CVE-2024-46750 PCI: Add missing bridge lock to pci_bus_lock()
A missing lock in the Linux kernel PCI subsystem can cause a deadlock during bus resets, leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-46750?
CVE-2024-46750 is a high-severity vulnerability in Linux kernel, published on 18 Sep 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
PCI: Add missing bridge lock to pci_bus_lock()
One of the true positives that the cfg_access_lock lockdep effort identified is this sequence:
WARNING: CPU: 14 PID: 1 at drivers/pci/pci.c:4886 pci_bridge_secondary_bus_reset+0x5d/0x70 RIP: 0010:pci_bridge_secondary_bus_reset+0x5d/0x70 Call Trace: <TASK> ? __warn+0x8c/0x190 ? pci_bridge_secondary_bus_reset+0x5d/0x70 ? report_bug+0x1f8/0x200 ? handle_bug+0x3c/0x70 ? exc_invalid_op+0x18/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? pci_bridge_secondary_bus_reset+0x5d/0x70 pci_reset_bus+0x1d8/0x270 vmd_probe+0x778/0xa10 pci_device_probe+0x95/0x120
Where pci_reset_bus() users are triggering unlocked secondary bus resets. Ironically pci_bus_reset(), several calls down from pci_reset_bus(), uses pci_bus_lock() before issuing the reset which locks everything *but* the bridge itself.
For the same motivation as adding:
bridge = pci_upstream_bridge(dev); if (bridge) pci_dev_lock(bridge);
to pci_reset_function() for the "bus" and "cxl_bus" reset cases, add pci_dev_lock() for @bus->self to pci_bus_lock().
[bhelgaas: squash in recursive locking deadlock fix from Keith Busch: https://lore.kernel.org/r/[email protected]]
Weakness: CWE-667
Which versions are affected by CVE-2024-46750?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-46750?
Apply the vendor's patch.
Is CVE-2024-46750 being exploited?
There is no known exploitation of CVE-2024-46750 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-49776, BELL-CVE-2024-46750, DEBIAN-CVE-2024-46750, GHSA-mgvj-6w35-qhj7, UBUNTU-CVE-2024-46750.