Fix a bundle of trailing spaces in several files
[openssl.git] / ssl / statem / extensions.c
index f8bd47a..b4d85d9 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2016-2017 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -7,6 +7,7 @@
  * https://www.openssl.org/source/license.html
  */
 
+#include <string.h>
 #include "../ssl_locl.h"
 #include "statem_locl.h"
 
@@ -29,6 +30,15 @@ static int init_npn(SSL *s, unsigned int context);
 static int init_alpn(SSL *s, unsigned int context);
 static int final_alpn(SSL *s, unsigned int context, int sent, int *al);
 static int init_sig_algs(SSL *s, unsigned int context);
+static int init_certificate_authorities(SSL *s, unsigned int context);
+static EXT_RETURN tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
+                                                        unsigned int context,
+                                                        X509 *x,
+                                                        size_t chainidx,
+                                                        int *al);
+static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx, int *al);
 #ifndef OPENSSL_NO_SRP
 static int init_srp(SSL *s, unsigned int context);
 #endif
@@ -43,6 +53,7 @@ static int final_key_share(SSL *s, unsigned int context, int sent, int *al);
 static int init_srtp(SSL *s, unsigned int context);
 #endif
 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al);
+static int final_early_data(SSL *s, unsigned int context, int sent, int *al);
 
 /* Structure to define a built-in extension */
 typedef struct extensions_definition_st {
@@ -65,11 +76,11 @@ typedef struct extensions_definition_st {
     int (*parse_stoc)(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
                       size_t chainidx, int *al);
     /* Construct extension sent from server to client */
-    int (*construct_stoc)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                          size_t chainidx, int *al);
+    EXT_RETURN (*construct_stoc)(SSL *s, WPACKET *pkt, unsigned int context,
+                                 X509 *x, size_t chainidx, int *al);
     /* Construct extension sent from client to server */
-    int (*construct_ctos)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                          size_t chainidx, int *al);
+    EXT_RETURN (*construct_ctos)(SSL *s, WPACKET *pkt, unsigned int context,
+                                 X509 *x, size_t chainidx, int *al);
     /*
      * Finalise extension after parsing. Always called where an extensions was
      * initialised even if the extension was not present. |sent| is set to 1 if
@@ -80,7 +91,7 @@ typedef struct extensions_definition_st {
 
