X-Git-Url: https://vcs.fsf.org/?a=blobdiff_plain;f=src%2Fsrc%2Ftls-gnu.c;h=5a37fae563348fb448bb517ec711a80073a7bca9;hb=b83314e3a331dfca74d382fb09529d447b9d63f0;hp=8391914b6bf97f3fd897e9134a73663272ebaecd;hpb=b34fc30c7704c469a25b5a933fc38867f5128630;p=exim.git diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index 8391914b6..5c9fd3965 100644 --- a/src/src/tls-gnu.c +++ b/src/src/tls-gnu.c @@ -2,7 +2,7 @@ * Exim - an Internet mail transport agent * *************************************************/ -/* Copyright (c) University of Cambridge 1995 - 2012 */ +/* Copyright (c) University of Cambridge 1995 - 2017 */ /* 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, @@ -39,6 +39,48 @@ 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 +# 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 +#if GNUTLS_VERSION_NUMBER >= 0x030506 && !defined(DISABLE_OCSP) +# define SUPPORT_SRV_OCSP_STACK +#endif +#if GNUTLS_VERSION_NUMBER >= 0x030000 && defined(EXPERIMENTAL_DANE) +# define SUPPORT_DANE +# define DANESSL_USAGE_DANE_TA 2 +# define DANESSL_USAGE_DANE_EE 3 +#endif +#if GNUTLS_VERSION_NUMBER < 0x999999 && defined(EXPERIMENTAL_DANE) +# define GNUTLS_BROKEN_DANE_VALIDATION +#endif + +#ifndef DISABLE_OCSP +# include +#endif +#ifdef SUPPORT_DANE +# include +#endif /* GnuTLS 2 vs 3 @@ -53,7 +95,8 @@ 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, VERIFY_DANE }; /* 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 @@ -63,22 +106,25 @@ 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 { - 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; + int fd_in; + int fd_out; + BOOL peer_cert_verified; + BOOL peer_dane_verified; + BOOL trigger_sni_changes; + BOOL have_set_peerdn; const struct host_item *host; - uschar *peerdn; - uschar *received_sni; + gnutls_x509_crt_t peercert; + uschar *peerdn; + uschar *ciphersuite; + uschar *received_sni; const uschar *tls_certificate; const uschar *tls_privatekey; @@ -86,29 +132,70 @@ 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; + const uschar *exp_tls_verify_cert_hostnames; +#ifndef DISABLE_EVENT + uschar *event_action; +#endif +#ifdef SUPPORT_DANE + char * const * dane_data; + const int * dane_data_len; +#endif + + 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, NULL, NULL, NULL, - NULL, NULL, NULL, NULL, NULL, NULL, - NULL, 0, 0, 0, 0, - "" + .session = NULL, + .x509_cred = NULL, + .priority_cache = NULL, + .verify_requirement = VERIFY_NONE, + .fd_in = -1, + .fd_out = -1, + .peer_cert_verified = FALSE, + .peer_dane_verified = FALSE, + .trigger_sni_changes =FALSE, + .have_set_peerdn = FALSE, + .host = NULL, + .peercert = NULL, + .peerdn = NULL, + .ciphersuite = NULL, + .received_sni = NULL, + + .tls_certificate = NULL, + .tls_privatekey = NULL, + .tls_sni = NULL, + .tls_verify_certificates = NULL, + .tls_crl = NULL, + .tls_require_ciphers =NULL, + + .exp_tls_certificate = NULL, + .exp_tls_privatekey = NULL, + .exp_tls_verify_certificates = NULL, + .exp_tls_crl = NULL, + .exp_tls_require_ciphers = NULL, + .exp_tls_verify_cert_hostnames = NULL, +#ifndef DISABLE_EVENT + .event_action = NULL, +#endif + .tlsp = NULL, + + .xfer_buffer = NULL, + .xfer_buffer_lwm = 0, + .xfer_buffer_hwm = 0, + .xfer_eof = 0, + .xfer_error = 0, }; /* Not only do we have our own APIs which don't pass around state, assuming @@ -118,10 +205,11 @@ 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; -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 @@ -139,6 +227,10 @@ 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 */ @@ -147,25 +239,44 @@ 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. */ -#define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 +callbacks. Possibly GNuTLS also looks for an environment variable +"GNUTLS_DEBUG_LEVEL". */ +#ifndef EXIM_GNUTLS_LIBRARY_LOG_LEVEL +# define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 +#endif -#define EXIM_CLIENT_DH_MIN_BITS 1024 +#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. */ -#define EXIM_SERVER_DH_BITS_PRE2_12 1024 +#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) +#define exim_gnutls_err_check(rc, Label) do { \ + 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 */ #endif @@ -180,6 +291,10 @@ 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 @@ -203,28 +318,18 @@ 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; } @@ -248,7 +353,8 @@ 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), @@ -256,7 +362,18 @@ 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); + } } @@ -266,12 +383,40 @@ 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 @@ -279,61 +424,40 @@ 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 -Also: - current_global_tls_state for API limitations + 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) +extract_exim_vars_from_tls_state(exim_gnutls_state_st * state) { -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 +tls_support * tlsp = state->tlsp; -current_global_tls_state = state; - -tls_active = state->fd_out; +tlsp->active = state->fd_out; cipher = gnutls_cipher_get(state->session); /* returns size in "bytes" */ -tls_bits = gnutls_cipher_get_key_size(cipher) * 8; +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; +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; +tlsp->certificate_verified = state->peer_cert_verified; +#ifdef SUPPORT_DANE +tlsp->dane_verified = state->peer_dane_verified; +#endif /* 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. */ @@ -348,15 +472,23 @@ 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 -tls_peerdn = state->peerdn; +/* 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; -tls_sni = state->received_sni; + tlsp->ourcert = cert && import_cert(cert, &crt)==0 ? crt : NULL; + } } @@ -376,33 +508,73 @@ 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 */ static int -init_server_dh(void) +init_server_dh(uschar ** errstr) { int fd, rc; unsigned int dh_bits; -gnutls_datum m; -uschar filename[PATH_MAX]; +gnutls_datum_t m; +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"); rc = gnutls_dh_params_init(&dh_server_params); -exim_gnutls_err_check(US"gnutls_dh_params_init"); +exim_gnutls_err_check(rc, US"gnutls_dh_params_init"); + +m.data = NULL; +m.size = 0; + +if (!expand_check(tls_dhparam, US"tls_dhparam", &exp_tls_dhparam, errstr)) + 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] != '/') + { + 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 + { + 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(rc, 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. */ 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); @@ -413,15 +585,27 @@ 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, 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; @@ -431,42 +615,39 @@ 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); rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); free(m.data); - exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); + exim_gnutls_err_check(rc, US"gnutls_dh_params_import_pkcs3"); DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); } @@ -481,7 +662,7 @@ 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 @@ -492,20 +673,38 @@ 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", - 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 */ - DEBUG(D_tls) debug_printf("generating %d bits Diffie-Hellman key ...\n", dh_bits); - rc = gnutls_dh_params_generate2(dh_server_params, dh_bits); - exim_gnutls_err_check(US"gnutls_dh_params_generate2"); + /* 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(rc, US"gnutls_dh_params_generate2"); /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, and I confirmed that a NULL call to get the size first is how the GnuTLS @@ -516,40 +715,38 @@ if (rc < 0) rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, m.data, &sz); if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) - exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); + exim_gnutls_err_check(rc, 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); if (rc != GNUTLS_E_SUCCESS) { free(m.data); - exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); + exim_gnutls_err_check(rc, 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) + 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); } @@ -561,6 +758,95 @@ 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; +} + + + + +/* Add certificate and key, from files. + +Return: + Zero or negative: good. Negate value for certificate index if < 0. + Greater than zero: FAIL or DEFER code. +*/ + +static int +tls_add_certfile(exim_gnutls_state_st * state, const host_item * host, + uschar * certfile, uschar * keyfile, uschar ** errstr) +{ +int rc = gnutls_certificate_set_x509_key_file(state->x509_cred, + CS certfile, CS keyfile, GNUTLS_X509_FMT_PEM); +if (rc < 0) + return tls_error( + string_sprintf("cert/key