src: fix use-after-free in CleanupHookThunkRun - #65196
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CleanupHookThunkRun() read thunk->isolate/fun/arg from the CleanupHookThunk after invoking thunk->fun(). For every node::ObjectWrap alive at teardown, thunk->fun is ObjectWrap::CleanupHook, which deletes the wrap; ~ObjectWrap() calls RemoveEnvironmentCleanupHook() itself, erasing the CleanupHookThunk from the registry and freeing the node it lives in. The subsequent read of thunk->isolate/fun/arg to make the (now redundant) second RemoveEnvironmentCleanupHook() call was therefore a use-after-free. Cache the fields before running the hook so nothing is read from `thunk` once it may have been freed. Fixes: nodejs#65195
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cc @addaleax (you wrote both #63642 and #63985, whose interaction causes this) and @legendecas (reviewed #63642) — would appreciate a look when you have a chance. |
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cc @nsavoire — thanks for the thorough root-cause writeup and repro in the issue, it made this a straightforward fix to apply. If you get a chance to re-run your valgrind repro (test/addons/worker-addon-exit) against this branch, that would help confirm it before a maintainer looks at it. |
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Summary
CleanupHookThunkRun()readthunk->isolate/thunk->fun/thunk->argfrom the
CleanupHookThunkafter invokingthunk->fun(). For everynode::ObjectWrapstill alive at teardown,thunk->funisObjectWrap::CleanupHook, which deletes the wrap. Since #63642,~ObjectWrap()callsRemoveEnvironmentCleanupHook()itself, which erasesthe
CleanupHookThunkfromcleanup_hook_registryand frees the node itlives in. The subsequent read to make the (now redundant) second
RemoveEnvironmentCleanupHook()call was therefore a use-after-free — thisis now the ordinary teardown path for every
ObjectWrap-based addon, not anedge case.
The fix caches
isolate/fun/argbefore invoking the hook, so nothing isread from
thunkonce it may have already been freed.Root cause and fix as diagnosed in the issue.
Fixes: #65195
Test plan
test/addons/worker-addon-exit(built withnode-gyp, run undervalgrind) is the existing repro described in the issue.