CVEvulnerability
CVE-2026-99024
- Status
- Received
- Published
- 2026-10-23
- Last modified
- 2026-10-23
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Description
In the Linux kernel, the following vulnerability has been resolved:
optee: register TEE devices only once fully initialized
optee_probe() called tee_device_register() on both the client and the
supplicant device before the rest of struct optee had been initialized.
tee_device_register() calls cdev_device_add(), which does two things at
once: it creates /dev/tee0 and /dev/teepriv0, and it links the device
into the tee class so that class_find_device() can find it. From that
moment on the device is reachable both from user space via tee_open()
and from kernel space via tee_client_open_context(). The only gate in
teedev_open() is tee_device_get(), which merely checks that
teedev->desc is non-NULL, which was already set by tee_device_alloc().
Therefore, there is effectively no gate at all.
A context opened in that window can run against a struct optee where
- optee->call_queue.mutex is not initialized by optee_cq_init()
- optee->supp mutex and completions is not initialized by
optee_supp_init()
- optee->rpmb_dev_mutex is not initialized yet,
- the message argument cache is not initialized by
optee_shm_arg_cache_init()
- optee->ctx is still NULL
Any open session or invoke during this window takes uninitialized
mutexes and dereferences a NULL pointer.
Fix it by moving both tee_device_register() calls down to the point
where all of struct optee is set up.
[JW: adding fixes and cc]
References
- https://git.kernel.org/stable/c/262062c01f5a817104c88bf6eacb7c6ffdc7018d git.kernel.org
- https://git.kernel.org/stable/c/2f7240f0a6fd83df274fc0a2abf0609b4e6bd388 git.kernel.org
- https://git.kernel.org/stable/c/681adbc9c7a820279582a295e183fa6a1d1b4ec4 git.kernel.org
- https://git.kernel.org/stable/c/8cae1605be8a047ae3a62df07b9474d61462c4f6 git.kernel.org
- https://git.kernel.org/stable/c/c108feca0a096f8db25d1b69130035025e9e936d git.kernel.org