Fix ALPN

* Perform ALPN after the SNI callback; the SSL_CTX may change due to
  that processing
* Add flags to indicate that we actually sent ALPN, to properly error
  out if unexpectedly received.
* document ALPN functions
* unit tests

Backport of commit 817cd0d52f0462039d1fe60462150be7f59d2002

Reviewed-by: Emilia Käsper <emilia@openssl.org>
Reviewed-by: Dr. Stephen Henson <steve@openssl.org>

8 files changed, 399 insertions, 42 deletions

diff --git a/CHANGES b/CHANGES
index 4e118e6d11..2d73627aaa 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,10 @@
 
  Changes between 1.0.2g and 1.0.2h [xx XXX xxxx]
 
+  *) Modify behavior of ALPN to invoke callback after SNI/servername
+     callback, such that updates to the SSL_CTX affect ALPN.
+     [Todd Short]
+
   *) Remove LOW from the DEFAULT cipher list.  This removes singles DES from the
      default.
      [Kurt Roeckx]
diff --git a/doc/ssl/SSL_CTX_set_alpn_select_cb.pod b/doc/ssl/SSL_CTX_set_alpn_select_cb.pod
new file mode 100644
index 0000000000..80ba8ab9c4
--- /dev/null
+++ b/doc/ssl/SSL_CTX_set_alpn_select_cb.pod
@@ -0,0 +1,126 @@
+=pod
+
+=head1 NAME
+
+SSL_CTX_set_alpn_protos, SSL_set_alpn_protos, SSL_CTX_set_alpn_select_cb,
+SSL_select_next_proto, SSL_get0_alpn_selected - handle application layer
+protocol negotiation (ALPN)
+
+=head1 SYNOPSIS
+
+ #include <openssl/ssl.h>
+
+ int SSL_CTX_set_alpn_protos(SSL_CTX *ctx, const unsigned char *protos,
+                             unsigned protos_len);
+ int SSL_set_alpn_protos(SSL *ssl, const unsigned char *protos,
+                         unsigned protos_len);
+ void SSL_CTX_set_alpn_select_cb(SSL_CTX *ctx,
+                                 int (*cb) (SSL *ssl,
+                                            const unsigned char **out,
+                                            unsigned char *outlen,
+                                            const unsigned char *in,
+                                            unsigned int inlen,
+                                            void *arg), void *arg);
+ int SSL_select_next_proto(unsigned char **out, unsigned char *outlen,
+                           const unsigned char *server,
+                           unsigned int server_len,
+                           const unsigned char *client,
+                           unsigned int client_len)
+ void SSL_get0_alpn_selected(const SSL *ssl, const unsigned char **data,
+                             unsigned int *len);
+
+=head1 DESCRIPTION
+
+SSL_CTX_set_alpn_protos() and SSL_set_alpn_protos() are used by the client to
+set the list of protocols available to be negotiated. The B<protos> must be in
+protocol-list format, described below. The length of B<protos> is specified in
+B<protos_len>.
+
+SSL_CTX_set_alpn_select_cb() sets the application callback B<cb> used by a
+server to select which protocol to use for the incoming connection. When B<cb>
+is NULL, ALPN is not used. The B<arg> value is a pointer which is passed to
+the application callback.
+
+B<cb> is the application defined callback. The B<in>, B<inlen> parameters are a
+vector in protocol-list format. The value of the B<out>, B<outlen> vector
+should be set to the value of a single protocol selected from the B<in>,
+B<inlen> vector. The B<arg> parameter is the pointer set via
+SSL_CTX_set_alpn_select_cb().
+
+SSL_select_next_proto() is a helper function used to select protocols. It
+implements the standard protocol selection. It is expected that this function
+is called from the application callback B<cb>. The protocol data in B<server>,
+B<server_len> and B<client>, B<client_len> must be in the protocol-list format
+described below. The first item in the B<server>, B<server_len> list that
+matches an item in the B<client>, B<client_len> list is selected, and returned
+in B<out>, B<outlen>. The B<out> value will point into either B<server> or
+B<client>, so it should be copied immediately. If no match is found, the first
+item in B<client>, B<client_len> is returned in B<out>, B<outlen>. This
+function can also be used in the NPN callback.
+
+SSL_get0_alpn_selected() returns a pointer to the selected protocol in B<data>
+with length B<len>. It is not NUL-terminated. B<data> is set to NULL and B<len>
+is set to 0 if no protocol has been selected. B<data> must not be freed.
+
+=head1 NOTES
+
+The protocol-lists must be in wire-format, which is defined as a vector of
+non-empty, 8-bit length-prefixed, byte strings. The length-prefix byte is not
+included in the length. Each string is limited to 255 bytes. A byte-string
+length of 0 is invalid. A truncated byte-string is invalid. The length of the
+vector is not in the vector itself, but in a separate variable.
+
+Example:
+
+ unsigned char vector[] = {
+     6, 's', 'p', 'd', 'y', '/', '1',
+     8, 'h', 't', 't', 'p', '/', '1', '.', '1'
+ };
+ unsigned int length = sizeof(vector);
+
+The ALPN callback is executed after the servername callback; as that servername
+callback may update the SSL_CTX, and subsequently, the ALPN callback.
+
+If there is no ALPN proposed in the ClientHello, the ALPN callback is not
+invoked.
+
+=head1 RETURN VALUES
+
+SSL_CTX_set_alpn_protos() and SSL_set_alpn_protos() return 0 on success, and
+non-0 on failure. WARNING: these functions reverse the return value convention.
+
+SSL_select_next_proto() returns one of the following:
+
+=over 4
+
+=item OPENSSL_NPN_NEGOTIATED
+
+A match was found and is returned in B<out>, B<outlen>.
+
+=item OPENSSL_NPN_NO_OVERLAP
+
+No match was found. The first item in B<client>, B<client_len> is returned in
+B<out>, B<outlen>.
+
+=back
+
+The ALPN select callback B<cb>, must return one of the following:
+
+=over 4
+
+=item SSL_TLSEXT_ERR_OK
+
+ALPN protocol selected.
+
+=item SSL_TLSEXT_ERR_NOACK
+
+ALPN protocol not selected.
+
+=back
+
+=head1 SEE ALSO
+
+L<ssl(3)>, L<SSL_CTX_set_tlsext_servername_callback(3)>,
+L<SSL_CTX_set_tlsext_servername_arg(3)>
+
+=cut
diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index a73f866cb9..acc5361544 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c
@@ -504,6 +504,8 @@ void ssl_cert_free(CERT *c)
 #ifndef OPENSSL_NO_TLSEXT
     custom_exts_free(&c->cli_ext);
     custom_exts_free(&c->srv_ext);
+    if (c->alpn_proposed)
+        OPENSSL_free(c->alpn_proposed);
 #endif
     OPENSSL_free(c);
 }
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index f1279bbf91..fd94325bb3 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -244,7 +244,16 @@ int SSL_clear(SSL *s)
     ssl_clear_hash_ctx(&s->write_hash);
 