setup: cert=%s key=%s", certfile, keyfile), + gnutls_strerror(rc), host, errstr); +return -rc; +} + + /************************************************* * Variables re-expanded post-SNI * *************************************************/ @@ -575,13 +861,15 @@ 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; const host_item *host = state->host; /* macro should be reconsidered? */ uschar *saved_tls_certificate = NULL; @@ -591,11 +879,14 @@ 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 (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; @@ -603,12 +894,19 @@ 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; saved_tls_crl = state->exp_tls_crl; } - } + +rc = gnutls_certificate_allocate_credentials(&state->x509_cred); +exim_gnutls_err_check(rc, US"gnutls_certificate_allocate_credentials"); + +#ifdef SUPPORT_SRV_OCSP_STACK +gnutls_certificate_set_flags(state->x509_cred, GNUTLS_CERTIFICATE_API_V2); +#endif /* remember: expand_check_tlsvar() is expand_check() but fiddling with state members, assuming consistent naming; and expand_check() returns @@ -617,21 +915,20 @@ 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 */ @@ -645,36 +942,98 @@ 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); 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"); - setit = FALSE; } else { DEBUG(D_tls) debug_printf("TLS SNI: have a changed cert/key pair.\n"); } - } - if (setit) + if (!host) /* server */ + { + const uschar * clist = state->exp_tls_certificate; + const uschar * klist = state->exp_tls_privatekey; + const uschar * olist; + int csep = 0, ksep = 0, osep = 0, cnt = 0; + uschar * cfile, * kfile, * ofile; + +#ifndef DISABLE_OCSP + if (!expand_check(tls_ocsp_file, US"tls_ocsp_file", &ofile, errstr)) + return DEFER; + olist = ofile; +#endif + + while (cfile = string_nextinlist(&clist, &csep, NULL, 0)) + + if (!(kfile = string_nextinlist(&klist, &ksep, NULL, 0))) + return tls_error(US"cert/key setup: out of keys", NULL, host, errstr); + else if (0 < (rc = tls_add_certfile(state, host, cfile, kfile, errstr))) + return rc; + else + { + int gnutls_cert_index = -rc; + DEBUG(D_tls) debug_printf("TLS: cert/key %s registered\n", cfile); + + /* Set the OCSP stapling server info */ + +#ifndef DISABLE_OCSP + if (tls_ocsp_file) + if (gnutls_buggy_ocsp) + { + DEBUG(D_tls) + debug_printf("GnuTLS library is buggy for OCSP; avoiding\n"); + } + else if ((ofile = string_nextinlist(&olist, &osep, NULL, 0))) + { + /* Use the full callback method for stapling just to get + observability. More efficient would be to read the file once only, + if it never changed (due to SNI). Would need restart on file update, + or watch datestamp. */ + +# ifdef SUPPORT_SRV_OCSP_STACK + rc = gnutls_certificate_set_ocsp_status_request_function2( + state->x509_cred, gnutls_cert_index, + server_ocsp_stapling_cb, ofile); + + exim_gnutls_err_check(rc, + US"gnutls_certificate_set_ocsp_status_request_function2"); +# else + if (cnt++ > 0) + { + DEBUG(D_tls) + debug_printf("oops; multiple OCSP files not supported\n"); + break; + } + gnutls_certificate_set_ocsp_status_request_function( + state->x509_cred, server_ocsp_stapling_cb, ofile); +# endif + + DEBUG(D_tls) debug_printf("OCSP response file = %s\n", ofile); + } + else + DEBUG(D_tls) debug_printf("ran out of OCSP response files in list\n"); +#endif + } + } + else { - 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)); + if (0 < (rc = tls_add_certfile(state, host, + state->exp_tls_certificate, state->exp_tls_privatekey, errstr))) + return rc; 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 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 @@ -683,116 +1042,195 @@ 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)) + 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->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; + } +#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 + { 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)); + "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, + strerror(errno)); return DEFER; } - if (!S_ISREG(statbuf.st_mode)) +#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 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)"); + 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 not a file", - state->exp_tls_verify_certificates); + "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); + 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) + 