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…attribute php_libxml_node_free_resource() freed a detached ID attribute's children before xmlFreeProp() called xmlRemoveID(), which reads the ID value from those children, so the entry was not found and the document's ID table kept pointing at the freed attribute. Remove the ID before freeing the children, as php_libxml_node_free_list() already does. This also covers removeAttribute() while a reference to the attribute node is still held.
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Submitted upstream as php#25351. |
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When a detached ID attribute is freed,
php_libxml_node_free_resource()freed its children beforexmlFreeProp()calledxmlRemoveID(). xmlRemoveID() reads the ID value from those children, so it found no entry and the document's ID table kept pointing at the freed attribute. A latergetElementById()for that ID then read freed memory. Remove the ID before freeing the children, asphp_libxml_node_free_list()already does.Reproduced on PHP-8.4 under ASAN with
xml:id, DTD-declared IDs andDom\XMLDocument.removeAttribute()frees the attribute with its children intact, so it is not affected. Found while fixing the XPath callback use-after-free in the follow-up PR.