 /*
  * Definitions of all built-in extensions. NOTE: Changes in the number or order
- * of these extensions should be mirrored with equivalent changes to the 
+ * of these extensions should be mirrored with equivalent changes to the
  * indexes ( TLSEXT_IDX_* ) defined in ssl_locl.h.
  * Each extension has an initialiser, a client and
  * server side parser and a finaliser. The initialiser is called (if the
@@ -105,16 +116,16 @@ typedef struct extensions_definition_st {
 static const EXTENSION_DEFINITION ext_defs[] = {
     {
         TLSEXT_TYPE_renegotiate,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_SSL3_ALLOWED
-        | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_SSL3_ALLOWED | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         NULL, tls_parse_ctos_renegotiate, tls_parse_stoc_renegotiate,
         tls_construct_stoc_renegotiate, tls_construct_ctos_renegotiate,
         final_renegotiate
     },
     {
         TLSEXT_TYPE_server_name,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
-        | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
         init_server_name,
         tls_parse_ctos_server_name, tls_parse_stoc_server_name,
         tls_construct_stoc_server_name, tls_construct_ctos_server_name,
@@ -123,37 +134,26 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #ifndef OPENSSL_NO_SRP
     {
         TLSEXT_TYPE_srp,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         init_srp, tls_parse_ctos_srp, NULL, NULL, tls_construct_ctos_srp, NULL
     },
 #else
     INVALID_EXTENSION,
 #endif
-    {
-        TLSEXT_TYPE_early_data_info,
-        EXT_TLS1_3_NEW_SESSION_TICKET,
-        NULL, NULL, tls_parse_stoc_early_data_info,
-        tls_construct_stoc_early_data_info, NULL, NULL
-    },
-    {
-        TLSEXT_TYPE_early_data,
-        EXT_CLIENT_HELLO | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
-        NULL, tls_parse_ctos_early_data, NULL, tls_construct_stoc_early_data,
-        tls_construct_ctos_early_data, NULL
-    },
 #ifndef OPENSSL_NO_EC
     {
         TLSEXT_TYPE_ec_point_formats,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         NULL, tls_parse_ctos_ec_pt_formats, tls_parse_stoc_ec_pt_formats,
         tls_construct_stoc_ec_pt_formats, tls_construct_ctos_ec_pt_formats,
         final_ec_pt_formats
     },
     {
         TLSEXT_TYPE_supported_groups,
-        EXT_CLIENT_HELLO | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
         NULL, tls_parse_ctos_supported_groups, NULL,
-        NULL /* TODO(TLS1.3): Need to add this */,
+        tls_construct_stoc_supported_groups,
         tls_construct_ctos_supported_groups, NULL
     },
 #else
@@ -162,22 +162,24 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #endif
     {
         TLSEXT_TYPE_session_ticket,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         init_session_ticket, tls_parse_ctos_session_ticket,
         tls_parse_stoc_session_ticket, tls_construct_stoc_session_ticket,
         tls_construct_ctos_session_ticket, NULL
     },
     {
         TLSEXT_TYPE_signature_algorithms,
-        EXT_CLIENT_HELLO,
-        init_sig_algs, tls_parse_ctos_sig_algs, NULL, NULL,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST,
+        init_sig_algs, tls_parse_ctos_sig_algs,
+        tls_parse_ctos_sig_algs, tls_construct_ctos_sig_algs,
         tls_construct_ctos_sig_algs, final_sig_algs
     },
 #ifndef OPENSSL_NO_OCSP
     {
         TLSEXT_TYPE_status_request,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
-        | EXT_TLS1_3_CERTIFICATE,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_3_CERTIFICATE,
         init_status_request, tls_parse_ctos_status_request,
         tls_parse_stoc_status_request, tls_construct_stoc_status_request,
         tls_construct_ctos_status_request, NULL
@@ -188,7 +190,8 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #ifndef OPENSSL_NO_NEXTPROTONEG
     {
         TLSEXT_TYPE_next_proto_neg,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         init_npn, tls_parse_ctos_npn, tls_parse_stoc_npn,
         tls_construct_stoc_next_proto_neg, tls_construct_ctos_npn, NULL
     },
@@ -201,16 +204,16 @@ static const EXTENSION_DEFINITION ext_defs[] = {
          * happens after server_name callbacks
          */
         TLSEXT_TYPE_application_layer_protocol_negotiation,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
-        | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
         init_alpn, tls_parse_ctos_alpn, tls_parse_stoc_alpn,
         tls_construct_stoc_alpn, tls_construct_ctos_alpn, final_alpn
     },
 #ifndef OPENSSL_NO_SRTP
     {
         TLSEXT_TYPE_use_srtp,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
-        | EXT_TLS1_3_ENCRYPTED_EXTENSIONS | EXT_DTLS_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS | SSL_EXT_DTLS_ONLY,
         init_srtp, tls_parse_ctos_use_srtp, tls_parse_stoc_use_srtp,
         tls_construct_stoc_use_srtp, tls_construct_ctos_use_srtp, NULL
     },
@@ -219,15 +222,16 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #endif
     {
         TLSEXT_TYPE_encrypt_then_mac,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY | EXT_SSL3_ALLOWED,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm,
         tls_construct_stoc_etm, tls_construct_ctos_etm, NULL
     },
 #ifndef OPENSSL_NO_CT
     {
         TLSEXT_TYPE_signed_certificate_timestamp,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
-        | EXT_TLS1_3_CERTIFICATE,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_3_CERTIFICATE,
         NULL,
         /*
          * No server side support for this, but can be provided by a custom
@@ -241,20 +245,23 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #endif
     {
         TLSEXT_TYPE_extended_master_secret,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         init_ems, tls_parse_ctos_ems, tls_parse_stoc_ems,
         tls_construct_stoc_ems, tls_construct_ctos_ems, final_ems
     },
     {
         TLSEXT_TYPE_supported_versions,
-        EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY
+        | SSL_EXT_TLS1_3_ONLY,
         NULL,
         /* Processed inline as part of version selection */
         NULL, NULL, NULL, tls_construct_ctos_supported_versions, NULL
     },
     {
         TLSEXT_TYPE_psk_kex_modes,
-        EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY
+        | SSL_EXT_TLS1_3_ONLY,
         init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL,
         tls_construct_ctos_psk_kex_modes, NULL
     },
@@ -265,28 +272,51 @@ static const EXTENSION_DEFINITION ext_defs[] = {
          * been parsed before we do this one.
          */
         TLSEXT_TYPE_key_share,
-        EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO
-        | EXT_TLS1_3_HELLO_RETRY_REQUEST | EXT_TLS_IMPLEMENTATION_ONLY
-        | EXT_TLS1_3_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO
+        | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST | SSL_EXT_TLS_IMPLEMENTATION_ONLY
+        | SSL_EXT_TLS1_3_ONLY,
         NULL, tls_parse_ctos_key_share, tls_parse_stoc_key_share,
         tls_construct_stoc_key_share, tls_construct_ctos_key_share,
         final_key_share
     },
 #endif
+    {
+        TLSEXT_TYPE_cookie,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST
+        | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY,
+        NULL, NULL, tls_parse_stoc_cookie, NULL, tls_construct_ctos_cookie,
+        NULL
+    },
     {
         /*
          * Special unsolicited ServerHello extension only used when
          * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
          */
         TLSEXT_TYPE_cryptopro_bug,
-        EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_TLS1_2_SERVER_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
     },
+    {
+        TLSEXT_TYPE_early_data,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS
+        | SSL_EXT_TLS1_3_NEW_SESSION_TICKET,
+        NULL, tls_parse_ctos_early_data, tls_parse_stoc_early_data,
+        tls_construct_stoc_early_data, tls_construct_ctos_early_data,
+        final_early_data
+    },
+    {
+        TLSEXT_TYPE_certificate_authorities,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
+        | SSL_EXT_TLS1_3_ONLY,
+        init_certificate_authorities,
+        tls_parse_certificate_authorities, tls_parse_certificate_authorities,
+        tls_construct_certificate_authorities,
+        tls_construct_certificate_authorities, NULL,
+    },
     {
         /* Must be immediately before pre_shared_key */
-        /* TODO(TLS1.3): Fix me */
         TLSEXT_TYPE_padding,
-        EXT_CLIENT_HELLO,
+        SSL_EXT_CLIENT_HELLO,
         NULL,
         /* We send this, but don't read it */
         NULL, NULL, NULL, tls_construct_ctos_padding, NULL
@@ -294,18 +324,35 @@ static const EXTENSION_DEFINITION ext_defs[] = {
     {
         /* Required by the TLSv1.3 spec to always be the last extension */
         TLSEXT_TYPE_psk,
-        EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO | EXT_TLS_IMPLEMENTATION_ONLY
-        | EXT_TLS1_3_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO
+        | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY,
         NULL, tls_parse_ctos_psk, tls_parse_stoc_psk, tls_construct_stoc_psk,
         tls_construct_ctos_psk, NULL
     }
 };
 
