X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/a63be306e4bcb803e7aa3ab673a2e1d867adaaba..a5ffa9b475a426bc73366db01f7cc92a3811bc3a:/src/src/tls-gnu.c diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index 280744ec0..c68d11d72 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 - 2013 */ +/* Copyright (c) University of Cambridge 1995 - 2015 */ /* See the file NOTICE for conditions of use and distribution. */ /* Copyright (c) Phil Pennock 2012 */ @@ -13,7 +13,7 @@ tls.c when USE_GNUTLS has been set. The code herein is a revamp of GnuTLS integration using the current APIs; the original tls-gnu.c was based on a patch which was contributed by Nikos -Mavroyanopoulos. The revamp is partially a rewrite, partially cut&paste as +Mavrogiannopoulos. The revamp is partially a rewrite, partially cut&paste as appropriate. APIs current as of GnuTLS 2.12.18; note that the GnuTLS manual is for GnuTLS 3, @@ -42,6 +42,30 @@ require current GnuTLS, then we'll drop support for the ancient libraries). /* needed to disable PKCS11 autoload unless requested */ #if GNUTLS_VERSION_NUMBER >= 0x020c00 # include +# define SUPPORT_PARAM_TO_PK_BITS +#endif +#if GNUTLS_VERSION_NUMBER < 0x030103 && !defined(DISABLE_OCSP) +# warning "GnuTLS library version too old; define DISABLE_OCSP in Makefile" +# define DISABLE_OCSP +#endif +#if GNUTLS_VERSION_NUMBER < 0x020a00 && !defined(DISABLE_EVENT) +# warning "GnuTLS library version too old; tls:cert event unsupported" +# define DISABLE_EVENT +#endif +#if GNUTLS_VERSION_NUMBER >= 0x030306 +# define SUPPORT_CA_DIR +#else +# undef SUPPORT_CA_DIR +#endif +#if GNUTLS_VERSION_NUMBER >= 0x030014 +# define SUPPORT_SYSDEFAULT_CABUNDLE +#endif +#if GNUTLS_VERSION_NUMBER >= 0x030109 +# define SUPPORT_CORK +#endif + +#ifndef DISABLE_OCSP +# include #endif /* GnuTLS 2 vs 3 @@ -57,7 +81,8 @@ Changes: /* Values for verify_requirement */ -enum peer_verify_requirement { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; +enum peer_verify_requirement + { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; /* This holds most state for server or client; with this, we can set up an outbound TLS-enabled connection in an ACL callout, while not stomping all @@ -71,19 +96,20 @@ 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; @@ -91,12 +117,17 @@ typedef struct exim_gnutls_state { const uschar *tls_verify_certificates; const uschar *tls_crl; const uschar *tls_require_ciphers; + uschar *exp_tls_certificate; uschar *exp_tls_privatekey; - uschar *exp_tls_sni; uschar *exp_tls_verify_certificates; uschar *exp_tls_crl; uschar *exp_tls_require_ciphers; + uschar *exp_tls_ocsp_file; + const uschar *exp_tls_verify_cert_hostnames; +#ifndef DISABLE_EVENT + uschar *event_action; +#endif tls_support *tlsp; /* set in tls_init() */ @@ -111,7 +142,11 @@ 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, +#ifndef DISABLE_EVENT + NULL, +#endif NULL, NULL, 0, 0, 0, 0, }; @@ -123,7 +158,9 @@ context we're currently dealing with" pointer and rely upon being single-threaded to keep from processing data on an inbound TLS connection while talking to another TLS connection for an outbound check. This does mean that there's no way for heart-beats to be responded to, for the duration of the -second connection. */ +second connection. +XXX But see gnutls_session_get_ptr() +*/ static exim_gnutls_state_st state_server, state_client; @@ -143,6 +180,10 @@ static const char * const exim_default_gnutls_priority = "NORMAL"; static BOOL exim_gnutls_base_init_done = FALSE; +#ifndef DISABLE_OCSP +static BOOL gnutls_buggy_ocsp = FALSE; +#endif + /* ------------------------------------------------------------------------ */ /* macros */ @@ -153,38 +194,41 @@ static BOOL exim_gnutls_base_init_done = FALSE; 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 +# define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 #endif #ifndef EXIM_CLIENT_DH_MIN_BITS -#define EXIM_CLIENT_DH_MIN_BITS 1024 +# 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 +# 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) + if (rc != GNUTLS_E_SUCCESS) \ + return tls_error((Label), gnutls_strerror(rc), host, errstr); \ + } while (0) -#define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) +#define expand_check_tlsvar(Varname, errstr) \ + expand_check(state->Varname, US #Varname, &state->exp_##Varname, errstr) #if GNUTLS_VERSION_NUMBER >= 0x020c00 -#define HAVE_GNUTLS_SESSION_CHANNEL_BINDING -#define HAVE_GNUTLS_SEC_PARAM_CONSTANTS -#define HAVE_GNUTLS_RND +# define HAVE_GNUTLS_SESSION_CHANNEL_BINDING +# define HAVE_GNUTLS_SEC_PARAM_CONSTANTS +# define HAVE_GNUTLS_RND /* The security fix we provide with the gnutls_allow_auto_pkcs11 option * (4.82 PP/09) introduces a compatibility regression. The symbol simply * isn't available sometimes, so this needs to become a conditional * compilation; the sanest way to deal with this being a problem on * older OSes is to block it in the Local/Makefile with this compiler * definition */ -#ifndef AVOID_GNUTLS_PKCS11 -#define HAVE_GNUTLS_PKCS11 -#endif /* AVOID_GNUTLS_PKCS11 */ +# ifndef AVOID_GNUTLS_PKCS11 +# define HAVE_GNUTLS_PKCS11 +# endif /* AVOID_GNUTLS_PKCS11 */ #endif @@ -199,6 +243,10 @@ static void exim_gnutls_logger_cb(int level, const char *message); static int exim_sni_handling_cb(gnutls_session_t session); +#ifndef DISABLE_OCSP +static int server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, + gnutls_datum_t * ocsp_response); +#endif @@ -222,28 +270,18 @@ Argument: usually obtained from gnutls_strerror() host NULL if setting up a server; the connected host if setting