     s->first_packet = 0;
-
+#ifndef OPENSSL_NO_TLSEXT
+    if (s->cert != NULL) {
+        if (s->cert->alpn_proposed) {
+            OPENSSL_free(s->cert->alpn_proposed);
+            s->cert->alpn_proposed = NULL;
+        }
+        s->cert->alpn_proposed_len = 0;
+        s->cert->alpn_sent = 0;
+    }
+#endif
 #if 1
     /*
      * Check to see if we were changed into a different method, if so, revert
@@ -3174,6 +3183,12 @@ SSL_CTX *SSL_set_SSL_CTX(SSL *ssl, SSL_CTX *ctx)
             ssl->cert->ciphers_rawlen = ocert->ciphers_rawlen;
             ocert->ciphers_raw = NULL;
         }
+#ifndef OPENSSL_NO_TLSEXT
+        ssl->cert->alpn_proposed = ocert->alpn_proposed;
+        ssl->cert->alpn_proposed_len = ocert->alpn_proposed_len;
+        ocert->alpn_proposed = NULL;
+        ssl->cert->alpn_sent = ocert->alpn_sent;
+#endif
         ssl_cert_free(ocert);
     }
 
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 54c191a7bb..747e718a52 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -688,6 +688,10 @@ typedef struct cert_st {
     custom_ext_methods cli_ext;
     custom_ext_methods srv_ext;
     int references;             /* >1 only if SSL_copy_session_id is used */
+    /* non-optimal, but here due to compatibility */
+    unsigned char *alpn_proposed;   /* server */
+    unsigned int alpn_proposed_len;
+    int alpn_sent;                  /* client */
 } CERT;
 
 typedef struct sess_cert_st {
diff --git a/ssl/ssltest.c b/ssl/ssltest.c
index aaf6c6bd89..1db84ad5f9 100644
--- a/ssl/ssltest.c
+++ b/ssl/ssltest.c
@@ -217,6 +217,9 @@
 # define TEST_CLIENT_CERT "../apps/client.pem"
 #endif
 