+/* Check whether an extension's context matches the current context */
+static int validate_context(SSL *s, unsigned int extctx, unsigned int thisctx)
+{
+    /* Check we're allowed to use this extension in this context */
+    if ((thisctx & extctx) == 0)
+        return 0;
+
+    if (SSL_IS_DTLS(s)) {
+        if ((extctx & SSL_EXT_TLS_ONLY) != 0)
+            return 0;
+    } else if ((extctx & SSL_EXT_DTLS_ONLY) != 0) {
+        return 0;
+    }
+
+    return 1;
+}
+
 /*
  * Verify whether we are allowed to use the extension |type| in the current
  * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to
  * indicate the extension is not allowed. If returning 1 then |*found| is set to
- * 1 if we found a definition for the extension, and |*idx| is set to its index
+ * the definition for the extension we found.
  */
 static int verify_extension(SSL *s, unsigned int context, unsigned int type,
                             custom_ext_methods *meths, RAW_EXTENSION *rawexlist,
@@ -317,38 +364,31 @@ static int verify_extension(SSL *s, unsigned int context, unsigned int type,
 
     for (i = 0, thisext = ext_defs; i < builtin_num; i++, thisext++) {
         if (type == thisext->type) {
-            /* Check we're allowed to use this extension in this context */
-            if ((context & thisext->context) == 0)
+            if (!validate_context(s, thisext->context, context))
                 return 0;
 
-            if (SSL_IS_DTLS(s)) {
-                if ((thisext->context & EXT_TLS_ONLY) != 0)
-                    return 0;
-            } else if ((thisext->context & EXT_DTLS_ONLY) != 0) {
-                    return 0;
-            }
-
             *found = &rawexlist[i];
             return 1;
         }
     }
 
