[CONC-294] Access violation on mysql_close with a connection plugin. Created: 2017-11-12  Updated: 2018-01-21  Resolved: 2018-01-21

Status: Closed
Project: MariaDB Connector/C
Component/s: None
Affects Version/s: 3.0.2
Fix Version/s: 3.0.4

Type: Bug Priority: Major
Reporter: Andrey Volk Assignee: Georg Richter
Resolution: Fixed Votes: 0
Labels: None


 Description    

int
 
mthd_my_send_cmd(MYSQL *mysql,enum enum_server_command command, const char *arg,
 
	       size_t length, my_bool skipp_check, void *opt_arg)
 
{
 
......
 
  if (IS_CONNHDLR_ACTIVE(mysql)) // <- Wrongly thinks that mysql->extension->conn_hdlr has something after free(p) at line 1920
 
  {
 
    result= mysql->extension->conn_hdlr->plugin->set_connection(mysql, command, arg, length, skipp_check, opt_arg); // <- Exception!!!
 
    if (result== -1)
 
      return(result);
 
  }
 
....

The problem is because mysql->extension->conn_hdlr is kept with a value after "free(p);" at line 1920.

    if (mysql->extension && mysql->extension->conn_hdlr)
 
    {
 
      MA_CONNECTION_HANDLER *p= mysql->extension->conn_hdlr;
 
      p->plugin->close(mysql);
 
      free(p); // <- HERE
 
    }
 
 
 
    if (mysql->methods)
 
      mysql->methods->db_close(mysql); // <- Problem!

Should be

    if (mysql->extension && mysql->extension->conn_hdlr)
 
    {
 
      MA_CONNECTION_HANDLER *p= mysql->extension->conn_hdlr;
 
      p->plugin->close(mysql);
 
      free(p);
 
      mysql->extension->conn_hdlr = NULL; // <- Solution
 
    }
 
 
 
    if (mysql->methods)
 
      mysql->methods->db_close(mysql);



 Comments   
Comment by Georg Richter [ 2018-01-21 ]

Fixed (rev. 00903bb676384c21fc30427e3913c6f189497fac)

Generated at Thu Feb 08 03:04:17 UTC 2024 using Jira 8.20.16#820016-sha1:9d11dbea5f4be3d4cc21f03a88dd11d8c8687422.