A crash occurred in the odbc_handle_closer function

There is an issue with the order of resource release that needs to be corrected by modifying the code.

• https://github.com/swoole/swoole-src/issues/5956

https://github.com/php/php-src/blob/833120eb72295fd9a6d0cacc68e85cbbeaa6a535/ext/pdo_odbc/odbc_driver.c#L138

The correct code might be:

static void odbc_handle_closer(pdo_dbh_t *dbh) {
    pdo_odbc_db_handle *H = (pdo_odbc_db_handle *) dbh->driver_data;

    SQLFreeHandle(SQL_HANDLE_ENV, H->env);
    H->env = NULL;

    if (H->dbc != SQL_NULL_HANDLE) {
        SQLEndTran(SQL_HANDLE_DBC, H->dbc, SQL_ROLLBACK);
        SQLDisconnect(H->dbc);
        SQLFreeHandle(SQL_HANDLE_DBC, H->dbc);
        H->dbc = NULL;
    }

    pefree(H, dbh->is_persistent);
    dbh->driver_data = NULL;
}

I don't quite understand the logic of the ODBC PDO driver, please review the code above.

==45879== Invalid read of size 8
==45879==    at 0x1185F941: ??? (in /usr/lib/libodbccr.so.2.0.0)
==45879==    by 0x734F411: ??? (in /usr/lib/libodbc.so.2.0.0)
==45879==    by 0x7351182: ??? (in /usr/lib/libodbc.so.2.0.0)
==45879==    by 0x7359691: ??? (in /usr/lib/libodbc.so.2.0.0)
==45879==    by 0x7B01E10: odbc_handle_closer (odbc_driver.c:139)
==45879==    by 0x73F800E: ??? (in /usr/lib/php84/modules/pdo.so)
==45879==    by 0x5CE98E: zend_objects_store_del (in /usr/bin/php84)
==45879==    by 0x586F32: ??? (in /usr/bin/php84)
==45879==    by 0x534247: execute_ex (in /usr/bin/php84)
==45879==    by 0x52D64B: zend_call_function (in /usr/bin/php84)
==45879==    by 0x799996A: swoole::PHPCoroutine::main_func(void*) (swoole_coroutine.cc:773)
==45879==    by 0x7A2B6C7: operator() (std_function.h:591)
==45879==    by 0x7A2B6C7: swoole::coroutine::Context::context_func(transfer_t) (context.cc:149)
==45879==  Address 0x11079928 is 2,344 bytes inside a block of size 5,256 free'd
==45879==    at 0x48B2ECF: free (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==45879==    by 0x73788CA: ??? (in /usr/lib/libodbc.so.2.0.0)
==45879==    by 0x73597E7: ??? (in /usr/lib/libodbc.so.2.0.0)
==45879==    by 0x7B01DFB: odbc_handle_closer (odbc_driver.c:136)
==45879==    by 0x73F800E: ??? (in /usr/lib/php84/modules/pdo.so)
==45879==    by 0x5CE98E: zend_objects_store_del (in /usr/bin/php84)
==45879==    by 0x586F32: ??? (in /usr/bin/php84)
==45879==    by 0x534247: execute_ex (in /usr/bin/php84)
==45879==    by 0x52D64B: zend_call_function (in /usr/bin/php84)
==45879==    by 0x799996A: swoole::PHPCoroutine::main_func(void*) (swoole_coroutine.cc:773)
==45879==    by 0x7A2B6C7: operator() (std_function.h:591)
==45879==    by 0x7A2B6C7: swoole::coroutine::Context::context_func(transfer_t) (context.cc:149)
==45879==    by 0x7B1F70E: swoole_make_fcontext (make_x86_64_sysv_elf_gas.S:135)
==45879==  Block was alloc'd at
==45879==    at 0x48B640A: calloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==45879==    by 0x7378711: ??? (in /usr/lib/libodbc.so.2.0.0)
==45879==    by 0x734A3EE: ??? (in /usr/lib/libodbc.so.2.0.0)
==45879==    by 0x7B022FE: pdo_odbc_handle_factory (odbc_driver.c:498)
==45879==    by 0x73F2A2D: php_pdo_internal_construct_driver (in /usr/lib/php84/modules/pdo.so)
==45879==    by 0x552BD0: ??? (in /usr/bin/php84)
==45879==    by 0x534247: execute_ex (in /usr/bin/php84)
==45879==    by 0x52D64B: zend_call_function (in /usr/bin/php84)
==45879==    by 0x799996A: swoole::PHPCoroutine::main_func(void*) (swoole_coroutine.cc:773)
==45879==    by 0x7A2B6C7: operator() (std_function.h:591)
==45879==    by 0x7A2B6C7: swoole::coroutine::Context::context_func(transfer_t) (context.cc:149)
==45879==    by 0x7B1F70E: swoole_make_fcontext (make_x86_64_sysv_elf_gas.S:135)

Bắt đầu trong ext/pdo_odbc/odbc_driver.c tại odbc_handle_closer quanh các dòng 136-139, sau đó kiểm tra pdo_odbc_handle_factory quanh dòng 498 và Valgrind trace được liên kết. Xác minh thứ tự giải phóng tài nguyên dựa trên lần đọc không hợp lệ đã được báo cáo và xác nhận rằng kịch bản đã được báo cáo không còn truy cập vào trạng thái ODBC đã được giải phóng.