-    if ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) == 0) {
-        /*
-         * Custom extensions only apply to <=TLS1.2. This extension is unknown
-         * in this context - we allow it
-         */
-        *found = NULL;
-        return 1;
-    }
-
     /* Check the custom extensions */
     if (meths != NULL) {
-        for (i = builtin_num; i < builtin_num + meths->meths_count; i++) {
-            if (meths->meths[i - builtin_num].ext_type == type) {
-                *found = &rawexlist[i];
-                return 1;
-            }
+        size_t offset = 0;
+        ENDPOINT role = ENDPOINT_BOTH;
+        custom_ext_method *meth = NULL;
+
+        if ((context & SSL_EXT_CLIENT_HELLO) != 0)
+            role = ENDPOINT_SERVER;
+        else if ((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0)
+            role = ENDPOINT_CLIENT;
+
+        meth = custom_ext_find(meths, role, type, &offset);
+        if (meth != NULL) {
+            if (!validate_context(s, meth->context, context))
+                return 0;
+            *found = &rawexlist[offset + builtin_num];
+            return 1;
         }
     }
 
@@ -362,16 +402,16 @@ static int verify_extension(SSL *s, unsigned int context, unsigned int type,
  * the extension is relevant for the current context |thisctx| or not. Returns
  * 1 if the extension is relevant for this context, and 0 otherwise
  */
-static int extension_is_relevant(SSL *s, unsigned int extctx,
-                                 unsigned int thisctx)
+int extension_is_relevant(SSL *s, unsigned int extctx, unsigned int thisctx)
 {
     if ((SSL_IS_DTLS(s)
-                && (extctx & EXT_TLS_IMPLEMENTATION_ONLY) != 0)
+                && (extctx & SSL_EXT_TLS_IMPLEMENTATION_ONLY) != 0)
             || (s->version == SSL3_VERSION
-                    && (extctx & EXT_SSL3_ALLOWED) == 0)
+                    && (extctx & SSL_EXT_SSL3_ALLOWED) == 0)
             || (SSL_IS_TLS13(s)
-                && (extctx & EXT_TLS1_2_AND_BELOW_ONLY) != 0)
-            || (!SSL_IS_TLS13(s) && (extctx & EXT_TLS1_3_ONLY) != 0))
+                && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0)
+            || (!SSL_IS_TLS13(s) && (extctx & SSL_EXT_TLS1_3_ONLY) != 0)
+            || (s->hit && (extctx & SSL_EXT_IGNORE_ON_RESUMPTION) != 0))
         return 0;
 
     return 1;
@@ -383,8 +423,9 @@ static int extension_is_relevant(SSL *s, unsigned int extctx,
  * stored in |*res| on success. In the event of an error the alert type to use
  * is stored in |*al|. We don't actually process the content of the extensions
  * yet, except to check their types. This function also runs the initialiser
- * functions for all known extensions (whether we have collected them or not).
- * If successful the caller is responsible for freeing the contents of |*res|.
+ * functions for all known extensions if |init| is nonzero (whether we have
+ * collected them or not). If successful the caller is responsible for freeing
+ * the contents of |*res|.
  *
  * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
  * more than one extension of the same type in a ClientHello or ServerHello.
@@ -394,12 +435,13 @@ static int extension_is_relevant(SSL *s, unsigned int extctx,
  * extensions that we know about. We ignore others.
  */
 int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
-                           RAW_EXTENSION **res, int *al, size_t *len)
+                           RAW_EXTENSION **res, int *al, size_t *len,
+                           int init)
 {
     PACKET extensions = *packet;
     size_t i = 0;
     size_t num_exts;
-    custom_ext_methods *exts = NULL;
+    custom_ext_methods *exts = &s->cert->custext;
     RAW_EXTENSION *raw_extensions = NULL;
     const EXTENSION_DEFINITION *thisexd;
 
@@ -409,12 +451,8 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
      * Initialise server side custom extensions. Client side is done during
      * construction of extensions for the ClientHello.
      */
-    if ((context & EXT_CLIENT_HELLO) != 0) {
-        exts = &s->cert->srv_ext;
-        custom_ext_init(&s->cert->srv_ext);
-    } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
-        exts = &s->cert->cli_ext;
-    }
+    if ((context & SSL_EXT_CLIENT_HELLO) != 0)
+        custom_ext_init(&s->cert->custext);
 
     num_exts = OSSL_NELEM(ext_defs) + (exts != NULL ? exts->meths_count : 0);
     raw_extensions = OPENSSL_zalloc(num_exts * sizeof(*raw_extensions));
@@ -425,7 +463,7 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
     }
 
     while (PACKET_remaining(&extensions) > 0) {
-        unsigned int type;
+        unsigned int type, idx;
         PACKET extension;
         RAW_EXTENSION *thisex;
 
