Input: cros_ec_keyb - fix an invalid memory access

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: Input: cros_ec_keyb - fix an invalid memory access If cros_ec_keyb_register_matrix() isn't called (due to `buttons_switches_only`) in cros_ec_keyb_probe(), `ckdev->idev` remains NULL. An invalid memory access is observed in cros_ec_keyb_process() when receiving an EC_MKBP_EVENT_KEY_MATRIX event in cros_ec_keyb_work() in such case. Unable to handle kernel read from unreadable memory at virtual address 0000000000000028 ... x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: input_event cros_ec_keyb_work blocking_notifier_call_chain ec_irq_thread It's still unknown about why the kernel receives such malformed event, in any cases, the kernel shouldn't access `ckdev->idev` and friends if the driver doesn't intend to initialize them.

References

• https://git.kernel.org/stable/c/d74864291cb8bd784d44d1d02e87109cf88666bb
• https://git.kernel.org/stable/c/9cf59f4724a9ee06ebb06c76b8678ac322e850b7
• https://git.kernel.org/stable/c/6d81068685154535af06163eb585d6d9663ec7ec
• https://git.kernel.org/stable/c/2d251c15c27e2dd16d6318425d2f7260cbd47d39
• https://git.kernel.org/stable/c/e08969c4d65ac31297fcb4d31d4808c789152f68