CVE-2022-49824 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_tlink_add()
In ata_tlink_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: 33 PID: 13850 Comm: rmmod Kdump: loaded Tainted: G W 6.1.0-rc3+ #12 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_tlink_delete+0x88/0xb0 [libata]
ata_tport_delete+0x2c/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_tlink_add().
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Analysis
by VulDB Data Team • 03/20/2026
This vulnerability exists within the Linux kernel's libata-transport subsystem where the ata_tlink_add() function fails to properly validate the return value from transport_add_device() during device registration. The flaw represents a classic null pointer dereference condition that occurs when the kernel attempts to remove a module that was never successfully added to the transport layer. The issue stems from inadequate error handling in the device addition process, where the system proceeds with subsequent operations assuming device registration succeeded when it actually failed. This creates a scenario where transport_remove_device() is invoked on a device that was never properly registered, leading to a kernel panic when attempting to access invalid memory addresses. The vulnerability specifically manifests during module removal operations when the kernel tries to clean up device entries that were never actually created in the transport infrastructure.
The technical execution of this vulnerability follows a well-defined pattern that aligns with common kernel development pitfalls and security best practices. When the ata_tlink_add() function calls transport_add_device(), it must validate whether the operation completed successfully before proceeding with additional device management operations. The absence of this validation creates a race condition where subsequent code paths assume successful device registration, resulting in memory corruption during cleanup. The crash trace demonstrates the execution path leading to the NULL pointer dereference at virtual address 00000000000000d0, which represents a fundamental memory management failure. The call stack shows the sequence from device_del() through transport_remove_classdev() and ultimately to ata_tlink_delete(), illustrating how the error propagates through the transport subsystem. This type of vulnerability falls under the CWE-476 category for NULL pointer dereference and represents a failure in defensive programming practices that should be enforced in kernel space operations.
The operational impact of this vulnerability extends beyond simple system instability to potentially compromise system availability and integrity in production environments. When triggered during module removal, the kernel panic prevents normal system shutdown procedures and may require manual intervention to recover from the crash state. This vulnerability is particularly concerning in embedded systems or server environments where automated module management is common, as it could lead to unexpected system reboots or service disruptions. The flaw affects the libata subsystem which handles ata device communications, potentially impacting storage functionality and data access across affected systems. Organizations running Linux kernels with this vulnerability face risks of unavailability during normal operations when module removal occurs, especially in environments where storage controllers are frequently reconfigured or updated. The vulnerability also demonstrates poor error handling practices that could indicate broader issues within the kernel's transport layer management.
Mitigation strategies for this vulnerability should focus on immediate patch application and system hardening measures. The recommended solution involves implementing proper error checking in the ata_tlink_add() function to validate the return value from transport_add_device() before proceeding with device management operations. This fix aligns with the principle of defensive programming and follows established kernel development practices for error handling. System administrators should prioritize updating to kernel versions that include the specific fix for CVE-2022-49824, as this addresses the root cause rather than implementing workarounds. Additionally, monitoring systems should be enhanced to detect abnormal module removal patterns that might indicate this vulnerability's exploitation. The fix should be applied across all affected kernel versions, particularly in mission-critical environments where system stability is paramount. Organizations should also implement regular kernel security audits to identify similar error handling gaps in other subsystems that might present analogous vulnerabilities. This approach reduces the attack surface and ensures that the kernel's device management infrastructure maintains proper state consistency during all operations.