up a client + errstr pointer to returned error string Returns: OK/DEFER/FAIL */ static int -tls_error(const uschar *prefix, const char *msg, const host_item *host) +tls_error(const uschar *prefix, const char *msg, const host_item *host, + uschar ** errstr) { -if (host) - { - log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s", - host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); - return FAIL; - } -else - { - uschar *conn_info = smtp_get_connection_info(); - if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) - conn_info += 5; - log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", - conn_info, prefix, msg ? ": " : "", msg ? msg : ""); - return DEFER; - } +if (errstr) + *errstr = string_sprintf("(%s)%s%s", prefix, msg ? ": " : "", msg ? msg : ""); +return host ? FAIL : DEFER; } @@ -267,7 +305,8 @@ Returns: nothing static void record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) { -const char *msg; +const char * msg; +uschar * errstr; if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), @@ -275,7 +314,18 @@ if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) else msg = gnutls_strerror(rc); -tls_error(when, msg, state->host); +(void) tls_error(when, msg, state->host, &errstr); + +if (state->host) + log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection %s", + state->host->name, state->host->address, errstr); +else + { + uschar * conn_info = smtp_get_connection_info(); + if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; + /* I'd like to get separated H= here, but too hard for now */ + log_write(0, LOG_MAIN, "TLS error on %s %s", conn_info, errstr); + } } @@ -285,12 +335,40 @@ 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_t * 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 +376,17 @@ 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 +394,19 @@ 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. */ @@ -340,14 +421,23 @@ if (rc) { } else { old_pool = store_pool; store_pool = POOL_PERM; - tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); + tls_channelbinding_b64 = b64encode(channel.data, (int)channel.size); store_pool = old_pool; DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); } #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_t * cert = gnutls_certificate_get_ours(state->session); + gnutls_x509_crt_t crt; + + tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; + } } @@ -371,11 +461,11 @@ Returns: OK/DEFER/FAIL */ static int -init_server_dh(void) +init_server_dh(uschar ** errstr) { int fd, rc; unsigned int dh_bits; -gnutls_datum m; +gnutls_datum_t m; uschar filename_buf[PATH_MAX]; uschar *filename = NULL; size_t sz; @@ -392,7 +482,7 @@ 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)) +if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) return DEFER; if (!exp_tls_dhparam) @@ -410,9 +500,8 @@ else if (Ustrcmp(exp_tls_dhparam, "none") == 0) } 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); + if (!(m.data = US std_dh_prime_named(exp_tls_dhparam))) + return tls_error(US"No standard prime named", CS exp_tls_dhparam, NULL, errstr); m.size = Ustrlen(m.data); } else @@ -434,7 +523,7 @@ if (m.data) different filename and ensure we have sufficient bits. */ dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); if (!dh_bits) - return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); + return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL, errstr); DEBUG(D_tls) debug_printf("GnuTLS tells us that for D-H PK, NORMAL is %d bits.\n", dh_bits); @@ -458,15 +547,14 @@ 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); + return tls_error(US"overlong filename", NULL, NULL, errstr); filename = filename_buf; } /* Open the cache file for reading and if successful, read it and set up the parameters. */ -fd = Uopen(filename, O_RDONLY, 0); -if (fd >= 0) +if ((fd = Uopen(filename, O_RDONLY, 0)) >= 0) { struct stat statbuf; FILE *fp; @@ -476,36 +564,33 @@ if (fd >= 0) { saved_errno = errno; (void)close(fd); - return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); + return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL, errstr); } if (!S_ISREG(statbuf.st_mode)) { (void)close(fd); - return tls_error(US"TLS cache not a file", NULL, NULL); + return tls_error(US"TLS cache not a file", NULL, NULL, errstr); } - fp = fdopen(fd, "rb"); - if (!fp) + if (!(fp = fdopen(fd, "rb"))) { saved_errno = errno; (void)close(fd); return tls_error(US"fdopen(TLS cache stat fd) failed", - strerror(saved_errno), NULL); + strerror(saved_errno), NULL, errstr); } m.size = statbuf.st_size; - m.data = malloc(m.size); - if (m.data == NULL) + if (!(m.data = malloc(m.size))) { fclose(fp); - return tls_error(US"malloc failed", strerror(errno), NULL); + return tls_error(US"malloc failed", strerror(errno), NULL, errstr); } - sz = fread(m.data, m.size, 1, fp); - if (!sz) + if (!(sz = fread(m.data, m.size, 1, fp))) { saved_errno = errno; fclose(fp); free(m.data); - return tls_error(US"fread failed", strerror(saved_errno), NULL); + return tls_error(US"fread failed", strerror(saved_errno), NULL, errstr); } fclose(fp); @@ -526,7 +611,7 @@ else if (errno == ENOENT) } else return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), - NULL, NULL); + NULL, NULL, errstr); /* If ret < 0, either the cache file does not exist, or the data it contains is not useful. One particular case of this is when upgrading from an older @@ -541,12 +626,11 @@ if (rc < 0) if ((PATH_MAX - Ustrlen(filename)) < 10) return tls_error(US"Filename too long to generate replacement", - CS filename, NULL); + CS filename, NULL, errstr); temp_fn = string_copy(US "%s.XXXXXXX"); - fd = mkstemp(CS temp_fn); /* modifies temp_fn */ - if (fd < 0) - return tls_error(US"Unable to open temp file", strerror(errno), NULL); + if ((fd = mkstemp(CS temp_fn)) < 0) /* modifies temp_fn */ + return tls_error(US"Unable to open temp file", strerror(errno), NULL, errstr); (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ /* GnuTLS overshoots! @@ -582,9 +666,9 @@ if (rc < 0) if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); m.size = sz; - m.data = malloc(m.size); - if (m.data == NULL) - return tls_error(US"memory allocation failed", strerror(errno), NULL); + if (!