+static SSL_CTX *s_ctx = NULL;
+static SSL_CTX *s_ctx2 = NULL;
+
 /*
  * There is really no standard for this, so let's assign some tentative
  * numbers.  In any case, these numbers are only for this test
@@ -300,9 +303,51 @@ static BIO *bio_err = NULL;
 static BIO *bio_stdout = NULL;
 
 static const char *alpn_client;
-static const char *alpn_server;
+static char *alpn_server;
+static char *alpn_server2;
 static const char *alpn_expected;
 static unsigned char *alpn_selected;
+static const char *sn_client;
+static const char *sn_server1;
+static const char *sn_server2;
+static int sn_expect = 0;
+
+static int servername_cb(SSL *s, int *ad, void *arg)
+{
+    const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name);
+    if (sn_server2 == NULL) {
+        BIO_printf(bio_stdout, "Servername 2 is NULL\n");
+        return SSL_TLSEXT_ERR_NOACK;
+    }
+
+    if (servername != NULL) {
+        if (s_ctx2 != NULL && sn_server2 != NULL &&
+            !strcasecmp(servername, sn_server2)) {
+            BIO_printf(bio_stdout, "Switching server context.\n");
+            SSL_set_SSL_CTX(s, s_ctx2);
+        }
+    }
+    return SSL_TLSEXT_ERR_OK;
+}
+static int verify_servername(SSL *client, SSL *server)
+{
+    /* just need to see if sn_context is what we expect */
+    SSL_CTX* ctx = SSL_get_SSL_CTX(server);
+    if (sn_expect == 0)
+        return 0;
+    if (sn_expect == 1 && ctx == s_ctx)
+        return 0;
+    if (sn_expect == 2 && ctx == s_ctx2)
+        return 0;
+    BIO_printf(bio_stdout, "Servername: expected context %d\n", sn_expect);
+    if (ctx == s_ctx2)
+        BIO_printf(bio_stdout, "Servername: context is 2\n");
+    else if (ctx == s_ctx)
+        BIO_printf(bio_stdout, "Servername: context is 1\n");
+    else
+        BIO_printf(bio_stdout, "Servername: context is unknown\n");
+    return -1;
+}
 
 /*-
  * next_protos_parse parses a comma separated list of strings into a string
@@ -350,11 +395,12 @@ static int cb_server_alpn(SSL *s, const unsigned char **out,
 {
     unsigned char *protos;
     unsigned short protos_len;
+    char* alpn_str = arg;
 
-    protos = next_protos_parse(&protos_len, alpn_server);
+    protos = next_protos_parse(&protos_len, alpn_str);
     if (protos == NULL) {
         fprintf(stderr, "failed to parser ALPN server protocol string: %s\n",
-                alpn_server);
+                alpn_str);
         abort();
     }
 
@@ -417,8 +463,17 @@ static int verify_alpn(SSL *client, SSL *server)
     BIO_printf(bio_stdout, "', server: '");
     BIO_write(bio_stdout, server_proto, server_proto_len);
     BIO_printf(bio_stdout, "'\n");
-    BIO_printf(bio_stdout, "ALPN configured: client: '%s', server: '%s'\n",
-               alpn_client, alpn_server);
+    BIO_printf(bio_stdout, "ALPN configured: client: '%s', server: ",
+                   alpn_client);
+    if (SSL_get_SSL_CTX(server) == s_ctx2) {
+        BIO_printf(bio_stdout, "'%s'\n",
+                   alpn_server2);
+    } else if (SSL_get_SSL_CTX(server) == s_ctx){
+        BIO_printf(bio_stdout, "'%s'\n",
+                   alpn_server);
+    } else {
+        BIO_printf(bio_stdout, "unknown\n");
+    }
     return -1;
 }
 
@@ -756,8 +811,15 @@ static void sv_usage(void)
             " -custom_ext - try various custom extension callbacks\n");
     fprintf(stderr, " -alpn_client <string> - have client side offer ALPN\n");
     fprintf(stderr, " -alpn_server <string> - have server side offer ALPN\n");
+    fprintf(stderr, " -alpn_server1 <string> - alias for -alpn_server\n");
+    fprintf(stderr, " -alpn_server2 <string> - have server side context 2 offer ALPN\n");
     fprintf(stderr,
             " -alpn_expected <string> - the ALPN protocol that should be negotiated\n");
+    fprintf(stderr, " -sn_client <string>  - have client request this servername\n");
+    fprintf(stderr, " -sn_server1 <string> - have server context 1 respond to this servername\n");
+    fprintf(stderr, " -sn_server2 <string> - have server context 2 respond to this servername\n");
+    fprintf(stderr, " -sn_expect1          - expected server 1\n");
+    fprintf(stderr, " -sn_expect2          - expected server 2\n");
 }
 
