Fixed possible crash in php_mssql_get_column_content_without_type()

# Also fix NEWS entry in PHP_5_2 for previous commit

Author: KalleZ

NEWS

@@ -11,6 +11,8 @@
   (Kalle)
 - Changed the $context parameter on copy() to actually have an effect. (Kalle)
 
+- Fixed possible crash in php_mssql_get_column_content_without_type(). (Kalle)
+
 - Fixed bug #52636 (php_mysql_fetch_hash writes long value into int). 
   (Kalle, rein at basefarm dot no)
 - Fixed bug #52613 (crash in mysqlnd after hitting memory limit). (Andrey)

ext/mssql/php_mssql.c

@@ -1059,6 +1059,14 @@ static void php_mssql_get_column_content_without_type(mssql_link *mssql_ptr,int
 		unsigned char *res_buf;
 		int res_length = dbdatlen(mssql_ptr->link, offset);
 
+		if (res_length == 0) {
+			ZVAL_NULL(result);
+			return;
+		} else if (res_length < 0) {
+			ZVAL_FALSE(result);
+			return;
+		}
+
 		res_buf = (unsigned char *) emalloc(res_length+1);
 		bin = ((DBBINARY *)dbdata(mssql_ptr->link, offset));
 		res_buf[res_length] = '\0';