X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/3634fc257bd0667daef14d72005cd87c735bbb24..7be682ca5ebd9571a01b762195b11c34cd231830:/src/src/tls-openssl.c diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c index e5d12cb84..8cc2457e5 100644 --- a/src/src/tls-openssl.c +++ b/src/src/tls-openssl.c @@ -34,6 +34,7 @@ static BOOL verify_callback_called = FALSE; static const uschar *sid_ctx = US"exim"; static SSL_CTX *ctx = NULL; +static SSL_CTX *ctx_sni = NULL; static SSL *ssl = NULL; static char ssl_errstring[256]; @@ -41,8 +42,26 @@ static char ssl_errstring[256]; static int ssl_session_timeout = 200; static BOOL verify_optional = FALSE; +static BOOL reexpand_tls_files_for_sni = FALSE; +typedef struct tls_ext_ctx_cb { + uschar *certificate; + uschar *privatekey; + uschar *dhparam; + /* these are cached from first expand */ + uschar *server_cipher_list; + /* only passed down to tls_error: */ + host_item *host; +} tls_ext_ctx_cb; + +/* should figure out a cleanup of API to handle state preserved per +implementation, for various reasons, which can be void * in the APIs. +For now, we hack around it. */ +tls_ext_ctx_cb *static_cbinfo = NULL; + +static int +setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional); /************************************************* @@ -201,8 +220,8 @@ return 1; /* accept */ *************************************************/ /* The SSL library functions call this from time to time to indicate what they -are doing. We copy the string to the debugging output when the level is high -enough. +are doing. We copy the string to the debugging output when TLS debugging has +been requested. Arguments: s the SSL connection @@ -279,6 +298,145 @@ return yield; +/************************************************* +* Expand key and cert file specs * +*************************************************/ + +/* Called once during tls_init and possibly againt during TLS setup, for a +new context, if Server Name Indication was used and tls_sni was seen in +the certificate string. + +Arguments: + sctx the SSL_CTX* to update + cbinfo various parts of session state + +Returns: OK/DEFER/FAIL +*/ + +static int +tls_expand_session_files(SSL_CTX *sctx, const tls_ext_ctx_cb *cbinfo) +{ +uschar *expanded; + +if (cbinfo->certificate == NULL) + return OK; + +if (Ustrstr(cbinfo->certificate, US"tls_sni")) + reexpand_tls_files_for_sni = TRUE; + +if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded)) + return DEFER; + +if (expanded != NULL) + { + DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); + if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded)) + return tls_error(string_sprintf( + "SSL_CTX_use_certificate_chain_file file=%s", expanded), + cbinfo->host, NULL); + } + +if (cbinfo->privatekey != NULL && + !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded)) + return DEFER; + +/* If expansion was forced to fail, key_expanded will be NULL. If the result +of the expansion is an empty string, ignore it also, and assume the private +key is in the same file as the certificate. */ + +if (expanded != NULL && *expanded != 0) + { + DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); + if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM)) + return tls_error(string_sprintf( + "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL); + } + +return OK; +} + + + + +/************************************************* +* Callback to handle SNI * +*************************************************/ + +/* Called when acting as server during the TLS session setup if a Server Name +Indication extension was sent by the client. + +API documentation is OpenSSL s_server.c implementation. + +Arguments: + s SSL* of the current session + ad unknown (part of OpenSSL API) (unused) + arg Callback of "our" registered data + +Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK} +*/ + +static int +tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg); +/* pre-declared for SSL_CTX_set_tlsext_servername_callback call within func */ + +static int +tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg) +{ +const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name); +const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; +int rc; + +if (!servername) + return SSL_TLSEXT_ERR_OK; + +DEBUG(D_tls) debug_printf("TLS SNI: %s%s\n", servername, + reexpand_tls_files_for_sni ? "" : " (unused for certificate selection)"); + +/* Make the extension value available for expansion */ +tls_sni = servername; + +if (!reexpand_tls_files_for_sni) + return SSL_TLSEXT_ERR_OK; + +/* Can't find an SSL_CTX_clone() or equivalent, so we do it manually; +not confident that memcpy wouldn't break some internal reference counting. +Especially since there's a references struct member, which would be off. */ + +ctx_sni = SSL_CTX_new(SSLv23_server_method()); +if (!ctx_sni) + { + ERR_error_string(ERR_get_error(), ssl_errstring); + DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring); + return SSL_TLSEXT_ERR_NOACK; + } + +/* Not sure how many of these are actually needed, since SSL object +already exists. Might even need this selfsame callback, for reneg? */ + +SSL_CTX_set_info_callback(ctx_sni, SSL_CTX_get_info_callback(ctx)); +SSL_CTX_set_mode(ctx_sni, SSL_CTX_get_mode(ctx)); +SSL_CTX_set_options(ctx_sni, SSL_CTX_get_options(ctx)); +SSL_CTX_set_timeout(ctx_sni, SSL_CTX_get_timeout(ctx)); +SSL_CTX_set_tlsext_servername_callback(ctx_sni, tls_servername_cb); +SSL_CTX_set_tlsext_servername_arg(ctx_sni, cbinfo); +if (cbinfo->server_cipher_list) + SSL_CTX_set_cipher_list(ctx_sni, CS cbinfo->server_cipher_list); + +rc = tls_expand_session_files(ctx_sni, cbinfo); +if (rc != OK) return SSL_TLSEXT_ERR_NOACK; + +rc = setup_certs(ctx_sni, tls_verify_certificates, tls_crl, NULL, FALSE); +if (rc != OK) return SSL_TLSEXT_ERR_NOACK; + +DEBUG(D_tls) debug_printf("Switching SSL context.\n"); +SSL_set_SSL_CTX(s, ctx_sni); + +return SSL_TLSEXT_ERR_OK; +} + + + + /************************************************* * Initialize for TLS * *************************************************/ @@ -301,7 +459,15 @@ tls_init(host_item *host, uschar *dhparam, uschar *certificate, uschar *privatekey, address_item *addr) { long init_options; +int rc; BOOL okay; +tls_ext_ctx_cb *cbinfo; + +cbinfo = store_malloc(sizeof(tls_ext_ctx_cb)); +cbinfo->certificate = certificate; +cbinfo->privatekey = privatekey; +cbinfo->dhparam = dhparam; +cbinfo->host = host; SSL_load_error_strings(); /* basic set up */ OpenSSL_add_ssl_algorithms(); @@ -347,6 +513,9 @@ level. */ SSL_CTX_set_info_callback(ctx, (void (*)())info_callback); +/* Automatically re-try reads/writes after renegotiation. */ +(void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY); + /* Apply administrator-supplied work-arounds. Historically we applied just one requested option, SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS, but when bug 994 requested a second, we @@ -376,36 +545,16 @@ if (!init_dh(dhparam, host)) return DEFER; /* Set up certificate and key */ -if (certificate != NULL) - { - uschar *expanded; - if (!expand_check(certificate, US"tls_certificate", &expanded)) - return DEFER; - - if (expanded != NULL) - { - DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded); - if (!SSL_CTX_use_certificate_chain_file(ctx, CS expanded)) - return tls_error(string_sprintf( - "SSL_CTX_use_certificate_chain_file file=%s", expanded), host, NULL); - } - - if (privatekey != NULL && - !expand_check(privatekey, US"tls_privatekey", &expanded)) - return DEFER; - - /* If expansion was forced to fail, key_expanded will be NULL. If the result - of the expansion is an empty string, ignore it also, and assume the private - key is in the same file as the certificate. */ +rc = tls_expand_session_files(ctx, cbinfo); +if (rc != OK) return rc; - if (expanded != NULL && *expanded != 0) - { - DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded); - if (!SSL_CTX_use_PrivateKey_file(ctx, CS expanded, SSL_FILETYPE_PEM)) - return tls_error(string_sprintf( - "SSL_CTX_use_PrivateKey_file file=%s", expanded), host, NULL); - } - } +/* If we need to handle SNI, do so */ +#if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT) +/* We always do this, so that $tls_sni is available even if not used in +tls_certificate */ +SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb); +SSL_CTX_set_tlsext_servername_arg(ctx, cbinfo); +#endif /* Set up the RSA callback */ @@ -415,6 +564,9 @@ SSL_CTX_set_tmp_rsa_callback(ctx, rsa_callback); SSL_CTX_set_timeout(ctx, ssl_session_timeout); DEBUG(D_tls) debug_printf("Initialized TLS\n"); + +static_cbinfo = cbinfo; + return OK; } @@ -441,7 +593,6 @@ yet reflect that. It should be a safe change anyway, even 