X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/753739fdef6d9753ee4a7e89afd959a4034d2ad9..d954f4b2539fb156ff85edb45eddcfb03fa45d79:/src/src/tls-openssl.c diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c index 4636f3c32..e975eae4d 100644 --- a/src/src/tls-openssl.c +++ b/src/src/tls-openssl.c @@ -3,7 +3,7 @@ *************************************************/ /* Copyright (c) University of Cambridge 1995 - 2019 */ -/* Copyright (c) The Exim Maintainers 2020 */ +/* Copyright (c) The Exim Maintainers 2020 - 2021 */ /* See the file NOTICE for conditions of use and distribution. */ /* Portions Copyright (c) The OpenSSL Project 1999 */ @@ -48,7 +48,6 @@ functions from the OpenSSL library. */ #if OPENSSL_VERSION_NUMBER >= 0x10100000L # define EXIM_HAVE_OCSP_RESP_COUNT # define OPENSSL_AUTO_SHA256 -# define EXIM_HAVE_ALPN #else # define EXIM_HAVE_EPHEM_RSA_KEX # define EXIM_HAVE_RAND_PSEUDO @@ -81,6 +80,7 @@ change this guard and punt the issue for a while longer. */ # ifndef DISABLE_OCSP # define EXIM_HAVE_OCSP # endif +# define EXIM_HAVE_ALPN /* fail ret from hshake-cb is ignored by LibreSSL */ # else # define EXIM_NEED_OPENSSL_INIT # endif @@ -90,6 +90,10 @@ change this guard and punt the issue for a while longer. */ # endif #endif +#if LIBRESSL_VERSION_NUMBER >= 0x3040000fL +# define EXIM_HAVE_OPENSSL_CIPHER_GET_ID +#endif + #if !defined(LIBRESSL_VERSION_NUMBER) \ || LIBRESSL_VERSION_NUMBER >= 0x20010000L # if !defined(OPENSSL_NO_ECDH) @@ -228,12 +232,16 @@ static exim_openssl_option exim_openssl_options[] = { { US"no_tlsv1", SSL_OP_NO_TLSv1 }, #endif #ifdef SSL_OP_NO_TLSv1_1 -#if SSL_OP_NO_TLSv1_1 == 0x00000400L +# if OPENSSL_VERSION_NUMBER < 0x30000000L +# 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 +# warning OpenSSL 1.0.1a uses a bad value for SSL_OP_NO_TLSv1_1, ignoring +# define NO_SSL_OP_NO_TLSv1_1 +# endif +# endif +# ifndef NO_SSL_OP_NO_TLSv1_1 { US"no_tlsv1_1", SSL_OP_NO_TLSv1_1 }, -#endif +# endif #endif #ifdef SSL_OP_NO_TLSv1_2 { US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 }, @@ -307,6 +315,9 @@ builtin_macro_create(US"_TLS_BAD_MULTICERT_IN_OURCERT"); builtin_macro_create(US"_HAVE_TLS_OCSP"); builtin_macro_create(US"_HAVE_TLS_OCSP_LIST"); # endif +# ifdef EXIM_HAVE_ALPN +builtin_macro_create(US"_HAVE_TLS_ALPN"); +# endif } #else @@ -359,6 +370,9 @@ typedef struct { #ifdef EXIM_HAVE_OPENSSL_TLSEXT static SSL_CTX *server_sni = NULL; #endif +#ifdef EXIM_HAVE_ALPN +static BOOL server_seen_alpn = FALSE; +#endif static char ssl_errstring[256]; @@ -535,23 +549,27 @@ EVP_add_digest(EVP_sha256()); *************************************************/ /* If dhparam is set, expand it, and load up the parameters for DH encryption. +Server only. Arguments: sctx The current SSL CTX (inbound or outbound) dhparam DH parameter file or fixed parameter identity string - host connected host, if client; NULL if server errstr error string pointer Returns: TRUE if OK (nothing to set up, or setup worked) */ static BOOL -init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host, uschar ** errstr) +init_dh(SSL_CTX * sctx, uschar * dhparam, uschar ** errstr) { -BIO *bio; -DH *dh; -uschar *dhexpanded; -const char *pem; +BIO * bio; +#if OPENSSL_VERSION_NUMBER < 0x30000000L +DH * dh; +#else +EVP_PKEY * pkey; +#endif +uschar * dhexpanded; +const char * pem; int dh_bitsize; if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded, errstr)) @@ -564,7 +582,7 @@ else if (dhexpanded[0] == '/') if (!