 static void print_details(SSL *c_ssl, const char *prefix)
@@ -896,7 +958,6 @@ int main(int argc, char *argv[])
 #ifndef OPENSSL_NO_ECDH
     char *named_curve = NULL;
 #endif
-    SSL_CTX *s_ctx = NULL;
     SSL_CTX *c_ctx = NULL;
     const SSL_METHOD *meth = NULL;
     SSL *c_ssl, *s_ssl;
@@ -1151,14 +1212,35 @@ int main(int argc, char *argv[])
             if (--argc < 1)
                 goto bad;
             alpn_client = *(++argv);
-        } else if (strcmp(*argv, "-alpn_server") == 0) {
+        } else if (strcmp(*argv, "-alpn_server") == 0 ||
+                   strcmp(*argv, "-alpn_server1") == 0) {
             if (--argc < 1)
                 goto bad;
             alpn_server = *(++argv);
+        } else if (strcmp(*argv, "-alpn_server2") == 0) {
+            if (--argc < 1)
+                goto bad;
+            alpn_server2 = *(++argv);
         } else if (strcmp(*argv, "-alpn_expected") == 0) {
             if (--argc < 1)
                 goto bad;
             alpn_expected = *(++argv);
+        } else if (strcmp(*argv, "-sn_client") == 0) {
+            if (--argc < 1)
+                goto bad;
+            sn_client = *(++argv);
+        } else if (strcmp(*argv, "-sn_server1") == 0) {
+            if (--argc < 1)
+                goto bad;
+            sn_server1 = *(++argv);
+        } else if (strcmp(*argv, "-sn_server2") == 0) {
+            if (--argc < 1)
+                goto bad;
+            sn_server2 = *(++argv);
+        } else if (strcmp(*argv, "-sn_expect1") == 0) {
+            sn_expect = 1;
+        } else if (strcmp(*argv, "-sn_expect2") == 0) {
+            sn_expect = 2;
         } else {
             fprintf(stderr, "unknown option %s\n", *argv);
             badop = 1;
@@ -1304,7 +1386,8 @@ int main(int argc, char *argv[])
 
     c_ctx = SSL_CTX_new(meth);
     s_ctx = SSL_CTX_new(meth);
-    if ((c_ctx == NULL) || (s_ctx == NULL)) {
+    s_ctx2 = SSL_CTX_new(meth); /* no SSL_CTX_dup! */
+    if ((c_ctx == NULL) || (s_ctx == NULL) || (s_ctx2 == NULL)) {
         ERR_print_errors(bio_err);
         goto end;
     }
@@ -1312,7 +1395,9 @@ int main(int argc, char *argv[])
     if (cipher != NULL) {
         SSL_CTX_set_cipher_list(c_ctx, cipher);
         SSL_CTX_set_cipher_list(s_ctx, cipher);
+        SSL_CTX_set_cipher_list(s_ctx2, cipher);
     }
+
 #ifndef OPENSSL_NO_DH
     if (!no_dhe) {
         if (dhe1024dsa) {
@@ -1320,12 +1405,14 @@ int main(int argc, char *argv[])
              * use SSL_OP_SINGLE_DH_USE to avoid small subgroup attacks
              */
             SSL_CTX_set_options(s_ctx, SSL_OP_SINGLE_DH_USE);
+            SSL_CTX_set_options(s_ctx2, SSL_OP_SINGLE_DH_USE);
             dh = get_dh1024dsa();
         } else if (dhe512)
             dh = get_dh512();
         else
             dh = get_dh1024();
         SSL_CTX_set_tmp_dh(s_ctx, dh);
+        SSL_CTX_set_tmp_dh(s_ctx2, dh);
         DH_free(dh);
     }
 #else
@@ -1353,7 +1440,9 @@ int main(int argc, char *argv[])
         }
 
         SSL_CTX_set_tmp_ecdh(s_ctx, ecdh);
+        SSL_CTX_set_tmp_ecdh(s_ctx2, ecdh);
         SSL_CTX_set_options(s_ctx, SSL_OP_SINGLE_ECDH_USE);
+        SSL_CTX_set_options(s_ctx2, SSL_OP_SINGLE_ECDH_USE);
         EC_KEY_free(ecdh);
     }
 #else
@@ -1362,15 +1451,18 @@ int main(int argc, char *argv[])
 
 #ifndef OPENSSL_NO_RSA
     SSL_CTX_set_tmp_rsa_callback(s_ctx, tmp_rsa_cb);
+    SSL_CTX_set_tmp_rsa_callback(s_ctx2, tmp_rsa_cb);
 #endif
 
 #ifdef TLSEXT_TYPE_opaque_prf_input
     SSL_CTX_set_tlsext_opaque_prf_input_callback(c_ctx, opaque_prf_input_cb);
     SSL_CTX_set_tlsext_opaque_prf_input_callback(s_ctx, opaque_prf_input_cb);
+    SSL_CTX_set_tlsext_opaque_prf_input_callback(s_ctx2, opaque_prf_input_cb);
     /* or &co2 or NULL */
     SSL_CTX_set_tlsext_opaque_prf_input_callback_arg(c_ctx, &co1);
     /* or &so2 or NULL */
     SSL_CTX_set_tlsext_opaque_prf_input_callback_arg(s_ctx, &so1);
+    SSL_CTX_set_tlsext_opaque_prf_input_callback_arg(s_ctx2, &so1);
 #endif
 
     if (!SSL_CTX_use_certificate_file(s_ctx, server_cert, SSL_FILETYPE_PEM)) {
@@ -1383,6 +1475,16 @@ int main(int argc, char *argv[])
         goto end;
     }
 
