Fix segfault comparing uninitialized SimpleXMLElement instances - #23067
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Fix segfault comparing uninitialized SimpleXMLElement instances#23067iliaal wants to merge 1 commit into
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sxe_objects_compare dereferenced document->ptr when both nodes were NULL without checking document. A subclass that skips parent __construct leaves document NULL, so $a == $b segfaulted. Treat two NULL documents as equal and mixed NULL/non-NULL as uncomparable. Closes phpGH-23067
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| if (sxe1->node == NULL && sxe2->node == NULL) { | ||
| /* Both nodes not set: Only support equality comparison between documents. */ | ||
| if (sxe1->document == NULL || sxe2->document == NULL) { | ||
| if (sxe1->document == sxe2->document) { |
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we should only compare documents (not referring to the field name).
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Switched to comparing the documents, with a missing document resolving to NULL.
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| if (sxe1->document->ptr == sxe2->document->ptr) { | ||
| xmlDocPtr doc1 = sxe1->document ? sxe1->document->ptr : NULL; | ||
| xmlDocPtr doc2 = sxe2->document ? sxe2->document->ptr : NULL; | ||
| if (doc1 == doc2) { |
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I meant
if (sxe1->document != NULL && sxe2->document != NULL && sxe1->document->ptr == sxe2->document->ptr)
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Ah, misread the first time. Applied as written.
sxe_objects_compare dereferenced document->ptr when both nodes were NULL without checking document. A subclass that skips parent __construct leaves document NULL, so $a == $b segfaulted. Compare the documents only when both are set; anything else is uncomparable.
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sxe_objects_compare reaches sxe1->document->ptr whenever both operands have a NULL node, without checking that document is set. A subclass whose constructor skips parent::__construct leaves both fields NULL, so
new MySXE == new MySXEdereferences NULL and segfaults. The documents are compared only when both are set, so two uninitialized instances are uncomparable, matching the node comparison directly above.