Only accept early_data if the negotiated ALPN is the same

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2737)

ssl/ssl_asn1.c

@@ -66,6 +66,7 @@ typedef struct {
 #endif
     long flags;
     uint32_t max_early_data;
+    ASN1_OCTET_STRING *alpn_selected;
 } SSL_SESSION_ASN1;
 
 ASN1_SEQUENCE(SSL_SESSION_ASN1) = {
@@ -93,7 +94,8 @@ ASN1_SEQUENCE(SSL_SESSION_ASN1) = {
 #endif
     ASN1_EXP_OPT(SSL_SESSION_ASN1, flags, ZLONG, 13),
     ASN1_EXP_OPT(SSL_SESSION_ASN1, tlsext_tick_age_add, ZLONG, 14),
-    ASN1_EXP_OPT(SSL_SESSION_ASN1, max_early_data, ZLONG, 15)
+    ASN1_EXP_OPT(SSL_SESSION_ASN1, max_early_data, ZLONG, 15),
+    ASN1_EXP_OPT(SSL_SESSION_ASN1, alpn_selected, ASN1_OCTET_STRING, 16)
 } static_ASN1_SEQUENCE_END(SSL_SESSION_ASN1)
 
 IMPLEMENT_STATIC_ASN1_ENCODE_FUNCTIONS(SSL_SESSION_ASN1)
@@ -134,16 +136,14 @@ int i2d_SSL_SESSION(SSL_SESSION *in, unsigned char **pp)
     ASN1_OCTET_STRING comp_id;
     unsigned char comp_id_data;
 #endif
-
     ASN1_OCTET_STRING tlsext_hostname, tlsext_tick;
-
 #ifndef OPENSSL_NO_SRP
     ASN1_OCTET_STRING srp_username;
 #endif
-
 #ifndef OPENSSL_NO_PSK
     ASN1_OCTET_STRING psk_identity, psk_identity_hint;
 #endif
+    ASN1_OCTET_STRING alpn_selected;
 
     long l;
 
@@ -207,6 +207,12 @@ int i2d_SSL_SESSION(SSL_SESSION *in, unsigned char **pp)
     as.flags = in->flags;
     as.max_early_data = in->ext.max_early_data;
 
+    if (in->ext.alpn_selected == NULL)
+        as.alpn_selected = NULL;
+    else
+        ssl_session_oinit(&as.alpn_selected, &alpn_selected,
+                          in->ext.alpn_selected, in->ext.alpn_selected_len);
+
     return i2d_SSL_SESSION_ASN1(&as, pp);
 
 }
@@ -362,6 +368,16 @@ SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const unsigned char **pp,
     ret->flags = as->flags;
     ret->ext.max_early_data = as->max_early_data;
 
+    if (as->alpn_selected != NULL) {
+        if (!ssl_session_strndup((char **)&ret->ext.alpn_selected,
+                                 as->alpn_selected))
+            goto err;
+        ret->ext.alpn_selected_len = as->alpn_selected->length;
+    } else {
+        ret->ext.alpn_selected = NULL;
+        ret->ext.alpn_selected_len = 0;
+    }
+
     M_ASN1_free_of(as, SSL_SESSION_ASN1);
 
     if ((a != NULL) && (*a == NULL))

ssl/ssl_locl.h

@@ -580,6 +580,9 @@ struct ssl_session_st {
         int tick_identity;
         /* Max number of bytes that can be sent as early data */
         uint32_t max_early_data;
+        /* The ALPN protocol selected for this session */
+        unsigned char *alpn_selected;
+        size_t alpn_selected_len;
     } ext;
 # ifndef OPENSSL_NO_SRP
     char *srp_username;

ssl/ssl_sess.c

@@ -791,6 +791,7 @@ void SSL_SESSION_free(SSL_SESSION *ss)
 #ifndef OPENSSL_NO_SRP
     OPENSSL_free(ss->srp_username);
 #endif
+    OPENSSL_free(ss->ext.alpn_selected);
     CRYPTO_THREAD_lock_free(ss->lock);
     OPENSSL_clear_free(ss, sizeof(*ss));
 }

ssl/statem/extensions.c

@@ -7,6 +7,7 @@
  * https://www.openssl.org/source/license.html
  */
 
+#include <string.h>
 #include "../ssl_locl.h"
 #include "statem_locl.h"
 
@@ -1242,7 +1243,10 @@ static int final_early_data(SSL *s, unsigned int context, int sent, int *al)
             || s->session->ext.tick_identity != 0
             || s->early_data_state != SSL_EARLY_DATA_ACCEPTING
             || !s->ext.early_data_ok
-            || s->hello_retry_request) {
+            || s->hello_retry_request
+            || s->s3->alpn_selected_len != s->session->ext.alpn_selected_len
+            || 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;

ssl/statem/statem_srvr.c

@@ -3401,6 +3401,18 @@ int tls_construct_new_session_ticket(SSL *s, WPACKET *pkt)
             goto err;
         s->session->ext.tick_age_add = age_add_u.age_add;
         s->session->time = (long)time(NULL);
+        if (s->s3->alpn_selected != NULL) {
+            OPENSSL_free(s->session->ext.alpn_selected);
+            s->session->ext.alpn_selected =
+                OPENSSL_memdup(s->s3->alpn_selected, s->s3->alpn_selected_len);
+            if (s->session->ext.alpn_selected == NULL) {
+                SSLerr(SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET,
+                       ERR_R_MALLOC_FAILURE);
+                goto err;
+            }
+            s->session->ext.alpn_selected_len = s->s3->alpn_selected_len;
+        }
+        s->session->ext.max_early_data = s->max_early_data;
     }
 
     /* get session encoding length */
@@ -3410,13 +3422,13 @@ int tls_construct_new_session_ticket(SSL *s, WPACKET *pkt)
      * long
      */
     if (slen_full == 0 || slen_full > 0xFF00) {
-        ossl_statem_set_error(s);
-        return 0;
+        SSLerr(SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET, ERR_R_INTERNAL_ERROR);
+        goto err;
     }
     senc = OPENSSL_malloc(slen_full);
     if (senc == NULL) {
-        ossl_statem_set_error(s);
-        return 0;
+        SSLerr(SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET, ERR_R_MALLOC_FAILURE);
+        goto err;
     }
 
     ctx = EVP_CIPHER_CTX_new();
@@ -3545,6 +3557,7 @@ int tls_construct_new_session_ticket(SSL *s, WPACKET *pkt)
 
     return 1;
  err:
+    ossl_statem_set_error(s);
     OPENSSL_free(senc);
     EVP_CIPHER_CTX_free(ctx);
     HMAC_CTX_free(hctx);