Bug #74376 [NEW]: Invalid free of persistent results on error/connection loss

From: dev at pp3345 dot net Operating system: Irrelevant PHP version: 7.1.3 Package: MySQL related Bug Type: Bug Bug description:Invalid free of persistent results on error/connection loss Description: ------------ mysqlnd allocates result objects in mysqlnd_result.c:1899 (mysqlnd_result_init): MYSQLND_RES * ret = mnd_pecalloc(1, alloc_size, persistent); Note that these objects may be allocated persistently if the underlying connection is persistent. Normally these objects will be free'd in mysqlnd_result.c:347 (mysqlnd_res::free_result_internal): mnd_pefree(result, result->persistent); Here, the persistency flag is respected. However, in some cases (query errors or connection loss), mysqlnd_ps.c will use mnd_efree() instead of mnd_pefree() to free a result object: line 132 (mysqlnd_stmt::store_result): mnd_efree(stmt->result); line 359 (mysqlnd_stmt_prepare_read_eof): mnd_efree(stmt->result); This will cause segfaults/"zend_mm_heap corrupted" in the above-mentioned cases. Test script: --------------- <?php $conn = new PDO("mysql:...", "...", "...", [PDO::ATTR_PERSISTENT => true, PDO::ATTR_EMULATE_PREPARES => false]); $conn->query("select (select 1 union select 2)"); Expected result: ---------------- Script executes successfully. Actual result: -------------- segfault -- Edit bug report at https://bugs.php.net/bug.php?id=74376&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=74376&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=74376&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=74376&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=74376&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=74376&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=74376&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=74376&r=needscript Try newer version: https://bugs.php.net/fix.php?id=74376&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=74376&r=support Expected behavior: https://bugs.php.net/fix.php?id=74376&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=74376&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=74376&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=74376&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=74376&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=74376&r=dst IIS Stability: https://bugs.php.net/fix.php?id=74376&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=74376&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=74376&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=74376&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=74376&r=mysqlcfg