@@ -437,14 +475,45 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
         }
         /*
          * Verify this extension is allowed. We only check duplicates for
-         * extensions that we recognise.
+         * extensions that we recognise. We also have a special case for the
+         * PSK extension, which must be the last one in the ClientHello.
          */
         if (!verify_extension(s, context, type, exts, raw_extensions, &thisex)
-                || (thisex != NULL && thisex->present == 1)) {
+                || (thisex != NULL && thisex->present == 1)
+                || (type == TLSEXT_TYPE_psk
+                    && (context & SSL_EXT_CLIENT_HELLO) != 0
+                    && PACKET_remaining(&extensions) != 0)) {
             SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
             *al = SSL_AD_ILLEGAL_PARAMETER;
             goto err;
         }
+        idx = thisex - raw_extensions;
+        /*-
+         * Check that we requested this extension (if appropriate). Requests can
+         * be sent in the ClientHello and CertificateRequest. Unsolicited
+         * extensions can be sent in the NewSessionTicket. We only do this for
+         * the built-in extensions. Custom extensions have a different but
+         * similar check elsewhere.
+         * Special cases:
+         * - The HRR cookie extension is unsolicited
+         * - The renegotiate extension is unsolicited (the client signals
+         *   support via an SCSV)
+         * - The signed_certificate_timestamp extension can be provided by a
+         * custom extension or by the built-in version. We let the extension
+         * itself handle unsolicited response checks.
+         */
+        if (idx < OSSL_NELEM(ext_defs)
+                && (context & (SSL_EXT_CLIENT_HELLO
+                               | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
+                               | SSL_EXT_TLS1_3_NEW_SESSION_TICKET)) == 0
+                && type != TLSEXT_TYPE_cookie
+                && type != TLSEXT_TYPE_renegotiate
+                && type != TLSEXT_TYPE_signed_certificate_timestamp
+                && (s->ext.extflags[idx] & SSL_EXT_FLAG_SENT) == 0) {
+            SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_UNSOLICITED_EXTENSION);
+            *al = SSL_AD_UNSUPPORTED_EXTENSION;
+            goto err;
+        }
         if (thisex != NULL) {
             thisex->data = extension;
             thisex->present = 1;
@@ -452,16 +521,19 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
         }
     }
 
-    /*
-     * Initialise all known extensions relevant to this context, whether we have
-     * found them or not
-     */
-    for (thisexd = ext_defs, i = 0; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
-        if(thisexd->init != NULL && (thisexd->context & context) != 0
+    if (init) {
+        /*
+         * Initialise all known extensions relevant to this context,
+         * whether we have found them or not
+         */
+        for (thisexd = ext_defs, i = 0; i < OSSL_NELEM(ext_defs);
+             i++, thisexd++) {
+            if (thisexd->init != NULL && (thisexd->context & context) != 0
                 && extension_is_relevant(s, thisexd->context, context)
                 && !thisexd->init(s, context)) {
-            *al = SSL_AD_INTERNAL_ERROR;
-            goto err;
+                *al = SSL_AD_INTERNAL_ERROR;
+                goto err;
+            }
         }
     }
 
@@ -528,21 +600,11 @@ int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
          */
     }
 
-    /*
-     * This is a custom extension. We only allow this if it is a non
-     * resumed session on the server side.
-     *chain
-     * TODO(TLS1.3): We only allow old style <=TLS1.2 custom extensions.
-     * We're going to need a new mechanism for TLS1.3 to specify which
-     * messages to add the custom extensions to.
-     */
-    if ((!s->hit || !s->server)
-            && (context
-                & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
-            && custom_ext_parse(s, s->server, currext->type,
-                                PACKET_data(&currext->data),
-                                PACKET_remaining(&currext->data),
-                                al) <= 0)
+    /* Parse custom extensions */
+    if (custom_ext_parse(s, context, currext->type,
+                         PACKET_data(&currext->data),
+                         PACKET_remaining(&currext->data),
+                         x, chainidx, al) <= 0)
         return 0;
 
     return 1;
@@ -550,24 +612,20 @@ int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
 
