CVE-2024-56660 in Linux
Summary
by MITRE • 12/27/2024
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: DR, prevent potential error pointer dereference
The dr_domain_add_vport_cap() function generally returns NULL on error but sometimes we want it to return ERR_PTR(-EBUSY) so the caller can retry. The problem here is that "ret" can be either -EBUSY or -ENOMEM and if it's and -ENOMEM then the error pointer is propogated back and eventually dereferenced in dr_ste_v0_build_src_gvmi_qpn_tag().
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Analysis
by VulDB Data Team • 01/12/2026
The vulnerability CVE-2024-56660 resides within the Linux kernel's mlx5 driver, specifically in the Data Route (DR) subsystem responsible for managing network packet forwarding operations. This issue affects Mellanox ConnectX series network adapters that utilize the mlx5 driver for high-performance networking capabilities. The flaw manifests in the dr_domain_add_vport_cap() function which serves as a critical component for adding virtual port capabilities to the data routing domain. The function is designed to return NULL upon general errors but must occasionally return ERR_PTR(-EBUSY) to allow callers to implement retry logic when resources are temporarily unavailable. This design requirement creates a complex error handling scenario where the same return variable 'ret' must accommodate multiple error conditions with different semantic meanings.
The technical flaw stems from improper error pointer handling within the mlx5 driver's data routing subsystem. When the dr_domain_add_vport_cap() function encounters a memory allocation failure, it returns -ENOMEM which gets converted into an error pointer and subsequently propagated throughout the call stack. The problematic execution path leads to dr_ste_v0_build_src_gvmi_qpn_tag() function where this error pointer is eventually dereferenced without proper validation. This represents a classic null pointer dereference vulnerability that can occur when error codes are incorrectly converted to error pointers and then passed to functions that expect proper validation before dereferencing. The vulnerability is particularly concerning because it operates at the kernel level where such errors can lead to system crashes, memory corruption, or potentially privilege escalation scenarios.
The operational impact of this vulnerability extends beyond simple system stability issues to encompass potential denial of service conditions and security risks within network infrastructure environments. Systems utilizing Mellanox ConnectX adapters in high-throughput networking scenarios are particularly vulnerable since the error conditions that trigger this flaw can occur during active network traffic processing. When the error pointer dereference occurs, it can cause immediate kernel panics or system hangs that require manual intervention to recover. The vulnerability affects any system running a Linux kernel with the mlx5 driver and active network operations, making it particularly dangerous in production environments where network availability is critical. Additionally, the timing of when this error occurs can be unpredictable, making it difficult to detect and mitigate through conventional monitoring approaches.
Mitigation strategies for CVE-2024-56660 should focus on immediate kernel updates from the vendor, as the fix involves correcting the error pointer handling logic in the mlx5 driver code. Organizations should prioritize patching their systems with the latest kernel versions that contain the resolved vulnerability, particularly those that deploy Mellanox network adapters in production environments. System administrators should also implement enhanced monitoring for kernel panics and system crashes that may indicate exploitation attempts. The fix addresses the core issue by ensuring that error codes are properly validated before being converted to error pointers and propagated through the system. This vulnerability aligns with CWE-476 which describes null pointer dereference conditions, and may map to ATT&CK technique T1059.001 for privilege escalation opportunities that could arise from kernel memory corruption. Organizations should also consider implementing network segmentation and access controls to limit potential attack surfaces where this vulnerability could be exploited to gain unauthorized access to network infrastructure components.