CVE-2024-50209 in Linux
Summary
by MITRE • 11/08/2024
In the Linux kernel, the following vulnerability has been resolved:
RDMA/bnxt_re: Add a check for memory allocation
__alloc_pbl() can return error when memory allocation fails. Driver is not checking the status on one of the instances.
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Analysis
by VulDB Data Team • 12/14/2024
The vulnerability identified as CVE-2024-50209 resides within the Linux kernel's RDMA subsystem, specifically within the bnxt_re driver that manages Broadcom NetXtreme II network adapters. This issue represents a critical memory management flaw that could potentially lead to system instability or denial of service conditions. The vulnerability manifests in the __alloc_pbl() function which is responsible for allocating page-based lists used in RDMA operations. When memory allocation fails during the execution of this function, it properly returns an error code to indicate the failure condition. However, the bnxt_re driver implementation contains a code path where this error status is not being properly checked or handled, creating a potential execution flow that could lead to undefined behavior.
The technical flaw stems from inadequate error handling within the driver's memory allocation routine. The __alloc_pbl() function, which is designed to allocate memory for page-based lists essential for RDMA operations, correctly implements error detection by returning appropriate error codes when memory allocation fails. The driver code fails to validate the return status from this function in at least one instance, allowing execution to proceed with potentially invalid or null pointer references. This pattern violates fundamental software engineering principles and represents a classic example of error handling omission that can lead to system crashes or unpredictable behavior. The vulnerability is categorized under CWE-703, which addresses improper check or handling of exceptional conditions, and specifically relates to CWE-252, indicating that an error code is not checked.
The operational impact of this vulnerability extends beyond simple memory allocation failures and can result in significant system stability issues for environments relying on RDMA networking capabilities. When the memory allocation fails and the error is not properly handled, the driver may attempt to use invalid memory references or continue processing with corrupted data structures. This can lead to kernel oops, system crashes, or more subtle denial of service conditions where the network adapter becomes unresponsive to RDMA operations. The vulnerability affects systems utilizing Broadcom NetXtreme II adapters with RDMA capabilities, potentially impacting high-performance computing clusters, data center networks, and any infrastructure requiring low-latency network operations. The ATT&CK framework categorizes this under T1499.004, which deals with Network Denial of Service, as the vulnerability can lead to service disruption through system instability.
Mitigation strategies for CVE-2024-50209 should prioritize applying the latest kernel updates that contain the patched driver implementation. System administrators should ensure that all RDMA-enabled systems are updated to kernel versions that include the proper error handling for the __alloc_pbl() function. The fix typically involves adding explicit error checking after calls to __alloc_pbl() to validate the return status and handle allocation failures gracefully. Organizations should also implement monitoring systems to detect potential kernel oops or system crashes that may indicate this vulnerability being exploited. Additionally, maintaining proper memory management practices in kernel modules and conducting thorough code reviews for error handling patterns can prevent similar issues in other driver implementations. The vulnerability highlights the importance of comprehensive error handling in kernel space code, where memory allocation failures can have cascading effects on system stability and security.