARG_UNUSED, -#endif - int dh_min_bits, int timeout) + void *v_ob) { +smtp_transport_options_block *ob = v_ob; int rc; const char *error; exim_gnutls_state_st *state = NULL; +#ifdef EXPERIMENTAL_OCSP +BOOL require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, + NULL, host->name, host->address, NULL) == OK; +BOOL request_ocsp = require_ocsp ? TRUE + : verify_check_this_host(&ob->hosts_request_ocsp, + NULL, host->name, host->address, NULL) == OK; +#endif DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); -rc = tls_init(host, certificate, privatekey, - sni, verify_certs, verify_crl, require_ciphers, &state); -if (rc != OK) return rc; +if ((rc = tls_init(host, ob->tls_certificate, ob->tls_privatekey, + ob->tls_sni, ob->tls_verify_certificates, ob->tls_crl, + ob->tls_require_ciphers, &state)) != OK) + return rc; -if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) { - DEBUG(D_tls) - debug_printf("WARNING: tls_dh_min_bits far too low, clamping %d up to %d\n", - dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); - dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; - } + int dh_min_bits = ob->tls_dh_min_bits; + if (dh_min_bits < EXIM_CLIENT_DH_MIN_MIN_BITS) + { + DEBUG(D_tls) + debug_printf("WARNING: tls_dh_min_bits far too low," + " clamping %d up to %d\n", + dh_min_bits, EXIM_CLIENT_DH_MIN_MIN_BITS); + dh_min_bits = EXIM_CLIENT_DH_MIN_MIN_BITS; + } -DEBUG(D_tls) debug_printf("Setting D-H prime minimum acceptable bits to %d\n", - dh_min_bits); -gnutls_dh_set_prime_bits(state->session, dh_min_bits); + DEBUG(D_tls) debug_printf("Setting D-H prime minimum" + " acceptable bits to %d\n", + dh_min_bits); + gnutls_dh_set_prime_bits(state->session, dh_min_bits); + } -if (verify_certs == NULL) +/* Stick to the old behaviour for compatibility if tls_verify_certificates is +set but both tls_verify_hosts and tls_try_verify_hosts are unset. Check only +the specified host patterns if one of them is defined */ + +if (( state->exp_tls_verify_certificates + && !ob->tls_verify_hosts + && !ob->tls_try_verify_hosts + ) + || + verify_check_host(&ob->tls_verify_hosts) == OK + ) { - DEBUG(D_tls) debug_printf("TLS: server certificate verification not required\n"); - state->verify_requirement = VERIFY_NONE; - /* we still ask for it, to log it, etc */ + DEBUG(D_tls) debug_printf("TLS: server certificate verification required.\n"); + state->verify_requirement = VERIFY_REQUIRED; + gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); + } +else if (verify_check_host(&ob->tls_try_verify_hosts) == OK) + { + DEBUG(D_tls) debug_printf("TLS: server certificate verification optional.\n"); + state->verify_requirement = VERIFY_OPTIONAL; gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); } else { - DEBUG(D_tls) debug_printf("TLS: server certificate verification required\n"); - state->verify_requirement = VERIFY_REQUIRED; - gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); + DEBUG(D_tls) debug_printf("TLS: server certificate verification not required.\n"); + state->verify_requirement = VERIFY_NONE; + gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); } -gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)fd); +#ifdef EXPERIMENTAL_OCSP /* since GnuTLS 3.1.3 */ +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); + tls_out.ocsp = OCSP_NOT_RESP; + } +#endif + +gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)(long) fd); state->fd_in = fd; state->fd_out = fd; +DEBUG(D_tls) debug_printf("about to gnutls_handshake\n"); /* There doesn't seem to be a built-in timeout on connection. */ sigalrm_seen = FALSE; -alarm(timeout); +alarm(ob->command_timeout); do { rc = gnutls_handshake(state->session); @@ -1642,14 +1756,42 @@ if (state->verify_requirement != VERIFY_NONE && !verify_certificate(state, &error)) return tls_error(US"certificate verification failed", error, state->host); +#ifdef EXPERIMENTAL_OCSP +if (require_ocsp) + { + DEBUG(D_tls) + { + gnutls_datum_t stapling; + gnutls_ocsp_resp_t resp; + gnutls_datum_t printed; + if ( (rc= gnutls_ocsp_status_request_get(state->session, &stapling)) == 0 + && (rc= gnutls_ocsp_resp_init(&resp)) == 0 + && (rc= gnutls_ocsp_resp_import(resp, &stapling)) == 0 + && (rc= gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &printed)) == 0 + ) + { + debug_printf("%.4096s", printed.data); + gnutls_free(printed.data); + } + else + (void) tls_error(US"ocsp decode", gnutls_strerror(rc), state->host); + } + + if (gnutls_ocsp_status_request_is_checked(state->session, 0) == 0) + return tls_error(US"certificate status check failed", NULL, state->host); + DEBUG(D_tls) debug_printf("Passed OCSP checking\n"); + tls_out.ocsp = OCSP_VFIED; + } +#endif + /* Figure out peer DN, and if authenticated, etc. */ -rc = peer_status(state); -if (rc != OK) return rc; +if ((rc = peer_status(state)) != OK) + return rc; /* Sets various Exim expansion variables; may need to adjust for ACL callouts */ -extract_exim_vars_from_tls_state(state, FALSE); +extract_exim_vars_from_tls_state(state); return OK; } @@ -1747,8 +1889,9 @@ if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) state->tlsp->active = -1; state->tlsp->bits = 0; state->tlsp->certificate_verified = FALSE; - tls_channelbinding_b64 = NULL; /*XXX JGH */ + tls_channelbinding_b64 = NULL; state->tlsp->cipher = NULL; + state->tlsp->peercert = NULL; state->tlsp->peerdn = NULL; return smtp_getc(); @@ -2031,4 +2174,6 @@ fprintf(f, "Library version: GnuTLS: Compile: %s\n" gnutls_check_version(NULL)); } +/* vi: aw ai sw=2 +*/ /* End of tls-gnu.c */