Avoid "excessive message size" for session tickets

We received a report of an "excessive message size" for a received
session ticket. Our maximum size was significantly less than the theoretical
maximum. The server may put any data it likes in the session ticket
including (for example) the full certificate chain so we should be able to
handle longer tickets. Update the value to the maximum allowed by the spec.

Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15877)

(cherry picked from commit e54f0c9b2fe3dd2dcb5e8100e2c69e5b2f6eb681)

diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index 5543e08c59e66ec6063597447b63484491ffa248..d1a39698124b0f039c2abe901d289af816db04d4 100644 (file)
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -1001,7 +1001,8 @@ size_t ossl_statem_client_max_message_size(SSL *s)
         return CCS_MAX_LENGTH;
 
     case TLS_ST_CR_SESSION_TICKET:
-        return SSL3_RT_MAX_PLAIN_LENGTH;
+        return (SSL_IS_TLS13(s)) ? SESSION_TICKET_MAX_LENGTH_TLS13
+                                 : SESSION_TICKET_MAX_LENGTH_TLS12;
 
     case TLS_ST_CR_FINISHED:
         return FINISHED_MAX_LENGTH;

diff --git a/ssl/statem/statem_local.h b/ssl/statem/statem_local.h
index e27c0c13a2bbd54bc0064ced3610204de8b97460..3efa1c5a1c5b79011220cf77d8888dd4e04b500f 100644 (file)
--- a/ssl/statem/statem_local.h
+++ b/ssl/statem/statem_local.h
@@ -22,6 +22,8 @@
 #define SERVER_HELLO_MAX_LENGTH         20000
 #define HELLO_RETRY_REQUEST_MAX_LENGTH  20000
 #define ENCRYPTED_EXTENSIONS_MAX_LENGTH 20000
+#define SESSION_TICKET_MAX_LENGTH_TLS13 131338
+#define SESSION_TICKET_MAX_LENGTH_TLS12 65541
 #define SERVER_KEY_EXCH_MAX_LENGTH      102400
 #define SERVER_HELLO_DONE_MAX_LENGTH    0
 #define KEY_UPDATE_MAX_LENGTH           1