X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/b34fc30c7704c469a25b5a933fc38867f5128630..42bfef1e908fe60f8a7a86e66616b51702f1c0fb:/src/src/tls-gnu.c diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index 8391914b6..c90ae1411 100644 --- a/src/src/tls-gnu.c +++ b/src/src/tls-gnu.c @@ -39,6 +39,10 @@ require current GnuTLS, then we'll drop support for the ancient libraries). #include /* man-page is incorrect, gnutls_rnd() is not in gnutls.h: */ #include +/* needed to disable PKCS11 autoload unless requested */ +#if GNUTLS_VERSION_NUMBER >= 0x020c00 +# include +#endif /* GnuTLS 2 vs 3 @@ -63,8 +67,7 @@ Some of these correspond to variables in globals.c; those variables will be set to point to content in one of these instances, as appropriate for the stage of the process lifetime. -Not handled here: globals tls_active, tls_bits, tls_cipher, tls_peerdn, -tls_certificate_verified, tls_channelbinding_b64, tls_sni. +Not handled here: global tls_channelbinding_b64. */ typedef struct exim_gnutls_state { @@ -76,8 +79,10 @@ typedef struct exim_gnutls_state { 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; const uschar *tls_certificate; @@ -93,22 +98,22 @@ typedef struct exim_gnutls_state { uschar *exp_tls_crl; uschar *exp_tls_require_ciphers; + tls_support *tlsp; /* set in tls_init() */ + uschar *xfer_buffer; int xfer_buffer_lwm; int xfer_buffer_hwm; int xfer_eof; int xfer_error; - - uschar cipherbuf[256]; } exim_gnutls_state_st; static const exim_gnutls_state_st exim_gnutls_state_init = { - NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, - NULL, NULL, NULL, + 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, 0, 0, 0, 0, - "" }; /* Not only do we have our own APIs which don't pass around state, assuming @@ -121,7 +126,6 @@ there's no way for heart-beats to be responded to, for the duration of the second connection. */ static exim_gnutls_state_st state_server, state_client; -static exim_gnutls_state_st *current_global_tls_state; /* 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 @@ -148,14 +152,20 @@ static BOOL exim_gnutls_base_init_done = 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. */ +#ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL #define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 +#endif +#ifndef EXIM_CLIENT_DH_MIN_BITS #define EXIM_CLIENT_DH_MIN_BITS 1024 +#endif /* With GnuTLS 2.12.x+ we have gnutls_sec_param_to_pk_bits() with which we can ask for a bit-strength. Without that, we stick to the constant we had before, for now. */ +#ifndef EXIM_SERVER_DH_BITS_PRE2_12 #define EXIM_SERVER_DH_BITS_PRE2_12 1024 +#endif #define exim_gnutls_err_check(Label) do { \ if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) @@ -166,6 +176,7 @@ before, for now. */ #define HAVE_GNUTLS_SESSION_CHANNEL_BINDING #define HAVE_GNUTLS_SEC_PARAM_CONSTANTS #define HAVE_GNUTLS_RND +#define HAVE_GNUTLS_PKCS11 #endif @@ -281,59 +292,32 @@ Sets: tls_cipher a string tls_peerdn a string tls_sni a (UTF-8) string -Also: - current_global_tls_state for API limitations Argument: state the relevant exim_gnutls_state_st * */ static void -extract_exim_vars_from_tls_state(exim_gnutls_state_st *state) +extract_exim_vars_from_tls_state(exim_gnutls_state_st *state, BOOL is_server) { -gnutls_protocol_t protocol; gnutls_cipher_algorithm_t cipher; -gnutls_kx_algorithm_t kx; -gnutls_mac_algorithm_t mac; -uschar *p; #ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING int old_pool; int rc; gnutls_datum_t channel; #endif -current_global_tls_state = state; - -tls_active = state->fd_out; +state->tlsp->active = state->fd_out; cipher = gnutls_cipher_get(state->session); /* returns size in "bytes" */ -tls_bits = gnutls_cipher_get_key_size(cipher) * 8; +state->tlsp->bits = gnutls_cipher_get_key_size(cipher) * 8; -if (!*state->cipherbuf) - { - protocol = gnutls_protocol_get_version(state->session); - mac = gnutls_mac_get(state->session); - kx = gnutls_kx_get(state->session); - - string_format(state->cipherbuf, sizeof(state->cipherbuf), - "%s:%s:%u", - gnutls_protocol_get_name(protocol), - gnutls_cipher_suite_get_name(kx, cipher, mac), - tls_bits); - - /* I don't see a way that spaces could occur, in the current GnuTLS - code base, but it was a concern in the old code and perhaps older GnuTLS - releases did return "TLS 1.0"; play it safe, just in case. */ - for (p = state->cipherbuf; *p != '\0'; ++p) - if (isspace(*p)) - *p = '-'; - } -tls_cipher = state->cipherbuf; +state->tlsp->cipher = state->ciphersuite; -DEBUG(D_tls) debug_printf("cipher: %s\n", tls_cipher); +DEBUG(D_tls) debug_printf("cipher: %s\n", state->ciphersuite); -tls_certificate_verified = state->peer_cert_verified; +state->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. */ @@ -354,9 +338,8 @@ if (rc) { } #endif -tls_peerdn = state->peerdn; - -tls_sni = state->received_sni; +state->tlsp->peerdn = state->peerdn; +state->tlsp->sni = state->received_sni; } @@ -376,9 +359,6 @@ file is never present. If two processes both compute some new parameters, you waste a bit of effort, but it doesn't seem worth messing around with locking to prevent this. -Argument: - host NULL for server, server for client (for error handling) - Returns: OK/DEFER/FAIL */ @@ -388,8 +368,12 @@ init_server_dh(void) int fd, rc; unsigned int dh_bits; gnutls_datum m; -uschar filename[PATH_MAX]; +uschar filename_buf[PATH_MAX]; +uschar *filename = NULL; size_t sz; +uschar *exp_tls_dhparam; +BOOL use_file_in_spool = FALSE; +BOOL use_fixed_file = FALSE; host_item *host = NULL; /* dummy for macros */ DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); @@ -397,6 +381,46 @@ DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); rc = gnutls_dh_params_init(&dh_server_params); exim_gnutls_err_check(US"gnutls_dh_params_init"); +m.data = NULL; +m.size = 0; + +if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam)) + return DEFER; + +if (!exp_tls_dhparam) + { + DEBUG(D_tls) debug_printf("Loading default hard-coded DH params\n"); + m.data = US std_dh_prime_default(); + m.size = Ustrlen(m.data); + } +else if (Ustrcmp(exp_tls_dhparam, "historic") == 0) + use_file_in_spool = TRUE; +else if (Ustrcmp(exp_tls_dhparam, "none") == 0) + { + DEBUG(D_tls) debug_printf("Requested no DH parameters.\n"); + return OK; + } +else if (exp_tls_dhparam[0] != '/') + { + m.data = US std_dh_prime_named(exp_tls_dhparam); + if (m.data == NULL) + return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL); + m.size = Ustrlen(m.data); + } +else + { + use_fixed_file = TRUE; + filename = exp_tls_dhparam; + } + +if (m.data) + { + rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); + exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); + DEBUG(D_tls) debug_printf("Loaded fixed standard D-H parameters\n"); + return OK; + } + #ifdef HAVE_GNUTLS_SEC_PARAM_CONSTANTS /* If you change this constant, also change dh_param_fn_ext so that we can use a different filename and ensure we have sufficient bits. */ @@ -413,9 +437,22 @@ DEBUG(D_tls) dh_bits); #endif -if (!string_format(filename, sizeof(filename), - "%s/gnutls-params-%d", spool_directory, dh_bits)) - return tls_error(US"overlong filename", NULL, NULL); +/* Some clients have hard-coded limits. */ +if (dh_bits > tls_dh_max_bits) + { + DEBUG(D_tls) + debug_printf("tls_dh_max_bits clamping override, using %d bits instead.\n", + tls_dh_max_bits); + dh_bits = tls_dh_max_bits; + } + +if (use_file_in_spool) + { + if (!string_format(filename_buf, sizeof(filename_buf), + "%s/gnutls-params-%d", spool_directory, dh_bits)) + return tls_error(US"overlong filename", NULL, NULL); + filename = filename_buf; + } /* Open the cache file for reading and if successful, read it and set up the parameters. */ @@ -492,6 +529,7 @@ case. */ if (rc < 0) { uschar *temp_fn; + unsigned int dh_bits_gen = dh_bits; if ((PATH_MAX - Ustrlen(filename)) < 10) return tls_error(US"Filename too long to generate replacement", @@ -503,8 +541,26 @@ if (rc < 0) return tls_error(US"Unable to open temp file", strerror(errno), NULL); (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ - DEBUG(D_tls) debug_printf("generating %d bits Diffie-Hellman key ...\n", dh_bits); - rc = gnutls_dh_params_generate2(dh_server_params, dh_bits); + /* GnuTLS overshoots! + * If we ask for 2236, we might get 2237 or more. + * But there's no way to ask GnuTLS how many bits there really are. + * We can ask how many bits were used in a TLS session, but that's it! + * The prime itself is hidden behind too much abstraction. + * So we ask for less, and proceed on a wing and a prayer. + * First attempt, subtracted 3 for 2233 and got 2240. + */ + if (dh_bits >= EXIM_CLIENT_DH_MIN_BITS + 10) + { + dh_bits_gen = dh_bits - 10; + DEBUG(D_tls) + debug_printf("being paranoid about DH generation, make it '%d' bits'\n", + dh_bits_gen); + } + + DEBUG(D_tls) + debug_printf("requesting generation of %d bit Diffie-Hellman prime ...