CVE-2022-49030 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
libbpf: Handle size overflow for ringbuf mmap
The maximum size of ringbuf is 2GB on x86-64 host, so 2 * max_entries will overflow u32 when mapping producer page and data pages. Only casting max_entries to size_t is not enough, because for 32-bits application on 64-bits kernel the size of read-only mmap region also could overflow size_t.
So fixing it by casting the size of read-only mmap region into a __u64 and checking whether or not there will be overflow during mmap.
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Analysis
by VulDB Data Team • 01/19/2026
The vulnerability described in CVE-2022-49030 resides within the Linux kernel's libbpf library, specifically addressing a critical issue in ring buffer memory management during memory mapping operations. This flaw manifests when handling large ring buffer configurations where the maximum size limit of 2GB on x86-64 architectures creates mathematical overflow conditions during memory allocation. The vulnerability stems from insufficient type casting and overflow protection mechanisms when calculating memory mapping regions for both producer pages and data pages within the ring buffer structure.
The technical implementation flaw occurs due to improper handling of integer overflow conditions in the memory mapping process. When applications attempt to map ring buffer memory regions, the calculation of 2 * max_entries can exceed the maximum value representable by a 32-bit unsigned integer, resulting in a wraparound condition that compromises memory integrity. This issue is particularly severe because the fix proposed only addresses the casting of max_entries to size_t, which proves inadequate when 32-bit applications execute on 64-bit kernel environments. The underlying problem demonstrates a fundamental misunderstanding of how memory mapping regions behave across different architecture bit-widths and how overflow conditions can propagate through the system.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially enabling privilege escalation attacks and system instability when malicious applications exploit the overflow conditions. Attackers could leverage this flaw to manipulate memory mapping regions, potentially leading to denial of service conditions or unauthorized access to kernel memory spaces. The vulnerability affects systems running Linux kernels with libbpf support, particularly those utilizing eBPF programs that rely on ring buffer functionality for data collection and processing. This creates a significant security risk for systems where eBPF-based monitoring, tracing, or networking applications are deployed, as these applications may be subject to exploitation through crafted ring buffer configurations.
The mitigation strategy involves implementing comprehensive overflow checking mechanisms that explicitly cast memory region sizes to 64-bit unsigned integers before performing mapping operations. This approach aligns with common security practices outlined in the CWE database, specifically addressing CWE-190 which covers integer overflow and CWE-191 which deals with integer underflow conditions. The fix requires modifications to the kernel's memory management subsystem to ensure proper bounds checking during mmap operations, preventing the overflow conditions that could lead to memory corruption. Additionally, this vulnerability highlights the importance of adherence to the ATT&CK framework's system security principles, particularly in relation to privilege escalation and memory corruption techniques that attackers might exploit through such kernel-level flaws. Organizations should ensure their systems are updated with patches that implement proper integer overflow protection in the libbpf subsystem to prevent potential exploitation of this vulnerability.