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Fix use-after-free when pclose() closes a stream from its user filter - #24175
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Sjord
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Oct 7, 2026
fclose() refuses a stream marked PHP_STREAM_FLAG_NO_FCLOSE, which a user filter's callback sets on its stream; pclose() closed it anyway, freeing the stream and the filter under the running callback.
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Looks good. proc_close seems to have a similar issue.
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The proc_open similar issue addressed in #25281 |
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While a user filter's
filter()runs, its stream carriesPHP_STREAM_FLAG_NO_FCLOSE, sofclose()from the callback fails with a warning.pclose()did not check the flag: it freed the stream and the filter under the running callback (use-after-free under Valgrind, no Fibers needed).pclose()now refuses such a stream with the same warning asfclose()and returns -1, its documented error value. One visible change:pclose()of anopendir()handle, which also carries the flag, now fails the wayfclose()of it already does.Test:
ext/standard/tests/filters/pclose_in_filter.phpt.