+    if (!SSL_CTX_use_certificate_file(s_ctx2, server_cert, SSL_FILETYPE_PEM)) {
+        ERR_print_errors(bio_err);
+    } else if (!SSL_CTX_use_PrivateKey_file(s_ctx2,
+                                            (server_key ? server_key :
+                                             server_cert),
+                                            SSL_FILETYPE_PEM)) {
+        ERR_print_errors(bio_err);
+        goto end;
+    }
+
     if (client_auth) {
         SSL_CTX_use_certificate_file(c_ctx, client_cert, SSL_FILETYPE_PEM);
         SSL_CTX_use_PrivateKey_file(c_ctx,
@@ -1392,6 +1494,8 @@ int main(int argc, char *argv[])
 
     if ((!SSL_CTX_load_verify_locations(s_ctx, CAfile, CApath)) ||
         (!SSL_CTX_set_default_verify_paths(s_ctx)) ||
+        (!SSL_CTX_load_verify_locations(s_ctx2, CAfile, CApath)) ||
+        (!SSL_CTX_set_default_verify_paths(s_ctx2)) ||
         (!SSL_CTX_load_verify_locations(c_ctx, CAfile, CApath)) ||
         (!SSL_CTX_set_default_verify_paths(c_ctx))) {
         /* fprintf(stderr,"SSL_load_verify_locations\n"); */
@@ -1406,6 +1510,11 @@ int main(int argc, char *argv[])
                            verify_callback);
         SSL_CTX_set_cert_verify_callback(s_ctx, app_verify_callback,
                                          &app_verify_arg);
+        SSL_CTX_set_verify(s_ctx2,
+                           SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
+                           verify_callback);
+        SSL_CTX_set_cert_verify_callback(s_ctx2, app_verify_callback,
+                                         &app_verify_arg);
     }
     if (server_auth) {
         BIO_printf(bio_err, "server authentication\n");
@@ -1418,6 +1527,8 @@ int main(int argc, char *argv[])
         int session_id_context = 0;
         SSL_CTX_set_session_id_context(s_ctx, (void *)&session_id_context,
                                        sizeof session_id_context);
+        SSL_CTX_set_session_id_context(s_ctx2, (void *)&session_id_context,
+                                       sizeof session_id_context);
     }
 
     /* Use PSK only if PSK key is given */
@@ -1436,6 +1547,7 @@ int main(int argc, char *argv[])
 #ifndef OPENSSL_NO_PSK
         SSL_CTX_set_psk_client_callback(c_ctx, psk_client_callback);
         SSL_CTX_set_psk_server_callback(s_ctx, psk_server_callback);
+        SSL_CTX_set_psk_server_callback(s_ctx2, psk_server_callback);
         if (debug)
             BIO_printf(bio_err, "setting PSK identity hint to s_ctx\n");
         if (!SSL_CTX_use_psk_identity_hint(s_ctx, "ctx server identity_hint")) {
@@ -1443,6 +1555,11 @@ int main(int argc, char *argv[])
             ERR_print_errors(bio_err);
             goto end;
         }
+        if (!SSL_CTX_use_psk_identity_hint(s_ctx2, "ctx server identity_hint")) {
+            BIO_printf(bio_err, "error setting PSK identity hint to s_ctx2\n");
+            ERR_print_errors(bio_err);
+            goto end;
+        }
 #endif
     }
 #ifndef OPENSSL_NO_SRP
@@ -1461,8 +1578,11 @@ int main(int argc, char *argv[])
 
     if (srp_server_arg.expected_user != NULL) {
         SSL_CTX_set_verify(s_ctx, SSL_VERIFY_NONE, verify_callback);
+        SSL_CTX_set_verify(s_ctx2, SSL_VERIFY_NONE, verify_callback);
         SSL_CTX_set_srp_cb_arg(s_ctx, &srp_server_arg);
+        SSL_CTX_set_srp_cb_arg(s_ctx2, &srp_server_arg);
         SSL_CTX_set_srp_username_callback(s_ctx, ssl_srp_server_param_cb);
+        SSL_CTX_set_srp_username_callback(s_ctx2, ssl_srp_server_param_cb);
     }
 #endif
 
