X-Git-Url: https://vcs.fsf.org/?a=blobdiff_plain;f=src%2Fsrc%2Ftls-openssl.c;h=4de3cad513428b1951e160b1b0a56d057d7fd257;hb=723fe533c452eb258a5a7e0b808d714bbbc7cb01;hp=201636db046b34a354c33a7ba72358d129bc55e8;hpb=12ee8cf9db5b6c81b0e492c64f305d7ba1cf4dc2;p=exim.git diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c index 201636db0..4de3cad51 100644 --- a/src/src/tls-openssl.c +++ b/src/src/tls-openssl.c @@ -25,6 +25,10 @@ functions from the OpenSSL library. */ #ifndef DISABLE_OCSP # include #endif +#ifdef EXPERIMENTAL_DANE +# include +#endif + #ifndef DISABLE_OCSP # define EXIM_OCSP_SKEW_SECONDS (300L) @@ -116,6 +120,9 @@ typedef struct tls_ext_ctx_cb { #ifdef EXPERIMENTAL_CERTNAMES uschar * verify_cert_hostnames; #endif +#ifdef EXPERIMENTAL_EVENT + uschar * event_action; +#endif } tls_ext_ctx_cb; /* should figure out a cleanup of API to handle state preserved per @@ -160,27 +167,28 @@ Returns: OK/DEFER/FAIL static int tls_error(uschar *prefix, host_item *host, uschar *msg) { -if (msg == NULL) +if (!msg) { ERR_error_string(ERR_get_error(), ssl_errstring); msg = (uschar *)ssl_errstring; } -if (host == NULL) +if (host) + { + log_write(0, LOG_MAIN, "H=%s [%s] TLS error on connection (%s): %s", + host->name, host->address, prefix, msg); + return FAIL; + } +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): %s", conn_info, prefix, msg); return DEFER; } -else - { - log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s", - host->name, host->address, prefix, msg); - return FAIL; - } } @@ -262,6 +270,9 @@ when asked. We get here only if a certificate has been received. Handling of optional verification for this case is done when requesting SSL to verify, by setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case. +May be called multiple times for different issues with a certificate, even +for a given "depth" in the certificate chain. + Arguments: state current yes/no state as 1/0 x509ctx certificate information. @@ -275,6 +286,8 @@ verify_callback(int state, X509_STORE_CTX *x509ctx, tls_support *tlsp, BOOL *calledp, BOOL *optionalp) { X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); +int depth = X509_STORE_CTX_get_error_depth(x509ctx); +uschar * ev; static uschar txt[256]; X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt)); @@ -282,7 +295,7 @@ X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt)); if (state == 0) { log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s", - X509_STORE_CTX_get_error_depth(x509ctx), + depth, X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), txt); tlsp->certificate_verified = FALSE; @@ -296,10 +309,9 @@ if (state == 0) "tls_try_verify_hosts)\n"); } -else if (X509_STORE_CTX_get_error_depth(x509ctx) != 0) +else if (depth != 0) { - DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", - X509_STORE_CTX_get_error_depth(x509ctx), txt); + DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, txt); #ifndef DISABLE_OCSP if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store) { /* client, wanting stapling */ @@ -310,6 +322,23 @@ else if (X509_STORE_CTX_get_error_depth(x509ctx) != 0) cert)) ERR_clear_error(); } +#endif +#ifdef EXPERIMENTAL_EVENT + ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; + if (ev) + { + tlsp->peercert = X509_dup(cert); + if (event_raise(ev, US"tls:cert", string_sprintf("%d", depth)) == DEFER) + { + log_write(0, LOG_MAIN, "SSL verify denied by event-action: " + "depth=%d cert=%s", depth, txt); + tlsp->certificate_verified = FALSE; + *calledp = TRUE; + return 0; /* reject */ + } + X509_free(tlsp->peercert); + tlsp->peercert = NULL; + } #endif } else @@ -361,6 +390,19 @@ else return 0; /* reject */ } # endif +#endif /*EXPERIMENTAL_CERTNAMES*/ + +#ifdef EXPERIMENTAL_EVENT + ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action; + if (ev) + if (event_raise(ev, US"tls:cert", US"0") == DEFER) + { + log_write(0, LOG_MAIN, "SSL verify denied by event-action: " + "depth=0 cert=%s", txt); + tlsp->certificate_verified = FALSE; + *calledp = TRUE; + return 0; /* reject */ + } #endif DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n", @@ -369,7 +411,7 @@ else *calledp = TRUE; } -return 1; /* accept */ +return 1; /* accept, at least for this level */ } static int @@ -385,6 +427,53 @@ return verify_callback(state, x509ctx, &tls_in, &server_verify_callback_called, } +#ifdef EXPERIMENTAL_DANE + +/* This gets called *by* the dane library verify callback, which interposes +itself. +*/ +static int +verify_callback_client_dane(int state, X509_STORE_CTX * x509ctx) +{ +X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx); +static uschar txt[256]; +#ifdef EXPERIMENTAL_EVENT +int depth = X509_STORE_CTX_get_error_depth(x509ctx); +#endif + +X509_NAME_oneline(X509_get_subject_name(cert), CS txt, sizeof(txt)); + +DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s\n", txt); +tls_out.peerdn = txt; +tls_out.peercert = X509_dup(cert); + +#ifdef EXPERIMENTAL_EVENT + if (client_static_cbinfo->event_action) + { + if (event_raise(client_static_cbinfo->event_action, + US"tls:cert", string_sprintf("%d", depth)) == DEFER) + { + log_write(0, LOG_MAIN, "DANE verify denied by event-action: " + "depth=%d cert=%s", depth, txt); + tls_out.certificate_verified = FALSE; + return 0; /* reject */ + } + if (depth != 0) + { + X509_free(tls_out.peercert); + tls_out.peercert = NULL; + } + } +#endif + +if (state == 1) + tls_out.dane_verified = + tls_out.certificate_verified = TRUE; +return 1; +} + +#endif /*EXPERIMENTAL_DANE*/ + /************************************************* * Information callback * @@ -888,7 +977,7 @@ if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len))) { tls_out.ocsp = OCSP_FAILED; if (log_extra_selector & LX_tls_cipher) - log_write(0, LOG_MAIN, "Received TLS status response, parse error"); + log_write(0, LOG_MAIN, "Received TLS cert status response, parse error"); else DEBUG(D_tls) debug_printf(" parse error\n"); return 0; @@ -898,7 +987,7 @@ if(!(bs = OCSP_response_get1_basic(rsp))) { tls_out.ocsp = OCSP_FAILED; if (log_extra_selector & LX_tls_cipher) - log_write(0, LOG_MAIN, "Received TLS status response, error parsing response"); + log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response"); else DEBUG(D_tls) debug_printf(" error parsing response\n"); OCSP_RESPONSE_free(rsp); @@ -928,6 +1017,8 @@ if(!(bs = OCSP_response_get1_basic(rsp))) cbinfo->u_ocsp.client.verify_store, 0)) <= 0) { tls_out.ocsp = OCSP_FAILED; + if (log_extra_selector & LX_tls_cipher) + log_write(0, LOG_MAIN, "Received TLS cert status response, itself unverifiable"); BIO_printf(bp, "OCSP response verify failure\n"); ERR_print_errors(bp); i = cbinfo->u_ocsp.client.verify_required ? 0 : 1; @@ -999,7 +1090,6 @@ return i; #endif /*!DISABLE_OCSP*/ - /************************************************* * Initialize for TLS * *************************************************/ @@ -1031,7 +1121,7 @@ tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, long init_options; int rc; BOOL okay; -tls_ext_ctx_cb *cbinfo; +tls_ext_ctx_cb * cbinfo; cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); cbinfo->certificate = certificate; @@ -1049,6 +1139,9 @@ else cbinfo->dhparam = dhparam; cbinfo->server_cipher_list = NULL; cbinfo->host = host; +#ifdef EXPERIMENTAL_EVENT +cbinfo->event_action = NULL; +#endif SSL_load_error_strings(); /* basic set up */ OpenSSL_add_ssl_algorithms(); @@ -1283,9 +1376,23 @@ if (expcerts != NULL && *expcerts != '\0') !