0.9.8 versions have the accessor functions use const in the prototype. */ const SSL_CIPHER *c; uschar *ver; -int bits; switch (ssl->session->ssl_version) { @@ -457,15 +608,27 @@ switch (ssl->session->ssl_version) ver = US"TLSv1"; break; +#ifdef TLS1_1_VERSION + case TLS1_1_VERSION: + ver = US"TLSv1.1"; + break; +#endif + +#ifdef TLS1_2_VERSION + case TLS1_2_VERSION: + ver = US"TLSv1.2"; + break; +#endif + default: ver = US"UNKNOWN"; } c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl); -SSL_CIPHER_get_bits(c, &bits); +SSL_CIPHER_get_bits(c, &tls_bits); string_format(cipherbuf, sizeof(cipherbuf), "%s:%s:%u", ver, - SSL_CIPHER_get_name(c), bits); + SSL_CIPHER_get_name(c), tls_bits); tls_cipher = cipherbuf; DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); @@ -482,6 +645,7 @@ DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf); /* Called by both client and server startup Arguments: + sctx SSL_CTX* to initialise certs certs file or NULL crl CRL file or NULL host NULL in a server; the remote host in a client @@ -492,7 +656,7 @@ Returns: OK/DEFER/FAIL */ static int -setup_certs(uschar *certs, uschar *crl, host_item *host, BOOL optional) +setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional) { uschar *expcerts, *expcrl; @@ -502,7 +666,7 @@ if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) if (expcerts != NULL) { struct stat statbuf; - if (!SSL_CTX_set_default_verify_paths(ctx)) + if (!SSL_CTX_set_default_verify_paths(sctx)) return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); if (Ustat(expcerts, &statbuf) < 0) @@ -525,12 +689,12 @@ if (expcerts != NULL) says no certificate was supplied.) But this is better. */ if ((file == NULL || statbuf.st_size > 0) && - !SSL_CTX_load_verify_locations(ctx, CS file, CS dir)) + !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); if (file != NULL) { - SSL_CTX_set_client_CA_list(ctx, SSL_load_client_CA_file(CS file)); + SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file)); } } @@ -562,7 +726,7 @@ if (expcerts != NULL) { /* is it a file or directory? */ uschar *file, *dir; - X509_STORE *cvstore = SSL_CTX_get_cert_store(ctx); + X509_STORE *cvstore = SSL_CTX_get_cert_store(sctx); if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR) { file = NULL; @@ -589,7 +753,7 @@ if (expcerts != NULL) /* If verification is optional, don't fail if no certificate */ - SSL_CTX_set_verify(ctx, + SSL_CTX_set_verify(sctx, SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT), verify_callback); } @@ -627,6 +791,7 @@ tls_server_start(uschar *require_ciphers, uschar *require_mac, { int rc; uschar *expciphers; +tls_ext_ctx_cb *cbinfo; /* Check for previous activation */ @@ -642,6 +807,7 @@ the error. */ rc = tls_init(NULL, tls_dhparam, tls_certificate, tls_privatekey, NULL); if (rc != OK) return rc; +cbinfo = static_cbinfo; if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) return FAIL; @@ -657,6 +823,7 @@ if (expciphers != NULL) DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers); if (!SSL_CTX_set_cipher_list(ctx, CS expciphers)) return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL); + cbinfo->server_cipher_list = expciphers; } /* If this is a host for which certificate verification is mandatory or @@ -667,13 +834,13 @@ verify_callback_called = FALSE; if (verify_check_host(&tls_verify_hosts) == OK) { - rc = setup_certs(tls_verify_certificates, tls_crl, NULL, FALSE); + rc = setup_certs(ctx, tls_verify_certificates, tls_crl, NULL, FALSE); if (rc != OK) return rc; verify_optional = FALSE; } else if (verify_check_host(&tls_try_verify_hosts) == OK) { - rc = setup_certs(tls_verify_certificates, tls_crl, NULL, TRUE); + rc = setup_certs(ctx, tls_verify_certificates, tls_crl, NULL, TRUE); if (rc != OK) return rc; verify_optional = TRUE; } @@ -681,7 +848,19 @@ else if (verify_check_host(&tls_try_verify_hosts) == OK) /* Prepare for new connection */ if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL); -SSL_clear(ssl); + +/* Warning: we used to SSL_clear(ssl) here, it was removed. + * + * With the SSL_clear(), we get strange interoperability bugs with + * OpenSSL 1.0.1b and TLS1.1/1.2. It looks as though this may be a bug in + * OpenSSL itself, as a clear should not lead to inability to follow protocols. + * + * The SSL_clear() call is to let an existing SSL* be reused, typically after + * session