From 5aa2ed265f80664f57073213b17c83b1dac42ab4 Mon Sep 17 00:00:00 2001
From: Chris Double <chris.double@double.co.nz>
Date: Wed, 23 Sep 2015 20:48:56 +1200
Subject: [PATCH] textops: prevent null dereference on tr_txt_eval_re error

- Check for NULL pointer before calling subst_expr_free
  to prevent NULL pointer dereference when there is an
  unknown subtype error.
---
 modules/textops/txt_var.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/textops/txt_var.c b/modules/textops/txt_var.c
index 0f704e37cdb..41201f74eac 100644
--- a/modules/textops/txt_var.c
+++ b/modules/textops/txt_var.c
@@ -124,7 +124,7 @@ int tr_txt_eval_re(struct sip_msg *msg, tr_param_t *tp, int subtype,
 	return 0;
 
 error:
-	if (tp->type == TR_PARAM_SPEC) {
+	if (tp->type == TR_PARAM_SPEC && se!=NULL) {
 		subst_expr_free(se);
 	}
 	return -1;