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); + /* Load the list of CAs for which we will accept certs, for sending + to the client. This is only for the one-file tls_verify_certificates + variant. + If a list isn't loaded into the server, but + some verify locations are set, the server end appears to make + a wildcard reqest for client certs. + Meanwhile, the client library as deafult behaviour *ignores* the list + we send over the wire - see man SSL_CTX_set_client_cert_cb. + Because of this, and that the dir variant is likely only used for + the public-CA bundle (not for a private CA), not worth fixing. + */ if (file != NULL) { - SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file)); + STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); +DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", + sk_X509_NAME_num(names)); + SSL_CTX_set_client_CA_list(sctx, names); } } @@ -1421,6 +1528,9 @@ if (expciphers != NULL) optional, set up appropriately. */ tls_in.certificate_verified = FALSE; +#ifdef EXPERIMENTAL_DANE +tls_in.dane_verified = FALSE; +#endif server_verify_callback_called = FALSE; if (verify_check_host(&tls_verify_hosts) == OK) @@ -1579,6 +1689,66 @@ else if (verify_check_host(&ob->tls_try_verify_hosts) == OK) return OK; } + +#ifdef EXPERIMENTAL_DANE +static int +dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa) +{ +dns_record * rr; +dns_scan dnss; +const char * hostnames[2] = { CS host->name, NULL }; +int found = 0; + +if (DANESSL_init(ssl, NULL, hostnames) != 1) + return tls_error(US"hostnames load", host, NULL); + +for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); + rr; + rr = dns_next_rr(dnsa, &dnss, RESET_NEXT) + ) if (rr->type == T_TLSA) + { + uschar * p = rr->data; + uint8_t usage, selector, mtype; + const char * mdname; + + usage = *p++; + + /* Only DANE-TA(2) and DANE-EE(3) are supported */ + if (usage != 2 && usage != 3) continue; + + selector = *p++; + mtype = *p++; + + switch (mtype) + { + default: continue; /* Only match-types 0, 1, 2 are supported */ + case 0: mdname = NULL; break; + case 1: mdname = "sha256"; break; + case 2: mdname = "sha512"; break; + } + + found++; + switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3)) + { + default: + case 0: /* action not taken */ + return tls_error(US"tlsa load", host, NULL); + case 1: break; + } + + tls_out.tlsa_usage |= 1<options_block; static uschar txt[256]; uschar * expciphers; X509 * server_cert; @@ -1611,80 +1787,36 @@ static uschar cipherbuf[256]; BOOL request_ocsp = FALSE; BOOL require_ocsp = FALSE; #endif -#ifdef EXPERIMENTAL_DANE -dns_answer tlsa_dnsa; -BOOL dane = FALSE; -BOOL dane_required; -#endif #ifdef EXPERIMENTAL_DANE -/*XXX TBD: test for transport options, and for TLSA records */ -/*dane = TRUE;*/ - -# ifdef notyet -dane_required = verify_check_this_host(&ob->hosts_require_dane, NULL, - host->name, host->address, NULL) == OK; -# else -dane_required = FALSE; +tls_out.tlsa_usage = 0; #endif -if (host->dnssec == DS_YES) +#ifndef DISABLE_OCSP { - if( dane_required - || verify_check_this_host(&ob->hosts_try_dane, NULL, - host->name, host->address, NULL) == OK - ) +# ifdef EXPERIMENTAL_DANE + if ( tlsa_dnsa + && ob->hosts_request_ocsp[0] == '*' + && ob->hosts_request_ocsp[1] == '\0' + ) { - /* move this out to host.c given the similarity to dns_lookup() ? */ - uschar buffer[300]; - int prefix_length; /* why do we want this? */ - uschar * fullname = buffer; - - /* TLSA lookup string */ - (void)sprintf(CS buffer, "_%d._tcp.