CVE-2023-53785
What it is
In the Linux kernel, the following vulnerability has been resolved: mt76: mt7921: don't assume adequate headroom for SDIO headers mt7921_usb_sdio_tx_prepare_skb() calls mt7921_usb_sdio_write_txwi() and mt7921_skb_add_usb_sdio_hdr(), both of which blindly assume that adequate headroom will be available in the passed skb. This assumption typically is satisfied when the skb was allocated in the net core for transmission via the mt7921 netdev (although even that is only an optimization and is not strictly guaranteed), but the assumption is sometimes not satisfied when the skb originated in the receive path of another netdev and was passed through to the mt7921, such as by the bridge layer. Blindly prepending bytes to an skb is always wrong. This commit introduces a call to skb_cow_head() before the call to mt7921_usb_sdio_write_txwi() in mt7921_usb_sdio_tx_prepare_skb() to ensure that at least MT_SDIO_TXD_SIZE + MT_SDIO_HDR_SIZE bytes can be pushed onto the skb. Without this fix, I can trivially cause kernel panics by bridging an MT7921AU-based USB 802.11ax interface with an Ethernet interface on an Intel Atom-based x86 system using its onboard RTL8169 PCI Ethernet adapter and also on an ARM-based Raspberry Pi 1 using its onboard SMSC9512 USB Ethernet adapter. Note that the panics do not occur in every system configuration, as they occur only if the receiving netdev leaves less headroom in its received skbs than the mt7921 needs for its SDIO headers. Here is an example stack trace of this panic on Raspberry Pi OS Lite 2023-02-21 running kernel 6.1.24+ [1]: skb_panic from skb_push+0x44/0x48 skb_push from mt7921_usb_sdio_tx_prepare_skb+0xd4/0x190 [mt7921_common] mt7921_usb_sdio_tx_prepare_skb [mt7921_common] from mt76u_tx_queue_skb+0x94/0x1d0 [mt76_usb] mt76u_tx_queue_skb [mt76_usb] from __mt76_tx_queue_skb+0x4c/0xc8 [mt76] __mt76_tx_queue_skb [mt76] from mt76_txq_schedule.part.0+0x13c/0x398 [mt76] mt76_txq_schedule.part.0 [mt76] from mt76_txq_schedule_all+0x24/0x30 [mt76] mt76_txq_schedule_all [mt76] from mt7921_tx_worker+0x58/0xf4 [mt7921_common] mt7921_tx_worker [mt7921_common] from __mt76_worker_fn+0x9c/0xec [mt76] __mt76_worker_fn [mt76] from kthread+0xbc/0xe0 kthread from ret_from_fork+0x14/0x34 After this fix, bridging the mt7921 interface works fine on both of my previously problematic systems. [1] https://github.com/raspberrypi/firmware/tree/5c276f55a4b21345cd4d6200a504ee991851ff7a
At a glance
- Exploitability
- Can be exploited from the same network segment without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.3% chance of exploitation in the next 30 days (EPSS).
- Fix
- No patch or advisory is linked yet. Look at mitigations or restrict exposure.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.3% in the next 30 days (EPSS).
- Severity: 8.8 HIGH (CVSS).
- Fix: none linked yet, which raises it.
Details
- Published
- Last modified
- Exploit probability
- 0.3% · EPSS, next 30 days
- Record status
- Deferred
Attack profile CVSS 3.1 · 8.8
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2023-53785.md and follow it. Check whether this project is affected by CVE-2023-53785. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