(m.data = malloc(m.size))) + return tls_error(US"memory allocation failed", strerror(errno), NULL, errstr); + /* 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); @@ -595,27 +679,23 @@ if (rc < 0) } m.size = sz; /* shrink by 1, probably */ - sz = write_to_fd_buf(fd, m.data, (size_t) m.size); - if (sz != m.size) + if ((sz = write_to_fd_buf(fd, m.data, (size_t) m.size)) != m.size) { free(m.data); return tls_error(US"TLS cache write D-H params failed", - strerror(errno), NULL); + strerror(errno), NULL, errstr); } free(m.data); - sz = write_to_fd_buf(fd, US"\n", 1); - if (sz != 1) + if ((sz = write_to_fd_buf(fd, US"\n", 1)) != 1) return tls_error(US"TLS cache write D-H params final newline failed", - strerror(errno), NULL); + strerror(errno), NULL, errstr); - rc = close(fd); - if (rc) - return tls_error(US"TLS cache write close() failed", - strerror(errno), NULL); + if ((rc = close(fd))) + return tls_error(US"TLS cache write close() failed", strerror(errno), NULL, errstr); if (Urename(temp_fn, filename) < 0) return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", - temp_fn, filename), strerror(errno), NULL); + temp_fn, filename), strerror(errno), NULL, errstr); DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); } @@ -627,6 +707,74 @@ return OK; +/* Create and install a selfsigned certificate, for use in server mode */ + +static int +tls_install_selfsign(exim_gnutls_state_st * state, uschar ** errstr) +{ +gnutls_x509_crt_t cert = NULL; +time_t now; +gnutls_x509_privkey_t pkey = NULL; +const uschar * where; +int rc; + +where = US"initialising pkey"; +if ((rc = gnutls_x509_privkey_init(&pkey))) goto err; + +where = US"initialising cert"; +if ((rc = gnutls_x509_crt_init(&cert))) goto err; + +where = US"generating pkey"; +if ((rc = gnutls_x509_privkey_generate(pkey, GNUTLS_PK_RSA, +#ifdef SUPPORT_PARAM_TO_PK_BITS + gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA, GNUTLS_SEC_PARAM_LOW), +#else + 1024, +#endif + 0))) + goto err; + +where = US"configuring cert"; +now = 0; +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))) + || (rc = gnutls_x509_crt_set_expiration_time(cert, now + 60 * 60)) /* 1 hr */ + || (rc = gnutls_x509_crt_set_key(cert, pkey)) + + || (rc = gnutls_x509_crt_set_dn_by_oid(cert, + GNUTLS_OID_X520_COUNTRY_NAME, 0, "UK", 2)) + || (rc = gnutls_x509_crt_set_dn_by_oid(cert, + GNUTLS_OID_X520_ORGANIZATION_NAME, 0, "Exim Developers", 15)) + || (rc = gnutls_x509_crt_set_dn_by_oid(cert, + GNUTLS_OID_X520_COMMON_NAME, 0, + smtp_active_hostname, Ustrlen(smtp_active_hostname))) + ) + goto err; + +where = US"signing cert"; +if ((rc = gnutls_x509_crt_sign(cert, cert, pkey))) goto err; + +where = US"installing selfsign cert"; + /* Since: 2.4.0 */ +if ((rc = gnutls_certificate_set_x509_key(state->x509_cred, &cert, 1, pkey))) + goto err; + +rc = OK; + +out: + if (cert) gnutls_x509_crt_deinit(cert); + if (pkey) gnutls_x509_privkey_deinit(pkey); + return rc; + +err: + rc = tls_error(where, gnutls_strerror(rc), NULL, errstr); + goto out; +} + + + + /************************************************* * Variables re-expanded post-SNI * *************************************************/ @@ -641,12 +789,13 @@ which we are responsible for setting on the first pass through. Arguments: state exim_gnutls_state_st * + errstr error string pointer Returns: OK/DEFER/FAIL */ static int -tls_expand_session_files(exim_gnutls_state_st *state) +tls_expand_session_files(exim_gnutls_state_st *state, uschar ** errstr) { struct stat statbuf; int rc; @@ -658,8 +807,7 @@ 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) { if (state->tls_certificate && @@ -680,7 +828,6 @@ if (!state->host) saved_tls_verify_certificates = state->exp_tls_verify_certificates; saved_tls_crl = state->exp_tls_crl; } - } rc = gnutls_certificate_allocate_credentials(&state->x509_cred); exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); @@ -692,21 +839,20 @@ false if expansion failed, unless expansion was forced to fail. */ /* check if we at least have a certificate, before doing expensive D-H generation. */ -if (!expand_check_tlsvar(tls_certificate)) +if (!expand_check_tlsvar(tls_certificate, errstr)) return DEFER; /* certificate is mandatory in server, optional in client */ -if ((state->exp_tls_certificate == NULL) || - (*state->exp_tls_certificate == '\0')) - { - if (state->host == NULL) - return tls_error(US"no TLS server certificate is specified", NULL, NULL); +if ( !state->exp_tls_certificate + || !