Change Post Handshake auth so that it is opt-in

Having post handshake auth automatically switched on breaks some
applications written for TLSv1.2. This changes things so that an explicit
function call is required for a client to indicate support for
post-handshake auth.

Fixes #6933.
Reviewed-by: NTim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6938)

apps/s_client.c

@@ -595,7 +595,7 @@ typedef enum OPTION_choice {
     OPT_CT, OPT_NOCT, OPT_CTLOG_FILE,
 #endif
     OPT_DANE_TLSA_RRDATA, OPT_DANE_EE_NO_NAME,
-    OPT_FORCE_PHA,
+    OPT_ENABLE_PHA,
     OPT_R_ENUM
 } OPTION_CHOICE;
 
@@ -786,7 +786,7 @@ const OPTIONS s_client_options[] = {
 #endif
     {"keylogfile", OPT_KEYLOG_FILE, '>', "Write TLS secrets to file"},
     {"early_data", OPT_EARLY_DATA, '<', "File to send as early data"},
-    {"force_pha", OPT_FORCE_PHA, '-', "Force-enable post-handshake-authentication"},
+    {"enable_pha", OPT_ENABLE_PHA, '-', "Enable post-handshake-authentication"},
     {NULL, OPT_EOF, 0x00, NULL}
 };
 
@@ -975,7 +975,7 @@ int s_client_main(int argc, char **argv)
     int isdtls = 0;
 #endif
     char *psksessf = NULL;
-    int force_pha = 0;
+    int enable_pha = 0;
 
     FD_ZERO(&readfds);
     FD_ZERO(&writefds);
@@ -1492,8 +1492,8 @@ int s_client_main(int argc, char **argv)
         case OPT_EARLY_DATA:
             early_data_file = opt_arg();
             break;
-        case OPT_FORCE_PHA:
-            force_pha = 1;
+        case OPT_ENABLE_PHA:
+            enable_pha = 1;
             break;
         }
     }
@@ -1944,8 +1944,8 @@ int s_client_main(int argc, char **argv)
     if (con == NULL)
         goto end;
 
-    if (force_pha)
-        SSL_force_post_handshake_auth(con);
+    if (enable_pha)
+        SSL_set_post_handshake_auth(con, 1);
 
     if (sess_in != NULL) {
         SSL_SESSION *sess;

doc/man1/s_client.pod

@@ -134,7 +134,7 @@ B<openssl> B<s_client>
 [B<-ctlogfile>]
 [B<-keylogfile file>]
 [B<-early_data file>]
-[B<-force_pha>]
+[B<-enable_pha>]
 [B<target>]
 
 =head1 DESCRIPTION
@@ -700,10 +700,10 @@ Reads the contents of the specified file and attempts to send it as early data
 to the server. This will only work with resumed sessions that support early
 data and when the server accepts the early data.
 
-=item B<-force_pha>
+=item B<-enable_pha>
 
-For TLSv1.3 only, always send the Post-Handshake Authentication extension,
-whether or not a certificate has been provided via B<-cert>.
+For TLSv1.3 only, send the Post-Handshake Authentication extension. This will
+happen whether or not a certificate has been provided via B<-cert>.
 
 =item B<[target]>
 

doc/man3/SSL_CTX_set_verify.pod

@@ -7,7 +7,7 @@ SSL_CTX_set_verify, SSL_set_verify,
 SSL_CTX_set_verify_depth, SSL_set_verify_depth,
 SSL_verify_cb,
 SSL_verify_client_post_handshake,
-SSL_force_post_handshake_auth
+SSL_set_post_handshake_auth
 - set peer certificate verification parameters
 
 =head1 SYNOPSIS
@@ -24,7 +24,7 @@ SSL_force_post_handshake_auth
  void SSL_set_verify_depth(SSL *ssl, int depth);
 
  int SSL_verify_client_post_handshake(SSL *ssl);
- void SSL_force_post_handshake_auth(SSL *ssl);
+ void SSL_set_post_handshake_auth(SSL *ssl, int val);
 
 =head1 DESCRIPTION
 
@@ -48,11 +48,12 @@ verification that shall be allowed for B<ctx>.
 SSL_set_verify_depth() sets the maximum B<depth> for the certificate chain
 verification that shall be allowed for B<ssl>.
 