 /*
  * Parse all remaining extensions that have not yet been parsed. Also calls the
- * finalisation for all extensions at the end, whether we collected them or not.
- * Returns 1 for success or 0 for failure. If we are working on a Certificate
- * message then we also pass the Certificate |x| and its position in the
- * |chainidx|, with 0 being the first certificate. On failure, |*al| is
- * populated with a suitable alert code.
+ * finalisation for all extensions at the end if |fin| is nonzero, whether we
+ * collected them or not. Returns 1 for success or 0 for failure. If we are
+ * working on a Certificate message then we also pass the Certificate |x| and
+ * its position in the |chainidx|, with 0 being the first certificate. On
+ * failure, |*al| is populated with a suitable alert code.
  */
 int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
-                             size_t chainidx, int *al)
+                             size_t chainidx, int *al, int fin)
 {
     size_t i, numexts = OSSL_NELEM(ext_defs);
     const EXTENSION_DEFINITION *thisexd;
 
     /* Calculate the number of extensions in the extensions list */
-    if ((context & EXT_CLIENT_HELLO) != 0) {
-        numexts += s->cert->srv_ext.meths_count;
-    } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
-        numexts += s->cert->cli_ext.meths_count;
-    }
+    numexts += s->cert->custext.meths_count;
 
     /* Parse each extension in turn */
     for (i = 0; i < numexts; i++) {
@@ -575,20 +633,46 @@ int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
             return 0;
     }
 
-    /*
-     * Finalise all known extensions relevant to this context, whether we have
-     * found them or not
-     */
-    for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
-        if(thisexd->final != NULL
-                && (thisexd->context & context) != 0
+    if (fin) {
+        /*
+         * Finalise all known extensions relevant to this context,
+         * whether we have found them or not
+         */
+        for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs);
+             i++, thisexd++) {
+            if (thisexd->final != NULL && (thisexd->context & context) != 0
                 && !thisexd->final(s, context, exts[i].present, al))
-            return 0;
+                return 0;
+        }
     }
 
     return 1;
 }
 
+int should_add_extension(SSL *s, unsigned int extctx, unsigned int thisctx,
+                         int max_version)
+{
+    /* Skip if not relevant for our context */
+    if ((extctx & thisctx) == 0)
+        return 0;
+
+    /* Check if this extension is defined for our protocol. If not, skip */
+    if ((SSL_IS_DTLS(s) && (extctx & SSL_EXT_TLS_IMPLEMENTATION_ONLY) != 0)
+            || (s->version == SSL3_VERSION
+                    && (extctx & SSL_EXT_SSL3_ALLOWED) == 0)
+            || (SSL_IS_TLS13(s)
+                && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0)
+            || (!SSL_IS_TLS13(s)
+                && (extctx & SSL_EXT_TLS1_3_ONLY) != 0
+                && (thisctx & SSL_EXT_CLIENT_HELLO) == 0)
+            || ((extctx & SSL_EXT_TLS1_3_ONLY) != 0
+                && (thisctx & SSL_EXT_CLIENT_HELLO) != 0
+                && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION)))
+        return 0;
+
+    return 1;
+}
+
 /*
  * Construct all the extensions relevant to the current |context| and write
  * them to |pkt|. If this is an extension for a Certificate in a Certificate
@@ -602,7 +686,7 @@ int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
                              X509 *x, size_t chainidx, int *al)
 {
     size_t i;
-    int addcustom = 0, min_version, max_version = 0, reason, tmpal;
+    int min_version, max_version = 0, reason, tmpal;
     const EXTENSION_DEFINITION *thisexd;
 
     /*
@@ -616,16 +700,17 @@ int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
                 * If extensions are of zero length then we don't even add the
                 * extensions length bytes to a ClientHello/ServerHello in SSLv3
                 */
-            || ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
-               && s->version == SSL3_VERSION
-               && !WPACKET_set_flags(pkt,
+            || ((context &
+                 (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0
+                && s->version == SSL3_VERSION
+                && !WPACKET_set_flags(pkt,
                                      WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH))) {
         SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
         goto err;
     }
 
-    if ((context & EXT_CLIENT_HELLO) != 0) {
-        reason = ssl_get_client_min_max_version(s, &min_version, &max_version);
+    if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
+        reason = ssl_get_min_max_version(s, &min_version, &max_version);
         if (reason != 0) {
             SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, reason);
             goto err;
@@ -633,57 +718,38 @@ int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
     }
 
