#45751 [Com]: Php crashes when using auto_prepend_file (out of scope stack address use).

ID: 45751 Comment by: basant dot kukreja at sun dot com Reported By: basant dot kukreja at sun dot com Status: Open Bug Type: Reproducible crash Operating System: Solaris 10 PHP Version: 5.2.6 New Comment: The issue was that we are saving stack address execute_data.opline into EG(opline_ptr) in execute function in zend_vm_execute.h (line 74). EG(opline_ptr) = &EX(opline); After function execute is finished, EG(opline_ptr) is not reset to NULL. This point to previously used stack. Fix is that before we return we should set EG(opline_ptr) to NULL. Suggested Patch : --- Zend/zend_vm_execute_ORIG.h 2008-08-07 18:42:47.876727000 -0700 +++ Zend/zend_vm_execute.h 2008-08-07 18:44:40.481725000 -0700 @@ -90,6 +90,7 @@ #endif if (EX(opline)->handler(&execute_data TSRMLS_CC) > 0) { + EG(opline_ptr) = NULL; return; } Previous Comments: ------------------------------------------------------------------------ [2008-08-08 04:35:06] basant dot kukreja at sun dot com Description: ------------ Stack pointer &execute_data.opline (&EG(opline)) is used beyond the scope and hence crashes php with auto_preprend_file. I wrote a small test plugin : test.c and then loaded the plugin into php using php.ini extension=test.so $ ./sapi/cli/php -d "auto_prepend_file=inc.inc" -d "include_path=/opt2/coolstackbld/svn/CoolStackDev/src/php5/php-5.2.6/tests/lang" -f /tmp/test.php Included! Segmentation Fault (core dumped) Reproduce code: --------------- Test plugin location : (skydrive) : http://yqaghq.blu.livefilestore.com/y1phzvjT69U9PiUNjW9NjakZZ5It3VOAEhADJusnkoorLiwGfeVlK6zTz-8AprvloPplXlNkaHUYD9sS9idFWZhcg/test.c?download Expected result: ---------------- Normal behaviour Actual result: -------------- php crashes $ pstack core core 'core' of 23827: ./sapi/cli/php -d auto_prepend_file=inc.inc -d include_path=/opt2/cool 003b8e4c zend_get_executed_lineno (5be8a0, 5897c, ffe39448, 55570c, ff1531c0, 57400) + 3c 003d9f78 zend_execute_scripts (8, 0, 3, 1, 2, 5763c) + 11c 0032d9bc php_execute_script (ffffffff, ffbff2cd, 5be3e0, ffbfefe0, 0, 5ae3a0) + 2b0 0048e5e4 main (10000, 5addc8, 2d, 2f, 48cac0, 1ac0) + 1ae4 000a8f28 _start (0, 0, 0, 0, 0, 0) + 108 Debugger showed that it was crashing in line 394 of zend_execute_API.c : 391 ZEND_API uint zend_get_executed_lineno(TSRMLS_D) 392 { 393 if (EG(opline_ptr)) { 394 return active_opline->lineno; EG(online_ptr) points to arbitrary value ( a pointer value in stack) and it crashes in active_opline->lineno. active_opline->lineno is *EG(opline_ptr) We found this issue when php was crashing while dtrace plugin was loaded : $ ./sapi/cli/php -d "auto_prepend_file=inc.inc" -d "include_path=/opt2/coolstackbld/svn/CoolStackDev/src/php5/php-5.2.6/tests/lang" -f /tmp/test.php To simpilfy thing, I wrote my test plugin and reproduced the crash. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=45751&edit=1