-SSL_force_post_handshake_auth() forces the Post-Handshake Authentication
-extension to be added to the ClientHello regardless of certificate configuration
-at the time of the initial handshake, such that post-handshake authentication
-can be requested by the server. A certificate callback will need to be set via
-SSL_CTX_set_client_cert_cb() if no certificate is provided at initialization.
+SSL_set_post_handshake_auth() enables the Post-Handshake Authentication
+extension to be added to the ClientHello such that post-handshake authentication
+can be requested by the server. If B<val> is 0 then the extension is not sent,
+otherwise it is. By default the extension is not sent. A certificate callback
+will need to be set via SSL_CTX_set_client_cert_cb() if no certificate is
+provided at initialization.
 
 SSL_verify_client_post_handshake() causes a CertificateRequest message to be
 sent by a server on the given B<ssl> connection. The SSL_VERIFY_PEER flag must
@@ -341,7 +342,7 @@ L<CRYPTO_get_ex_new_index(3)>
 =head1 HISTORY
 
 The SSL_VERIFY_POST_HANDSHAKE option, and the SSL_verify_client_post_handshake()
-and SSL_force_post_handshake_auth() functions were added in OpenSSL 1.1.1.
+and SSL_set_post_handshake_auth() functions were added in OpenSSL 1.1.1.
 
 =head1 COPYRIGHT
 

include/openssl/ssl.h

@@ -1898,7 +1898,7 @@ int SSL_renegotiate_abbreviated(SSL *s);
 __owur int SSL_renegotiate_pending(SSL *s);
 int SSL_shutdown(SSL *s);
 __owur int SSL_verify_client_post_handshake(SSL *s);
-void SSL_force_post_handshake_auth(SSL *s);
+void SSL_set_post_handshake_auth(SSL *s, int val);
 
 __owur const SSL_METHOD *SSL_CTX_get_ssl_method(SSL_CTX *ctx);
 __owur const SSL_METHOD *SSL_get_ssl_method(SSL *s);

ssl/ssl_lib.c

@@ -5455,9 +5455,9 @@ int SSL_stateless(SSL *s)
     return -1;
 }
 
-void SSL_force_post_handshake_auth(SSL *ssl)
+void SSL_set_post_handshake_auth(SSL *ssl, int val)
 {
-    ssl->pha_forced = 1;
+    ssl->pha_enabled = val;
 }
 
 int SSL_verify_client_post_handshake(SSL *ssl)

ssl/ssl_locl.h

@@ -1391,7 +1391,7 @@ struct ssl_st {
     int key_update;
     /* Post-handshake authentication state */
     SSL_PHA_STATE post_handshake_auth;
-    int pha_forced;
+    int pha_enabled;
     uint8_t* pha_context;
     size_t pha_context_len;
     int certreqs_sent;

ssl/statem/extensions_clnt.c

@@ -1193,23 +1193,8 @@ EXT_RETURN tls_construct_ctos_post_handshake_auth(SSL *s, WPACKET *pkt,
                                                   X509 *x, size_t chainidx)
 {
 #ifndef OPENSSL_NO_TLS1_3
-    if (!s->pha_forced) {
-        int i, n = 0;
-
-        /* check for cert, if present, we can do post-handshake auth */
-        if (s->cert == NULL)
-            return EXT_RETURN_NOT_SENT;
-
-        for (i = 0; i < SSL_PKEY_NUM; i++) {
-            if (s->cert->pkeys[i].x509 != NULL
-                    && s->cert->pkeys[i].privatekey != NULL)
-                n++;
-        }
-
-        /* no identity certificates, so no extension */
-        if (n == 0)
-            return EXT_RETURN_NOT_SENT;
-    }
+    if (!s->pha_enabled)
+        return EXT_RETURN_NOT_SENT;
 
     /* construct extension - 0 length, no contents */
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_post_handshake_auth)

test/handshake_helper.c

@@ -726,8 +726,8 @@ static void configure_handshake_ssl(SSL *server, SSL *client,
     if (extra->client.servername != SSL_TEST_SERVERNAME_NONE)
         SSL_set_tlsext_host_name(client,
                                  ssl_servername_name(extra->client.servername));
-    if (extra->client.force_pha)
-        SSL_force_post_handshake_auth(client);
+    if (extra->client.enable_pha)
+        SSL_set_post_handshake_auth(client, 1);
 }
 
