CVE-2024-56649: net: enetc: Do not configure preemptible TCs if SIs do not support
In the Linux kernel, the following vulnerability has been resolved:
net: enetc: Do not configure preemptible TCs if SIs do not support
Both ENETC PF and VF drivers share enetcsetuptcmqprio() to configure MQPRIO. And enetcsetuptcmqprio() calls enetcchangepreemptibletcs() to configure preemptible TCs. However, only PF is able to configure preemptible TCs. Because only PF has related registers, while VF does not have these registers. So for VF, its hw->port pointer is NULL. Therefore, VF will access an invalid pointer when accessing a non-existent register, which will cause a crash issue. The simplified log is as follows.
root@ls1028ardb:~# tc qdisc add dev eno0vf0 parent root handle 100: \ mqprio numtc 4 map 0 0 1 1 2 2 3 3 queues 1@0 1@1 1@2 1@3 hw 1 [ 187.290775] Unable to handle kernel paging request at virtual address 0000000000001f00 [ 187.424831] pc : enetcmmcommitpreemptibletcs+0x1c4/0x400 [ 187.430518] lr : enetcmmcommitpreemptibletcs+0x30c/0x400 [ 187.511140] Call trace: [ 187.513588] enetcmmcommitpreemptibletcs+0x1c4/0x400 [ 187.518918] enetcsetuptcmqprio+0x180/0x214 [ 187.523374] enetcvfsetuptc+0x1c/0x30 [ 187.527306] mqprioenableoffload+0x144/0x178 [ 187.531766] mqprioinit+0x3ec/0x668 [ 187.535351] qdisccreate+0x15c/0x488 [ 187.539023] tcmodifyqdisc+0x398/0x73c [ 187.542958] rtnetlinkrcvmsg+0x128/0x378 [ 187.547064] netlinkrcvskb+0x60/0x130 [ 187.550910] rtnetlinkrcv+0x18/0x24 [ 187.554492] netlinkunicast+0x300/0x36c [ 187.558425] netlinksendmsg+0x1a8/0x420 [ 187.606759] ---[ end trace 0000000000000000 ]---
In addition, some PFs also do not support configuring preemptible TCs, such as eno1 and eno3 on LS1028A. It won't crash like it does for VFs, but we should prevent these PFs from accessing these unimplemented registers.
Other sources
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— Launchpad
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2024-56649?
The severity of CVE-2024-56649 is classified as medium, as it may lead to improper configuration in the Linux kernel.
How do I fix CVE-2024-56649?
To fix CVE-2024-56649, update the Linux kernel to versions later than 6.6.66, between 6.7 and 6.12.5, or to 6.13-rc1.
Which systems are affected by CVE-2024-56649?
CVE-2024-56649 affects multiple versions of the Linux kernel including versions from 6.4 to 6.6.66 and 6.7 to 6.12.5.
What components are involved in CVE-2024-56649?
CVE-2024-56649 involves the enetc PF and VF drivers which share functionality for configuring MQPRIO.
Is there a workaround for CVE-2024-56649?
Currently, there are no known workarounds for CVE-2024-56649, and updating the kernel is the recommended action.