@@ -1475,11 +1595,16 @@ int main(int argc, char *argv[])
                                       NULL, NULL, NULL,
                                       serverinfo_cli_parse_cb, NULL);
 
-    if (serverinfo_file)
+    if (serverinfo_file) {
         if (!SSL_CTX_use_serverinfo_file(s_ctx, serverinfo_file)) {
             BIO_printf(bio_err, "missing serverinfo file\n");
             goto end;
         }
+        if (!SSL_CTX_use_serverinfo_file(s_ctx2, serverinfo_file)) {
+            BIO_printf(bio_err, "missing serverinfo file\n");
+            goto end;
+        }
+    }
 
     if (custom_ext) {
         SSL_CTX_add_client_custom_ext(c_ctx, CUSTOM_EXT_TYPE_0,
@@ -1515,10 +1640,29 @@ int main(int argc, char *argv[])
                                       custom_ext_3_srv_add_cb,
                                       NULL, NULL,
                                       custom_ext_3_srv_parse_cb, NULL);
+
+        SSL_CTX_add_server_custom_ext(s_ctx2, CUSTOM_EXT_TYPE_0,
+                                      custom_ext_0_srv_add_cb,
+                                      NULL, NULL,
+                                      custom_ext_0_srv_parse_cb, NULL);
+        SSL_CTX_add_server_custom_ext(s_ctx2, CUSTOM_EXT_TYPE_1,
+                                      custom_ext_1_srv_add_cb,
+                                      NULL, NULL,
+                                      custom_ext_1_srv_parse_cb, NULL);
+        SSL_CTX_add_server_custom_ext(s_ctx2, CUSTOM_EXT_TYPE_2,
+                                      custom_ext_2_srv_add_cb,
+                                      NULL, NULL,
+                                      custom_ext_2_srv_parse_cb, NULL);
+        SSL_CTX_add_server_custom_ext(s_ctx2, CUSTOM_EXT_TYPE_3,
+                                      custom_ext_3_srv_add_cb,
+                                      NULL, NULL,
+                                      custom_ext_3_srv_parse_cb, NULL);
     }
 
     if (alpn_server)
-        SSL_CTX_set_alpn_select_cb(s_ctx, cb_server_alpn, NULL);
+        SSL_CTX_set_alpn_select_cb(s_ctx, cb_server_alpn, alpn_server);
+    if (alpn_server2)
+        SSL_CTX_set_alpn_select_cb(s_ctx2, cb_server_alpn, alpn_server2);
 
     if (alpn_client) {
         unsigned short alpn_len;
@@ -1532,9 +1676,15 @@ int main(int argc, char *argv[])
         OPENSSL_free(alpn);
     }
 
+    if (sn_server1 || sn_server2)
+        SSL_CTX_set_tlsext_servername_callback(s_ctx, servername_cb);
+
     c_ssl = SSL_new(c_ctx);
     s_ssl = SSL_new(s_ctx);
 
+    if (sn_client)
+        SSL_set_tlsext_host_name(c_ssl, sn_client);
+
 #ifndef OPENSSL_NO_KRB5
     if (c_ssl && c_ssl->kssl_ctx) {
         char localhost[MAXHOSTNAMELEN + 2];
@@ -1588,12 +1738,19 @@ int main(int argc, char *argv[])
 #endif
     }
 
+    if (verify_alpn(c_ssl, s_ssl) < 0)
+        ret = 1;
+    if (verify_servername(c_ssl, s_ssl) < 0)
+        ret = 1;
+
     SSL_free(s_ssl);
     SSL_free(c_ssl);
 
  end:
     if (s_ctx != NULL)
         SSL_CTX_free(s_ctx);
+    if (s_ctx2 != NULL)
+        SSL_CTX_free(s_ctx2);
     if (c_ctx != NULL)
         SSL_CTX_free(c_ctx);
 
@@ -1961,10 +2118,6 @@ int doit_biopair(SSL *s_ssl, SSL *c_ssl, long count,
         ret = 1;
         goto err;
     }
-    if (verify_alpn(c_ssl, s_ssl) < 0) {
-        ret = 1;
-        goto err;
-    }
 
     if (custom_ext_error) {
         ret = 1;
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 0bf0ea5363..dd5bd0050d 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -1539,6 +1539,7 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *buf,
         s2n(s->alpn_client_proto_list_len, ret);
         memcpy(ret, s->alpn_client_proto_list, s->alpn_client_proto_list_len);
         ret += s->alpn_client_proto_list_len;
+        s->cert->alpn_sent = 1;
     }
 # ifndef OPENSSL_NO_SRTP
     if (SSL_IS_DTLS(s) && SSL_get_srtp_profiles(s)) {
@@ -1906,7 +1907,7 @@ static void ssl_check_for_safari(SSL *s, const unsigned char *data,
 # endif                         /* !OPENSSL_NO_EC */
 
