CVE-2016-8636 in Linux
Summary
by MITRE • 01/25/2023
Integer overflow in the mem_check_range function in drivers/infiniband/sw/rxe/rxe_mr.c in the Linux kernel before 4.9.10 allows local users to cause a denial of service (memory corruption), obtain sensitive information from kernel memory, or possibly have unspecified other impact via a write or read request involving the "RDMA protocol over infiniband" (aka Soft RoCE) technology.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability described in CVE-2016-8636 represents a critical integer overflow flaw within the Linux kernel's InfiniBand software runtime execution engine component. This issue resides in the mem_check_range function located in drivers/infiniband/sw/rxe/rxe_mr.c file and affects kernel versions prior to 4.9.10. The vulnerability specifically targets the Soft RoCE (RDMA over Converged Ethernet) implementation, which enables high-performance networking through InfiniBand protocols over standard ethernet infrastructure. The flaw manifests when processing read or write requests that utilize the RDMA protocol over InfiniBand technology, creating a potential pathway for malicious local users to exploit the system.
The technical nature of this vulnerability stems from an integer overflow condition that occurs during memory range validation within the RDMA memory management subsystem. When processing memory access requests, the mem_check_range function fails to properly validate integer values that could exceed the maximum representable value for the data type being used. This overflow condition leads to incorrect memory boundary calculations, which can result in memory corruption when the system attempts to access memory regions beyond the intended boundaries. The vulnerability operates at the kernel level, meaning that successful exploitation can bypass normal user-space protections and directly impact the kernel's memory management structures.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass potential information disclosure and system instability. Local attackers can leverage this flaw to cause memory corruption that may result in unpredictable system behavior, including system crashes, memory leaks, or data corruption within kernel memory spaces. The vulnerability also presents a risk for sensitive information disclosure, as the memory corruption can potentially expose kernel memory contents to unauthorized users. According to CWE-190, this represents an integer overflow condition that can lead to memory corruption and arbitrary code execution in kernel contexts, while the ATT&CK framework would categorize this as a privilege escalation technique through kernel memory corruption. The attack surface is particularly concerning as it requires only local access to the system, making it a significant risk for environments where local user privileges are not properly restricted.
Mitigation strategies for CVE-2016-8636 primarily focus on kernel version upgrades to 4.9.10 or later, which contain the necessary patches to address the integer overflow condition. System administrators should prioritize applying these kernel updates across all affected systems, particularly those running InfiniBand or Soft RoCE implementations. Additionally, implementing proper access controls to limit local user privileges can reduce the attack surface, though this should not be considered a substitute for the kernel patch. Network segmentation and monitoring of InfiniBand traffic can help detect potential exploitation attempts, while regular security assessments should verify that the patched kernel versions are properly deployed and functioning correctly. Organizations utilizing Soft RoCE technology should also consider implementing additional monitoring for system stability indicators and memory usage patterns that could signal exploitation attempts. The vulnerability demonstrates the importance of thorough input validation in kernel space operations, particularly when dealing with memory management functions that handle user-provided parameters.