CVE-2017-5547 in Linux
Summary
by MITRE
drivers/hid/hid-corsair.c in the Linux kernel 4.9.x before 4.9.6 interacts incorrectly with the CONFIG_VMAP_STACK option, which allows local users to cause a denial of service (system crash or memory corruption) or possibly have unspecified other impact by leveraging use of more than one virtual page for a DMA scatterlist.
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Analysis
by VulDB Data Team • 11/11/2022
The vulnerability described in CVE-2017-5547 resides within the Linux kernel's HID (Human Interface Device) subsystem, specifically in the hid-corsair driver that handles Corsair gaming peripherals. This flaw manifests when the kernel is compiled with the CONFIG_VMAP_STACK option enabled, a configuration that maps kernel stacks using virtual memory areas. The issue affects Linux kernel versions 4.9.x prior to 4.9.6, representing a critical security concern that could be exploited by local attackers to compromise system stability.
The technical root cause of this vulnerability stems from improper handling of DMA (Direct Memory Access) scatterlists within the hid-corsair driver when virtual stack mapping is active. When multiple virtual pages are required for a DMA operation, the driver fails to correctly manage the memory mapping between the virtual stack and the physical DMA buffers. This mismanagement creates a scenario where memory corruption can occur during the processing of input events from Corsair devices, particularly when the driver attempts to access memory regions that have been improperly mapped due to the interaction between vmap stack functionality and the driver's memory handling routines.
The operational impact of this vulnerability extends beyond simple denial of service, though that represents the primary concern. Local attackers with access to the system can trigger the memory corruption through normal device usage, potentially causing system crashes that result in complete system hangs or reboots. However, the vulnerability's potential for more severe consequences exists, as memory corruption in kernel space can provide opportunities for privilege escalation or arbitrary code execution. The attack vector requires local system access but does not need elevated privileges, making it particularly dangerous in multi-user environments where untrusted users might have access to gaming peripherals.
This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a specific instance of improper memory management in kernel space. The ATT&CK framework categorizes this as a privilege escalation technique through kernel vulnerabilities, as local users can leverage such flaws to gain elevated system privileges. The use of virtual memory mapping in kernel stacks introduces additional complexity that can lead to memory management errors, particularly when drivers are not properly tested against various kernel configurations.
Mitigation strategies for CVE-2017-5547 primarily involve updating to Linux kernel versions 4.9.6 or later, where the vulnerability has been patched through proper handling of DMA scatterlist operations in the hid-corsair driver. System administrators should also consider disabling the CONFIG_VMAP_STACK option if it is not required for their specific use case, though this may impact performance characteristics of the kernel. Additionally, monitoring for unusual system crashes or memory corruption patterns can help detect exploitation attempts. Organizations should implement comprehensive patch management procedures to ensure all kernel components are kept up to date, particularly in environments where gaming peripherals are used and where local privilege escalation risks are a concern. The vulnerability demonstrates the importance of thorough testing of kernel drivers against various kernel configuration options and highlights the potential security implications of complex memory management features in kernel space.