OpenSSL: support OCSP stapling on multi-cert servers
authorJeremy Harris <jgh146exb@wizmail.org>
Sun, 29 Sep 2019 13:16:36 +0000 (14:16 +0100)
committerJeremy Harris <jgh146exb@wizmail.org>
Sun, 29 Sep 2019 13:58:02 +0000 (14:58 +0100)
doc/doc-docbook/spec.xfpt
doc/doc-txt/NewStuff
src/src/tls-openssl.c
test/aux-fixed/exim-ca/example_ec.com/CA/index.valid.txt
test/aux-fixed/exim-ca/example_ec.com/server1.example_ec.com/server1.example_ec.com.ocsp.good.resp
test/aux-fixed/exim-ca/genall
test/confs/5602 [new symlink]
test/confs/5652
test/scripts/5600-OCSP-OpenSSL/5602 [new file with mode: 0644]
test/scripts/5650-OCSP-GnuTLS/5652

index d7e8fe0c422bbe64e2f00eb4e19a0723eb1e0af7..9833f19e42a3b49f3c2b291e2031bc8630e46a92 100644 (file)
@@ -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.
 
index a1534c55072734fb9ac6606a5fa96994063f0bb3..aa05e67d59931269d41e7f6a87f79b55a8c5b7be 100644 (file)
@@ -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
 --------------
index a1dee6dd03f08394bab50bf6c67aa908a684e2f5..057a0e006cdb3ac1cc8a0172d03b7ad93109e0e7 100644 (file)
@@ -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;
index 4dc4d2d633f028fa7fdcef2a6ae4c9c0eb0f5fe5..1ae59f7a8357ae2b9c84bc227689f7697ac9899a 100644 (file)
@@ -1 +1 @@
-V      130110200751Z           65      unknown CN=server1.example_ec.com
+V      130110200751Z           835     unknown CN=server1.example_ec.com
index d129311d1f9a856df09c98af2ad8464e42c1b835..10e9941504db109d915865defa906478c69fd64b 100644 (file)
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
index 9904cfa6f29a644ab400207d0cb5cc253c4b7c1b..8efda889fe658cbffb4f9153b7d79c81df96743e 100755 (executable)
@@ -263,7 +263,7 @@ do
 # 5: DN, index
 
     cat >$CADIR/index.valid.txt <<EOF
-V      130110200751Z           65      unknown CN=server1.$iname
+V      130110200751Z           835     unknown CN=server1.$iname
 EOF
 
     # Now create all the ocsp requests and responses
diff --git a/test/confs/5602 b/test/confs/5602
new file mode 120000 (symlink)
index 0000000..4602aa5
--- /dev/null
@@ -0,0 +1 @@
+5652
\ No newline at end of file
index 5b29f5b689db77394b9e2a0d60cd27967ec3dd2b..da6e5197a9f6206cbfcb7e37b6f8bbab85cea8f7 100644 (file)
@@ -1,5 +1,5 @@
 # Exim test configuration 5652
-# OCSP stapling, server, multiple certs
+# OCSP stapling, server, multiple leaf-certs
 
 .include DIR/aux-var/tls_conf_prefix
 
@@ -29,7 +29,12 @@ tls_ocsp_file =   DRSA/server1.example.com/server1.example.com.ocsp.good.resp \
              : DECDSA/server1.example_ec.com/server1.example_ec.com.ocsp.good.resp
 
 
+.ifdef _HAVE_GNUTLS
 tls_require_ciphers = NORMAL:!VERS-ALL:+VERS-TLS1.2:+VERS-TLS1.0
+.endif
+.ifdef _OPT_OPENSSL_NO_TLSV1_3_X
+openssl_options = +no_tlsv1_3
+.endif
 
