Vulnerability CVE-2024-35997
Published: 2024-05-20

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

HID: i2c-hid: remove I2C_HID_READ_PENDING flag to prevent lock-up

The flag I2C_HID_READ_PENDING is used to serialize I2C operations.
However, this is not necessary, because I2C core already has its own
locking for that.

More importantly, this flag can cause a lock-up: if the flag is set in
i2c_hid_xfer() and an interrupt happens, the interrupt handler
(i2c_hid_irq) will check this flag and return immediately without doing
anything, then the interrupt handler will be invoked again in an
infinite loop.

Since interrupt handler is an RT task, it takes over the CPU and the
flag-clearing task never gets scheduled, thus we have a lock-up.

Delete this unnecessary flag.

 References:
https://git.kernel.org/stable/c/21bfca822cfc1e71796124e93b46e0d9fa584401
https://git.kernel.org/stable/c/c448a9fd50f77e8fb9156ff64848aa4295eb3003
https://git.kernel.org/stable/c/5095b93021b899f54c9355bebf36d78854c33a22
https://git.kernel.org/stable/c/b65fb50e04a95eec34a9d1bc138454a98a5578d8
https://git.kernel.org/stable/c/0561b65fbd53d3e788c5b0222d9112ca016fd6a1
https://git.kernel.org/stable/c/29e94f295bad5be59cf4271a93e22cdcf5536722
https://git.kernel.org/stable/c/418c5575d56410c6e186ab727bf32ae32447d497
https://git.kernel.org/stable/c/9c0f59e47a90c54d0153f8ddc0f80d7a36207d0e
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