\n", + dh_bits_gen); + rc = gnutls_dh_params_generate2(dh_server_params, dh_bits_gen); exim_gnutls_err_check(US"gnutls_dh_params_generate2"); /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, @@ -521,6 +577,7 @@ if (rc < 0) m.data = malloc(m.size); if (m.data == NULL) return tls_error(US"memory allocation failed", strerror(errno), NULL); + /* this will return a size 1 less than the allocation size above */ rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, m.data, &sz); if (rc != GNUTLS_E_SUCCESS) @@ -528,6 +585,7 @@ if (rc < 0) free(m.data); exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); } + m.size = sz; /* shrink by 1, probably */ sz = write_to_fd_buf(fd, m.data, (size_t) m.size); if (sz != m.size) @@ -582,6 +640,7 @@ Returns: OK/DEFER/FAIL static int tls_expand_session_files(exim_gnutls_state_st *state) { +struct stat statbuf; int rc; const host_item *host = state->host; /* macro should be reconsidered? */ uschar *saved_tls_certificate = NULL; @@ -595,7 +654,11 @@ if (!state->host) { if (!state->received_sni) { - if (Ustrstr(state->tls_certificate, US"tls_sni")) + if (state->tls_certificate && + (Ustrstr(state->tls_certificate, US"tls_sni") || + Ustrstr(state->tls_certificate, US"tls_in_sni") || + Ustrstr(state->tls_certificate, US"tls_out_sni") + )) { DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); state->trigger_sni_changes = TRUE; @@ -603,6 +666,7 @@ if (!state->host) } else { + /* useful for debugging */ saved_tls_certificate = state->exp_tls_certificate; saved_tls_privatekey = state->exp_tls_privatekey; saved_tls_verify_certificates = state->exp_tls_verify_certificates; @@ -610,6 +674,9 @@ if (!state->host) } } +rc = gnutls_certificate_allocate_credentials(&state->x509_cred); +exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); + /* remember: expand_check_tlsvar() is expand_check() but fiddling with state members, assuming consistent naming; and expand_check() returns false if expansion failed, unless expansion was forced to fail. */ @@ -645,7 +712,6 @@ if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') if (state->exp_tls_certificate && *state->exp_tls_certificate) { - BOOL setit = TRUE; DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", state->exp_tls_certificate, state->exp_tls_privatekey); @@ -655,7 +721,6 @@ if (state->exp_tls_certificate && *state->exp_tls_certificate) (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) { DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); - setit = FALSE; } else { @@ -663,16 +728,13 @@ if (state->exp_tls_certificate && *state->exp_tls_certificate) } } - if (setit) - { - rc = gnutls_certificate_set_x509_key_file(state->x509_cred, - CS state->exp_tls_certificate, CS state->exp_tls_privatekey, - GNUTLS_X509_FMT_PEM); - exim_gnutls_err_check( - string_sprintf("cert/key setup: cert=%s key=%s", - state->exp_tls_certificate, state->exp_tls_privatekey)); - DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); - } + rc = gnutls_certificate_set_x509_key_file(state->x509_cred, + CS state->exp_tls_certificate, CS state->exp_tls_privatekey, + GNUTLS_X509_FMT_PEM); + exim_gnutls_err_check( + string_sprintf("cert/key setup: cert=%s key=%s", + state->exp_tls_certificate, state->exp_tls_privatekey)); + DEBUG(D_tls) debug_printf("TLS: cert/key registered\n"); } /* tls_certificate */ /* Set the trusted CAs file if one is provided, and then add the CRL if one is @@ -683,112 +745,135 @@ behaviour. */ if (state->tls_verify_certificates && *state->tls_verify_certificates) { - struct stat statbuf; - BOOL setit_vc = TRUE, setit_crl = TRUE; - if (!expand_check_tlsvar(tls_verify_certificates)) return DEFER; if (state->tls_crl && *state->tls_crl) if (!expand_check_tlsvar(tls_crl)) return DEFER; - if (state->received_sni) - { - state->exp_tls_verify_certificates, state->exp_tls_verify_certificates, - saved_tls_verify_certificates, saved_tls_verify_certificates); - if (!(state->exp_tls_verify_certificates || saved_tls_verify_certificates)) - setit_vc = FALSE; /* never was set */ - else if (!state->exp_tls_verify_certificates || !saved_tls_verify_certificates) - setit_vc = TRUE; /* changed whether set */ - else if (Ustrcmp(state->exp_tls_verify_certificates, saved_tls_verify_certificates) == 0) - setit_vc = FALSE; /* not changed value */ - - state->exp_tls_crl, state->exp_tls_crl, - saved_tls_crl, saved_tls_crl); - if (!(state->exp_tls_crl || saved_tls_crl)) - setit_crl = FALSE; /* never was set */ - else if (!state->exp_tls_crl || !saved_tls_crl) - setit_crl = TRUE; /* changed whether set */ - else if (Ustrcmp(state->exp_tls_crl, saved_tls_crl) == 0) - setit_crl = FALSE; /* not changed value */ - } - - /* nb: early exit; change if add more expansions to this function */ - if (!(setit_vc || setit_crl)) + if (!