 # ------ ACL ------
 
@@ -70,9 +75,21 @@ remote_delivery:
   driver =                     smtp
   port =                       PORT_D
   hosts_require_tls =          *
-  tls_require_ciphers =                OPT
+.ifdef _HAVE_GNUTLS
+  tls_require_ciphers =                NONE:\
+                               ${if eq {SELECTOR}{auth_ecdsa} \
+                                       {+SIGN-ECDSA-SHA512:+VERS-TLS-ALL:+KX-ALL:} \
+                                       {+SIGN-RSA-SHA256:+VERS-TLS-ALL:+ECDHE-RSA:+DHE-RSA:+RSA:}}\
+                               +CIPHER-ALL:+MAC-ALL:+COMP-NULL:+CURVE-ALL:+CTYPE-X509
+.endif
+.ifdef _HAVE_OPENSSL
+  tls_require_ciphers =                ${if eq {SELECTOR}{auth_ecdsa} {ECDSA:RSA:!COMPLEMENTOFDEFAULT} {RSA}}
+.endif
   hosts_require_ocsp =         *
-  tls_verify_certificates =    CERT
+  tls_verify_certificates =    CADIR/\
+                               ${if eq {SELECTOR}{auth_ecdsa} \
+                                       {example_ec.com/server1.example_ec.com/ca_chain.pem}\
+                                       {example.com/server1.example.com/ca_chain.pem}}
   tls_verify_cert_hostnames =  :
 
 local_delivery:
diff --git a/test/scripts/5600-OCSP-OpenSSL/5602 b/test/scripts/5600-OCSP-OpenSSL/5602
new file mode 100644 (file)
index 0000000..07fda29
--- /dev/null
@@ -0,0 +1,31 @@
+# OCSP stapling, server, multiple leaf-certs
+#
+#
+#
+exim -z '1: Server sends good staple on request, to client requiring RSA auth'
+****
+#
+exim -bd -oX PORT_D -DSERVER=server
+****
+exim -odf -DSELECTOR=auth_rsa rsa.auth@test.ex
+Subject: test
+
+.
+****
+killdaemon
+#
+#
+#
+#
+exim -z '2: Server sends good staple on request, to client preferring ECDSA auth'
+****
+#
+exim -bd -oX PORT_D -DSERVER=server
+****
+exim -odf -DSELECTOR=auth_ecdsa ecdsa.auth@test.ex
+Subject: test
+
+.
+****
+killdaemon
+no_msglog_check
index 9130f65e6170765dcbb3d5e5ffda0338b5d29390..07fda294c47f91c049ab74f93045076f14844f04 100644 (file)
@@ -1,4 +1,4 @@
-# OCSP stapling, server, multiple leaf certs
+# OCSP stapling, server, multiple leaf-certs
 #
 #
 #
@@ -7,10 +7,7 @@ exim -z '1: Server sends good staple on request, to client requiring RSA auth'
 #
 exim -bd -oX PORT_D -DSERVER=server
 ****
-exim -odf \
-  -DOPT=NONE:+SIGN-RSA-SHA256:+VERS-TLS-ALL:+ECDHE-RSA:+DHE-RSA:+RSA:+CIPHER-ALL:+MAC-ALL:+COMP-NULL:+CURVE-ALL:+CTYPE-X509 \
-  -DCERT=DIR/aux-fixed/exim-ca/example.com/server1.example.com/ca_chain.pem \
-  rsa.auth@test.ex
+exim -odf -DSELECTOR=auth_rsa rsa.auth@test.ex
 Subject: test
 
 .
@@ -25,10 +22,7 @@ exim -z '2: Server sends good staple on request, to client preferring ECDSA auth
 #
 exim -bd -oX PORT_D -DSERVER=server
 ****
-exim -odf \
-  -DOPT=NONE:+SIGN-ECDSA-SHA512:+VERS-TLS-ALL:+KX-ALL:+CIPHER-ALL:+MAC-ALL:+COMP-NULL:+CURVE-ALL:+CTYPE-X509 \
-  -DCERT=DIR/aux-fixed/exim-ca/example_ec.com/server1.example_ec.com/ca_chain.pem \
-  ecdsa.auth@test.ex
+exim -odf -DSELECTOR=auth_ecdsa ecdsa.auth@test.ex
 Subject: test
 
 .