CVE-2011-1044 in Linux
Summary
by MITRE
The ib_uverbs_poll_cq function in drivers/infiniband/core/uverbs_cmd.c in the Linux kernel before 2.6.37 does not initialize a certain response buffer, which allows local users to obtain potentially sensitive information from kernel memory via vectors that cause this buffer to be only partially filled, a different vulnerability than CVE-2010-4649.
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Analysis
by VulDB Data Team • 10/17/2021
The vulnerability identified as CVE-2011-1044 resides within the Linux kernel's Infiniband subsystem, specifically in the ib_uverbs_poll_cq function located in drivers/infiniband/core/uverbs_cmd.c. This flaw represents a classic case of information disclosure through improper memory initialization, where the kernel fails to adequately clear or initialize certain response buffers before populating them with data. The vulnerability affects Linux kernel versions prior to 2.6.37, making it a significant concern for systems running older kernel versions that rely on Infiniband networking capabilities for high-performance computing environments.
The technical implementation of this vulnerability stems from the function's handling of response buffers during Infiniband completion queue polling operations. When the ib_uverbs_poll_cq function processes vectors that cause the response buffer to be only partially filled, it fails to properly initialize the unused portions of the buffer before returning data to user-space applications. This incomplete initialization leaves residual kernel memory contents visible in the response, creating a potential information leakage vector that could expose sensitive data from kernel memory regions. The flaw is particularly concerning because it operates at the kernel level where access to memory contents could reveal system internals, cryptographic keys, or other confidential information that should remain protected from user-space access.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates opportunities for attackers to gather intelligence about the system's kernel memory layout and potentially identify other vulnerabilities. Local users with access to Infiniband interfaces can exploit this weakness to extract kernel memory contents through carefully crafted polling operations, making it a significant concern for environments where local privilege escalation is possible or where Infiniband is used in security-sensitive contexts. The vulnerability operates under CWE-248, an information exposure weakness, and aligns with ATT&CK technique T1005 by enabling data from local system resources to be accessed. Systems utilizing high-performance computing clusters, data centers with Infiniband networking, or any environment where Infiniband drivers are active face increased risk from this vulnerability.
Mitigation strategies for CVE-2011-1044 primarily involve upgrading to Linux kernel versions 2.6.37 or later where the vulnerability has been addressed through proper buffer initialization. System administrators should also implement additional security measures such as restricting local access to Infiniband interfaces, monitoring for unusual polling patterns, and ensuring that kernel updates are applied promptly. The fix implemented in kernel 2.6.37 specifically addresses the root cause by ensuring that response buffers are properly initialized before data is copied to user-space, eliminating the possibility of information leakage from uninitialized memory regions. Organizations should also consider implementing network segmentation to limit access to Infiniband interfaces and maintain comprehensive monitoring of system calls related to Infiniband operations to detect potential exploitation attempts.