CVE-2022-49825 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
ata: libata-transport: fix error handling in ata_tport_add()
In ata_tport_add(), the return value of transport_add_device() is not checked. As a result, it causes null-ptr-deref while removing the module, because transport_remove_device() is called to remove the device that was not added.
Unable to handle kernel NULL pointer dereference at virtual address 00000000000000d0 CPU: 12 PID: 13605 Comm: rmmod Kdump: loaded Tainted: G W 6.1.0-rc3+ #8 pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : device_del+0x48/0x39c lr : device_del+0x44/0x39c Call trace: device_del+0x48/0x39c attribute_container_class_device_del+0x28/0x40 transport_remove_classdev+0x60/0x7c attribute_container_device_trigger+0x118/0x120 transport_remove_device+0x20/0x30 ata_tport_delete+0x34/0x60 [libata]
ata_port_detach+0x148/0x1b0 [libata]
ata_pci_remove_one+0x50/0x80 [libata]
ahci_remove_one+0x4c/0x8c [ahci]
Fix this by checking and handling return value of transport_add_device() in ata_tport_add().
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Analysis
by VulDB Data Team • 11/10/2025
This vulnerability exists within the Linux kernel's libata-transport subsystem where the ata_tport_add() function fails to properly validate the return value from transport_add_device(). The flaw represents a classic error handling deficiency that can lead to system instability and potential denial of service conditions. When transport_add_device() returns an error condition, the calling function continues execution without proper error checking, creating a scenario where subsequent cleanup operations attempt to process a device that was never successfully added to the transport framework. This oversight directly violates the principle of defensive programming and can result in unpredictable system behavior during module removal operations.
The technical implementation of this vulnerability manifests as a null pointer dereference during kernel module removal processes. Specifically, when the rmmod command executes and triggers the removal sequence, the transport_remove_device() function is called on a device that was never properly registered due to the unchecked return value. The kernel crash occurs at virtual address 0x00000000000000d0, indicating a critical memory access violation that terminates the module removal process. This behavior can be categorized under CWE-476 as a null pointer dereference, and the execution flow shows how the system transitions from normal operation through device deletion to a critical kernel panic state.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise system stability and availability in production environments. During module removal operations, the kernel becomes unstable and may require system reboot to recover. This vulnerability affects storage subsystems that rely on libata and the ahci driver, which are fundamental components in most modern Linux systems. The timing of the failure during module unload operations means that systems may experience unexpected downtime during maintenance windows, updates, or normal system shutdown procedures, creating operational risks for server and embedded system deployments where stability is paramount.
Mitigation strategies for this vulnerability involve implementing proper error handling within the ata_tport_add() function by checking the return value of transport_add_device() and handling failure conditions appropriately. The fix should ensure that if transport_add_device() fails, the system does not proceed with subsequent operations that assume successful device registration. This approach aligns with ATT&CK technique T1489 which involves denying access to resources, and represents a fundamental defensive programming practice. System administrators should prioritize applying kernel updates that contain the patched implementation, while monitoring for potential system instability during module removal operations. Additionally, implementing robust error handling practices in kernel modules and conducting thorough testing of device removal sequences can prevent similar issues in other subsystems, aligning with industry best practices for kernel security hardening and compliance with security frameworks such as those outlined in the NIST Cybersecurity Framework.