Only allow one SGC handshake restart for SSL/TLS. (CVE-2011-4619)
[openssl.git] / ssl / s3_srvr.c
index c7b9c2c..7266b82 100644 (file)
@@ -297,6 +297,7 @@ int ssl3_accept(SSL *s)
                                }
 
                        s->init_num=0;
+                       s->s3->flags &= ~SSL3_FLAGS_SGC_RESTART_DONE;
 
                        if (s->state != SSL_ST_RENEGOTIATE)
                                {
@@ -871,6 +872,14 @@ int ssl3_check_client_hello(SSL *s)
        int ok;
        long n;
 
+       /* We only allow the client to restart the handshake once per
+        * negotiation. */
+       if (s->s3->flags & SSL3_FLAGS_SGC_RESTART_DONE)
+               {
+               SSLerr(SSL_F_SSL3_CHECK_CLIENT_HELLO, SSL_R_MULTIPLE_SGC_RESTARTS);
+               return -1;
+               }
+
        /* this function is called when we really expect a Certificate message,
         * so permit appropriate message length */
        n=s->method->ssl_get_message(s,
@@ -899,6 +908,7 @@ int ssl3_check_client_hello(SSL *s)
                        s->s3->tmp.ecdh = NULL;
                        }
 #endif
+               s->s3->flags |= SSL3_FLAGS_SGC_RESTART_DONE;
                return 2;
                }
        return 1;