(bio = BIO_new_file(CS dhexpanded, "r"))) { tls_error(string_sprintf("could not read dhparams file %s", dhexpanded), - host, US strerror(errno), errstr); + NULL, US strerror(errno), errstr); return FALSE; } } @@ -579,53 +597,80 @@ else if (!(pem = std_dh_prime_named(dhexpanded))) { tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded), - host, US strerror(errno), errstr); + NULL, US strerror(errno), errstr); return FALSE; } bio = BIO_new_mem_buf(CS pem, -1); } -if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL))) +if (!( +#if OPENSSL_VERSION_NUMBER < 0x30000000L + dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL) +#else + pkey = PEM_read_bio_Parameters_ex(bio, NULL, NULL, NULL) +#endif + ) ) { BIO_free(bio); tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded), - host, NULL, errstr); + NULL, NULL, errstr); return FALSE; } /* note: our default limit of 2236 is not a multiple of 8; the limit comes from - * an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with - * 2236. But older OpenSSL can only report in bytes (octets), not bits. - * If someone wants to dance at the edge, then they can raise the limit or use - * current libraries. */ -#ifdef EXIM_HAVE_OPENSSL_DH_BITS +an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with 2236. +But older OpenSSL can only report in bytes (octets), not bits. If someone wants +to dance at the edge, then they can raise the limit or use current libraries. */ + +#if OPENSSL_VERSION_NUMBER < 0x30000000L +# ifdef EXIM_HAVE_OPENSSL_DH_BITS /* Added in commit 26c79d5641d; `git describe --contains` says OpenSSL_1_1_0-pre1~1022 - * This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */ +This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */ dh_bitsize = DH_bits(dh); -#else +# else dh_bitsize = 8 * DH_size(dh); +# endif +#else /* 3.0.0 + */ +dh_bitsize = EVP_PKEY_get_bits(pkey); #endif -/* Even if it is larger, we silently return success rather than cause things - * to fail out, so that a too-large DH will not knock out all TLS; it's a - * debatable choice. */ -if (dh_bitsize > tls_dh_max_bits) +/* Even if it is larger, we silently return success rather than cause things to +fail out, so that a too-large DH will not knock out all TLS; it's a debatable +choice. Likewise for a failing attempt to set one. */ + +if (dh_bitsize <= tls_dh_max_bits) { - DEBUG(D_tls) - debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n", - dh_bitsize, tls_dh_max_bits); + if ( +#if OPENSSL_VERSION_NUMBER < 0x30000000L + SSL_CTX_set_tmp_dh(sctx, dh) +#else + SSL_CTX_set0_tmp_dh_pkey(sctx, pkey) +#endif + == 0) + { + ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); + log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (D-H param setting '%s'): %s", + dhexpanded ? dhexpanded : US"default", ssl_errstring); +#if OPENSSL_VERSION_NUMBER >= 0x30000000L + /* EVP_PKEY_free(pkey); crashes */ +#endif + } + else + DEBUG(D_tls) + debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", + dhexpanded ? dhexpanded : US"default", dh_bitsize); } else - { - SSL_CTX_set_tmp_dh(sctx, dh); DEBUG(D_tls) - debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n", - dhexpanded ? dhexpanded : US"default", dh_bitsize); - } + debug_printf("dhparams '%s' %d bits, is > tls_dh_max_bits limit of %d\n", + dhexpanded ? dhexpanded : US"default", dh_bitsize, tls_dh_max_bits); +#if OPENSSL_VERSION_NUMBER < 0x30000000L DH_free(dh); -BIO_free(bio); +#endif +/* The EVP_PKEY ownership stays with the ctx; do not free it */ +BIO_free(bio); return TRUE; } @@ -636,7 +681,7 @@ return TRUE; * Initialize for ECDH * *************************************************/ -/* Load parameters for ECDH encryption. +/* Load parameters for ECDH encryption. Server only. For now, we stick to NIST P-256 because: it's simple and easy to configure; it avoids any patent issues that might bite redistributors; despite events in @@ -654,27 +699,22 @@ Patches welcome. Arguments: sctx The current SSL CTX (inbound or outbound) - host connected host, if client; NULL if server errstr error string pointer Returns: TRUE if OK (nothing to set up, or setup worked) */ static BOOL -init_ecdh(SSL_CTX * sctx, host_item * host, uschar ** errstr) +init_ecdh(SSL_CTX * sctx, uschar ** errstr) { #ifdef OPENSSL_NO_ECDH return TRUE; #else -EC_KEY * ecdh; uschar * exp_curve; int nid; BOOL rv; -if (host) /* No ECDH setup for clients, only for servers */ - return TRUE; - # ifndef EXIM_HAVE_ECDH DEBUG(D_tls) debug_printf("No OpenSSL API to define ECDH parameters, skipping\n"); @@ -721,25 +761,38 @@ if ( (nid = OBJ_sn2nid (CCS exp_curve)) == NID_undef ) { tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve), - host, NULL, errstr); + NULL, NULL, errstr); return FALSE; } -if (!(ecdh = EC_KEY_new_by_curve_name(nid))) - { - tls_error(US"Unable to create ec curve", host, NULL, errstr); - return FALSE; - } +# if OPENSSL_VERSION_NUMBER < 0x30000000L + { + EC_KEY * ecdh; + if (!(ecdh = EC_KEY_new_by_curve_name(nid))) + { + tls_error(US"Unable to create ec curve", NULL, NULL, errstr); + return FALSE; + } -/* The "tmp" in the name here refers to setting a temporary key -not to the stability of the interface. */ + /* The "tmp" in the name here refers to setting a temporary key + not to the stability of the interface. */ + + if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0)) + tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), NULL, NULL, errstr); + else + DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve); + EC_KEY_free(ecdh); + } -if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0)) - tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL, errstr); +#else /* v 3.0.0 + */ + +if ((rv = SSL_CTX_set1_groups(sctx, &nid, 1)) == 0) + tls_error(string_sprintf("Error enabling '%s' group", exp_curve), NULL, NULL, errstr); else - DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve); + DEBUG(D_tls) debug_printf("ECDH: enabled '%s' group\n", exp_curve); + +#endif -EC_KEY_free(ecdh); return !rv; # endif /*EXIM_HAVE_ECDH*/ @@ -752,6 +805,7 @@ return !rv; * Expand key and cert file specs * *************************************************/ +#if OPENSSL_VERSION_NUMBER < 0x30000000L /* Arguments: s SSL connection (not used) @@ -771,14 +825,14 @@ BIGNUM *bn = BN_new(); DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength); -#ifdef EXIM_HAVE_RSA_GENKEY_EX +# ifdef EXIM_HAVE_RSA_GENKEY_EX if ( !BN_set_word(bn, (unsigned long)RSA_F4) || !(rsa_key = RSA_new()) || !RSA_generate_key_ex(rsa_key, keylength, bn, NULL) ) -#else +# else if (!(rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL))) -#endif +# endif { ERR_error_string_n(ERR_get_error(), ssl_errstring, sizeof(ssl_errstring)); @@ -788,6 +842,7 @@ if (!(rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL))) } return rsa_key; } +#endif /* pre-3.0.0 */ @@ -801,7 +856,6 @@ tls_install_selfsign(SSL_CTX * sctx, uschar ** errstr) { X509 * x509 = NULL; EVP_PKEY * pkey; -RSA * rsa; X509_NAME * name; uschar * where; @@ -815,12 +869,19 @@ if (!(x509 = X509_new())) goto err; where = US"generating pkey"; -if (!(rsa = rsa_callback(NULL, 0, 2048))) - goto err; +#if OPENSSL_VERSION_NUMBER < 0x30000000L + { + RSA * rsa; + if (!(rsa = rsa_callback(NULL, 0, 2048))) + goto err; -where = US"assigning pkey"; -if (!EVP_PKEY_assign_RSA(pkey, rsa)) - goto err; + where = US"assigning pkey"; + if (!EVP_PKEY_assign_RSA(pkey, rsa)) + goto err; + } +#else +pkey = EVP_RSA_gen(2048); +#endif X509_set_version(x509, 2); /* N+1 - version 3 */ ASN1_INTEGER_set(X509_get_serialNumber(x509), 1); @@ -1648,15 +1709,19 @@ state_server.lib_state.lib_ctx = ctx; if (opt_unset_or_noexpand(tls_dhparam)) { DEBUG(D_tls) debug_printf("TLS: preloading DH params for server\n"); - if (init_dh(ctx, tls_dhparam, NULL, &dummy_errstr)) + if (init_dh(ctx, tls_dhparam, &dummy_errstr)) state_server.lib_state.dh = TRUE; } +else + DEBUG(D_tls) debug_printf("TLS: not preloading DH params for server\n"); if (opt_unset_or_noexpand(tls_eccurve)) { DEBUG(D_tls) debug_printf("TLS: preloading ECDH curve for server\n"); - if (init_ecdh(ctx, NULL, &dummy_errstr)) + if (init_ecdh(ctx, &dummy_errstr)) state_server.lib_state.ecdh = TRUE; } +else + DEBUG(D_tls) debug_printf("TLS: not preloading ECDH curve for server\n"); #if defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT) /* If we can, preload the server-side cert, key and ocsp */ @@ -1768,19 +1833,6 @@ ob->tls_preload.lib_ctx = ctx; tpt_dummy_state.lib_state = ob->tls_preload; -if (opt_unset_or_noexpand(tls_dhparam)) - { - DEBUG(D_tls) debug_printf("TLS: preloading DH params for transport '%s'\n", t->name); - if (init_dh(ctx, tls_dhparam, NULL, &dummy_errstr)) - ob->tls_preload.dh = TRUE; - } -if (opt_unset_or_noexpand(tls_eccurve)) - { - DEBUG(D_tls) debug_printf("TLS: preloading ECDH curve for transport '%s'\n", t->name); - if (init_ecdh(ctx, NULL, &dummy_errstr)) - ob->tls_preload.ecdh = TRUE; - } - #if defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT) if ( opt_set_and_noexpand(ob->tls_certificate) && opt_unset_or_noexpand(ob->tls_privatekey)) @@ -1901,7 +1953,11 @@ typedef struct { /* Session ticket encryption key */ const EVP_CIPHER * aes_cipher; uschar aes_key[32]; /* size needed depends on cipher. aes_128 implies 128/8 = 16? */ +# if OPENSSL_VERSION_NUMBER < 0x30000000L const EVP_MD * hmac_hash; +# else + const uschar * hmac_hashname; +# endif uschar hmac_key[16]; time_t renew; time_t expire; @@ -1930,7 +1986,11 @@ if (RAND_bytes(exim_tk.name+1, sizeof(exim_tk.name)-1) <= 0) return; exim_tk.name[0] = 'E'; exim_tk.aes_cipher = EVP_aes_256_cbc(); +# if OPENSSL_VERSION_NUMBER < 0x30000000L exim_tk.hmac_hash = EVP_sha256(); +# else +exim_tk.hmac_hashname = US "sha256"; +# endif exim_tk.expire = t + ssl_session_timeout; exim_tk.renew = t + ssl_session_timeout/2; } @@ -1950,10 +2010,49 @@ return