     /* Add custom extensions first */
-    if ((context & EXT_CLIENT_HELLO) != 0) {
-        custom_ext_init(&s->cert->cli_ext);
-        addcustom = 1;
-    } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
-        /*
-         * We already initialised the custom extensions during ClientHello
-         * parsing.
-         *
-         * TODO(TLS1.3): We're going to need a new custom extension mechanism
-         * for TLS1.3, so that custom extensions can specify which of the
-         * multiple message they wish to add themselves to.
-         */
-        addcustom = 1;
+    if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
+        /* On the server side with initiase during ClientHello parsing */
+        custom_ext_init(&s->cert->custext);
     }
-
-    if (addcustom && !custom_ext_add(s, s->server, pkt, &tmpal)) {
+    if (!custom_ext_add(s, context, pkt, x, chainidx, max_version, &tmpal)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
         goto err;
     }
 
     for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
-        int (*construct)(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                         size_t chainidx, int *al);
+        EXT_RETURN (*construct)(SSL *s, WPACKET *pkt, unsigned int context,
+                                X509 *x, size_t chainidx, int *al);
+        EXT_RETURN ret;
 
         /* Skip if not relevant for our context */
-        if ((thisexd->context & context) == 0)
+        if (!should_add_extension(s, thisexd->context, context, max_version))
             continue;
 
         construct = s->server ? thisexd->construct_stoc
                               : thisexd->construct_ctos;
 
-        /* Check if this extension is defined for our protocol. If not, skip */
-        if ((SSL_IS_DTLS(s)
-                    && (thisexd->context & EXT_TLS_IMPLEMENTATION_ONLY)
-                       != 0)
-                || (s->version == SSL3_VERSION
-                        && (thisexd->context & EXT_SSL3_ALLOWED) == 0)
-                || (SSL_IS_TLS13(s)
-                    && (thisexd->context & EXT_TLS1_2_AND_BELOW_ONLY)
-                       != 0)
-                || (!SSL_IS_TLS13(s)
-                    && (thisexd->context & EXT_TLS1_3_ONLY) != 0
-                    && (context & EXT_CLIENT_HELLO) == 0)
-                || ((thisexd->context & EXT_TLS1_3_ONLY) != 0
-                    && (context & EXT_CLIENT_HELLO) != 0
-                    && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION))
-                || construct == NULL)
+        if (construct == NULL)
             continue;
 
-        if (!construct(s, pkt, context, x, chainidx, &tmpal))
+        ret = construct(s, pkt, context, x, chainidx, &tmpal);
+        if (ret == EXT_RETURN_FAIL)
             goto err;
+        if (ret == EXT_RETURN_SENT
+                && (context & (SSL_EXT_CLIENT_HELLO
+                               | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
+                               | SSL_EXT_TLS1_3_NEW_SESSION_TICKET)) != 0)
+            s->ext.extflags[i] |= SSL_EXT_FLAG_SENT;
     }
 
     if (!WPACKET_close(pkt)) {
@@ -861,8 +927,8 @@ static int init_alpn(SSL *s, unsigned int context)
 {
     OPENSSL_free(s->s3->alpn_selected);
     s->s3->alpn_selected = NULL;
+    s->s3->alpn_selected_len = 0;
     if (s->server) {
-        s->s3->alpn_selected_len = 0;
         OPENSSL_free(s->s3->alpn_proposed);
         s->s3->alpn_proposed = NULL;
         s->s3->alpn_proposed_len = 0;
@@ -896,6 +962,9 @@ static int final_alpn(SSL *s, unsigned int context, int sent, int *al)
             /* ALPN takes precedence over NPN. */
             s->s3->npn_seen = 0;
 #endif
+        } else if (r == SSL_TLSEXT_ERR_NOACK) {
+            /* Behave as if no callback was present. */
+            return 1;
         } else {
             *al = SSL_AD_NO_APPLICATION_PROTOCOL;
             return 0;
@@ -957,6 +1026,49 @@ static int final_ems(SSL *s, unsigned int context, int sent, int *al)
     return 1;
 }
 
+static int init_certificate_authorities(SSL *s, unsigned int context)
+{
+    sk_X509_NAME_pop_free(s->s3->tmp.peer_ca_names, X509_NAME_free);
+    s->s3->tmp.peer_ca_names = NULL;
+    return 1;
+}
+
+static EXT_RETURN tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
+                                                        unsigned int context,
+                                                        X509 *x,
+                                                        size_t chainidx,
+                                                        int *al)
+{
+    const STACK_OF(X509_NAME) *ca_sk = SSL_get0_CA_list(s);
+
+    if (ca_sk == NULL || sk_X509_NAME_num(ca_sk) == 0)
+        return EXT_RETURN_NOT_SENT;
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_certificate_authorities)
+        || !WPACKET_start_sub_packet_u16(pkt)
+        || !construct_ca_names(s, pkt)
+        || !WPACKET_close(pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERTIFICATE_AUTHORITIES,
+               ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx, int *al)
+{
+    if (!parse_ca_names(s, pkt, al))
+        return 0;
+    if (PACKET_remaining(pkt) != 0) {
+        *al = SSL_AD_DECODE_ERROR;
+        return 0;
+    }
+    return 1;
+}
+
 #ifndef OPENSSL_NO_SRTP
 static int init_srtp(SSL *s, unsigned int context)
 {
@@ -969,7 +1081,7 @@ static int init_srtp(SSL *s, unsigned int context)
 
