From: Jeremy Harris Date: Sun, 29 Sep 2019 13:16:36 +0000 (+0100) Subject: OpenSSL: support OCSP stapling on multi-cert servers X-Git-Url: https://git.exim.org/users/jgh/exim.git/commitdiff_plain/5b2fd993eadb7b476e5ef14028c7db09fda6c3ae?ds=inline;hp=d896cef5f6f3ff1b7509fd832a4ee66403a7c57f OpenSSL: support OCSP stapling on multi-cert servers --- diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index d7e8fe0c4..9833f19e4 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -17832,7 +17832,10 @@ Certificate Authority. Usable for GnuTLS 3.4.4 or 3.3.17 or OpenSSL 1.1.0 (or later). -For GnuTLS 3.5.6 or later the expanded value of this option can be a list +.new +For OpenSSL, and +.wen +for GnuTLS 3.5.6 or later the expanded value of this option can be a list of files, to match a list given for the &%tls_certificate%& option. The ordering of the two lists must match. diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index a1534c550..aa05e67d5 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -37,6 +37,8 @@ Version 4.93 12. Under GnuTLS, with TLS1.3, support for full-chain OCSP stapling. +13. Dual-certificate stacks on servers now support OCSP stapling, under OpenSSL. + Version 4.92 -------------- diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c index a1dee6dd0..057a0e006 100644 --- a/src/src/tls-openssl.c +++ b/src/src/tls-openssl.c @@ -325,6 +325,11 @@ static BOOL server_verify_optional = FALSE; static BOOL reexpand_tls_files_for_sni = FALSE; +typedef struct ocsp_resp { + struct ocsp_resp * next; + OCSP_RESPONSE * resp; +} ocsp_resplist; + typedef struct tls_ext_ctx_cb { tls_support * tlsp; uschar *certificate; @@ -335,8 +340,8 @@ typedef struct tls_ext_ctx_cb { union { struct { uschar *file; - uschar *file_expanded; - OCSP_RESPONSE *response; + const uschar *file_expanded; + ocsp_resplist *olist; } server; struct { X509_STORE *verify_store; /* non-null if status requested */ @@ -1192,12 +1197,13 @@ ASSUMES: single response, for single cert. Arguments: sctx the SSL_CTX* to update cbinfo various parts of session state - expanded the filename putatively holding an OCSP response + filename the filename putatively holding an OCSP response */ static void -ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded) +ocsp_load_response(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, + const uschar * filename) { BIO * bio; OCSP_RESPONSE * resp; @@ -1208,17 +1214,12 @@ STACK_OF(X509) * sk; unsigned long verify_flags; int status, reason, i; -cbinfo->u_ocsp.server.file_expanded = string_copy(expanded); -if (cbinfo->u_ocsp.server.response) - { - OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response); - cbinfo->u_ocsp.server.response = NULL; - } +DEBUG(D_tls) debug_printf("tls_ocsp_file '%s'\n", filename); -if (!(bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb"))) +if (!(bio = BIO_new_file(CS filename, "rb"))) { DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n", - cbinfo->u_ocsp.server.file_expanded); + filename); return; } @@ -1237,6 +1238,14 @@ if ((status = OCSP_response_status(resp)) != OCSP_RESPONSE_STATUS_SUCCESSFUL) goto bad; } +#ifdef notdef + { + BIO * bp = BIO_new_fp(debug_file, BIO_NOCLOSE); + OCSP_RESPONSE_print(bp, resp, 0); /* extreme debug: stapling content */ + BIO_free(bp); + } +#endif + if (!(basic_response = OCSP_response_get1_basic(resp))) { DEBUG(D_tls) @@ -1290,7 +1299,10 @@ proves false, we need to extract a cert id from our issued cert (tls_certificate) and use that for OCSP_resp_find_status() (which finds the right cert in the stack and then calls OCSP_single_get0_status()). -I'm hoping to avoid reworking a bunch more of how we handle state here. */ +I'm hoping to avoid reworking a bunch more of how we handle state here. + +XXX that will change when we add support for (TLS1.3) whole-chain stapling +*/ if (!