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"); - } - - 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 */ + 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); + } + +if (cert_count < 0) + { + rc = cert_count; + exim_gnutls_err_check(rc, US"setting certificate trust"); + } +DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); + +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(rc, 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 * + errstr error string pointer + +Returns: OK/DEFER/FAIL +*/ + +static int +tls_set_remaining_x509(exim_gnutls_state_st *state, uschar ** errstr) +{ +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(errstr); + 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(rc, US"gnutls_credentials_set"); + +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. @@ -804,6 +1242,8 @@ Arguments: cas CA certs file crl CRL file require_ciphers tls_require_ciphers setting + caller_state returned state-info structure + errstr error string pointer Returns: OK/DEFER/FAIL */ @@ -817,7 +1257,8 @@ 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; @@ -830,8 +1271,21 @@ 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_allow_auto_pkcs11) + { + rc = gnutls_pkcs11_init(GNUTLS_PKCS11_FLAG_MANUAL, NULL); + exim_gnutls_err_check(rc, US"gnutls_pkcs11_init"); + } +#endif + rc = gnutls_global_init(); - exim_gnutls_err_check(US"gnutls_global_init"); + exim_gnutls_err_check(rc, US"gnutls_global_init"); #if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 DEBUG(D_tls) @@ -842,6 +1296,11 @@ 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; } @@ -849,6 +1308,7 @@ 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); } @@ -856,67 +1316,54 @@ 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); } -exim_gnutls_err_check(US"gnutls_init"); +exim_gnutls_err_check(rc, US"gnutls_init"); 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 */ 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; - -/* 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); - } +if ((rc = tls_expand_session_files(state, errstr)) != OK) return rc; -/* Link the credentials to the session. */ +/* These are all other parts of the x509_cred handling, since SNI in GnuTLS +requires a new structure afterwards. */ -rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); -exim_gnutls_err_check(US"gnutls_credentials_set"); +if ((rc = tls_set_remaining_x509(state, errstr)) != OK) return rc; /* set SNI in client, only */ if (host) { - if (!expand_check_tlsvar(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); - exim_gnutls_err_check(US"gnutls_server_name_set"); + GNUTLS_NAME_DNS, state->tlsp->sni, sz); + exim_gnutls_err_check(rc, US"gnutls_server_name_set"); } } else if (state->tls_sni) DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ - "have an SNI set for a client [%s]\n", state->tls_sni); + "have an SNI set for a server [%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. */ @@ -925,7 +1372,7 @@ 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) { @@ -940,17 +1387,20 @@ 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; } -exim_gnutls_err_check(string_sprintf( +exim_gnutls_err_check(rc, string_sprintf( "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", p, errpos - CS p, errpos)); rc = gnutls_priority_set(state->session, state->priority_cache); -exim_gnutls_err_check(US"gnutls_priority_set"); +exim_gnutls_err_check(rc, US"gnutls_priority_set"); gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); @@ -967,53 +1417,96 @@ if (gnutls_compat_mode) } *caller_state = state; -/* needs to happen before callbacks during handshake */ -current_global_tls_state = state; return OK; } - /************************************************* * Extract peer information * *************************************************/ /* 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 * + 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) { -const gnutls_datum *cert_list; -int rc; +uschar cipherbuf[256]; +const gnutls_datum_t *cert_list; +int old_pool, rc; unsigned int cert_list_size = 0; -gnutls_certificate_type_t ct; -gnutls_x509_crt_t crt; -uschar *dn_buf; +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 *p, *dn_buf; size_t sz; -if (state->peerdn) +if (state->have_set_peerdn) return OK; +state->have_set_peerdn = TRUE; + +state->peerdn = NULL; -state->peerdn = US"unknown"; +/* 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) + 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; } @@ -1021,26 +1514,31 @@ 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) + 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 = import_cert(&cert_list[0], &crt); +exim_gnutls_peer_err(US"cert 0"); -rc = gnutls_x509_crt_init(&crt); -exim_gnutls_peer_err(US"gnutls_x509_crt_init (crt)"); +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) @@ -1051,6 +1549,7 @@ 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; @@ -1070,8 +1569,8 @@ gnutls_certificate_set_verify_function() to fail the handshake if we dislike the peer information, but that's too new for some OSes. Arguments: - state exim_gnutls_state_st * - error where to put an error message + state exim_gnutls_state_st * + errstr where to put an error message Returns: FALSE if the session should be rejected @@ -1079,54 +1578,197 @@ 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; +uint verify; -*error = NULL; +if (state->verify_requirement == VERIFY_NONE) + return TRUE; -rc = peer_status(state); -if (rc != OK) +*errstr = NULL; + +if ((rc = peer_status(state, errstr)) != OK) { verify = GNUTLS_CERT_INVALID; - *error = "not supplied"; + *errstr = US"certificate not supplied"; } else + { +#ifdef SUPPORT_DANE + if (state->verify_requirement == VERIFY_DANE && state->host) + { + /* Using dane_verify_session_crt() would be easy, as it does it all for us + including talking to a DNS resolver. But we want to do that bit ourselves + as the testsuite intercepts and fakes its own DNS environment. */ + + dane_state_t s; + dane_query_t r; + uint lsize; + const gnutls_datum_t * certlist = + gnutls_certificate_get_peers(state->session, &lsize); + int usage = tls_out.tlsa_usage; + +# ifdef GNUTLS_BROKEN_DANE_VALIDATION + /* Split the TLSA records into two sets, TA and EE selectors. Run the + dane-verification separately so that we know which selector verified; + then we know whether to do CA-chain-verification and name-verification + (needed for TA but not EE). */ + + if (usage == ((1<dane_data_len[nrec]; ) nrec++; + nrec++; + + dd = store_get(nrec * sizeof(uschar *)); + ddl = store_get(nrec * sizeof(int)); + nrec--; + + if ((rc = dane_state_init(&s, 0))) + goto tlsa_prob; + + for (usage = DANESSL_USAGE_DANE_EE; + usage >= DANESSL_USAGE_DANE_TA; usage--) + { /* take records with this usage */ + for (j = i = 0; i < nrec; i++) + if (state->dane_data[i][0] == usage) + { + dd[j] = state->dane_data[i]; + ddl[j++] = state->dane_data_len[i]; + } + if (j) + { + dd[j] = NULL; + ddl[j] = 0; + + if ((rc = dane_raw_tlsa(s, &r, (char * const *)dd, ddl, 1, 0))) + goto tlsa_prob; + + if ((rc = dane_verify_crt_raw(s, certlist, lsize, + gnutls_certificate_type_get(state->session), + r, 0, + usage == DANESSL_USAGE_DANE_EE + ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, + &verify))) + { + DEBUG(D_tls) + debug_printf("TLSA record problem: %s\n", dane_strerror(rc)); + } + else if (verify == 0) /* verification passed */ + { + usage = 1 << usage; + break; + } + } + } + + if (rc) goto tlsa_prob; + } + else +# endif + { + if ( (rc = dane_state_init(&s, 0)) + || (rc = dane_raw_tlsa(s, &r, state->dane_data, state->dane_data_len, + 1, 0)) + || (rc = dane_verify_crt_raw(s, certlist, lsize, + gnutls_certificate_type_get(state->session), + r, 0, +# ifdef GNUTLS_BROKEN_DANE_VALIDATION + usage == (1 << DANESSL_USAGE_DANE_EE) + ? DANE_VFLAG_ONLY_CHECK_EE_USAGE : 0, +# else + 0, +# endif + &verify)) + ) + goto tlsa_prob; + } + + if (verify != 0) /* verification failed */ + { + gnutls_datum_t str; + (void) dane_verification_status_print(verify, &str, 0); + *errstr = US str.data; /* don't bother to free */ + goto badcert; + } + state->peer_dane_verified = TRUE; + +# ifdef GNUTLS_BROKEN_DANE_VALIDATION + /* If a TA-mode TLSA record was used for verification we must additionally + verify the CA chain and the cert name. For EE-mode, skip it. */ + + if (usage & (1 << DANESSL_USAGE_DANE_EE)) +# endif + { + state->peer_cert_verified = TRUE; + goto goodcert; + } + } +#endif + 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. */ +/* Handle the result of verification. INVALID is set if any others are. */ -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); + debug_printf("TLS certificate verification failed (%s): peerdn=\"%s\"\n", + *errstr, state->peerdn ? state->peerdn : US""); - if (state->verify_requirement == VERIFY_REQUIRED) - { - gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); - return FALSE; - } + if (state->verify_requirement >= VERIFY_REQUIRED) + goto badcert; 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 { + 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) + goto badcert; + return TRUE; + } + } 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; +goodcert: + state->tlsp->peerdn = state->peerdn; + return TRUE; -return TRUE; +#ifdef SUPPORT_DANE +tlsa_prob: + *errstr = string_sprintf("TLSA record problem: %s", dane_strerror(rc)); +#endif + +badcert: + gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); + return FALSE; } @@ -1143,7 +1785,14 @@ 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 +1810,7 @@ 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 @@ -1168,9 +1818,10 @@ 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; +uschar * dummy_errstr; rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); if (rc != GNUTLS_E_SUCCESS) @@ -1181,7 +1832,7 @@ if (rc != GNUTLS_E_SUCCESS) else debug_printf("TLS failure: gnutls_server_name_get(): %s [%d]\n", gnutls_strerror(rc), rc); - }; + } return 0; } @@ -1198,7 +1849,7 @@ 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)"); @@ -1206,18 +1857,93 @@ 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 = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); -return (rc == GNUTLS_E_SUCCESS) ? 0 : rc; +rc = tls_set_remaining_x509(state, &dummy_errstr); +if (rc != OK) return GNUTLS_E_APPLICATION_ERROR_MIN; + +return 0; +} + + + +#ifndef DISABLE_OCSP + +static int +server_ocsp_stapling_cb(gnutls_session_t session, void * ptr, + gnutls_datum_t * ocsp_response) +{ +int ret; +DEBUG(D_tls) debug_printf("OCSP stapling callback: %s\n", US ptr); + +if ((ret = gnutls_load_file(ptr, ocsp_response)) < 0) + { + DEBUG(D_tls) debug_printf("Failed to load ocsp stapling file %s\n", + CS 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 @@ -1237,27 +1963,25 @@ 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 */ -/* 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"); + tls_error(US"STARTTLS received after TLS started", "", NULL, errstr); + smtp_printf("554 Already in TLS\r\n", FALSE); return FAIL; } @@ -1266,33 +1990,44 @@ 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. */ @@ -1305,9 +2040,9 @@ 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"); + smtp_printf("220 TLS go ahead\r\n", FALSE); fflush(smtp_out); } @@ -1315,31 +2050,41 @@ if (!tls_on_connect) 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)); +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; @@ -1349,28 +2094,21 @@ DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); /* Verify after the fact */ -if (state->verify_requirement != VERIFY_NONE) +if (!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 */ @@ -1382,6 +2120,8 @@ 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; @@ -1393,6 +2133,96 @@ 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); + } +} + + + + +#ifdef SUPPORT_DANE +/* Given our list of RRs from the TLSA lookup, build a lookup block in +GnuTLS-DANE's preferred format. Hang it on the state str for later +use in DANE verification. + +We point at the dnsa data not copy it, so it must remain valid until +after verification is done.*/ + +static BOOL +dane_tlsa_load(exim_gnutls_state_st * state, dns_answer * dnsa) +{ +dns_record * rr; +dns_scan dnss; +int i; +const char ** dane_data; +int * dane_data_len; + +for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS), i = 1; + rr; + rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) + ) if (rr->type == T_TLSA) i++; + +dane_data = store_get(i * sizeof(uschar *)); +dane_data_len = store_get(i * sizeof(int)); + +for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS), i = 0; + rr; + rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) + ) if (rr->type == T_TLSA) + { + const uschar * p = rr->data; + uint8_t usage = p[0], sel = p[1], type = p[2]; + + DEBUG(D_tls) + debug_printf("TLSA: %d %d %d size %d\n", usage, sel, type, rr->size); + + if ( (usage != DANESSL_USAGE_DANE_TA && usage != DANESSL_USAGE_DANE_EE) + || (sel != 0 && sel != 1) + ) + continue; + switch(type) + { + case 0: /* Full: cannot check at present */ + break; + case 1: if (rr->size != 3 + 256/8) continue; /* sha2-256 */ + break; + case 2: if (rr->size != 3 + 