(state->exp_tls_verify_certificates && + *state->exp_tls_verify_certificates)) { DEBUG(D_tls) - debug_printf("TLS SNI: no change to tls_crl or tls_verify_certificates\n"); + debug_printf("TLS: tls_verify_certificates expanded empty, ignoring\n"); + /* With no tls_verify_certificates, we ignore tls_crl too */ return OK; } + } +else + { + DEBUG(D_tls) + debug_printf("TLS: tls_verify_certificates not set or empty, ignoring\n"); + return OK; + } - if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) - { - log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " - "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, - strerror(errno)); - return DEFER; - } +if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) + { + log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " + "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, + strerror(errno)); + return DEFER; + } - if (!S_ISREG(statbuf.st_mode)) - { - DEBUG(D_tls) - debug_printf("verify certificates path is not a file: \"%s\"\n%s\n", - state->exp_tls_verify_certificates, - S_ISDIR(statbuf.st_mode) - ? " it's a directory, that's OpenSSL, this is GnuTLS" - : " (not a directory either)"); - log_write(0, LOG_MAIN|LOG_PANIC, - "tls_verify_certificates \"%s\" is not a file", +/* The test suite passes in /dev/null; we could check for that path explicitly, +but who knows if someone has some weird FIFO which always dumps some certs, or +other weirdness. The thing we really want to check is that it's not a +directory, since while OpenSSL supports that, GnuTLS does not. +So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */ +if (S_ISDIR(statbuf.st_mode)) + { + DEBUG(D_tls) + debug_printf("verify certificates path is a dir: \"%s\"\n", state->exp_tls_verify_certificates); - return DEFER; - } + log_write(0, LOG_MAIN|LOG_PANIC, + "tls_verify_certificates \"%s\" is a directory", + state->exp_tls_verify_certificates); + return DEFER; + } - DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", - state->exp_tls_verify_certificates, statbuf.st_size); +DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", + state->exp_tls_verify_certificates, statbuf.st_size); - /* If the CA cert file is empty, there's no point in loading the CRL file, - as we aren't verifying, so checking for revocation is pointless. */ +if (statbuf.st_size == 0) + { + DEBUG(D_tls) + debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); + return OK; + } - if (statbuf.st_size > 0) - { - if (setit_vc) - { - cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred, - CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); - if (cert_count < 0) - { - rc = cert_count; - exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); - } - DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); - } - else - { - DEBUG(D_tls) debug_printf("TLS SNI: tls_verify_certificates unchanged\n"); - } +cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred, + CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); +if (cert_count < 0) + { + rc = cert_count; + exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); + } +DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); - if (setit_crl && state->tls_crl && *state->tls_crl) - { - if (state->exp_tls_crl && *state->exp_tls_crl) - { - DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); - rc = gnutls_certificate_set_x509_crl_file(state->x509_cred, - CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); - exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); - } - } - DEBUG(D_tls) - if (!setit_crl) debug_printf("TLS SNI: tls_crl unchanged\n"); - } /* statbuf.st_size */ - } /* tls_verify_certificates */ +if (state->tls_crl && *state->tls_crl && + state->exp_tls_crl && *state->exp_tls_crl) + { + DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); + cert_count = gnutls_certificate_set_x509_crl_file(state->x509_cred, + CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); + if (cert_count < 0) + { + rc = cert_count; + exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); + } + DEBUG(D_tls) debug_printf("Processed %d CRLs.\n", cert_count); + } return OK; -/* also above, during verify_certificates/crl, during SNI, if unchanged */ } +/************************************************* +* Set X.509 state variables * +*************************************************/ + +/* In GnuTLS, the registered cert/key are not replaced by a later +set of a cert/key, so for SNI support we need a whole new x509_cred +structure. Which means various other non-re-expanded pieces of state +need to be re-set in the new struct, so the setting logic is pulled +out to this. + +Arguments: + state exim_gnutls_state_st * + +Returns: OK/DEFER/FAIL +*/ + +static int +tls_set_remaining_x509(exim_gnutls_state_st *state) +{ +int rc; +const host_item *host = state->host; /* macro should be reconsidered? */ + +/* Create D-H parameters, or read them from the cache file. This function does +its own SMTP error messaging. This only happens for the server, TLS D-H ignores +client-side params. */ + +if (!state->host) + { + if (!dh_server_params) + { + rc = init_server_dh(); + if (rc != OK) return rc; + } + gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); + } + +/* Link the credentials to the session. */ + +rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); +exim_gnutls_err_check(US"gnutls_credentials_set"); + +return OK; +} + /************************************************* * Initialize for GnuTLS * *************************************************/ @@ -804,6 +889,7 @@ Arguments: cas CA certs file crl CRL file require_ciphers tls_require_ciphers setting + caller_state returned state-info structure Returns: OK/DEFER/FAIL */ @@ -830,6 +916,19 @@ if (!exim_gnutls_base_init_done) { DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); +#ifdef HAVE_GNUTLS_PKCS11 + /* By default, gnutls_global_init will init PKCS11 support in auto mode, + which loads modules from a config file, which sounds good and may be wanted + by some sysadmin, but also means in common configurations that GNOME keyring + environment variables are used and so breaks for users calling mailq. + To prevent this, we init PKCS11 first, which is the documented approach. */ + if (!gnutls_enable_pkcs11) + { + rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); + exim_gnutls_err_check(US"gnutls_pkcs11_init"); + } +#endif + rc = gnutls_global_init(); exim_gnutls_err_check(US"gnutls_global_init"); @@ -849,6 +948,7 @@ if (host) { state = &state_client; memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); + state->tlsp = &tls_out; DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); rc = gnutls_init(&state->session, GNUTLS_CLIENT); } @@ -856,6 +956,7 @@ else { state = &state_server; memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); + state->tlsp = &tls_in; DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); rc = gnutls_init(&state->session, GNUTLS_SERVER); } @@ -865,13 +966,11 @@ state->host = host; state->tls_certificate = certificate; state->tls_privatekey = privatekey; +state->tls_require_ciphers = require_ciphers; state->tls_sni = sni; state->tls_verify_certificates = cas; state->tls_crl = crl; -rc = gnutls_certificate_allocate_credentials(&state->x509_cred); -exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); - /* This handles the variables that might get re-expanded after TLS SNI; that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ @@ -880,26 +979,16 @@ DEBUG(D_tls) rc = tls_expand_session_files(state); if (rc != OK) return rc; -/* Create D-H parameters, or read them from the cache file. This function does -its own SMTP error messaging. This only happens for the server, TLS D-H ignores -client-side params. */ - -if (!host) - { - rc = init_server_dh(); - if (rc != OK) return rc; - gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); - } +/* These are all other parts of the x509_cred handling, since SNI in GnuTLS +requires a new structure afterwards. */ -/* Link the credentials to the session. */ - -rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); -exim_gnutls_err_check(US"gnutls_credentials_set"); +rc = tls_set_remaining_x509(state); +if (rc != OK) return rc; /* set SNI in client, only */ if (host) { - if (!expand_check_tlsvar(tls_sni)) + if (!expand_check(state->tlsp->sni, US"tls_out_sni", &state->exp_tls_sni)) return DEFER; if (state->exp_tls_sni && *state->exp_tls_sni) { @@ -916,7 +1005,7 @@ else if (state->tls_sni) "have an SNI set for a client [%s]\n", state->tls_sni); /* This is the priority string support, -http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html +http://www.gnutls.org/manual/html_node/Priority-Strings.html and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. This was backwards incompatible, but means Exim no longer needs to track all algorithms and provide string forms for them. */ @@ -940,6 +1029,9 @@ if (state->tls_require_ciphers && *state->tls_require_ciphers) } if (want_default_priorities) { + DEBUG(D_tls) + debug_printf("GnuTLS using default session cipher/priority \"%s\"\n", + exim_default_gnutls_priority); rc = gnutls_priority_init(&state->priority_cache, exim_default_gnutls_priority, &errpos); p = US exim_default_gnutls_priority; @@ -967,8 +1059,6 @@ if (gnutls_compat_mode) } *caller_state = state; -/* needs to happen before callbacks during handshake */ -current_global_tls_state = state; return OK; } @@ -980,7 +1070,22 @@ return OK; *************************************************/ /* Called from both server and client code. -Only this is allowed to set state->peerdn and we use that to detect double-calls. +Only this is allowed to set state->peerdn and state->have_set_peerdn +and we use that to detect double-calls. + +NOTE: the state blocks last while the TLS connection is up, which is fine +for logging in the server side, but for the client side, we log after teardown +in src/deliver.c. While the session is up, we can twist about states and +repoint tls_* globals, but those variables used for logging or other variable +expansion that happens _after_ delivery need to have a longer life-time. + +So for those, we get the data from POOL_PERM; the re-invoke guard keeps us from +doing this more than once per generation of a state context. We set them in +the state context, and repoint tls_* to them. After the state goes away, the +tls_* copies of the pointers remain valid and client delivery logging is happy. + +tls_certificate_verified is a BOOL, so the tls_peerdn and tls_cipher issues +don't apply. Arguments: state exim_gnutls_state_st * @@ -991,24 +1096,54 @@ Returns: OK/DEFER/FAIL static int peer_status(exim_gnutls_state_st *state) { +uschar cipherbuf[256]; const gnutls_datum *cert_list; -int rc; +int old_pool, rc; unsigned int cert_list_size = 0; +gnutls_protocol_t protocol; +gnutls_cipher_algorithm_t cipher; +gnutls_kx_algorithm_t kx; +gnutls_mac_algorithm_t mac; gnutls_certificate_type_t ct; gnutls_x509_crt_t crt; -uschar *dn_buf; +uschar *p, *dn_buf; size_t sz; -if (state->peerdn) +if (state->have_set_peerdn) return OK; +state->have_set_peerdn = TRUE; -state->peerdn = US"unknown"; +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); + +string_format(cipherbuf, sizeof(cipherbuf), + "%s:%s:%d", + gnutls_protocol_get_name(protocol), + gnutls_cipher_suite_get_name(kx, cipher, mac), + (int) gnutls_cipher_get_key_size(cipher) * 8); + +/* I don't see a way that spaces could occur, in the current GnuTLS +code base, but it was a concern in the old code and perhaps older GnuTLS +releases did return "TLS 1.0"; play it safe, just in case. */ +for (p = cipherbuf; *p != '\0'; ++p) + if (isspace(*p)) + *p = '-'; +old_pool = store_pool; +store_pool = POOL_PERM; +state->ciphersuite = string_copy(cipherbuf); +store_pool = old_pool; +state->tlsp->cipher = state->ciphersuite; + +/* tls_peerdn */ cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); if (cert_list == NULL || cert_list_size == 0) { - state->peerdn = US"unknown (no certificate)"; DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", cert_list, cert_list_size); if (state->verify_requirement == VERIFY_REQUIRED) @@ -1021,7 +1156,6 @@ ct = gnutls_certificate_type_get(state->session); if (ct != GNUTLS_CRT_X509) { const char *ctn = gnutls_certificate_type_get_name(ct); - state->peerdn = string_sprintf("unknown (type %s)", ctn); DEBUG(D_tls) debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); if (state->verify_requirement == VERIFY_REQUIRED) @@ -1108,7 +1242,7 @@ if ((rc < 0) || (verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0) DEBUG(D_tls) debug_printf("TLS certificate verification failed (%s): peerdn=%s\n", - *error, state->peerdn); + *error, state->peerdn ? state->peerdn : US""); if (state->verify_requirement == VERIFY_REQUIRED) { @@ -1116,15 +1250,16 @@ if ((rc < 0) || (verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0) return FALSE; } DEBUG(D_tls) - debug_printf("TLS verify failure overriden (host in tls_try_verify_hosts)\n"); + debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); } else { state->peer_cert_verified = TRUE; - DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", state->peerdn); + DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", + state->peerdn ? state->peerdn : US""); } -tls_peerdn = state->peerdn; +state->tlsp->peerdn = state->peerdn; return TRUE; } @@ -1143,7 +1278,14 @@ return TRUE; static void exim_gnutls_logger_cb(int level, const char *message) { - DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s\n", level, message); + size_t len = strlen(message); + if (len < 1) + { + DEBUG(D_tls) debug_printf("GnuTLS<%d> empty debug message\n", level); + return; + } + DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s%s", level, message, + message[len-1] == '\n' ? "" : "\n"); } #endif @@ -1161,6 +1303,7 @@ handshake.". For inability to get SNI information, we return 0. We only return non-zero if re-setup failed. +Only used for server-side TLS. */ static int @@ -1168,7 +1311,7 @@ exim_sni_handling_cb(gnutls_session_t session) { char sni_name[MAX_HOST_LEN]; size_t data_len = MAX_HOST_LEN; -exim_gnutls_state_st *state = current_global_tls_state; +exim_gnutls_state_st *state = &state_server; unsigned int sni_type; int rc, old_pool; @@ -1198,7 +1341,7 @@ state->received_sni = string_copyn(US sni_name, data_len); store_pool = old_pool; /* We set this one now so that variable expansions below will work */ -tls_sni = state->received_sni; +state->tlsp->sni = state->received_sni; DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, state->trigger_sni_changes ? "" : " (unused for certificate selection)"); @@ -1214,8 +1357,10 @@ if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; } -rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); -return (rc == GNUTLS_E_SUCCESS) ? 0 : rc; +rc = tls_set_remaining_x509(state); +if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; + +return 0; } @@ -1252,9 +1397,7 @@ const char *error; exim_gnutls_state_st *state = NULL; /* Check for previous activation */ -/* nb: this will not be TLS callout safe, needs reworking as part of that. */ - -if (tls_active >= 0) +if (tls_in.active >= 0) { tls_error(US"STARTTLS received after TLS started", "", NULL); smtp_printf("554 Already in TLS\r\n"); @@ -1305,10 +1448,10 @@ make them disconnect. We need to have an explicit fflush() here, to force out the response. Other smtp_printf() calls do not need it, because in non-TLS mode, the fflush() happens when smtp_getc() is called. */ -if (!tls_on_connect) +if (!state->tlsp->on_connect) { smtp_printf("220 TLS go ahead\r\n"); - fflush(smtp_out); + fflush(smtp_out); /*XXX JGH */ } /* Now negotiate the TLS session. We put our own timer on it, since it seems @@ -1325,7 +1468,8 @@ if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); do { rc = gnutls_handshake(state->session); - } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED)); + } while ((rc == GNUTLS_E_AGAIN) || + (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); alarm(0); if (rc != GNUTLS_E_SUCCESS) @@ -1374,7 +1518,7 @@ if (rc != OK) return rc; /* Sets various Exim expansion variables; always safe within server */ -extract_exim_vars_from_tls_state(state); +extract_exim_vars_from_tls_state(state, TRUE); /* TLS has been set up. Adjust the input functions to read via TLS, and initialize appropriately. */ @@ -1403,13 +1547,13 @@ Arguments: fd the fd of the connection host connected host (for messages) addr the first address (not used) - dhparam DH parameter file (ignored, we're a client) 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 Returns: OK/DEFER/FAIL (because using common functions), @@ -1418,10 +1562,14 @@ Returns: OK/DEFER/FAIL (because using common functions), int tls_client_start(int fd, host_item *host, - address_item *addr ARG_UNUSED, uschar *dhparam ARG_UNUSED, + address_item *addr ARG_UNUSED, uschar *certificate, uschar *privatekey, uschar *sni, uschar *verify_certs, uschar *verify_crl, - uschar *require_ciphers, int timeout) + uschar *require_ciphers, +#ifdef EXPERIMENTAL_OCSP + uschar *require_ocsp ARG_UNUSED, +#endif + int dh_min_bits, int timeout) { int rc; const char *error; @@ -1433,7 +1581,17 @@ rc = tls_init(host, certificate, privatekey, sni, verify_certs, verify_crl, require_ciphers, &state); if (rc != OK) return rc; -gnutls_dh_set_prime_bits(state->session, EXIM_CLIENT_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); if (verify_certs == NULL) { @@ -1460,9 +1618,14 @@ alarm(timeout); do { rc = gnutls_handshake(state->session); - } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED)); + } while ((rc == GNUTLS_E_AGAIN) || + (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); alarm(0); +if (rc != GNUTLS_E_SUCCESS) + return tls_error(US"gnutls_handshake", + sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host); + DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); /* Verify late */ @@ -1476,9 +1639,9 @@ if (state->verify_requirement != VERIFY_NONE && rc = peer_status(state); if (rc != OK) return rc; -/* Sets various Exim expansion variables; always safe within server */ +/* Sets various Exim expansion variables; may need to adjust for ACL callouts */ -extract_exim_vars_from_tls_state(state); +extract_exim_vars_from_tls_state(state, FALSE); return OK; } @@ -1499,11 +1662,11 @@ Returns: nothing */ void -tls_close(BOOL shutdown) +tls_close(BOOL is_server, BOOL shutdown) { -exim_gnutls_state_st *state = current_global_tls_state; +exim_gnutls_state_st *state = is_server ? &state_server : &state_client; -if (tls_active < 0) return; /* TLS was not active */ +if (!state->tlsp || state->tlsp->active < 0) return; /* TLS was not active */ if (shutdown) { @@ -1513,6 +1676,7 @@ if (shutdown) gnutls_deinit(state->session); +state->tlsp->active = -1; memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); if ((state_server.session == NULL) && (state_client.session == NULL)) @@ -1521,7 +1685,6 @@ if ((state_server.session == NULL) && (state_client.session == NULL)) exim_gnutls_base_init_done = FALSE; } -tls_active = -1; } @@ -1533,6 +1696,7 @@ tls_active = -1; /* This gets the next byte from the TLS input buffer. If the buffer is empty, it refills the buffer via the GnuTLS reading function. +Only used by the server-side TLS. This feeds DKIM and should be used for all message-body reads. @@ -1543,7 +1707,7 @@ Returns: the next character or EOF int tls_getc(void) { -exim_gnutls_state_st *state = current_global_tls_state; +exim_gnutls_state_st *state = &state_server; if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) { ssize_t inbytes; @@ -1572,12 +1736,12 @@ if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) gnutls_deinit(state->session); state->session = NULL; - tls_active = -1; - tls_bits = 0; - tls_certificate_verified = FALSE; - tls_channelbinding_b64 = NULL; - tls_cipher = NULL; - tls_peerdn = NULL; + state->tlsp->active = -1; + state->tlsp->bits = 0; + state->tlsp->certificate_verified = FALSE; + tls_channelbinding_b64 = NULL; /*XXX JGH */ + state->tlsp->cipher = NULL; + state->tlsp->peerdn = NULL; return smtp_getc(); } @@ -1611,6 +1775,7 @@ return state->xfer_buffer[state->xfer_buffer_lwm++]; /* This does not feed DKIM, so if the caller uses this for reading message body, then the caller must feed DKIM. + Arguments: buff buffer of data len size of buffer @@ -1620,9 +1785,9 @@ Returns: the number of bytes read */ int -tls_read(uschar *buff, size_t len) +tls_read(BOOL is_server, uschar *buff, size_t len) { -exim_gnutls_state_st *state = current_global_tls_state; +exim_gnutls_state_st *state = is_server ? &state_server : &state_client; ssize_t inbytes; if (len > INT_MAX) @@ -1658,6 +1823,7 @@ return -1; /* Arguments: + is_server channel specifier buff buffer of data len number of bytes @@ -1666,11 +1832,11 @@ Returns: the number of bytes after a successful write, */ int -tls_write(const uschar *buff, size_t len) +tls_write(BOOL is_server, const uschar *buff, size_t len) { ssize_t outbytes; size_t left = len; -exim_gnutls_state_st *state = current_global_tls_state; +exim_gnutls_state_st *state = is_server ? &state_server : &state_client; DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); while (left > 0) @@ -1773,6 +1939,71 @@ vaguely_random_number(int max) +/************************************************* +* Let tls_require_ciphers be checked at startup * +*************************************************/ + +/* The tls_require_ciphers option, if set, must be something which the +library can parse. + +Returns: NULL on success, or error message +*/ + +uschar * +tls_validate_require_cipher(void) +{ +int rc; +uschar *expciphers = NULL; +gnutls_priority_t priority_cache; +const char *errpos; + +#define validate_check_rc(Label) do { \ + if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ + return string_sprintf("%s failed: %s", (Label), gnutls_strerror(rc)); } } while (0) +#define return_deinit(Label) do { gnutls_global_deinit(); return (Label); } while (0) + +if (exim_gnutls_base_init_done) + log_write(0, LOG_MAIN|LOG_PANIC, + "already initialised GnuTLS, Exim developer bug"); + +#ifdef HAVE_GNUTLS_PKCS11 +if (!gnutls_enable_pkcs11) + { + rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); + validate_check_rc(US"gnutls_pkcs11_init"); + } +#endif +rc = gnutls_global_init(); +validate_check_rc(US"gnutls_global_init()"); +exim_gnutls_base_init_done = TRUE; + +if (!(tls_require_ciphers && *tls_require_ciphers)) + return_deinit(NULL); + +if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers)) + return_deinit(US"failed to expand tls_require_ciphers"); + +if (!(expciphers && *expciphers)) + return_deinit(NULL); + +DEBUG(D_tls) + debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers); + +rc = gnutls_priority_init(&priority_cache, CS expciphers, &errpos); +validate_check_rc(string_sprintf( + "gnutls_priority_init(%s) failed at offset %ld, \"%.8s..\"", + expciphers, errpos - CS expciphers, errpos)); + +#undef return_deinit +#undef validate_check_rc +gnutls_global_deinit(); + +return NULL; +} + + + + /************************************************* * Report the library versions. * *************************************************/