CVE-2022-49755
usb: gadget: f_fs: Prevent race during ffs_ep0_queue_wait
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Description
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Prevent race during ffs_ep0_queue_wait While performing fast composition switch, there is a possibility that the process of ffs_ep0_write/ffs_ep0_read get into a race condition due to ep0req being freed up from functionfs_unbind. Consider the scenario that the ffs_ep0_write calls the ffs_ep0_queue_wait by taking a lock &ffs->ev.waitq.lock. However, the functionfs_unbind isn't bounded so it can go ahead and mark the ep0req to NULL, and since there is no NULL check in ffs_ep0_queue_wait we will end up in use-after-free. Fix this by making a serialized execution between the two functions using a mutex_lock(ffs->mutex).
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
Patch and advisory references
- https://git.kernel.org/stable/c/6a19da111057f69214b97c62fb0ac59023970850
- https://git.kernel.org/stable/c/6aee197b7fbcd61596a78b47d553f2f99111f217
- https://git.kernel.org/stable/c/6dd9ea05534f323668db94fcc2726c7a84547e78
- https://git.kernel.org/stable/c/a8d40942df074f4ebcb9bd3413596d92f323b064
- https://git.kernel.org/stable/c/ae8e136bcaae96163b5821984de1036efc9abb1a
References (7)
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