%n%.256s", host->port, &prefix_length, - host->name); - - switch (rc = dns_lookup(&tlsa_dnsa, buffer, T_TLSA, &fullname)) - { - case DNS_AGAIN: - return DEFER; /* just defer this TLS'd conn */ - - default: - case DNS_FAIL: - if (dane_required) - { - /* log that TLSA lookup failed */ - return FAIL; - } - break; - - case DNS_SUCCEED: - if (!dns_is_secure(&tlsa_dnsa)) - { - /*log it - tlsa should never be non-dnssec */ - return DEFER; - } - dane = TRUE; - break; - } + /* Unchanged from default. Use a safer one under DANE */ + request_ocsp = TRUE; + ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} " + " {= {4}{$tls_out_tlsa_usage}} } " + " {*}{}}"; } - } -else if (dane_required && !dane) - { - /* log that dnssec pre-req failed. Hmm - what? */ - return FAIL; - } - -if (!dane) /*XXX todo: enable ocsp with dane */ -#endif +# endif -#ifndef DISABLE_OCSP - { - require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, - NULL, host->name, host->address, NULL) == OK; - request_ocsp = require_ocsp ? TRUE - : verify_check_this_host(&ob->hosts_request_ocsp, - NULL, host->name, host->address, NULL) == OK; + if ((require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, + NULL, host->name, host->address, NULL) == OK)) + request_ocsp = TRUE; + else +# ifdef EXPERIMENTAL_DANE + if (!request_ocsp) +# endif + request_ocsp = verify_check_this_host(&ob->hosts_request_ocsp, + NULL, host->name, host->address, NULL) == OK; } #endif @@ -1717,12 +1849,14 @@ if (expciphers != NULL) } #ifdef EXPERIMENTAL_DANE -if (dane) +if (tlsa_dnsa) { + SSL_CTX_set_verify(client_ctx, SSL_VERIFY_PEER, verify_callback_client_dane); + if (!DANESSL_library_init()) - return tls_error(US"library init", host, US"DANE library error"); + return tls_error(US"library init", host, NULL); if (DANESSL_CTX_init(client_ctx) <= 0) - return tls_error(US"context init", host, US"DANE library error"); + return tls_error(US"context init", host, NULL); } else @@ -1764,9 +1898,34 @@ if (ob->tls_sni) } } +#ifdef EXPERIMENTAL_DANE +if (tlsa_dnsa) + if ((rc = dane_tlsa_load(client_ssl, host, tlsa_dnsa)) != OK) + return rc; +#endif + #ifndef DISABLE_OCSP /* Request certificate status at connection-time. If the server does OCSP stapling we will get the callback (set in tls_init()) */ +# ifdef EXPERIMENTAL_DANE +if (request_ocsp) + { + const uschar * s; + if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) + || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage")) + ) + { /* Re-eval now $tls_out_tlsa_usage is populated. If + this means we avoid the OCSP request, we wasted the setup + cost in tls_init(). */ + require_ocsp = verify_check_this_host(&ob->hosts_require_ocsp, + NULL, host->name, host->address, NULL) == OK; + request_ocsp = require_ocsp ? TRUE + : verify_check_this_host(&ob->hosts_request_ocsp, + NULL, host->name, host->address, NULL) == OK; + } + } +# endif + if (request_ocsp) { SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp); @@ -1775,51 +1934,10 @@ if (request_ocsp) } #endif -#ifdef EXPERIMENTAL_DANE -if (dane) - { - dns_record * rr; - dns_scan dnss; - uschar * hostnames[2] = { host->name, NULL }; - - if (DANESSL_init(client_ssl, NULL, hostnames) != 1) - return tls_error(US"hostnames load", host, US"DANE library error"); - - for (rr = dns_next_rr(&tlsa_dnsa, &dnss, RESET_ANSWERS); - rr; - rr = dns_next_rr(&tlsa_dnsa, &dnss, RESET_NEXT) - ) if (rr->type == T_TLSA) - { - uschar * p = rr->data; - int usage, selector, mtype; - const char * mdname; - - GETSHORT(usage, p); - GETSHORT(selector, p); - GETSHORT(mtype, p); - - switch (mtype) - { - default: /* log bad */ return FAIL; - case 0: mdname = NULL; break; - case 1: mdname = "SHA2-256"; break; - case 2: mdname = "SHA2-512"; break; - } - - switch (DANESSL_add_tlsa(client_ssl, - (uint8_t) usage, (uint8_t) selector, - mdname, p, rr->size - (p - rr->data))) - { - default: - case 0: /* action not taken; log error */ - return FAIL; - case 1: break; - } - } - } +#ifdef EXPERIMENTAL_EVENT +client_static_cbinfo->event_action = tb->event_action; #endif - /* There doesn't seem to be a built-in timeout on connection. */ DEBUG(D_tls) debug_printf("Calling SSL_connect\n"); @@ -1829,8 +1947,8 @@ rc = SSL_connect(client_ssl); alarm(0); #ifdef EXPERIMENTAL_DANE -if (dane) - DANESSL_cleanup(client_ssl); /*XXX earliest possible callpoint. Too early? */ +if (tlsa_dnsa) + DANESSL_cleanup(client_ssl); #endif if (rc <= 0)