CVE-2022-49112: mt76: fix monitor mode crash with sdio driver
In the Linux kernel, the following vulnerability has been resolved:
mt76: fix monitor mode crash with sdio driver
mt7921s driver may receive frames with fragment buffers. If there is a CTS packet received in monitor mode, the payload is 10 bytes only and need 6 bytes header padding after RXD buffer. However, only RXD in the first linear buffer, if we pull buffer size RXD-size+6 bytes with skbpull(), that would trigger "BUGON(skb->len < skb->datalen)" in skbpull().
To avoid the nonlinear buffer issue, enlarge the RXD size from 128 to 256 to make sure all MCU operation in linear buffer.
[ 52.007562] kernel BUG at include/linux/skbuff.h:2313! [ 52.007578] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 52.007987] pc : skbpull+0x48/0x4c [ 52.008015] lr : mt7921queuerxskb+0x494/0x890 [mt7921common] [ 52.008361] Call trace: [ 52.008377] skbpull+0x48/0x4c [ 52.008400] mt76snetworker+0x134/0x1b0 [mt76sdio 35339a92c6eb7d4bbcc806a1d22f56365565135c] [ 52.008431] mt76workerfn+0xe8/0x170 [mt76 ef716597d11a77150bc07e3fdd68eeb0f9b56917] [ 52.008449] kthread+0x148/0x3ac [ 52.008466] retfromfork+0x10/0x30
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Linux kernel (mt76/mt7921s sdio driver)to a version that resolves this vulnerability.Patch mt76: fix monitor mode crash with sdio driver - Configuration
To avoid the nonlinear buffer issue and prevent the monitor-mode crash, enlarge the RXD size from 128 and ensure there are 6 bytes of header padding after the RXD buffer so that skb_pull() does not attempt to pull more data than available in the first linear buffer.
mt7921s/mt76 RXD ring buffer RXD size = enlarge from 128 to (RXD-size + 6 bytes linear buffer / add 6 bytes header padding after RXD buffer)