Bug #80186 [NEW]: Segfault when iterating over FFI object
From: as
Operating system:
PHP version: 8.0Git-2020-10-04 (Git)
Package: Reproducible crash
Bug Type: Bug
Bug description:Segfault when iterating over FFI object
Description:
------------
Currently zend_fake_get_properties in ext/ffi/ffi.c returns a
pointer to const HashTable zend_empty_array. Attempting to iterate
over this array in userland leads to a segfault because PHP tries to
increment zend_empty_array's nIteratorsCount which is const memory.
The proposed patch allows objects to return NULL for the
get_properties handler. In this case, the VM skips the foreach block.
If this approach is acceptable, there are other extensions and call
sites[1][2] to fix where zend_empty_array leaks into userland.
[1]
https://github.com/php/php-src/blob/107962208a19d8b6dc1a190cb25fc37614411e71/ext/com_dotnet/com_handlers.c#L221-L229
[2] https://github.com/protocolbuffers/protobuf/issues/7319
Test script:
---------------
<?php
$ffi = FFI::cdef('');
foreach ($ffi as $_) {
}
Expected result:
----------------
no segfault
Actual result:
--------------
segfault
--
Edit bug report at https://bugs.php.net/bug.php?id=80186&edit=1
--
Fix committed: https://bugs.php.net/fix.php?id=80186&r=fixed
Fixed in release: https://bugs.php.net/fix.php?id=80186&r=alreadyfixed
Need backtrace: https://bugs.php.net/fix.php?id=80186&r=needtrace
Need Reproduce Script: https://bugs.php.net/fix.php?id=80186&r=needscript
Try newer version: https://bugs.php.net/fix.php?id=80186&r=oldversion
Not developer issue: https://bugs.php.net/fix.php?id=80186&r=support
Expected behavior: https://bugs.php.net/fix.php?id=80186&r=notwrong
Not enough info: https://bugs.php.net/fix.php?id=80186&r=notenoughinfo
Submitted twice: https://bugs.php.net/fix.php?id=80186&r=submittedtwice
register_globals: https://bugs.php.net/fix.php?id=80186&r=globals
PHP version support discontinued: https://bugs.php.net/fix.php?id=80186&r=phptooold
Daylight Savings: https://bugs.php.net/fix.php?id=80186&r=dst
IIS Stability: https://bugs.php.net/fix.php?id=80186&r=isapi
Install GNU Sed: https://bugs.php.net/fix.php?id=80186&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=80186&r=float
No Zend Extensions: https://bugs.php.net/fix.php?id=80186&r=nozend
MySQL Configuration Error: https://bugs.php.net/fix.php?id=80186&r=mysqlcfg
Thread (4 messages)
- as@php.net