CVE-2024-50208 in Linux
Summary
by MITRE • 11/08/2024
In the Linux kernel, the following vulnerability has been resolved:
RDMA/bnxt_re: Fix a bug while setting up Level-2 PBL pages
Avoid memory corruption while setting up Level-2 PBL pages for the non MR resources when num_pages > 256K.
There will be a single PDE page address (contiguous pages in the case of > PAGE_SIZE), but, current logic assumes multiple pages, leading to invalid memory access after 256K PBL entries in the PDE.
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Analysis
by VulDB Data Team • 12/12/2024
The vulnerability CVE-2024-50208 represents a critical memory corruption issue within the Linux kernel's RDMA bnxt_re driver component. This flaw specifically affects the handling of Level-2 PBL (Page Build List) pages during resource setup operations. The vulnerability manifests when the system attempts to configure PBL pages for non-MR (Memory Region) resources where the number of pages exceeds 256K entries. The underlying issue stems from a fundamental misalignment between the expected memory layout and the actual implementation logic within the driver's memory management subsystem.
The technical root cause of this vulnerability lies in the driver's incorrect assumption about memory page allocation patterns. When processing PBL entries beyond the 256K threshold, the system expects multiple discrete page addresses to be available for PDE (Page Directory Entry) management. However, the implementation fails to properly account for cases where a single contiguous PDE page address is sufficient, particularly when dealing with page sizes exceeding the standard PAGE_SIZE boundary. This mismatch creates a scenario where the driver's memory access patterns become invalid, leading to potential memory corruption that can compromise system stability and security.
The operational impact of this vulnerability extends beyond simple system instability into potential security risks within RDMA (Remote Direct Memory Access) operations. When the driver encounters PBL entries exceeding 256K, the invalid memory access patterns can result in data corruption, system crashes, or potentially exploitable conditions that may allow privilege escalation. The vulnerability specifically targets non-MR resources, which are critical components in high-performance networking operations where memory management efficiency is paramount. This issue affects systems utilizing the bnxt_re driver for network interface operations, particularly in data center environments where RDMA acceleration is commonly deployed.
The flaw aligns with CWE-121, which addresses stack buffer overflow conditions, and demonstrates characteristics consistent with memory corruption vulnerabilities in kernel space drivers. From an ATT&CK framework perspective, this vulnerability could be leveraged in techniques involving privilege escalation and system compromise, particularly when exploited in environments where RDMA operations are actively utilized. The vulnerability's impact is particularly concerning in enterprise and cloud computing environments where RDMA acceleration is prevalent, as it could potentially allow attackers to gain unauthorized access to system memory or cause denial of service conditions that disrupt critical network operations. Mitigation efforts should focus on immediate kernel updates to address the memory management logic, along with monitoring for any signs of memory corruption or system instability in affected environments.
This vulnerability represents a significant concern for systems relying on RDMA acceleration, particularly in high-performance computing and data center environments where network interface performance and memory management efficiency are critical factors. The memory corruption potential could lead to cascading failures in network operations and may provide attackers with opportunities to exploit the system through memory-based attack vectors. System administrators should prioritize patching affected kernel versions and implementing monitoring solutions to detect any anomalous memory access patterns that might indicate exploitation attempts. The fix implemented in the kernel update addresses the core logic error in PBL page handling, ensuring proper memory allocation and access patterns regardless of the number of PBL entries processed, thereby restoring the stability and security of RDMA operations in affected systems.