CVE-2024-43823

What it actually does

NULL pointer dereference in ks_pcie_setup_rc_app_regs() when resource_list_first_type() returns NULL due to missing IORESOURCE_MEM in Device Tree, bypassing pci_parse_request_of_pci_ranges() warning.

Why it matters to the business

Kernel crash or denial of service during PCI controller initialization on affected embedded or server systems using Keystone PCIe, potentially requiring reboots and impacting availability; low exploit likelihood reduces urgency despite wide Linux kernel use.

How an attack unfolds

An attacker supplies a Device Tree lacking the required memory resource entry, triggering the error path in PCI setup where the missing NULL check leads to dereference during resource parsing and register setup.

How to fix it

Apply the upstream fix from commit bbba48ad67c53feea05936ea1e029dcca8057506 or later stable kernel versions containing the NULL check after resource_list_first_type(). Rebuild and deploy updated kernel images to affected systems.

How to confirm the fix worked

Confirm presence of the NULL return check in ks_pcie_setup_rc_app_regs() source after the resource_list_first_type() call; test boot with intentionally incomplete Device Tree to ensure graceful warning instead of panic; verify kernel version includes the fix commit.

Typical attack path

1. Craft or modify Device Tree blob to omit IORESOURCE_MEM for Keystone PCIe node
2. Load the malformed DT during system boot or module initialization
3. Trigger ks_pcie_setup_rc_app_regs() via pci keystone driver probe
4. resource_list_first_type() returns NULL causing dereference and kernel fault

How to detect it

Search kernel logs and dmesg for oops or panic messages referencing ks_pcie_setup_rc_app_regs, pci_parse_request_of_pci_ranges, or NULL pointer dereference during PCIe setup; inspect boot logs for warnings about missing IORESOURCE_MEM followed by crash.

• ks_pcie_setup_rc_app_regs
• pci_parse_request_of_pci_ranges
• IORESOURCE_MEM
• NULL pointer dereference in PCI keystone

What your security team should do

• Prioritize kernel updates to include bbba48ad67c53feea05936ea1e029dcca8057506 on all Keystone PCIe platforms
• Audit Device Tree sources for complete resource definitions to prevent error paths
• Monitor kernel logs for related oops during PCIe initialization as part of routine boot validation