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gh-158923: Fix use-after-free in xibufferview_getbuf() - #159005
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christianaurichzm wants to merge 1 commit into
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christianaurichzm wants to merge 1 commit into
christianaurichzm wants to merge 1 commit into
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xibufferview_getbuf() didn't incref view->obj. The wrapper is exposed as mv.obj, so something like bytes(mv.obj) released a reference it never took, and the wrapper could be freed while the shared memoryview was still using it.
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Fixes #158923
xibufferview_getbuf()setsview->objwithout an incref. That's fine for_memoryview_from_xid(), which passes its own reference to the new memoryview, but the wrapper is also visible from Python asmv.obj. Sobytes(mv.obj),memoryview(mv.obj)etc. release a reference they never got, the wrapper is freed, and the shared memoryview still points to it.Fix: incref in
xibufferview_getbuf()like any other getbuffer, and decref in_memoryview_from_xid()after creating the memoryview.Tested on a debug build: the reproducer from the issue and the new test both segfault without the patch and pass with it (the test also passes with
-R 3:3).test_interpreters,test__interpreters,test__interpchannels,test_crossinterpandtest_concurrent_futures.test_interpreter_poolpass._interpretersxibufferview_getbufmissing INCREF: shared-memoryview UAF #158923