memcmp(name, exim_tk.name, sizeof(exim_tk.name)) == 0 ? &exim_tk : NULL; } + +static int +tk_hmac_init( +# if OPENSSL_VERSION_NUMBER < 0x30000000L + HMAC_CTX * hctx, +#else + EVP_MAC_CTX * hctx, +#endif + exim_stek * key + ) +{ +/*XXX will want these dependent on the ssl session strength */ +# if OPENSSL_VERSION_NUMBER < 0x30000000L + HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key), + key->hmac_hash, NULL); +#else + { + OSSL_PARAM params[3]; + uschar * hk = string_copy(key->hmac_hashname); /* need nonconst */ + params[0] = OSSL_PARAM_construct_octet_string("key", key->hmac_key, sizeof(key->hmac_key)); + params[1] = OSSL_PARAM_construct_utf8_string("digest", CS hk, 0); + params[2] = OSSL_PARAM_construct_end(); + if (EVP_MAC_CTX_set_params(hctx, params) == 0) + { + DEBUG(D_tls) debug_printf("EVP_MAC_CTX_set_params: %s\n", + ERR_reason_error_string(ERR_get_error())); + return 0; /* error in mac initialisation */ + } +} +#endif +return 1; +} + /* Callback for session tickets, on server */ static int ticket_key_callback(SSL * ssl, uschar key_name[16], - uschar * iv, EVP_CIPHER_CTX * c_ctx, HMAC_CTX * hctx, int enc) + uschar * iv, EVP_CIPHER_CTX * c_ctx, +# if OPENSSL_VERSION_NUMBER < 0x30000000L + HMAC_CTX * hctx, +#else + EVP_MAC_CTX * hctx, +#endif + int enc) { tls_support * tlsp = state_server.tlsp; exim_stek * key; @@ -1971,9 +2070,7 @@ if (enc) memcpy(key_name, key->name, 16); DEBUG(D_tls) debug_printf("STEK expire " TIME_T_FMT "\n", key->expire - time(NULL)); - /*XXX will want these dependent on the ssl session strength */ - HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key), - key->hmac_hash, NULL); + if (tk_hmac_init(hctx, key) == 0) return 0; EVP_EncryptInit_ex(c_ctx, key->aes_cipher, NULL, key->aes_key, iv); DEBUG(D_tls) debug_printf("ticket created\n"); @@ -1996,8 +2093,7 @@ else return 0; } - HMAC_Init_ex(hctx, key->hmac_key, sizeof(key->hmac_key), - key->hmac_hash, NULL); + if (tk_hmac_init(hctx, key) == 0) return 0; EVP_DecryptInit_ex(c_ctx, key->aes_cipher, NULL, key->aes_key, iv); DEBUG(D_tls) debug_printf("ticket usable, STEK expire " TIME_T_FMT "\n", key->expire - now); @@ -2010,7 +2106,7 @@ else return key->renew < now ? 2 : 1; } } -#endif +#endif /* !DISABLE_TLS_RESUME */ @@ -2090,8 +2186,8 @@ already exists. Might even need this selfsame callback, for reneg? */ SSL_CTX_set_tlsext_servername_arg(server_sni, state); } -if ( !init_dh(server_sni, state->dhparam, NULL, &dummy_errstr) - || !init_ecdh(server_sni, NULL, &dummy_errstr) +if ( !init_dh(server_sni, state->dhparam, &dummy_errstr) + || !init_ecdh(server_sni, &dummy_errstr) ) goto bad; @@ -2140,16 +2236,15 @@ bad: return SSL_TLSEXT_ERR_ALERT_FATAL; * Callback to handle ALPN * *************************************************/ -/* SSL_CTX_set_alpn_select_cb() */ -/* Called on server when client offers ALPN, after the SNI callback. -If set and not e?smtp then we dump the connection */ +/* Called on server if tls_alpn nonblank after expansion, +when client offers ALPN, after the SNI callback. +If set and not matching the list then we dump the connection */ static int tls_server_alpn_cb(SSL *ssl, const uschar ** out, uschar * outlen, const uschar * in, unsigned int inlen, void * arg) { -const exim_openssl_state_st * state = arg; - +server_seen_alpn = TRUE; DEBUG(D_tls) { debug_printf("Received TLS ALPN offer:"); @@ -2159,23 +2254,32 @@ DEBUG(D_tls) if (pos + 1 + siz > inlen) siz = inlen - pos - 1; debug_printf(" '%.