(single_response = OCSP_resp_get0(basic_response, 0))) { @@ -1315,8 +1327,15 @@ if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX } supply_response: - /*XXX stack? (these tag points are for multiple leaf-cert support for ocsp */ - cbinfo->u_ocsp.server.response = resp; + /* Add the resp to the list used by tls_server_stapling_cb() */ + { + ocsp_resplist ** op = &cbinfo->u_ocsp.server.olist, * oentry; + while (oentry = *op) + op = &oentry->next; + *op = oentry = store_get(sizeof(ocsp_resplist), FALSE); + oentry->next = NULL; + oentry->resp = resp; + } return; bad: @@ -1332,6 +1351,16 @@ bad: } return; } + + +static void +ocsp_free_response_list(tls_ext_ctx_cb * cbinfo) +{ +for (ocsp_resplist * olist = cbinfo->u_ocsp.server.olist; olist; + olist = olist->next) + OCSP_RESPONSE_free(olist->resp); +cbinfo->u_ocsp.server.olist = NULL; +} #endif /*!DISABLE_OCSP*/ @@ -1407,7 +1436,7 @@ static int tls_add_certfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file, uschar ** errstr) { -DEBUG(D_tls) debug_printf("tls_certificate file %s\n", file); +DEBUG(D_tls) debug_printf("tls_certificate file '%s'\n", file); if (!SSL_CTX_use_certificate_chain_file(sctx, CS file)) return tls_error(string_sprintf( "SSL_CTX_use_certificate_chain_file file=%s", file), @@ -1419,7 +1448,7 @@ static int tls_add_pkeyfile(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar * file, uschar ** errstr) { -DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", file); +DEBUG(D_tls) debug_printf("tls_privatekey file '%s'\n", file); if (!SSL_CTX_use_PrivateKey_file(sctx, CS file, SSL_FILETYPE_PEM)) return tls_error(string_sprintf( "SSL_CTX_use_PrivateKey_file file=%s", file), cbinfo->host, NULL, errstr); @@ -1444,10 +1473,10 @@ Returns: OK/DEFER/FAIL */ static int -tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, +tls_expand_session_files(SSL_CTX * sctx, tls_ext_ctx_cb * cbinfo, uschar ** errstr) { -uschar *expanded; +uschar * expanded; if (!cbinfo->certificate) { @@ -1461,10 +1490,11 @@ else { int err; - if (Ustrstr(cbinfo->certificate, US"tls_sni") || - Ustrstr(cbinfo->certificate, US"tls_in_sni") || - Ustrstr(cbinfo->certificate, US"tls_out_sni") - ) + if ( !reexpand_tls_files_for_sni + && ( Ustrstr(cbinfo->certificate, US"tls_sni") + || Ustrstr(cbinfo->certificate, US"tls_in_sni") + || Ustrstr(cbinfo->certificate, US"tls_out_sni") + ) ) reexpand_tls_files_for_sni = TRUE; if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded, errstr)) @@ -1476,10 +1506,43 @@ else const uschar * file_list = expanded; int sep = 0; uschar * file; +#ifndef DISABLE_OCSP + const uschar * olist = cbinfo->u_ocsp.server.file; + int osep = 0; + uschar * ofile; + + if (olist) + if (!expand_check(olist, US"tls_ocsp_file", USS &olist, errstr)) + return DEFER; + if (olist && !*olist) + olist = NULL; + + if ( cbinfo->u_ocsp.server.file_expanded && olist + && (Ustrcmp(olist, cbinfo->u_ocsp.server.file_expanded) == 0)) + { + DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n"); + olist = NULL; + } + else + { + ocsp_free_response_list(cbinfo); + cbinfo->u_ocsp.server.file_expanded = olist; + } +#endif while (file = string_nextinlist(&file_list, &sep, NULL, 0)) + { if ((err = tls_add_certfile(sctx, cbinfo, file, errstr))) return err; + +#ifndef DISABLE_OCSP + if (olist) + if ((ofile = string_nextinlist(&olist, &osep, NULL, 0))) + ocsp_load_response(sctx, cbinfo, ofile); + else + DEBUG(D_tls) debug_printf("ran out of ocsp file list\n"); +#endif + } } else /* would there ever be a need for multiple client certs? */ if ((err = tls_add_certfile(sctx, cbinfo, expanded, errstr))) @@ -1509,27 +1572,6 @@ else return err; } -#ifndef DISABLE_OCSP -if (cbinfo->is_server && cbinfo->u_ocsp.server.file) - { - /*XXX stack*/ - if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded, errstr)) - return DEFER; - - if (expanded && *expanded) - { - DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded); - if ( cbinfo->u_ocsp.server.file_expanded - && (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0)) - { - DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n"); - } - else - ocsp_load_response(sctx, cbinfo, expanded); - } - } -#endif - return OK; } @@ -1659,27 +1701,70 @@ project. static int tls_server_stapling_cb(SSL *s, void *arg) { -const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg; -uschar *response_der; /*XXX blob */ +const tls_ext_ctx_cb * cbinfo = (tls_ext_ctx_cb *) arg; +ocsp_resplist * olist = cbinfo->u_ocsp.server.olist; +uschar * response_der; /*XXX blob */ int response_der_len; -/*XXX stack: use SSL_get_certificate() to see which cert; from that work -out which ocsp blob to send. Unfortunately, SSL_get_certificate is known -buggy in current OpenSSL; it returns the last cert loaded always rather than -the one actually presented. So we can't support a stack of OCSP proofs at -this time. */ - DEBUG(D_tls) - debug_printf("Received TLS status request (OCSP stapling); %s response\n", - cbinfo->u_ocsp.server.response ? "have" : "lack"); + debug_printf("Received TLS status