Fix GH-22063: stream filter chain UAF on self-removal during callback#67
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Fix GH-22063: stream filter chain UAF on self-removal during callback#67iliaal wants to merge 1 commit into
iliaal wants to merge 1 commit into
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A stream filter struct must stay live while a fops->filter() callback or chain iteration holds it. A php_user_filter that removes its own resource inside filter() frees the struct under userfilter_filter (&thisfilter->abstract deref) and under the three chain-walk sites (current->next read). Defer pefree via an in_callback counter until every C-level frame holding the filter releases it. Closes phpGH-22063
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Submitted upstream as php#22083 |
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php_user_filterthat callsstream_filter_removeon its own resource from insidefilter()frees thephp_stream_filterstruct whileuserfilter_filterstill dereferences&thisfilter->abstractand while the chain walks in_php_stream_filter_flush,_php_stream_write_filtered, and_php_stream_fill_read_bufferstill needcurrent->next. Two new fields onphp_stream_filter,in_callbackanddeferred_dtor, carry the deferral:php_stream_filter_remove(filter, true)unlinks and runszend_list_deleteimmediately but defers thepefree.