*s'", siz, in + pos + 1); } - debug_printf("\n"); + debug_printf(". Our list: '%s'\n", tls_alpn); } /* Look for an acceptable ALPN */ + if ( inlen > 1 /* at least one name */ && in[0]+1 == inlen /* filling the vector, so exactly one name */ - && ( Ustrncmp(in+1, "smtp", in[0]) == 0 - || Ustrncmp(in+1, "esmtp", in[0]) == 0 - ) ) + ) { - *out = in; /* we checked for exactly one, so can just point to it */ - *outlen = inlen; - return SSL_TLSEXT_ERR_OK; /* use ALPN */ + const uschar * list = tls_alpn; + int sep = 0; + for (uschar * name; name = string_nextinlist(&list, &sep, NULL, 0); ) + if (Ustrncmp(in+1, name, in[0]) == 0) + { + *out = in+1; /* we checked for exactly one, so can just point to it */ + *outlen = inlen; + return SSL_TLSEXT_ERR_OK; /* use ALPN */ + } } -/* Reject unacceptable ALPN */ -/* This will be fatal to the TLS conn; would be nice to kill TCP also */ +/* More than one name from clilent, or name did not match our list. */ + +/* This will be fatal to the TLS conn; would be nice to kill TCP also. +Maybe as an option in future; for now leave control to the config (must-tls). */ + +DEBUG(D_tls) debug_printf("TLS ALPN rejected\n"); return SSL_TLSEXT_ERR_ALERT_FATAL; } #endif /* EXIM_HAVE_ALPN */ @@ -2217,9 +2321,6 @@ if (!olist) const X509 * cert_sent = SSL_get_certificate(s); const ASN1_INTEGER * cert_serial = X509_get0_serialNumber(cert_sent); const BIGNUM * cert_bn = ASN1_INTEGER_to_BN(cert_serial, NULL); - const X509_NAME * cert_issuer = X509_get_issuer_name(cert_sent); - uschar * chash; - uint chash_len; for (; olist; olist = olist->next) { @@ -2591,15 +2692,18 @@ will never be used because we use a new context every time. */ /* Initialize with DH parameters if supplied */ /* Initialize ECDH temp key parameter selection */ -if (state->lib_state.dh) - { DEBUG(D_tls) debug_printf("TLS: DH params were preloaded\n"); } -else - if (!init_dh(ctx, state->dhparam, host, errstr)) return DEFER; +if (!host) + { + if (state->lib_state.dh) + { DEBUG(D_tls) debug_printf("TLS: DH params were preloaded\n"); } + else + if (!init_dh(ctx, state->dhparam, errstr)) return DEFER; -if (state->lib_state.ecdh) - { DEBUG(D_tls) debug_printf("TLS: ECDH curve was preloaded\n"); } -else - if (!init_ecdh(ctx, host, errstr)) return DEFER; + if (state->lib_state.ecdh) + { DEBUG(D_tls) debug_printf("TLS: ECDH curve was preloaded\n"); } + else + if (!init_ecdh(ctx, errstr)) return DEFER; + } /* Set up certificate and key (and perhaps OCSP info) */ @@ -2649,8 +2753,20 @@ if (!host) /* server */ tls_certificate */ SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb); SSL_CTX_set_tlsext_servername_arg(ctx, state); + # ifdef EXIM_HAVE_ALPN - SSL_CTX_set_alpn_select_cb(ctx, tls_server_alpn_cb, state); + if (tls_alpn && *tls_alpn) + { + uschar * exp_alpn; + if ( expand_check(tls_alpn, US"tls_alpn", &exp_alpn, errstr) + && *exp_alpn && !isblank(*exp_alpn)) + { + tls_alpn = exp_alpn; /* subprocess so ok to overwrite */ + SSL_CTX_set_alpn_select_cb(ctx, tls_server_alpn_cb, state); + } + else + tls_alpn = NULL; + } # endif } # ifndef DISABLE_OCSP @@ -2812,7 +2928,6 @@ chain_from_pem_file(const uschar * file, STACK_OF(X509) ** vp) { BIO * bp; STACK_OF(X509) * verify_stack = *vp; -X509 * x; if (verify_stack) while (sk_X509_num(verify_stack) > 0) @@ -3084,7 +3199,7 @@ else if (verify_check_host(&tls_try_verify_hosts) == OK) else goto skip_certs; - { + { uschar * expcerts; if (!expand_check(tls_verify_certificates, US"tls_verify_certificates", &expcerts, errstr)) @@ -3099,13 +3214,19 @@ else if (expcerts && *expcerts) setup_cert_verify(ctx, server_verify_optional, verify_callback_server); - } + } skip_certs: ; #ifndef DISABLE_TLS_RESUME +# if OPENSSL_VERSION_NUMBER < 0x30000000L SSL_CTX_set_tlsext_ticket_key_cb(ctx, ticket_key_callback); /* despite working, appears to always return failure, so ignoring */ +# else +SSL_CTX_set_tlsext_ticket_key_evp_cb(ctx, ticket_key_callback); +/* despite working, appears to always return failure, so ignoring */ +# endif #endif + #ifdef OPENSSL_HAVE_NUM_TICKETS # ifndef DISABLE_TLS_RESUME SSL_CTX_set_num_tickets(ctx, tls_in.host_resumable ? 1 : 0); @@ -3226,6 +3347,33 @@ if (SSL_session_reused(ssl)) } #endif +#ifdef EXIM_HAVE_ALPN +/* If require-alpn, check server_seen_alpn here. Else abort TLS */ +if (!tls_alpn || !*tls_alpn) + { DEBUG(D_tls) debug_printf("TLS: was not watching for ALPN\n"); } +else if (!server_seen_alpn) + if (verify_check_host(&hosts_require_alpn) == OK) + { + /* We'd like to send a definitive Alert but OpenSSL provides no facility */ + SSL_shutdown(ssl); + tls_error(US"handshake", NULL, US"ALPN required but not negotiated", errstr); + return FAIL; + } + else + { DEBUG(D_tls) debug_printf("TLS: no ALPN presented in handshake\n"); } +else DEBUG(D_tls) + { + const uschar * name; + unsigned len; + SSL_get0_alpn_selected(ssl, &name, &len); + if (len && name) + debug_printf("ALPN negotiated: '%.*s'\n", (int)*name, name+1); + else + debug_printf("ALPN: no protocol negotiated\n"); + } +#endif + + /* TLS has been set up. Record data for the connection, adjust the input functions to read via TLS, and initialize things. */ @@ -3294,10 +3442,10 @@ ssl_xfer_eof = ssl_xfer_error = FALSE; receive_getc = tls_getc; receive_getbuf = tls_getbuf; receive_get_cache = tls_get_cache; +receive_hasc = tls_hasc; receive_ungetc = tls_ungetc; receive_feof = tls_feof; receive_ferror = tls_ferror; -receive_smtp_buffered = tls_smtp_buffered; tls_in.active.sock = fileno(smtp_out); tls_in.active.tls_ctx = NULL; /* not using explicit ctx for server-side */ @@ -3333,7 +3481,7 @@ else if (verify_check_given_host(CUSS &ob->tls_try_verify_hosts, host) == OK) else return OK; - { + { uschar * expcerts; if (!expand_check(ob->tls_verify_certificates, US"tls_verify_certificates", &expcerts, errstr)) @@ -3348,7 +3496,7 @@ else if (expcerts && *expcerts) setup_cert_verify(ctx, client_verify_optional, verify_callback_client); - } + } if (verify_check_given_host(CUSS &ob->tls_verify_cert_hostnames, host) == OK) { @@ -3593,6 +3741,47 @@ if (SSL_session_reused(exim_client_ctx->ssl)) #endif /* !DISABLE_TLS_RESUME */ +#ifdef EXIM_HAVE_ALPN +/* Expand and convert an Exim list to an ALPN list. False return for fail. +NULL plist return for silent no-ALPN. +*/ + +static BOOL +tls_alpn_plist(const uschar * tls_alpn, const uschar ** plist, unsigned * plen, + uschar ** errstr) +{ +uschar * exp_alpn; + +if (!expand_check(tls_alpn, US"tls_alpn", &exp_alpn, errstr)) + return FALSE; + +if (!exp_alpn) + { + DEBUG(D_tls) debug_printf("Setting TLS ALPN forced