*state->exp_tls_certificate + ) + if (!host) + return tls_install_selfsign(state, errstr); else DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); - } -if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) +if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey, errstr)) return DEFER; /* tls_privatekey is optional, defaulting to same file as certificate */ @@ -724,9 +870,9 @@ if (state->exp_tls_certificate && *state->exp_tls_certificate) state->exp_tls_certificate, state->exp_tls_privatekey); if (state->received_sni) - { - if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) && - (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) + if ( Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0 + && Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0 + ) { DEBUG(D_tls) debug_printf("TLS SNI: cert and key unchanged\n"); } @@ -734,7 +880,6 @@ if (state->exp_tls_certificate && *state->exp_tls_certificate) { DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); } - } rc = gnutls_certificate_set_x509_key_file(state->x509_cred, CS state->exp_tls_certificate, CS state->exp_tls_privatekey, @@ -745,6 +890,37 @@ 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 */ + +#ifndef DISABLE_OCSP +if ( !host /* server */ + && tls_ocsp_file + ) + { + if (gnutls_buggy_ocsp) + { + DEBUG(D_tls) debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); + } + else + { + if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", + &state->exp_tls_ocsp_file, errstr)) + 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("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 @@ -753,10 +929,14 @@ behaviour. */ if (state->tls_verify_certificates && *state->tls_verify_certificates) { - if (!expand_check_tlsvar(tls_verify_certificates)) + if (!expand_check_tlsvar(tls_verify_certificates, errstr)) return DEFER; +#ifndef SUPPORT_SYSDEFAULT_CABUNDLE + if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) + state->exp_tls_verify_certificates = NULL; +#endif if (state->tls_crl && *state->tls_crl) - if (!expand_check_tlsvar(tls_crl)) + if (!expand_check_tlsvar(tls_crl, errstr)) return DEFER; if (!(state->exp_tls_verify_certificates && @@ -775,46 +955,65 @@ else return OK; } -if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) +#ifdef SUPPORT_SYSDEFAULT_CABUNDLE +if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) + cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); +else +#endif { - 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; + } -/* 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); - log_write(0, LOG_MAIN|LOG_PANIC, - "tls_verify_certificates \"%s\" is a directory", - state->exp_tls_verify_certificates); - return DEFER; - } +#ifndef SUPPORT_CA_DIR + /* 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 messaging ... */ + if (S_ISDIR(statbuf.st_mode)) + { + DEBUG(D_tls) + debug_printf("verify certificates path is a dir: \"%s\"\n", + state->exp_tls_verify_certificates); + log_write(0, LOG_MAIN|LOG_PANIC, + "tls_verify_certificates \"%s\" is a directory", + state->exp_tls_verify_certificates); + return DEFER; + } +#endif -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 (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) + { + DEBUG(D_tls) + debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); + return OK; + } + + cert_count = + +#ifdef SUPPORT_CA_DIR + (statbuf.st_mode & S_IFMT) == S_IFDIR + ? + gnutls_certificate_set_x509_trust_dir(state->x509_cred, + CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) + : +#endif + gnutls_certificate_set_x509_trust_file(state->x509_cred, + CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); } -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"); + exim_gnutls_err_check(US"setting certificate trust"); } DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); @@ -850,12 +1049,13 @@ out to this. Arguments: state exim_gnutls_state_st * + errstr error string pointer Returns: OK/DEFER/FAIL */ static int -tls_set_remaining_x509(exim_gnutls_state_st *state) +tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) { int rc; const host_item *host = state->host; /* macro should be reconsidered? */ @@ -868,7 +1068,7 @@ if (!state->host) { if (!dh_server_params) { - rc = init_server_dh(); + rc = init_server_dh(errstr); if (rc != OK) return rc; } gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); @@ -886,6 +1086,38 @@ return OK; * Initialize for GnuTLS * *************************************************/ + +#ifndef DISABLE_OCSP + +static BOOL +tls_is_buggy_ocsp(void) +{ +const uschar * s; +uschar maj, mid, mic; + +s = CUS gnutls_check_version(NULL); +maj = atoi(CCS s); +if (maj == 3) + { + while (*s && *s != '.') s++; + mid = atoi(CCS ++s); + if (mid <= 2) + return TRUE; + else if (mid >= 5) + return FALSE; + else + { + while (*s && *s != '.') s++; + mic = atoi(CCS ++s); + return mic <= (mid == 3 ? 16 : 3); + } + } +return FALSE; +} + +#endif + + /* Called from both server and client code. In the case of a server, errors before actual TLS negotiation return DEFER. @@ -898,6 +1130,7 @@ Arguments: crl CRL file require_ciphers tls_require_ciphers setting caller_state returned state-info structure + errstr error string pointer Returns: OK/DEFER/FAIL */ @@ -911,7 +1144,8 @@ tls_init( const uschar *cas, const uschar *crl, const uschar *require_ciphers, - exim_gnutls_state_st **caller_state) + exim_gnutls_state_st **caller_state, + uschar ** errstr) { exim_gnutls_state_st *state; int rc; @@ -949,6 +1183,11 @@ if (!exim_gnutls_base_init_done) } #endif +#ifndef DISABLE_OCSP + if (tls_ocsp_file && (gnutls_buggy_ocsp = tls_is_buggy_ocsp())) + log_write(0, LOG_MAIN, "OCSP unusable with this GnuTLS library version"); +#endif + exim_gnutls_base_init_done = TRUE; } @@ -984,27 +1223,25 @@ that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ DEBUG(D_tls) debug_printf("Expanding various TLS configuration options for session credentials.