usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.6.160, 6.12.109, 6.18.50, 7.2.4
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed In polled-VBUS mode (board.vbus_pin && board.vbus_polled), probe arms a self-restarting cycle: at91_vbus_timer() schedules vbus_timer_work, and at91_vbus_timer_work() calls at91_vbus_update() and re-arms the timer via mod_timer(). Both recover the same udc through container_of and dereference it on every iteration. Neither teardown path cancels this cycle. udc is devm-allocated, so it is freed after at91udc_remove() returns, and is likewise freed when probe fails and devres runs. A timer callback or work item that is pending or running at either point dereferences the freed udc. Add at91_udc_shutdown_vbus_timer() and call it from at91udc_remove() and from the usb_add_gadget_udc() failure path in probe; the remaining probe error paths fail before the timer is armed. timer_shutdown_sync() waits for a running callback and clears timer->function, which makes the work handler's mod_timer() a permanent no-op; cancel_work_sync() then drains any pending or running work whose re-arm attempt now does nothing. The timer must be shut down first, since cancelling the work alone would let the timer re-queue it. The guard mirrors probe: in IRQ mode the timer and work_struct are never initialized. This does not require a fault; a normal driver unbind can interleave with an already queued work item. This issue was found by an in-house static analysis tool.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 4037242c4f5ff77afe61bf07ca1e8a99490219e5 · fixed in 723d73b245843d4fff4c3f42e857c78c2b2d414e; From 4037242c4f5ff77afe61bf07ca1e8a99490219e5 · fixed in a2a602cb1e28d76a5398cec3fa21b0110385f501; From 4037242c4f5ff77afe61bf07ca1e8a99490219e5 · fixed in 51a311eb97e91ce1aed3005cb71ccb2e30f8cce8; From 4037242c4f5ff77afe61bf07ca1e8a99490219e5 · fixed in 557ef547d49ff5e6026a4d39bdd3113bd81d7688; From 4037242c4f5ff77afe61bf07ca1e8a99490219e5 · fixed in c27d13ce4bab80fbdf6523928071b6c24b37606c
- Linux Linux
2.6.36
- KernelLinux
From 2.6.36 · fixed in 6.6.160; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4