CVE-2021-47148 in Linux
Summary
by MITRE • 03/25/2024
In the Linux kernel, the following vulnerability has been resolved:
octeontx2-pf: fix a buffer overflow in otx2_set_rxfh_context()
This function is called from ethtool_set_rxfh() and "*rss_context" comes from the user. Add some bounds checking to prevent memory corruption.
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Analysis
by VulDB Data Team • 08/04/2025
The vulnerability identified as CVE-2021-47148 represents a critical buffer overflow condition within the Linux kernel's octeontx2-pf driver component. This flaw specifically manifests in the otx2_set_rxfh_context() function which processes receive-side scaling context information. The issue arises from insufficient input validation when handling user-provided data structures, creating a potential pathway for memory corruption attacks that could compromise system integrity.
The technical implementation of this vulnerability stems from the function's failure to properly validate the size and boundaries of the rss_context parameter received from user space through the ethtool_set_rxfh() interface. When ethtool issues commands to configure receive flow hashing contexts, the octeontx2-pf driver accepts this information without adequate bounds checking, allowing maliciously crafted input to exceed allocated buffer boundaries. This type of flaw directly corresponds to CWE-121, which categorizes buffer overflow conditions occurring in stack-based buffers, though the specific context here involves kernel memory management rather than user-space stack corruption.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially enabling privilege escalation attacks within the kernel space. An attacker with local access or control over network interface configuration could exploit this weakness to execute arbitrary code with kernel privileges, effectively bypassing standard security boundaries. The vulnerability affects systems running Linux kernels with the octeontx2-pf driver, particularly those utilizing network interface cards based on Cavium ThunderX2 architecture, making it relevant to data center and high-performance computing environments where such hardware is deployed.
From an attack perspective, this vulnerability aligns with ATT&CK technique T1068, which covers local privilege escalation through kernel exploits. The flaw can be leveraged by adversaries to gain root-level access to affected systems, potentially leading to complete system compromise. The exploitability of this condition requires an attacker to have access to the system's network configuration interfaces, though the potential impact remains severe given the kernel-level privileges that could be obtained. Mitigation strategies should include immediate kernel updates from trusted sources, along with network segmentation to limit access to affected interfaces and monitoring for unusual network configuration changes.
The resolution of this vulnerability required implementation of proper bounds checking mechanisms within the otx2_set_rxfh_context() function to validate the rss_context parameter size before processing. This approach follows established security practices for preventing buffer overflow conditions and aligns with kernel security guidelines emphasizing input validation and memory safety. System administrators should prioritize applying the relevant kernel patches to eliminate this attack vector, particularly in environments where network interface configuration can be manipulated by untrusted users or processes. The fix demonstrates the importance of robust input validation in kernel drivers and highlights the critical need for thorough security review of all kernel components that interface with user-space applications through system call interfaces.