CVE-2024-49980: vrf: revert "vrf: Remove unnecessary RCU-bh critical section"
In the Linux kernel, the following vulnerability has been resolved:
vrf: revert "vrf: Remove unnecessary RCU-bh critical section"
This reverts commit 504fc6f4f7f681d2a03aa5f68aad549d90eab853.
devqueuexmitnit is expected to be called with BH disabled. devqueuexmit has the following:
/ Disable soft irqs for various locks below. Also stops preemption for RCU. / rcureadlockbh();
VRF must follow this invariant. The referenced commit removed this protection. Which triggered a lockdep warning:
================================ WARNING: inconsistent lock state 6.11.0 #1 Tainted: G W -------------------------------- inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. btserver/134819 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff8882da30c118 (rlock-AFPACKET){+.?.}-{2:2}, at: tpacketrcv+0x863/0x3b30 {IN-SOFTIRQ-W} state was registered at: lockacquire+0x19a/0x4f0 rawspinlock+0x27/0x40 packetrcv+0xa33/0x1320 netifreceiveskbcore.constprop.0+0xcb0/0x3a90 netifreceiveskblistcore+0x2c9/0x890 netifreceiveskblistinternal+0x610/0xcc0 [...]
other info that might help us debug this: Possible unsafe locking scenario:
CPU0 ---- lock(rlock-AFPACKET); <Interrupt> lock(rlock-AFPACKET);
DEADLOCK
Call Trace: <TASK> dumpstacklvl+0x73/0xa0 marklock+0x102e/0x16b0 lockacquire+0x9ae/0x6170 lockacquire+0x19a/0x4f0 rawspinlock+0x27/0x40 tpacketrcv+0x863/0x3b30 devqueuexmitnit+0x709/0xa40 vrffinishdirect+0x26e/0x340 [vrf] vrfl3out+0x5f4/0xe80 [vrf] iplocalout+0x51e/0x7a0 [...]
Other sources
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— Launchpad
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2024-49980?
CVE-2024-49980 has a medium severity level due to potential impact on the Linux kernel's network functionality.
How do I fix CVE-2024-49980?
To fix CVE-2024-49980, update the Linux kernel to versions beyond 6.6.55, 6.10.14, 6.11.3, or 6.12-rc1 to include the necessary patches.
What systems are affected by CVE-2024-49980?
CVE-2024-49980 affects specific versions of the Linux kernel including versions 6.6 to 6.6.55, 6.7 to 6.10.14, and 6.11 to 6.11.3.
What are the symptoms of CVE-2024-49980 exploitation?
Symptoms of CVE-2024-49980 exploitation may include unexpected network behavior or performance degradation in systems running the affected kernel versions.
Is there a workaround for CVE-2024-49980?
There are no specific workarounds recommended for CVE-2024-49980; timely kernel updates are advised as the primary mitigation.