Implement certificate_authorities extension
[openssl.git] / ssl / statem / extensions.c
index 99326b2..d0b15d5 100644 (file)
@@ -7,6 +7,7 @@
  * https://www.openssl.org/source/license.html
  */
 
+#include <string.h>
 #include "../ssl_locl.h"
 #include "statem_locl.h"
 
@@ -29,6 +30,13 @@ 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 int 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
@@ -36,11 +44,14 @@ static int init_etm(SSL *s, unsigned int context);
 static int init_ems(SSL *s, unsigned int context);
 static int final_ems(SSL *s, unsigned int context, int sent, int *al);
 static int init_psk_kex_modes(SSL *s, unsigned int context);
+#ifndef OPENSSL_NO_EC
 static int final_key_share(SSL *s, unsigned int context, int sent, int *al);
+#endif
 #ifndef OPENSSL_NO_SRTP
 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 {
@@ -155,8 +166,9 @@ static const EXTENSION_DEFINITION ext_defs[] = {
     },
     {
         TLSEXT_TYPE_signature_algorithms,
-        EXT_CLIENT_HELLO,
-        init_sig_algs, tls_parse_ctos_sig_algs, NULL, NULL,
+        EXT_CLIENT_HELLO | 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
@@ -205,7 +217,7 @@ 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_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY | EXT_SSL3_ALLOWED,
         init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm,
         tls_construct_stoc_etm, tls_construct_ctos_etm, NULL
     },
@@ -244,6 +256,7 @@ static const EXTENSION_DEFINITION ext_defs[] = {
         init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL,
         tls_construct_ctos_psk_kex_modes, NULL
     },
+#ifndef OPENSSL_NO_EC
     {
         /*
          * Must be in this list after supported_groups. We need that to have
@@ -257,6 +270,14 @@ static const EXTENSION_DEFINITION ext_defs[] = {
         tls_construct_stoc_key_share, tls_construct_ctos_key_share,
         final_key_share
     },
+#endif
+    {
+        TLSEXT_TYPE_cookie,
+        EXT_CLIENT_HELLO | EXT_TLS1_3_HELLO_RETRY_REQUEST
+        | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
+        NULL, NULL, tls_parse_stoc_cookie, NULL, tls_construct_ctos_cookie,
+        NULL
+    },
     {
         /*
          * Special unsolicited ServerHello extension only used when
@@ -266,9 +287,24 @@ static const EXTENSION_DEFINITION ext_defs[] = {
         EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
         NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
     },
+    {
+        TLSEXT_TYPE_early_data,
+        EXT_CLIENT_HELLO | EXT_TLS1_3_ENCRYPTED_EXTENSIONS
+        | 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,
+        EXT_CLIENT_HELLO | EXT_TLS1_3_CERTIFICATE_REQUEST | 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,
         NULL,
@@ -378,10 +414,11 @@ 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)
+                           RAW_EXTENSION **res, int *al, size_t *len)
 {
     PACKET extensions = *packet;
     size_t i = 0;
+    size_t num_exts;
     custom_ext_methods *exts = NULL;
     RAW_EXTENSION *raw_extensions = NULL;
     const EXTENSION_DEFINITION *thisexd;
@@ -399,9 +436,8 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
         exts = &s->cert->cli_ext;
     }
 
-    raw_extensions = OPENSSL_zalloc((OSSL_NELEM(ext_defs)
-                                     + (exts != NULL ? exts->meths_count : 0))
-                                     * sizeof(*raw_extensions));
+    num_exts = OSSL_NELEM(ext_defs) + (exts != NULL ? exts->meths_count : 0);
+    raw_extensions = OPENSSL_zalloc(num_exts * sizeof(*raw_extensions));
     if (raw_extensions == NULL) {
         *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_MALLOC_FAILURE);
@@ -421,10 +457,14 @@ 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 & 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;
@@ -450,6 +490,8 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
     }
 
     *res = raw_extensions;
+    if (len != NULL)
+        *len = num_exts;
     return 1;
 
  err:
@@ -843,8 +885,8 @@ 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;
@@ -908,7 +950,7 @@ static int init_srp(SSL *s, unsigned int context)
 
 static int init_etm(SSL *s, unsigned int context)
 {
-    s->s3->flags &= ~TLS1_FLAGS_ENCRYPT_THEN_MAC;
+    s->ext.use_etm = 0;
 
     return 1;
 }
@@ -939,6 +981,47 @@ 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.ca_names, X509_NAME_free);
+    s->s3->tmp.ca_names = NULL;
+    return 1;
+}
+
+static int tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
+                                                 unsigned int context, X509 *x,
+                                                 size_t chainidx, int *al)
+{
+    STACK_OF(X509_NAME) *ca_sk = SSL_get_client_CA_list(s);
+
+    if (ca_sk == NULL || sk_X509_NAME_num(ca_sk) == 0)
+        return 1;
+
+    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 0;
+    }
+
+    return 1;
+}
+
+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)
 {
@@ -960,7 +1043,7 @@ static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al)
     return 1;
 }
 
-
+#ifndef OPENSSL_NO_EC
 static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
 {
     if (!SSL_IS_TLS13(s))
@@ -1018,7 +1101,7 @@ static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
                        != 0)) {
             const unsigned char *pcurves, *pcurvestmp, *clntcurves;
             size_t num_curves, clnt_num_curves, i;
-            unsigned int group_id;
+            unsigned int group_id = 0;
 
             /* Check if a shared group exists */
 
@@ -1078,6 +1161,7 @@ static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
 
     return 1;
 }
+#endif
 
 static int init_psk_kex_modes(SSL *s, unsigned int context)
 {
@@ -1210,3 +1294,32 @@ 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;
+}