512/8) continue; /* sha2-512 */ + break; + default: continue; + } + + tls_out.tlsa_usage |= 1<size; + } + +if (!i) return FALSE; + +dane_data[i] = NULL; +dane_data_len[i] = 0; + +state->dane_data = (char * const *)dane_data; +state->dane_data_len = dane_data_len; +return TRUE; +} +#endif + + + /************************************************* * Start a TLS session in a client * *************************************************/ @@ -1403,14 +2233,13 @@ 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 - timeout startup timeout + tb transport (always smtp) + tlsa_dnsa non-NULL, either request or require dane for this host, and + a TLSA record found. Therefore, dane verify required. + Which implies cert must be requested and supplied, dane + verify must pass, and cert verify irrelevant (incl. + hostnames), and (caller handled) require_tls + errstr error string pointer Returns: OK/DEFER/FAIL (because using common functions), but for a client, DEFER and FAIL have the same meaning @@ -1418,65 +2247,182 @@ 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, - uschar *certificate, uschar *privatekey, uschar *sni, - uschar *verify_certs, uschar *verify_crl, - uschar *require_ciphers, int timeout) + address_item *addr ARG_UNUSED, + transport_instance * tb, +#ifdef EXPERIMENTAL_DANE + dns_answer * tlsa_dnsa, +#endif + 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; +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; -gnutls_dh_set_prime_bits(state->session, EXIM_CLIENT_DH_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; + } -if (verify_certs == NULL) + 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 */ + +#ifdef SUPPORT_DANE +if (tlsa_dnsa && dane_tlsa_load(state, tlsa_dnsa)) { - 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 */ - gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); + DEBUG(D_tls) + debug_printf("TLS: server certificate DANE required.\n"); + state->verify_requirement = VERIFY_DANE; + gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); } else +#endif + 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 required\n"); + 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 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); - } 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) + 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); +if (!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; always safe within server */ +/* Sets various Exim expansion variables; may need to adjust for ACL callouts */ extract_exim_vars_from_tls_state(state); @@ -1499,11 +2445,11 @@ 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) { @@ -1512,7 +2458,10 @@ 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)); if ((state_server.session == NULL) && (state_client.session == NULL)) @@ -1520,86 +2469,149 @@ if ((state_server.session == NULL) && (state_client.session == NULL)) gnutls_global_deinit(); exim_gnutls_base_init_done = FALSE; } - -tls_active = -1; } +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 * *************************************************/ /* 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. -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 = current_global_tls_state; +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; - tls_active = -1; - tls_bits = 0; - tls_certificate_verified = FALSE; - tls_channelbinding_b64 = NULL; - tls_cipher = NULL; - tls_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; } @@ -1611,6 +2623,7 @@ 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 +2633,9 @@ 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) @@ -1658,21 +2671,30 @@ return -1; /* 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(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 = current_global_tls_state; +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", @@ -1703,6 +2725,14 @@ 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; } @@ -1773,6 +2803,73 @@ 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; +uschar * dummy_errstr; + +#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_allow_auto_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, + &dummy_errstr)) + 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. * *************************************************/ @@ -1792,4 +2889,6 @@ fprintf(f, "Library version: GnuTLS: Compile: %s\n" gnutls_check_version(NULL)); } +/* vi: aw ai sw=2 +*/ /* End of tls-gnu.c */