 /* The status for each connection phase. */

test/recipes/70-test_tls13messages.t

@@ -214,7 +214,7 @@ SKIP: {
 
 #Test 6: A client auth handshake
 $proxy->clear();
-$proxy->clientflags("-cert ".srctop_file("apps", "server.pem"));
+$proxy->clientflags("-enable_pha -cert ".srctop_file("apps", "server.pem"));
 $proxy->serverflags("-Verify 5");
 $proxy->start();
 checkhandshake($proxy, checkhandshake::CLIENT_AUTH_HANDSHAKE,

test/ssl-tests/26-tls13_client_auth.conf

@@ -299,6 +299,10 @@ ExpectedClientSignHash = SHA256
 ExpectedClientSignType = RSA-PSS
 ExpectedResult = Success
 HandshakeMode = PostHandshakeAuth
+client = 8-client-auth-TLSv1.3-require-post-handshake-client-extra
+
+[8-client-auth-TLSv1.3-require-post-handshake-client-extra]
+EnablePHA = Yes
 
 
 # ===========================================================
@@ -337,6 +341,10 @@ ExpectedClientSignHash = SHA256
 ExpectedClientSignType = RSA-PSS
 ExpectedResult = Success
 HandshakeMode = PostHandshakeAuth
+client = 9-client-auth-TLSv1.3-require-non-empty-names-post-handshake-client-extra
+
+[9-client-auth-TLSv1.3-require-non-empty-names-post-handshake-client-extra]
+EnablePHA = Yes
 
 
 # ===========================================================
@@ -369,6 +377,10 @@ VerifyMode = Peer
 ExpectedResult = ServerFail
 ExpectedServerAlert = UnknownCA
 HandshakeMode = PostHandshakeAuth
+client = 10-client-auth-TLSv1.3-noroot-post-handshake-client-extra
+
+[10-client-auth-TLSv1.3-noroot-post-handshake-client-extra]
+EnablePHA = Yes
 
 
 # ===========================================================
@@ -401,7 +413,7 @@ HandshakeMode = PostHandshakeAuth
 client = 11-client-auth-TLSv1.3-request-force-client-post-handshake-client-extra
 
 [11-client-auth-TLSv1.3-request-force-client-post-handshake-client-extra]
-ForcePHA = Yes
+EnablePHA = Yes
 
 
 # ===========================================================
@@ -471,6 +483,6 @@ client = 13-client-auth-TLSv1.3-request-force-both-post-handshake-client-extra
 ForcePHA = Yes
 
 [13-client-auth-TLSv1.3-request-force-both-post-handshake-client-extra]
-ForcePHA = Yes
+EnablePHA = Yes
 
 

test/ssl-tests/26-tls13_client_auth.conf.in

@@ -176,6 +176,9 @@ our @tests = (
             "MaxProtocol" => "TLSv1.3",
             "Certificate" => test_pem("ee-client-chain.pem"),
             "PrivateKey" => test_pem("ee-key.pem"),
+            extra => {
+                "EnablePHA" => "Yes",
+            },
         },
         test => {
             "ExpectedResult" => "Success",
@@ -201,6 +204,9 @@ our @tests = (
             "MaxProtocol" => "TLSv1.3",
             "Certificate" => test_pem("ee-client-chain.pem"),
             "PrivateKey" => test_pem("ee-key.pem"),
+            extra => {
+                "EnablePHA" => "Yes",
+            },
         },
         test => {
             "ExpectedResult" => "Success",
@@ -223,6 +229,9 @@ our @tests = (
             "MaxProtocol" => "TLSv1.3",
             "Certificate" => test_pem("ee-client-chain.pem"),
             "PrivateKey" => test_pem("ee-key.pem"),
+            extra => {
+                "EnablePHA" => "Yes",
+            },
         },
         test => {
             "ExpectedResult" => "ServerFail",
@@ -240,9 +249,9 @@ our @tests = (
         client => {
             "MinProtocol" => "TLSv1.3",
             "MaxProtocol" => "TLSv1.3",
-	    extra => {
-		"ForcePHA" => "Yes",
-	    },
+            extra => {
+                "EnablePHA" => "Yes",
+            },
         },
         test => {
             "ExpectedResult" => "Success",
@@ -255,9 +264,9 @@ our @tests = (
             "MinProtocol" => "TLSv1.3",
             "MaxProtocol" => "TLSv1.3",
             "VerifyMode" => "RequestPostHandshake",
-	    extra => {
-		"ForcePHA" => "Yes",
-	    },
+            extra => {
+                "ForcePHA" => "Yes",
+            },
         },
         client => {
             "MinProtocol" => "TLSv1.3",
@@ -274,16 +283,16 @@ our @tests = (
             "MinProtocol" => "TLSv1.3",
             "MaxProtocol" => "TLSv1.3",
             "VerifyMode" => "RequestPostHandshake",
-	    extra => {
-		"ForcePHA" => "Yes",
-	    },
+            extra => {
+                "ForcePHA" => "Yes",
+            },
         },
         client => {
             "MinProtocol" => "TLSv1.3",
             "MaxProtocol" => "TLSv1.3",
-	    extra => {
-		"ForcePHA" => "Yes",
-	    },
+            extra => {
+                "EnablePHA" => "Yes",
+            },
         },
         test => {
             "ExpectedResult" => "Success",