\n"); -rc = tls_expand_session_files(state); -if (rc != OK) return rc; +if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; /* These are all other parts of the x509_cred handling, since SNI in GnuTLS requires a new structure afterwards. */ -rc = tls_set_remaining_x509(state); -if (rc != OK) return rc; +if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; /* set SNI in client, only */ if (host) { - if (!expand_check(state->tlsp->sni, US"tls_out_sni", &state->exp_tls_sni)) + if (!expand_check(sni, US"tls_out_sni", &state->tlsp->sni, errstr)) return DEFER; - if (state->exp_tls_sni && *state->exp_tls_sni) + if (state->tlsp->sni && *state->tlsp->sni) { DEBUG(D_tls) - debug_printf("Setting TLS client SNI to \"%s\"\n", state->exp_tls_sni); - sz = Ustrlen(state->exp_tls_sni); + debug_printf("Setting TLS client SNI to \"%s\"\n", state->tlsp->sni); + sz = Ustrlen(state->tlsp->sni); rc = gnutls_server_name_set(state->session, - GNUTLS_NAME_DNS, state->exp_tls_sni, sz); + GNUTLS_NAME_DNS, state->tlsp->sni, sz); exim_gnutls_err_check(US"gnutls_server_name_set"); } } @@ -1022,7 +1259,7 @@ want_default_priorities = TRUE; if (state->tls_require_ciphers && *state->tls_require_ciphers) { - if (!expand_check_tlsvar(tls_require_ciphers)) + if (!expand_check_tlsvar(tls_require_ciphers, errstr)) return DEFER; if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) { @@ -1072,7 +1309,6 @@ return OK; - /************************************************* * Extract peer information * *************************************************/ @@ -1097,15 +1333,16 @@ don't apply. Arguments: state exim_gnutls_state_st * + errstr pointer to error string Returns: OK/DEFER/FAIL */ static int -peer_status(exim_gnutls_state_st *state) +peer_status(exim_gnutls_state_st *state, uschar ** errstr) { uschar cipherbuf[256]; -const gnutls_datum *cert_list; +const gnutls_datum_t *cert_list; int old_pool, rc; unsigned int cert_list_size = 0; gnutls_protocol_t protocol; @@ -1154,9 +1391,9 @@ if (cert_list == NULL || cert_list_size == 0) { DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", cert_list, cert_list_size); - if (state->verify_requirement == VERIFY_REQUIRED) + if (state->verify_requirement >= VERIFY_REQUIRED) return tls_error(US"certificate verification failed", - "no certificate received from peer", state->host); + "no certificate received from peer", state->host, errstr); return OK; } @@ -1166,23 +1403,29 @@ if (ct != GNUTLS_CRT_X509) const char *ctn = gnutls_certificate_type_get_name(ct); DEBUG(D_tls) debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); - if (state->verify_requirement == VERIFY_REQUIRED) + if (state->verify_requirement >= VERIFY_REQUIRED) return tls_error(US"certificate verification not possible, unhandled type", - ctn, state->host); + ctn, state->host, errstr); return OK; } -#define exim_gnutls_peer_err(Label) do { \ - if (rc != GNUTLS_E_SUCCESS) { \ - DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", (Label), gnutls_strerror(rc)); \ - if (state->verify_requirement == VERIFY_REQUIRED) { return tls_error((Label), gnutls_strerror(rc), state->host); } \ - return OK; } } while (0) +#define exim_gnutls_peer_err(Label) \ + do { \ + if (rc != GNUTLS_E_SUCCESS) \ + { \ + DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", \ + (Label), gnutls_strerror(rc)); \ + if (state->verify_requirement >= VERIFY_REQUIRED) \ + return tls_error((Label), gnutls_strerror(rc), state->host, errstr); \ + 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 +1436,7 @@ 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; @@ -1213,7 +1457,7 @@ the peer information, but that's too new for some OSes. Arguments: state exim_gnutls_state_st * - error where to put an error message + errstr where to put an error message Returns: FALSE if the session should be rejected @@ -1221,49 +1465,72 @@ Returns: */ static BOOL -verify_certificate(exim_gnutls_state_st *state, const char **error) +verify_certificate(exim_gnutls_state_st *state, uschar ** errstr) { int rc; unsigned int verify; -*error = NULL; +*errstr = NULL; -rc = peer_status(state); -if (rc != OK) +if ((rc = peer_status(state, errstr)) != OK) { verify = GNUTLS_CERT_INVALID; - *error = "not supplied"; + *errstr = US"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 (!*errstr) + *errstr = verify & GNUTLS_CERT_REVOKED + ? US"certificate revoked" : US"certificate invalid"; DEBUG(D_tls) - debug_printf("TLS certificate verification failed (%s): peerdn=%s\n", - *error, state->peerdn ? state->peerdn : US""); + debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", + *errstr, state->peerdn ? state->peerdn : US""); - if (state->verify_requirement == VERIFY_REQUIRED) + if (state->verify_requirement >= VERIFY_REQUIRED) { - gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); + gnutls_alert_send(state->session, + GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); return FALSE; } DEBUG(D_tls) debug_printf("TLS verify failure overridden (host in tls_try_verify_hosts)\n"); } + else { + if (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) + { + gnutls_alert_send(state->session, + GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); + return FALSE; + } + return TRUE; + } + } state->peer_cert_verified = TRUE; - DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", + DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=\"%s\"\n", state->peerdn ? state->peerdn : US""); } @@ -1322,6 +1589,7 @@ size_t data_len = MAX_HOST_LEN; exim_gnutls_state_st *state = &state_server; unsigned int sni_type; int rc, old_pool; +uschar * dummy_errstr; rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); if (rc != GNUTLS_E_SUCCESS) @@ -1332,7 +1600,7 @@ if (rc != GNUTLS_E_SUCCESS) else debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", gnutls_strerror(rc), rc); - }; + } return 