CVE-2014-3601 in Linux
Summary
by MITRE
The kvm_iommu_map_pages function in virt/kvm/iommu.c in the Linux kernel through 3.16.1 miscalculates the number of pages during the handling of a mapping failure, which allows guest OS users to (1) cause a denial of service (host OS memory corruption) or possibly have unspecified other impact by triggering a large gfn value or (2) cause a denial of service (host OS memory consumption) by triggering a small gfn value that leads to permanently pinned pages.
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Analysis
by VulDB Data Team • 02/15/2022
The vulnerability identified as CVE-2014-3601 resides within the Linux kernel's KVM (Kernel-based Virtual Machine) subsystem, specifically in the kvm_iommu_map_pages function located in virt/kvm/iommu.c. This flaw manifests in kernel versions through 3.16.1 and represents a critical memory management issue that affects virtualization environments where guests interact with IOMMU (Input-Output Memory Management Unit) mappings. The vulnerability stems from improper calculation of page counts during memory mapping operations, creating a scenario where guest operating systems can manipulate the host kernel's memory management subsystem through carefully crafted input parameters.
The technical flaw occurs when the kvm_iommu_map_pages function processes mapping failures and incorrectly calculates the number of pages to be mapped or unmapped. This miscalculation becomes problematic when guest OS users provide either extremely large gfn (guest frame number) values or extremely small gfn values. The improper page count calculation creates a condition where the host kernel's memory management structures become corrupted or exhausted. When large gfn values are provided, the calculation error leads to memory corruption within the host OS, potentially allowing for arbitrary code execution or system instability. When small gfn values are used, the vulnerability results in pages being permanently pinned in memory, causing memory exhaustion that leads to denial of service conditions.
The operational impact of this vulnerability spans multiple security domains and affects virtualized environments significantly. Attackers can leverage this flaw to either corrupt host memory structures, potentially leading to privilege escalation or system crashes, or to consume host system resources through memory pinning, resulting in denial of service conditions. The vulnerability affects any system running affected kernel versions with KVM virtualization enabled, making it particularly dangerous in cloud computing environments, server virtualization platforms, and containerized deployments where multiple guests share the same host resources. The impact extends beyond simple service disruption as the memory corruption aspect could potentially allow attackers to execute code on the host system, undermining the fundamental security isolation that virtualization is designed to provide.
This vulnerability maps directly to CWE-129 and CWE-131 within the Common Weakness Enumeration framework, representing weaknesses in input validation and memory management. From the MITRE ATT&CK framework perspective, this vulnerability aligns with techniques involving privilege escalation and denial of service, specifically targeting the host system through guest exploitation. The attack surface is particularly concerning in multi-tenant environments where a compromised guest could potentially affect other guests or the host itself. The vulnerability demonstrates a classic case of improper input validation combined with memory management flaws that can be exploited through guest-to-host privilege escalation pathways. Mitigation strategies should focus on kernel updates to versions containing the fix, implementation of virtualization security controls, and monitoring for unusual memory consumption patterns that might indicate exploitation attempts. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of such vulnerabilities in their virtualized infrastructure deployments.