request (OCSP stapling); %s response list\n", + olist ? "have" : "lack"); tls_in.ocsp = OCSP_NOT_RESP; -if (!cbinfo->u_ocsp.server.response) +if (!olist) return SSL_TLSEXT_ERR_NOACK; + { + 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) + { + OCSP_BASICRESP * bs = OCSP_response_get1_basic(olist->resp); + const OCSP_SINGLERESP * single = OCSP_resp_get0(bs, 0); + const OCSP_CERTID * cid = OCSP_SINGLERESP_get0_id(single); + ASN1_INTEGER * res_cert_serial; + const BIGNUM * resp_bn; + ASN1_OCTET_STRING * res_cert_iNameHash; + + + (void) OCSP_id_get0_info(&res_cert_iNameHash, NULL, NULL, &res_cert_serial, + (OCSP_CERTID *) cid); + resp_bn = ASN1_INTEGER_to_BN(res_cert_serial, NULL); + + DEBUG(D_tls) + { + debug_printf("cert serial: %s\n", BN_bn2hex(cert_bn)); + debug_printf("resp serial: %s\n", BN_bn2hex(resp_bn)); + } + + if (BN_cmp(cert_bn, resp_bn) == 0) + { + DEBUG(D_tls) debug_printf("matched serial for ocsp\n"); + + /*XXX TODO: check the rest of the list for duplicate matches. + If any, need to also check the Issuer Name hash. + Without this, we will provide the wrong status in the case of + duplicate id. */ + + break; + } + DEBUG(D_tls) debug_printf("not match serial for ocsp\n"); + } + if (!olist) + { + DEBUG(D_tls) debug_printf("failed to find match for ocsp\n"); + return SSL_TLSEXT_ERR_NOACK; + } + } + +/*XXX could we do the i2d earlier, rather than during the callback? */ response_der = NULL; -response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response, /*XXX stack*/ - &response_der); +response_der_len = i2d_OCSP_RESPONSE(olist->resp, &response_der); if (response_der_len <= 0) return SSL_TLSEXT_ERR_NOACK; @@ -1872,7 +1957,7 @@ static int tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate, uschar *privatekey, #ifndef DISABLE_OCSP - uschar *ocsp_file, /*XXX stack, in server*/ + uschar *ocsp_file, #endif address_item *addr, tls_ext_ctx_cb ** cbp, tls_support * tlsp, @@ -1894,7 +1979,7 @@ if (!host) { cbinfo->u_ocsp.server.file = ocsp_file; cbinfo->u_ocsp.server.file_expanded = NULL; - cbinfo->u_ocsp.server.response = NULL; + cbinfo->u_ocsp.server.olist = NULL; } else cbinfo->u_ocsp.client.verify_store = NULL; @@ -2046,7 +2131,7 @@ if ((rc = tls_expand_session_files(ctx, cbinfo, errstr)) != OK) if (!host) /* server */ { # ifndef DISABLE_OCSP - /* We check u_ocsp.server.file, not server.response, because we care about if + /* We check u_ocsp.server.file, not server.olist, because we care about if the option exists, not what the current expansion might be, as SNI might change the certificate and OCSP file in use between now and the time the callback is invoked. */ @@ -2273,6 +2358,10 @@ if (expcerts && *expcerts) /* In the server if we will be offering an OCSP proof, load chain from file for verifying the OCSP proof at load time. */ +/*XXX Glitch! The file here is tls_verify_certs: the chain for verifying the client cert. +This is inconsistent with the need to verify the OCSP proof of the server cert. +*/ + if ( !host && statbuf.st_size > 0 && server_static_cbinfo->u_ocsp.server.file @@ -2421,7 +2510,7 @@ the error. */ rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey, #ifndef DISABLE_OCSP - tls_ocsp_file, /*XXX stack*/ + tls_ocsp_file, #endif NULL, &server_static_cbinfo, &tls_in, errstr); if (rc != OK) return rc; diff --git a/test/aux-fixed/exim-ca/example_ec.com/CA/index.valid.txt b/test/aux-fixed/exim-ca/example_ec.com/CA/index.valid.txt index 4dc4d2d63..1ae59f7a8 100644 --- a/test/aux-fixed/exim-ca/example_ec.com/CA/index.valid.txt +++ b/test/aux-fixed/exim-ca/example_ec.com/CA/index.valid.txt @@ -1 +1 @@ -V 130110200751Z 65 unknown CN=server1.example_ec.com +V 130110200751Z 835 unknown CN=server1.example_ec.com diff --git a/test/aux-fixed/exim-ca/example_ec.com/server1.example_ec.com/server1.example_ec.com.ocsp.good.resp b/test/aux-fixed/exim-ca/example_ec.com/server1.example_ec.com/server1.example_ec.com.ocsp.good.resp index d129311d1..10e994150 100644 Binary files a/test/aux-fixed/exim-ca/example_ec.com/server1.example_ec.com/server1.example_ec.com.ocsp.good.resp and b/test/aux-fixed/exim-ca/example_ec.com/server1.example_ec.com/server1.example_ec.com.ocsp.good.resp differ diff --git a/test/aux-fixed/exim-ca/genall b/test/aux-fixed/exim-ca/genall index 9904cfa6f..8efda889f 100755 --- a/test/aux-fixed/exim-ca/genall +++ b/test/aux-fixed/exim-ca/genall @@ -263,7 +263,7 @@ do # 5: DN, index cat >$CADIR/index.valid.txt <