Description
In the Linux kernel, the following vulnerability has been resolved: io_uring: defer eventfd signaling when queued from a wakeup handler io_req_local_work_add() signals the CQ ring eventfd inline when it is the one to push the first entry onto ->work_list. For DEFER_TASKRUN rings that add is frequently done from a waitqueue wakeup handler, where an arbitrary waitqueue lock is held. eventfd_signal_mask() only refuses to recurse when current->in_eventfd is set, but that bit is set by eventfd_signal_mask() itself. If the wake chain starts somewhere else, signal goes out inline and can feed back into epoll. Add IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three waitqueue callbacks, and use it to force io_eventfd_signal() down the existing call_rcu_hurry() deferral instead of signaling inline.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
21a091b970cdbcf3e8ff829234b51be6f9192766 to < d0c240f25e654442a72af5ca021a02165ccce638affected21a091b970cdbcf3e8ff829234b51be6f9192766 to < 9d984451baf768ecd9e1fdad4637b729fcb2c9d5affected21a091b970cdbcf3e8ff829234b51be6f9192766 to < e22f4494cc9487d326e5e3067f33dea7c1e442b2affected21a091b970cdbcf3e8ff829234b51be6f9192766 to < b6bb334b0e9348887e3e55e1f494b0c3b8fbf59faffected21a091b970cdbcf3e8ff829234b51be6f9192766 to < 40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5aaffected21a091b970cdbcf3e8ff829234b51be6f9192766 to < cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6eaffected
Linux Linux
Default version status: affected
6.1affected0 to < 6.1unaffected6.6.160 to ≤ 6.6.*unaffected6.12.114 to ≤ 6.12.*unaffected6.18.49 to ≤ 6.18.*unaffected7.1.11 to ≤ 7.1.*unaffected7.2.1 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/d0c240f25e654442a72af5ca021a02165ccce638 ↗
- https://git.kernel.org/stable/c/9d984451baf768ecd9e1fdad4637b729fcb2c9d5 ↗
- https://git.kernel.org/stable/c/e22f4494cc9487d326e5e3067f33dea7c1e442b2 ↗
- https://git.kernel.org/stable/c/b6bb334b0e9348887e3e55e1f494b0c3b8fbf59f ↗
- https://git.kernel.org/stable/c/40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5a ↗
- https://git.kernel.org/stable/c/cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6e ↗