 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al)
 {
-    if (!sent && SSL_IS_TLS13(s)) {
+    if (!sent && SSL_IS_TLS13(s) && !s->hit) {
         *al = TLS13_AD_MISSING_EXTENSION;
         SSLerr(SSL_F_FINAL_SIG_ALGS, SSL_R_MISSING_SIGALGS_EXTENSION);
         return 0;
@@ -984,6 +1096,10 @@ static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
     if (!SSL_IS_TLS13(s))
         return 1;
 
+    /* Nothing to do for key_share in an HRR */
+    if ((context & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0)
+        return 1;
+
     /*
      * If
      *     we are a client
@@ -1000,7 +1116,7 @@ static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
             && (!s->hit
                 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
         /* Nothing left we can do - just fail */
-        *al = SSL_AD_HANDSHAKE_FAILURE;
+        *al = SSL_AD_MISSING_EXTENSION;
         SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
         return 0;
     }
@@ -1073,7 +1189,10 @@ static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
         if (!s->hit
                 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) {
             /* Nothing left we can do - just fail */
-            *al = SSL_AD_HANDSHAKE_FAILURE;
+            if (!sent)
+                *al = SSL_AD_MISSING_EXTENSION;
+            else
+                *al = SSL_AD_HANDSHAKE_FAILURE;
             SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
             return 0;
         }
@@ -1113,7 +1232,7 @@ int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
     EVP_MD_CTX *mctx = NULL;
     unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE];
     unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE];
-    const char resumption_label[] = "resumption psk binder key";
+    const char resumption_label[] = "res binder";
     size_t bindersize, hashsize = EVP_MD_size(md);
     int ret = -1;
 
@@ -1177,11 +1296,18 @@ int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
          * ClientHello - which we don't want - so we need to take that bit off.
          */
         if (s->server) {
-            if (hdatalen < s->init_num + SSL3_HM_HEADER_LENGTH) {
+            PACKET hashprefix, msg;
+
+            /* Find how many bytes are left after the first two messages */
+            if (!PACKET_buf_init(&hashprefix, hdata, hdatalen)
+                    || !PACKET_forward(&hashprefix, 1)
+                    || !PACKET_get_length_prefixed_3(&hashprefix, &msg)
+                    || !PACKET_forward(&hashprefix, 1)
+                    || !PACKET_get_length_prefixed_3(&hashprefix, &msg)) {
                 SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
                 goto err;
             }
-            hdatalen -= s->init_num + SSL3_HM_HEADER_LENGTH;
+            hdatalen -= PACKET_remaining(&hashprefix);
         }
 
         if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
@@ -1229,3 +1355,32 @@ int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
 
     return ret;
 }
+
+static int final_early_data(SSL *s, unsigned int context, int sent, int *al)
+{
+    if (!s->server || !sent)
+        return 1;
+
+    if (s->max_early_data == 0
+            || !s->hit
+            || s->session->ext.tick_identity != 0
+            || s->early_data_state != SSL_EARLY_DATA_ACCEPTING
+            || !s->ext.early_data_ok
+            || s->hello_retry_request
+            || s->s3->alpn_selected_len != s->session->ext.alpn_selected_len
+            || (s->s3->alpn_selected_len > 0
+                && memcmp(s->s3->alpn_selected, s->session->ext.alpn_selected,
+                          s->s3->alpn_selected_len) != 0)) {
+        s->ext.early_data = SSL_EARLY_DATA_REJECTED;
+    } else {
+        s->ext.early_data = SSL_EARLY_DATA_ACCEPTED;
+
+        if (!tls13_change_cipher_state(s,
+                    SSL3_CC_EARLY | SSL3_CHANGE_CIPHER_SERVER_READ)) {
+            *al = SSL_AD_INTERNAL_ERROR;
+            return 0;
+        }
+    }
+
+    return 1;
+}