CVE-2022-48790

In the Linux kernel, the following vulnerability has been resolved:

nvme: fix a possible use-after-free in controller reset during load

Unlike .queue_rq, in .submit_async_event drivers may not check the ctrl readiness for AER submission. This may lead to a use-after-free condition that was observed with nvme-tcp.

The race condition may happen in the following scenario:

1. driver executes its reset_ctrl_work
2. -> nvme_stop_ctrl - flushes ctrl async_event_work
3. ctrl sends AEN which is received by the host, which in turn schedules AEN handling
4. teardown admin queue (which releases the queue socket)
5. AEN processed, submits another AER, calling the driver to submit
6. driver attempts to send the cmd ==> use-after-free

In order to fix that, add ctrl state check to validate the ctrl is actually able to accept the AER submission.

This addresses the above race in controller resets because the driver during teardown should:

1. change ctrl state to RESETTING
2. flush async_event_work (as well as other async work elements)

So after 1,2, any other AER command will find the ctrl state to be RESETTING and bail out without submitting the AER.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/0ead57ceb21bbf15963b4874c2ac67143455382f
• https://git.kernel.org/stable/c/0fa0f99fc84e41057cbdd2efbfe91c6b2f47dd9d
• https://git.kernel.org/stable/c/70356b756a58704e5c8818cb09da5854af87e765
• https://git.kernel.org/stable/c/9e956a2596ae276124ef0d96829c013dd0faf861
• https://git.kernel.org/stable/c/a25e460fbb0340488d119fb2e28fe3f829b7417e
• https://git.kernel.org/stable/c/e043fb5a0336ee74614e26f0d9f36f1f5bb6d606
• https://git.kernel.org/stable/c/0ead57ceb21bbf15963b4874c2ac67143455382f
• https://git.kernel.org/stable/c/0fa0f99fc84e41057cbdd2efbfe91c6b2f47dd9d
• https://git.kernel.org/stable/c/70356b756a58704e5c8818cb09da5854af87e765
• https://git.kernel.org/stable/c/9e956a2596ae276124ef0d96829c013dd0faf861
• https://git.kernel.org/stable/c/a25e460fbb0340488d119fb2e28fe3f829b7417e
• https://git.kernel.org/stable/c/e043fb5a0336ee74614e26f0d9f36f1f5bb6d606