 /*
- * tls1_alpn_handle_client_hello is called to process the ALPN extension in a
+ * tls1_alpn_handle_client_hello is called to save the ALPN extension in a
  * ClientHello.  data: the contents of the extension, not including the type
  * and length.  data_len: the number of bytes in |data| al: a pointer to the
  * alert value to send in the event of a non-zero return.  returns: 0 on
@@ -1917,12 +1918,6 @@ static int tls1_alpn_handle_client_hello(SSL *s, const unsigned char *data,
 {
     unsigned i;
     unsigned proto_len;
-    const unsigned char *selected;
-    unsigned char selected_len;
-    int r;
-
-    if (s->ctx->alpn_select_cb == NULL)
-        return 0;
 
     if (data_len < 2)
         goto parse_error;
@@ -1953,19 +1948,15 @@ static int tls1_alpn_handle_client_hello(SSL *s, const unsigned char *data,
         i += proto_len;
     }
 
-    r = s->ctx->alpn_select_cb(s, &selected, &selected_len, data, data_len,
-                               s->ctx->alpn_select_cb_arg);
-    if (r == SSL_TLSEXT_ERR_OK) {
-        if (s->s3->alpn_selected)
-            OPENSSL_free(s->s3->alpn_selected);
-        s->s3->alpn_selected = OPENSSL_malloc(selected_len);
-        if (!s->s3->alpn_selected) {
-            *al = SSL_AD_INTERNAL_ERROR;
-            return -1;
-        }
-        memcpy(s->s3->alpn_selected, selected, selected_len);
-        s->s3->alpn_selected_len = selected_len;
+    if (s->cert->alpn_proposed != NULL)
+        OPENSSL_free(s->cert->alpn_proposed);
+    s->cert->alpn_proposed = OPENSSL_malloc(data_len);
+    if (s->cert->alpn_proposed == NULL) {
+        *al = SSL_AD_INTERNAL_ERROR;
+        return -1;
     }
+    memcpy(s->cert->alpn_proposed, data, data_len);
+    s->cert->alpn_proposed_len = data_len;
     return 0;
 
  parse_error:
@@ -1973,6 +1964,43 @@ static int tls1_alpn_handle_client_hello(SSL *s, const unsigned char *data,
     return -1;
 }
 
+/*
+ * Process the ALPN extension in a ClientHello.
+ * ret: a pointer to the TLSEXT return value: SSL_TLSEXT_ERR_*
+ * al: a pointer to the alert value to send in the event of a failure.
+ * returns 1 on success, 0 on failure: al/ret set only on failure
+ */
+static int tls1_alpn_handle_client_hello_late(SSL *s, int *ret, int *al)
+{
+    const unsigned char *selected = NULL;
+    unsigned char selected_len = 0;
+
+    if (s->ctx->alpn_select_cb != NULL && s->cert->alpn_proposed != NULL) {
+        int r = s->ctx->alpn_select_cb(s, &selected, &selected_len,
+                                       s->cert->alpn_proposed,
+                                       s->cert->alpn_proposed_len,
+                                       s->ctx->alpn_select_cb_arg);
+
+        if (r == SSL_TLSEXT_ERR_OK) {
+            OPENSSL_free(s->s3->alpn_selected);
+            s->s3->alpn_selected = OPENSSL_malloc(selected_len);
+            if (s->s3->alpn_selected == NULL) {
+                *al = SSL_AD_INTERNAL_ERROR;
+                *ret = SSL_TLSEXT_ERR_ALERT_FATAL;
+                return 0;
+            }
+            memcpy(s->s3->alpn_selected, selected, selected_len);
+            s->s3->alpn_selected_len = selected_len;
+# ifndef OPENSSL_NO_NEXTPROTONEG
+            /* ALPN takes precedence over NPN. */
+            s->s3->next_proto_neg_seen = 0;
+# endif
+        }
+    }
+
+    return 1;
+}
+
 static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p,
                                        unsigned char *limit, int *al)
 {
@@ -1992,6 +2020,12 @@ static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p,
         OPENSSL_free(s->s3->alpn_selected);
         s->s3->alpn_selected = NULL;
     }
+    s->s3->alpn_selected_len = 0;
+    if (s->cert->alpn_proposed) {
+        OPENSSL_free(s->cert->alpn_proposed);
+        s->cert->alpn_proposed = NULL;
+    }
+    s->cert->alpn_proposed_len = 0;
 # ifndef OPENSSL_NO_HEARTBEATS
     s->tlsext_heartbeat &= ~(SSL_TLSEXT_HB_ENABLED |
                              SSL_TLSEXT_HB_DONT_SEND_REQUESTS);
@@ -2359,8 +2393,7 @@ static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p,
 # endif
 # ifndef OPENSSL_NO_NEXTPROTONEG
         else if (type == TLSEXT_TYPE_next_proto_neg &&
-                 s->s3->tmp.finish_md_len == 0 &&
-                 s->s3->alpn_selected == NULL) {
+                 s->s3->tmp.finish_md_len == 0) {
             /*-
              * We shouldn't accept this extension on a
              * renegotiation.
@@ -2383,13 +2416,9 @@ static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p,
 # endif
 