shutdown. In this case, we have a brand new object and there's no + * obvious reason to immediately clear it. I'm guessing that this was + * originally added because of incomplete initialisation which the clear fixed, + * in some historic release. + */ /* Set context and tell client to go ahead, except in the case of TLS startup on connection, where outputting anything now upsets the clients and tends to @@ -813,7 +992,7 @@ if (expciphers != NULL) return tls_error(US"SSL_CTX_set_cipher_list", host, NULL); } -rc = setup_certs(verify_certs, crl, host, FALSE); +rc = setup_certs(ctx, verify_certs, crl, host, FALSE); if (rc != OK) return rc; if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", host, NULL); @@ -874,8 +1053,8 @@ if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) int error; int inbytes; - DEBUG(D_tls) debug_printf("Calling SSL_read(%lx, %lx, %u)\n", (long)ssl, - (long)ssl_xfer_buffer, ssl_xfer_buffer_size); + DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, + ssl_xfer_buffer, ssl_xfer_buffer_size); if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); inbytes = SSL_read(ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size); @@ -921,6 +1100,7 @@ if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) ssl_xfer_error = 1; return EOF; } + #ifndef DISABLE_DKIM dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); #endif @@ -954,8 +1134,8 @@ tls_read(uschar *buff, size_t len) int inbytes; int error; -DEBUG(D_tls) debug_printf("Calling SSL_read(%lx, %lx, %u)\n", (long)ssl, - (long)buff, (unsigned int)len); +DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl, + buff, (unsigned int)len); inbytes = SSL_read(ssl, CS buff, len); error = SSL_get_error(ssl, inbytes); @@ -997,10 +1177,10 @@ int outbytes; int error; int left = len; -DEBUG(D_tls) debug_printf("tls_do_write(%lx, %d)\n", (long)buff, left); +DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left); while (left > 0) { - DEBUG(D_tls) debug_printf("SSL_write(SSL, %lx, %d)\n", (long)buff, left); + DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left); outbytes = SSL_write(ssl, CS buff, left); error = SSL_get_error(ssl, outbytes); DEBUG(D_tls) debug_printf("outbytes=%d error=%d\n", outbytes, error); @@ -1178,7 +1358,7 @@ all options unless explicitly for DTLS, let the administrator choose which to apply. This list is current as of: - ==> 1.0.0c <== */ + ==> 1.0.1b <== */ static struct exim_openssl_option exim_openssl_options[] = { /* KEEP SORTED ALPHABETICALLY! */ #ifdef SSL_OP_ALL @@ -1214,6 +1394,9 @@ static struct exim_openssl_option exim_openssl_options[] = { #ifdef SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG { US"netscape_reuse_cipher_change_bug", SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG }, #endif +#ifdef SSL_OP_NO_COMPRESSION + { US"no_compression", SSL_OP_NO_COMPRESSION }, +#endif #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION { US"no_session_resumption_on_renegotiation", SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION }, #endif @@ -1229,6 +1412,17 @@ static struct exim_openssl_option exim_openssl_options[] = { #ifdef SSL_OP_NO_TLSv1 { US"no_tlsv1", SSL_OP_NO_TLSv1 }, #endif +#ifdef SSL_OP_NO_TLSv1_1 +#if SSL_OP_NO_TLSv1_1 == 0x00000400L + /* Error in chosen value in 1.0.1a; see first item in CHANGES for 1.0.1b */ +#warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring +#else + { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, +#endif +#endif +#ifdef SSL_OP_NO_TLSv1_2 + { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, +#endif #ifdef SSL_OP_SINGLE_DH_USE { US"single_dh_use", SSL_OP_SINGLE_DH_USE }, #endif @@ -1254,6 +1448,7 @@ static struct exim_openssl_option exim_openssl_options[] = { static int exim_openssl_options_size = sizeof(exim_openssl_options)/sizeof(struct exim_openssl_option); + static BOOL tls_openssl_one_option_parse(uschar *name, long *value) { @@ -1302,10 +1497,8 @@ uschar keep_c; BOOL adding, item_parsed; result = 0L; -/* We grandfather in as default the one option which we used to set always. */ -#ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS -result |= SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; -#endif +/* Prior to 4.78 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed + * from default because it increases BEAST susceptibility. */ if (option_spec == NULL) {