to fail, not sending\n"); + *plist = NULL; + } +else + { + /* The server implementation only accepts exactly one protocol name + but it's little extra code complexity in the client. */ + + const uschar * list = exp_alpn; + uschar * p = store_get(Ustrlen(exp_alpn), is_tainted(exp_alpn)), * s, * t; + int sep = 0; + uschar len; + + for (t = p; s = string_nextinlist(&list, &sep, NULL, 0); t += len) + { + *t++ = len = (uschar) Ustrlen(s); + memcpy(t, s, len); + } + *plist = (*plen = t - p) ? p : NULL; + } +return TRUE; +} +#endif /* EXIM_HAVE_ALPN */ + + /************************************************* * Start a TLS session in a client * *************************************************/ @@ -3778,6 +3967,28 @@ if (ob->tls_sni) } } +if (ob->tls_alpn) +#ifdef EXIM_HAVE_ALPN + { + const uschar * plist; + unsigned plen; + + if (!tls_alpn_plist(ob->tls_alpn, &plist, &plen, errstr)) + return FALSE; + if (plist) + if (SSL_set_alpn_protos(exim_client_ctx->ssl, plist, plen) != 0) + { + tls_error(US"alpn init", host, NULL, errstr); + return FALSE; + } + else + DEBUG(D_tls) debug_printf("Setting TLS ALPN '%s'\n", ob->tls_alpn); + } +#else + log_write(0, LOG_MAIN, "ALPN unusable with this OpenSSL library version; ignoring \"%s\"\n", + ob->tls_alpn); +#endif + #ifdef SUPPORT_DANE if (conn_args->dane) if (dane_tlsa_load(exim_client_ctx->ssl, host, &conn_args->tlsa_dnsa, errstr) != OK) @@ -3857,6 +4068,24 @@ DEBUG(D_tls) tls_client_resume_posthandshake(exim_client_ctx, tlsp); #endif +#ifdef EXIM_HAVE_ALPN +if (ob->tls_alpn) /* We requested. See what was negotiated. */ + { + const uschar * name; + unsigned len; + + SSL_get0_alpn_selected(exim_client_ctx->ssl, &name, &len); + if (len > 0) + { DEBUG(D_tls) debug_printf("ALPN negotiated %u: '%.*s'\n", len, (int)*name, name+1); } + else if (verify_check_given_host(CUSS &ob->hosts_require_alpn, host) == OK) + { + /* Would like to send a relevant fatal Alert, but OpenSSL has no API */ + tls_error(US"handshake", host, US"ALPN required but not negotiated", errstr); + return FALSE; + } + } +#endif + #ifdef SSL_get_extms_support tlsp->ext_master_secret = SSL_get_extms_support(exim_client_ctx->ssl) == 1; #endif @@ -3989,6 +4218,12 @@ if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; } +BOOL +tls_hasc(void) +{ +return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm; +} + uschar * tls_getbuf(unsigned * len) { @@ -4013,10 +4248,13 @@ return buf; void -tls_get_cache(void) +tls_get_cache(unsigned lim) { #ifndef DISABLE_DKIM int n = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm; +debug_printf("tls_get_cache\n"); +if (n > lim) + n = lim; if (n > 0) dkim_exim_verify_feed(ssl_xfer_buffer+ssl_xfer_buffer_lwm, n); #endif @@ -4024,7 +4262,7 @@ if (n > 0) BOOL -tls_could_read(void) +tls_could_getc(void) { return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm || SSL_pending(state_server.lib_state.lib_ssl) > 0; @@ -4275,10 +4513,10 @@ if (!o_ctx) /* server side */ receive_getc = smtp_getc; receive_getbuf = smtp_getbuf; receive_get_cache = smtp_get_cache; + receive_hasc = smtp_hasc; receive_ungetc = smtp_ungetc; receive_feof = smtp_feof; receive_ferror = smtp_ferror; - receive_smtp_buffered = smtp_buffered; tls_in.active.tls_ctx = NULL; tls_in.sni = NULL; /* Leave bits, peercert, cipher, peerdn, certificate_verified set, for logging */