         else if (type == TLSEXT_TYPE_application_layer_protocol_negotiation &&
-                 s->ctx->alpn_select_cb && s->s3->tmp.finish_md_len == 0) {
+                 s->s3->tmp.finish_md_len == 0) {
             if (tls1_alpn_handle_client_hello(s, data, size, al) != 0)
                 return 0;
-# ifndef OPENSSL_NO_NEXTPROTONEG
-            /* ALPN takes precedence over NPN. */
-            s->s3->next_proto_neg_seen = 0;
-# endif
         }
 
         /* session ticket processed earlier */
@@ -2698,7 +2727,7 @@ static int ssl_scan_serverhello_tlsext(SSL *s, unsigned char **p,
             unsigned len;
 
             /* We must have requested it. */
-            if (s->alpn_client_proto_list == NULL) {
+            if (!s->cert->alpn_sent) {
                 *al = TLS1_AD_UNSUPPORTED_EXTENSION;
                 return 0;
             }
@@ -2863,6 +2892,7 @@ int ssl_prepare_clienthello_tlsext(SSL *s)
     }
 # endif
 
+    s->cert->alpn_sent = 0;
     return 1;
 }
 
@@ -3066,6 +3096,10 @@ int ssl_check_clienthello_tlsext_late(SSL *s)
     } else
         s->tlsext_status_expected = 0;
 
+    if (!tls1_alpn_handle_client_hello_late(s, &ret, &al)) {
+        goto err;
+    }
+
  err:
     switch (ret) {
     case SSL_TLSEXT_ERR_ALERT_FATAL:
diff --git a/test/testssl b/test/testssl
index 747e4ba381..a6f9fa770b 100644
--- a/test/testssl
+++ b/test/testssl
@@ -236,6 +236,17 @@ $ssltest -bio_pair -tls1 -serverinfo_file $serverinfo -serverinfo_tack || exit 1
 $ssltest -bio_pair -tls1 -serverinfo_file $serverinfo -serverinfo_sct -serverinfo_tack || exit 1
 $ssltest -bio_pair -tls1 -custom_ext -serverinfo_file $serverinfo -serverinfo_sct -serverinfo_tack || exit 1
 
+#############################################################################
+# SNI tests
+
+$ssltest -bio_pair -sn_client foo || exit 1
+$ssltest -bio_pair -sn_server1 foo || exit 1
+$ssltest -bio_pair -sn_client foo -sn_server1 foo -sn_expect1 || exit 1
+$ssltest -bio_pair -sn_client foo -sn_server1 bar -sn_expect1 || exit 1
+$ssltest -bio_pair -sn_client foo -sn_server1 foo -sn_server2 bar -sn_expect1 || exit 1
+$ssltest -bio_pair -sn_client bar -sn_server1 foo -sn_server2 bar -sn_expect2 || exit 1
+# Negative test - make sure it doesn't crash, and doesn't switch contexts
+$ssltest -bio_pair -sn_client foobar -sn_server1 foo -sn_server2 bar -sn_expect1 || exit 1
 
 #############################################################################
 # ALPN tests
@@ -249,6 +260,14 @@ $ssltest -bio_pair -tls1 -alpn_client bar,foo -alpn_server bar,foo -alpn_expecte
 $ssltest -bio_pair -tls1 -alpn_client foo,bar -alpn_server bar,foo -alpn_expected bar || exit 1
 $ssltest -bio_pair -tls1 -alpn_client baz -alpn_server bar,foo || exit 1
 
+
+#############################################################################
+# ALPN + SNI
+
+$ssltest -bio_pair -alpn_client foo,bar -sn_client alice -alpn_server1 foo,123 -sn_server1 alice -alpn_server2 bar,456 -sn_server2 bob -alpn_expected foo || exit 1
+$ssltest -bio_pair -alpn_client foo,bar -sn_client bob -alpn_server1 foo,123 -sn_server1 alice -alpn_server2 bar,456 -sn_server2 bob -alpn_expected bar || exit 1
+$ssltest -bio_pair -alpn_client foo,bar -sn_client bob -sn_server1 alice -alpn_server2 bar,456 -sn_server2 bob -alpn_expected bar || exit 1
+
 if ../util/shlib_wrap.sh ../apps/openssl no-srp; then
   echo skipping SRP tests
 else