Fix race condition in ssl_parse_serverhello_tlsext

CVE-2014-3509
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NDr. Stephen Henson <steve@openssl.org>

ssl/t1_lib.c

@@ -2647,15 +2647,18 @@ static int ssl_scan_serverhello_tlsext(SSL *s, unsigned char **p, unsigned char
 				*al = TLS1_AD_DECODE_ERROR;
 				return 0;
 				}
-			s->session->tlsext_ecpointformatlist_length = 0;
-			if (s->session->tlsext_ecpointformatlist != NULL) OPENSSL_free(s->session->tlsext_ecpointformatlist);
-			if ((s->session->tlsext_ecpointformatlist = OPENSSL_malloc(ecpointformatlist_length)) == NULL)
+			if (!s->hit)
 				{
-				*al = TLS1_AD_INTERNAL_ERROR;
-				return 0;
+				s->session->tlsext_ecpointformatlist_length = 0;
+				if (s->session->tlsext_ecpointformatlist != NULL) OPENSSL_free(s->session->tlsext_ecpointformatlist);
+				if ((s->session->tlsext_ecpointformatlist = OPENSSL_malloc(ecpointformatlist_length)) == NULL)
+					{
+					*al = TLS1_AD_INTERNAL_ERROR;
+					return 0;
+					}
+				s->session->tlsext_ecpointformatlist_length = ecpointformatlist_length;
+				memcpy(s->session->tlsext_ecpointformatlist, sdata, ecpointformatlist_length);
 				}
-			s->session->tlsext_ecpointformatlist_length = ecpointformatlist_length;
-			memcpy(s->session->tlsext_ecpointformatlist, sdata, ecpointformatlist_length);
 #if 0
 			fprintf(stderr,"ssl_parse_serverhello_tlsext s->session->tlsext_ecpointformatlist ");
 			sdata = s->session->tlsext_ecpointformatlist;