HID: alps: fix use-after-free on input2 registration failure

Overview

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

HID: alps: fix use-after-free on input2 registration failure

alps_input_configured() stores data->input2 before calling input_register_device(). If registration fails, input_free_device() frees the input device but data->input2 still points to the freed memory. alps_input_configured() calls hid_hw_open() before allocating input2, so URBs are already active and raw_event can fire during the failure window. A U1_SP_ABSOLUTE_REPORT_ID report arriving then causes u1_raw_event() to dereference the freed data->input2 -> use-after-free.

Fix by only storing input2 into drvdata after successful registration and adding a NULL guard in the raw_event path.

Affected

• Linux >= 2562756dde550901c224e3805102bdfc17e7d13a < 64f824dccfd316fd3db8ea1cc4e8a76ad6a02740
• Linux >= 2562756dde550901c224e3805102bdfc17e7d13a < 2e55d76e6e8a756f6d87c241de975599f82b02fa
• Linux >= 2562756dde550901c224e3805102bdfc17e7d13a < ef8ca5bb4c8b9696f38b1bebce1c851baa02b77b
• Linux >= 2562756dde550901c224e3805102bdfc17e7d13a < 5a8ad63158165bacd6a1d7420e0fe5364c913b06
• Linux >= 2562756dde550901c224e3805102bdfc17e7d13a < 47e5e177e9e4e10da6f2759d5ce8d049e33efdc4
• Linux >= 2562756dde550901c224e3805102bdfc17e7d13a < 925da1d2a24787f24872de13a4680437c54de179
• Linux >= 2562756dde550901c224e3805102bdfc17e7d13a < 443f6b93442b10b972a16f57ceaaea75b77892b6
• Linux >= 2562756dde550901c224e3805102bdfc17e7d13a < d3aba3442798ce4a4c8ce3104d7b286d61e605f9
• Linux 4.8

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.