MySQL Bugs: #115162: Potential Memory Leak in file `xcom\network\xcom_network_provider_native

Bug #115162	Potential Memory Leak in file `xcom\network\xcom_network_provider_native_lib.cc`
Submitted:	29 May 2024 13:01	Modified:	17 Sep 2024 21:50
Reporter:	Yu Xiao	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Group Replication	Severity:	S2 (Serious)
Version:	8.0	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
File: plugin\group_replication\libmysqlgcs\src\bindings\xcom\xcom\network\xcom_network_provider_native_lib.cc
Function: Xcom_network_provider_library::announce_tcp
Details:
Please see the comment in the code snippet below:

result Xcom_network_provider_library::announce_tcp(xcom_port port) {
	...
    /* Assuming `sock_addr` is not nullptr, and 
    `bind(fd.val, sock_addr, sock_addr_len) < 0` is True. */
    if (sock_addr == nullptr || (bind(fd.val, sock_addr, sock_addr_len) < 0)) {
        fd = create_server_socket_v4();
        if (fd.val < 0) { // Assuming condition is True
          return fd; // return without free `sock_addr`
        }
        free(sock_addr);
        sock_addr = nullptr;
        ...
    }
}

How to repeat:
This is a static analyzer warning, we have not found an actual path that triggers the memory leak.

It seems this piece of code is not typically triggered, but fixing this potential memory leak is quite easy :)

Suggested fix:
It is safe to pass `nullptr` to the free function.
So just free `sock_addr` before `return fd` in the `fd.val<0` branch:

if (fd.val < 0) {
    free(sock_addr);
    return fd; 
}

Hi MR. Hershev,

Thank you for your contribution.

This is now a verified bug.

It affects 8.0 and higher .......

Since it is a memory leak, it has a Severity of 2.

Documented fix as follows in the MySQL 8.0.40, 8.4.3, and 9.1.0 changelogs:

    Removed a potential memory leak from
    xcom\network\xcom_network_provider_native_lib.cc.

Closed.

Thank you, Jon.