CVE-2019-11810 in Linux
Summary
by MITRE
An issue was discovered in the Linux kernel before 5.0.7. A NULL pointer dereference can occur when megasas_create_frame_pool() fails in megasas_alloc_cmds() in drivers/scsi/megaraid/megaraid_sas_base.c. This causes a Denial of Service, related to a use-after-free.
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Analysis
by VulDB Data Team • 09/12/2023
The vulnerability identified as CVE-2019-11810 represents a critical NULL pointer dereference flaw within the Linux kernel version 5.0.7 and earlier. This issue manifests in the megaraid_sas_base.c driver component which manages SCSI storage controllers from LSI MegaRAID series. The flaw occurs during the initialization sequence when the megasas_alloc_cmds() function attempts to allocate command structures for the storage controller. When the megasas_create_frame_pool() function fails to allocate the required memory pool, it returns a NULL pointer which is then improperly handled in the subsequent code execution path.
The technical nature of this vulnerability stems from inadequate error handling mechanisms within the storage driver's memory allocation process. Specifically, when memory allocation fails during the creation of frame pools for command handling, the code does not properly validate the return value before proceeding with operations that assume successful allocation. This failure to validate the allocation result leads to a NULL pointer dereference when the code attempts to access memory locations that were never actually allocated. The vulnerability is classified under CWE-476 as a NULL pointer dereference, which represents a fundamental error handling weakness in software development practices.
The operational impact of this vulnerability is significant as it results in a Denial of Service condition that can completely disrupt storage operations on affected systems. When the NULL pointer dereference occurs, the kernel crashes and typically results in a system panic or reboot, effectively rendering the storage subsystem inaccessible. This is particularly concerning in enterprise environments where storage reliability is paramount, as such a condition could lead to complete system outages. The vulnerability is further categorized under ATT&CK technique T1499.004 as a system network denial of service, since it affects the availability of storage services through kernel-level crashes.
The use-after-free aspect of this vulnerability indicates that the system may have already freed memory resources that are subsequently accessed, creating a potential attack surface for malicious actors. While the primary impact is Denial of Service, the underlying memory management flaw could potentially be exploited in more sophisticated attacks if combined with other vulnerabilities. The vulnerability affects systems running Linux kernel versions prior to 5.0.7, making it relevant to a wide range of enterprise and server deployments. Organizations should prioritize patching their kernel versions to address this vulnerability and implement proper memory allocation validation procedures in their software development lifecycle to prevent similar issues.
The mitigation strategy involves upgrading to Linux kernel version 5.0.7 or later where the memory allocation error handling has been corrected. System administrators should also implement monitoring solutions to detect potential kernel crashes and ensure proper system recovery procedures are in place. Additionally, regular security assessments should include verification of kernel module memory management practices to prevent similar NULL pointer dereference vulnerabilities from being introduced in custom or third-party kernel modules.