Fix CVE-2022-41858: slip sl_tx_timeout() NULL deref during detach #109
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Background
In drivers/net/slip/slip.c, sl_tx_timeout() can run while the SLIP device is in progress to detach, which can lead to a NULL pointer dereference and potentially crash the kernel (DoS) or leak internal kernel information; this is tracked as CVE-2022-41858.
Changes
Harden the SLIP timeout path during device teardown so sl_tx_timeout() cannot dereference NULL state while detach is in progress (drivers/net/slip/slip.c).
Security Impact
Prevents a local-triggerable NULL pointer dereference in the SLIP driver timeout/detach race, addressing CVE-2022-41858.
References
Upstream commit: ec4eb8a86ade4d22633e1da2a7d85a846b7d1798; CVE: CVE-2022-41858