0; } @@ -1357,15 +1625,14 @@ DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, if (!state->trigger_sni_changes) return 0; -rc = tls_expand_session_files(state); -if (rc != OK) +if ((rc = tls_expand_session_files(state, &dummy_errstr)) != OK) { /* If the setup of certs/etc failed before handshake, TLS would not have been offered. The best we can do now is abort. */ return GNUTLS_E_APPLICATION_ERROR_MIN; } -rc = tls_set_remaining_x509(state); +rc = tls_set_remaining_x509(state, &dummy_errstr); if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; return 0; @@ -1373,6 +1640,79 @@ return 0; +#ifndef DISABLE_OCSP + +static int +server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, + gnutls_datum_t * ocsp_response) +{ +int ret; + +if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) + { + DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", + (char *)ptr); + tls_in.ocsp = OCSP_NOT_RESP; + return GNUTLS_E_NO_CERTIFICATE_STATUS; + } + +tls_in.ocsp = OCSP_VFY_NOT_TRIED; +return 0; +} + +#endif + + +#ifndef DISABLE_EVENT +/* +We use this callback to get observability and detail-level control +for an exim TLS connection (either direction), raising a tls:cert event +for each cert in the chain presented by the peer. Any event +can deny verification. + +Return 0 for the handshake to continue or non-zero to terminate. +*/ + +static int +verify_cb(gnutls_session_t session) +{ +const gnutls_datum_t * cert_list; +unsigned int cert_list_size = 0; +gnutls_x509_crt_t crt; +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) + while (cert_list_size--) + { + rc = import_cert(&cert_list[cert_list_size], &crt); + if (rc != GNUTLS_E_SUCCESS) + { + DEBUG(D_tls) debug_printf("TLS: peer cert problem: depth %d: %s\n", + cert_list_size, gnutls_strerror(rc)); + break; + } + + state->tlsp->peercert = crt; + if ((yield = event_raise(state->event_action, + US"tls:cert", string_sprintf("%d", cert_list_size)))) + { + log_write(0, LOG_MAIN, + "SSL verify denied by event-action: depth=%d: %s", + cert_list_size, yield); + return 1; /* reject */ + } + state->tlsp->peercert = NULL; + } + +return 0; +} + +#endif + + /* ------------------------------------------------------------------------ */ /* Exported functions */ @@ -1390,25 +1730,25 @@ a TLS session. Arguments: require_ciphers list of allowed ciphers or NULL + errstr pointer to error string Returns: OK on success DEFER for errors before the start of the negotiation - FAIL for errors during the negotation; the server can't + FAIL for errors during the negotiation; the server can't continue running. */ int -tls_server_start(const uschar *require_ciphers) +tls_server_start(const uschar * require_ciphers, uschar ** errstr) { int rc; -const char *error; -exim_gnutls_state_st *state = NULL; +exim_gnutls_state_st * state = NULL; /* Check for previous activation */ if (tls_in.active >= 0) { - tls_error(US"STARTTLS received after TLS started", "", NULL); - smtp_printf("554 Already in TLS\r\n"); + tls_error(US"STARTTLS received after TLS started", "", NULL, errstr); + smtp_printf("554 Already in TLS\r\n", FALSE); return FAIL; } @@ -1417,33 +1757,44 @@ and sent an SMTP response. */ DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); -rc = tls_init(NULL, tls_certificate, tls_privatekey, +if ((rc = tls_init(NULL, tls_certificate, tls_privatekey, NULL, tls_verify_certificates, tls_crl, - require_ciphers, &state); -if (rc != OK) return rc; + require_ciphers, &state, errstr)) != OK) return rc; /* If this is a host for which certificate verification is mandatory or optional, set up appropriately. */ if (verify_check_host(&tls_verify_hosts) == OK) { - DEBUG(D_tls) debug_printf("TLS: a client certificate will be required.\n"); + DEBUG(D_tls) + debug_printf("TLS: a client certificate will be required.\n"); state->verify_requirement = VERIFY_REQUIRED; gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); } else if (verify_check_host(&tls_try_verify_hosts) == OK) { - DEBUG(D_tls) debug_printf("TLS: a client certificate will be requested but not required.\n"); + DEBUG(D_tls) + debug_printf("TLS: a client certificate will be requested but not required.\n"); state->verify_requirement = VERIFY_OPTIONAL; gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); } else { - DEBUG(D_tls) debug_printf("TLS: a client certificate will not be requested.\n"); + DEBUG(D_tls) + debug_printf("TLS: a client certificate will not be requested.\n"); state->verify_requirement = VERIFY_NONE; gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); } +#ifndef DISABLE_EVENT +if (event_action) + { + state->event_action = event_action; + gnutls_session_set_ptr(state->session, state); + gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); + } +#endif + /* Register SNI handling; always, even if not in tls_certificate, so that the expansion variable $tls_sni is always available. */ @@ -1458,40 +1809,49 @@ 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 */ + smtp_printf("220 TLS go ahead\r\n", FALSE); + 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_t)(long) fileno(smtp_in), + (gnutls_transport_ptr_t)(long) fileno(smtp_out)); state->fd_in = fileno(smtp_in); state->fd_out = fileno(smtp_out); sigalrm_seen = FALSE; if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); do - { rc = gnutls_handshake(state->session); - } while ((rc == GNUTLS_E_AGAIN) || - (rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen)); +while (rc == GNUTLS_E_AGAIN || rc == GNUTLS_E_INTERRUPTED && !sigalrm_seen); alarm(0); if (rc != GNUTLS_E_SUCCESS) { - tls_error(US"gnutls_handshake", - sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); /* It seems that, except in the case of a timeout, we have to close the connection right here; otherwise if the other end is running OpenSSL it hangs until the server times out. */ - if (!sigalrm_seen) + if (sigalrm_seen) + { + tls_error(US"gnutls_handshake", "timed out", NULL, errstr); + gnutls_db_remove_session(state->session); + } + else { + tls_error(US"gnutls_handshake", gnutls_strerror(rc), NULL, errstr); + (void) gnutls_alert_send_appropriate(state->session, rc); + gnutls_deinit(state->session); + gnutls_certificate_free_credentials(state->x509_cred); + millisleep(500); + shutdown(state->fd_out, SHUT_WR); + for (rc = 1024; fgetc(smtp_in) != EOF && rc > 0; ) rc--; /* drain skt */ (void)fclose(smtp_out); (void)fclose(smtp_in); + smtp_out = smtp_in = NULL; } return FAIL; @@ -1501,32 +1861,26 @@ 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, errstr)) { - 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; - } + (void) tls_error(US"certificate verification failed", *errstr, NULL, errstr); + return FAIL; } + DEBUG(D_tls) + debug_printf("TLS: continuing on only because verification was optional, after: %s\n", + *errstr); } /* Figure out peer DN, and if authenticated, etc. */ -rc = peer_status(state); -if (rc != OK) return rc; +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, TRUE); +extract_exim_vars_from_tls_state(state); /* TLS has been set up. Adjust the input functions to read via TLS, and initialize appropriately. */ @@ -1534,6 +1888,8 @@ and initialize appropriately. */ state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); receive_getc = tls_getc; +receive_getbuf = tls_getbuf; +receive_get_cache = tls_get_cache; receive_ungetc = tls_ungetc; receive_feof = tls_feof; receive_ferror = tls_ferror; @@ -1545,6 +1901,25 @@ return OK; +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) + { + state->exp_tls_verify_cert_hostnames = +#ifdef SUPPORT_I18N + string_domain_utf8_to_alabel(host->name, NULL); +#else + host->name; +#endif + DEBUG(D_tls) + debug_printf("TLS: server cert verification includes hostname: \"%s\".\n", + state->exp_tls_verify_cert_hostnames); + } +} + + /************************************************* * Start a TLS session in a client * *************************************************/ @@ -1555,16 +1930,9 @@ 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 - verify_hosts mandatory client verification - try_verify_hosts optional client verification + tb transport (always smtp) + + errstr error string pointer Returns: OK/DEFER/FAIL (because using common functions), but for a client, DEFER and FAIL have the same meaning @@ -1573,59 +1941,111 @@ 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, + transport_instance * tb, +#ifdef EXPERIMENTAL_DANE + dns_answer * tlsa_dnsa ARG_UNUSED, #endif - int dh_min_bits, int timeout, - uschar *verify_hosts, uschar *try_verify_hosts) + uschar ** errstr) { +smtp_transport_options_block *ob = + (smtp_transport_options_block *)tb->options_block; int rc; -const char *error; exim_gnutls_state_st *state = NULL; +#ifndef DISABLE_OCSP +BOOL require_ocsp = + verify_check_given_host(&ob->hosts_require_ocsp, host) == OK; +BOOL request_ocsp = require_ocsp ? TRUE + : verify_check_given_host(&ob->hosts_request_ocsp, host) == 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, errstr)) != 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); +/* 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 == NULL) +if ( ( state->exp_tls_verify_certificates + && !ob->tls_verify_hosts + && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts) + ) + || verify_check_given_host(&ob->tls_verify_hosts, host) == 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 */ + tls_client_setup_hostname_checks(host, state, ob); + 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_given_host(&ob->tls_try_verify_hosts, host) == OK) + { + tls_client_setup_hostname_checks(host, state, ob); + 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); +#ifndef DISABLE_OCSP + /* supported 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, errstr); + tls_out.ocsp = OCSP_NOT_RESP; + } +#endif + +#ifndef DISABLE_EVENT +if (tb->event_action) + { + state->event_action = tb->event_action; + gnutls_session_set_ptr(state->session, state); + gnutls_certificate_set_verify_function(state->x509_cred, verify_cb); + } +#endif + +gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr_t)(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); @@ -1634,25 +2054,61 @@ do alarm(0); if (rc != GNUTLS_E_SUCCESS) - return tls_error(US"gnutls_handshake", - sigalrm_seen ? "timed out" : gnutls_strerror(rc), state->host); + 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); + } + else + return tls_error(US"gnutls_handshake", gnutls_strerror(rc), state->host, errstr); DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); /* Verify late */ if (state->verify_requirement != VERIFY_NONE && - !verify_certificate(state, &error)) - return tls_error(US"certificate verification failed", error, state->host); + !verify_certificate(state, errstr)) + return tls_error(US"certificate verification failed", *errstr, state->host, errstr); + +#ifndef DISABLE_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, errstr); + } + + 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); + } + 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, errstr)) != 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; } @@ -1686,6 +2142,8 @@ if (shutdown) } gnutls_deinit(state->session); +gnutls_certificate_free_credentials(state->x509_cred); + state->tlsp->active = -1; memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); @@ -1695,12 +2153,80 @@ if ((state_server.session == NULL) && (state_client.session == NULL)) gnutls_global_deinit(); exim_gnutls_base_init_done = FALSE; } - } +static BOOL +tls_refill(unsigned lim) +{ +exim_gnutls_state_st * state = &state_server; +ssize_t inbytes; + +DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", + state->session, state->xfer_buffer, ssl_xfer_buffer_size); + +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); + +/* 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. */ + +if (sigalrm_seen) + { + DEBUG(D_tls) debug_printf("Got tls read timeout\n"); + state->xfer_error = 1; + return FALSE; + } + +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 = -1; + 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; + + return FALSE; + } + +/* Handle genuine errors */ + +else if (inbytes < 0) + { + record_io_error(state, (int) inbytes, US"recv", NULL); + state->xfer_error = 1; + return FALSE; + } +#ifndef DISABLE_DKIM +dkim_exim_verify_feed(state->xfer_buffer, inbytes); +#endif +state->xfer_buffer_hwm = (int) inbytes; +state->xfer_buffer_lwm = 0; +return TRUE; +} + /************************************************* * TLS version of getc * *************************************************/ @@ -1711,70 +2237,65 @@ Only used by the server-side TLS. This feeds DKIM and should be used for all message-body reads. -Arguments: none +Arguments: lim Maximum amount to read/bufffer Returns: the next character or EOF */ int -tls_getc(void) +tls_getc(unsigned lim) { -exim_gnutls_state_st *state = &state_server; +exim_gnutls_state_st * state = &state_server; + if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) - { - ssize_t inbytes; + if (!tls_refill(lim)) + return state->xfer_error ? EOF : smtp_getc(lim); - DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", - state->session, state->xfer_buffer, ssl_xfer_buffer_size); +/* Something in the buffer; return next uschar */ - if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); - inbytes = gnutls_record_recv(state->session, state->xfer_buffer, - ssl_xfer_buffer_size); - alarm(0); +return state->xfer_buffer[state->xfer_buffer_lwm++]; +} - /* 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. */ +uschar * +tls_getbuf(unsigned * len) +{ +exim_gnutls_state_st * state = &state_server; +unsigned size; +uschar * buf; - if (inbytes == 0) +if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) + if (!tls_refill(*len)) { - DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); - - receive_getc = smtp_getc; - receive_ungetc = smtp_ungetc; - receive_feof = smtp_feof; - receive_ferror = smtp_ferror; - receive_smtp_buffered = smtp_buffered; - - gnutls_deinit(state->session); - state->session = 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(); + if (!state->xfer_error) return smtp_getbuf(len); + *len = 0; + return NULL; } - /* Handle genuine errors */ +if ((size = state->xfer_buffer_hwm - state->xfer_buffer_lwm) > *len) + size = *len; +buf = &state->xfer_buffer[state->xfer_buffer_lwm]; +state->xfer_buffer_lwm += size; +*len = size; +return buf; +} - else if (inbytes < 0) - { - record_io_error(state, (int) inbytes, US"recv", NULL); - state->xfer_error = 1; - return EOF; - } + +void +tls_get_cache() +{ #ifndef DISABLE_DKIM - dkim_exim_verify_feed(state->xfer_buffer, inbytes); +exim_gnutls_state_st * state = &state_server; +int n = state->xfer_buffer_hwm - state->xfer_buffer_lwm; +if (n > 0) + dkim_exim_verify_feed(state->xfer_buffer+state->xfer_buffer_lwm, n); #endif - state->xfer_buffer_hwm = (int) inbytes; - state->xfer_buffer_lwm = 0; - } +} -/* Something in the buffer; return next uschar */ -return state->xfer_buffer[state->xfer_buffer_lwm++]; +BOOL +tls_could_read(void) +{ +return state_server.xfer_buffer_lwm < state_server.xfer_buffer_hwm + || gnutls_record_check_pending(state_server.session) > 0; } @@ -1837,19 +2358,27 @@ Arguments: is_server channel specifier buff buffer of data len number of bytes + more more data expected soon Returns: the number of bytes after a successful write, -1 after a failed write */ int -tls_write(BOOL is_server, const uschar *buff, size_t len) +tls_write(BOOL is_server, 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; +#ifdef SUPPORT_CORK +static BOOL corked = FALSE; + +if (more && !corked) gnutls_record_cork(state->session); +#endif + +DEBUG(D_tls) debug_printf("%s(%p, " SIZE_T_FMT "%s)\n", __FUNCTION__, + buff, left, more ? ", more" : ""); -DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); while (left > 0) { DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", @@ -1880,6 +2409,14 @@ if (len > INT_MAX) len = INT_MAX; } +#ifdef SUPPORT_CORK +if (more != corked) + { + if (!more) (void) gnutls_record_uncork(state->session, 0); + corked = more; + } +#endif + return (int) len; } @@ -1967,6 +2504,7 @@ int rc; uschar *expciphers = NULL; gnutls_priority_t priority_cache; const char *errpos; +uschar * dummy_errstr; #define validate_check_rc(Label) do { \ if (rc != GNUTLS_E_SUCCESS) { if (exim_gnutls_base_init_done) gnutls_global_deinit(); \ @@ -1991,7 +2529,8 @@ 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)) +if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers, + &dummy_errstr)) return_deinit(US"failed to expand tls_require_ciphers"); if (!(expciphers && *expciphers)) @@ -2034,4 +2573,6 @@ fprintf(f, "Library version: GnuTLS: Compile: %s\n" gnutls_check_version(NULL)); } +/* vi: aw ai sw=2 +*/ /* End of tls-gnu.c */