test/ssl_test_ctx.c

@@ -629,9 +629,9 @@ __owur static int parse_expected_client_ca_names(SSL_TEST_CTX *test_ctx,
 
 IMPLEMENT_SSL_TEST_STRING_OPTION(SSL_TEST_CTX, test, expected_cipher)
 
-/* Client and Server ForcePHA */
+/* Client and Server PHA */
 
-IMPLEMENT_SSL_TEST_BOOL_OPTION(SSL_TEST_CLIENT_CONF, client, force_pha)
+IMPLEMENT_SSL_TEST_BOOL_OPTION(SSL_TEST_CLIENT_CONF, client, enable_pha)
 IMPLEMENT_SSL_TEST_BOOL_OPTION(SSL_TEST_SERVER_CONF, server, force_pha)
 
 /* Known test options and their corresponding parse methods. */
@@ -689,7 +689,7 @@ static const ssl_test_client_option ssl_test_client_options[] = {
     { "SRPUser", &parse_client_srp_user },
     { "SRPPassword", &parse_client_srp_password },
     { "MaxFragmentLenExt", &parse_max_fragment_len_mode },
-    { "ForcePHA", &parse_client_force_pha },
+    { "EnablePHA", &parse_client_enable_pha },
 };
 
 /* Nested server options. */

test/ssl_test_ctx.h

@@ -108,8 +108,8 @@ typedef struct {
     char *reneg_ciphers;
     char *srp_user;
     char *srp_password;
-    /* Forced PHA */
-    int force_pha;
+    /* PHA enabled */
+    int enable_pha;
 } SSL_TEST_CLIENT_CONF;
 
 typedef struct {

test/sslapitest.c

@@ -1270,7 +1270,7 @@ static int check_resumption(int idx, SSL_CTX *sctx, SSL_CTX *cctx, int succ)
                 || !TEST_true(SSL_set_session(clientssl, sesscache[i])))
             goto end;
 
-        SSL_force_post_handshake_auth(clientssl);
+        SSL_set_post_handshake_auth(clientssl, 1);
 
         if (!TEST_true(create_ssl_connection(serverssl, clientssl,
                                                     SSL_ERROR_NONE)))
@@ -1377,7 +1377,7 @@ static int test_tickets(int stateful, int idx)
                                           &clientssl, NULL, NULL)))
         goto end;
 
-    SSL_force_post_handshake_auth(clientssl);
+    SSL_set_post_handshake_auth(clientssl, 1);
 
     if (!TEST_true(create_ssl_connection(serverssl, clientssl,
                                                 SSL_ERROR_NONE))
@@ -4336,7 +4336,7 @@ static int test_pha_key_update(void)
                                       NULL, NULL)))
         goto end;
 
-    SSL_force_post_handshake_auth(clientssl);
+    SSL_set_post_handshake_auth(clientssl, 1);
 
     if (!TEST_true(create_ssl_connection(serverssl, clientssl,
                                          SSL_ERROR_NONE)))

util/libssl.num

@@ -475,7 +475,7 @@ SSL_set_tlsext_max_fragment_length      475	1_1_1	EXIST::FUNCTION:
 SSL_SESSION_get_max_fragment_length     476	1_1_1	EXIST::FUNCTION:
 SSL_stateless                           477	1_1_1	EXIST::FUNCTION:
 SSL_verify_client_post_handshake        478	1_1_1	EXIST::FUNCTION:
-SSL_force_post_handshake_auth           479	1_1_1	EXIST::FUNCTION:
+SSL_set_post_handshake_auth             479	1_1_1	EXIST::FUNCTION:
 SSL_export_keying_material_early        480	1_1_1	EXIST::FUNCTION:
 SSL_CTX_use_cert_and_key                481	1_1_1	EXIST::FUNCTION:
 SSL_use_cert_and_key                    482	1_1_1	EXIST::FUNCTION: