Fix use after free errors #177
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Fixes a few cases where use after free could happen, and one where it can be easily reproduced. When using the FSEvents back-end, both the `Watcher` and a `State` pointers are passed as part of the context parameter to a C style callback. Both of these pointers may be free-ed before the callback is called before this commit. After this commit, these two pointers, as well as all most others in the codebase are replaced with `shared_ptr`. This is a lazy fix and goes against C++ core guidelines - "F.7". A secondary pass would use reference counting only in the shared ownership cases. For most back-ends this shared ownership happens on: error types, subscription maps/sets and state structs.
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I still need to:
While it is possible that use after free happens on other back-ends, main bug I can reproduce is related to macOS fsevents callback. |
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@devongovett I get errors on the |
yamadapc
assigned marcins, MonicaOlejniczak, JakeLane, mattcompiles, alshdavid, benjervis and Nikola-3 and unassigned marcins, MonicaOlejniczak, JakeLane, mattcompiles, alshdavid, benjervis and Nikola-3
devongovett
approved these changes
Jun 13, 2024
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Fixes a few cases where use after free could happen, and one where it can be easily reproduced.
When using the FSEvents back-end, both the
Watcherand aStatepointers are passed as part of the context parameter to a C style callback.Both of these pointers may be free-ed before the callback is called before this commit.
After this commit, these two pointers, as well as all most others in the codebase are replaced with
shared_ptr.This is a lazy fix and goes against C++ core guidelines - "F.7". (https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rf-smart)
A secondary pass would use reference counting only in the shared ownership cases. For most back-ends this shared ownership happens on: error types, subscription maps/sets and state structs. (https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rr-owner)