CVE-2017-7294 in Linux
Summary
by MITRE
The vmw_surface_define_ioctl function in drivers/gpu/drm/vmwgfx/vmwgfx_surface.c in the Linux kernel through 4.10.6 does not validate addition of certain levels data, which allows local users to trigger an integer overflow and out-of-bounds write, and cause a denial of service (system hang or crash) or possibly gain privileges, via a crafted ioctl call for a /dev/dri/renderD* device.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 11/22/2022
The vulnerability identified as CVE-2017-7294 resides within the VMware graphics driver implementation in the Linux kernel version 4.10.6 and earlier. This issue affects the vmw_surface_define_ioctl function located in drivers/gpu/drm/vmwgfx/vmwgfx_surface.c, which handles ioctl operations for the /dev/dri/renderD* device interface. The flaw represents a critical security weakness that can be exploited by local attackers to compromise system stability and potentially escalate privileges.
The technical root cause of this vulnerability stems from insufficient input validation within the vmw_surface_define_ioctl function. Specifically, the function fails to properly validate the addition of certain levels data during surface definition operations, creating a condition where integer overflow can occur. When maliciously crafted ioctl parameters are submitted to the graphics driver, the system processes these inputs without adequate bounds checking, leading to arithmetic overflow in integer calculations that determine memory allocation sizes. This overflow condition results in an out-of-bounds write operation that can corrupt kernel memory structures.
The operational impact of this vulnerability extends beyond simple system instability to potential privilege escalation. Local attackers who can execute ioctl calls against the graphics device interface can leverage this flaw to cause system hangs or crashes through denial of service attacks. However, the more concerning aspect involves the possibility of privilege escalation, where an attacker could potentially manipulate kernel memory to execute arbitrary code with elevated privileges. The vulnerability's exploitation requires local access to the system but does not require network connectivity, making it particularly dangerous in environments where local user access is possible.
From a cybersecurity perspective, this vulnerability maps to CWE-190, which specifically addresses integer overflow conditions that can lead to memory corruption. The attack vector aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' and T1499, covering 'Endpoint Denial of Service'. The vulnerability demonstrates how graphics driver components can serve as attack surfaces for kernel-level exploits, particularly when proper input validation is missing in ioctl handling functions. The impact severity is classified as high due to the potential for both system compromise and privilege escalation, with the integer overflow creating a direct path to memory corruption that can be leveraged for more sophisticated attacks.
Mitigation strategies for CVE-2017-7294 require immediate kernel updates to versions 4.10.7 and later where the vulnerability has been patched. System administrators should ensure all affected systems receive the appropriate kernel security updates from their respective distributions. Additionally, implementing proper access controls to limit local user access to graphics device interfaces can reduce the attack surface. Network segmentation and monitoring for suspicious ioctl activity on graphics devices can provide early detection of potential exploitation attempts. Organizations should also consider disabling unused graphics drivers and implementing kernel module blacklisting for unnecessary graphics components to minimize exposure. The patch addresses the core validation issue by implementing proper bounds checking on integer calculations before memory allocation operations occur, preventing the overflow condition that leads to the out-of-bounds write vulnerability.