CVE-2017-11029 in Android
Summary
by MITRE
In android for MSM, Firefox OS for MSM, QRD Android, with all Android releases from CAF using the Linux kernel, camera application triggers "user-memory-access" issue as the Camera CPP module Linux driver directly accesses the application provided buffer, which resides in user space. An unchecked userspace value (ioctl_ptr->len) is used to copy contents to a kernel buffer which can lead to kernel buffer overflow.
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Analysis
by VulDB Data Team • 12/07/2019
The vulnerability described in CVE-2017-11029 represents a critical memory safety issue affecting multiple Android-based platforms including MSM variants, Firefox OS for MSM, and QRD Android systems. This flaw exists within the camera application's interaction with the Linux kernel driver, specifically within the Camera CPP module where direct memory access patterns create significant security risks. The vulnerability stems from improper validation of user-supplied memory pointers and buffer sizes, creating a dangerous condition where kernel space operations directly reference user space memory without adequate bounds checking. This issue affects all Android releases from the Code Aurora Forum (CAF) that utilize the Linux kernel, indicating a widespread exposure across various mobile platforms.
The technical implementation of this vulnerability involves a classic buffer overflow scenario where the kernel driver accesses application-provided buffers without proper validation of the buffer length parameter. The ioctl_ptr->len field, which contains user-supplied data, is used directly in memory copy operations without verification of its legitimacy or bounds. This unchecked userspace value allows malicious actors to manipulate the buffer size parameter to cause kernel memory corruption, potentially leading to arbitrary code execution within kernel space. The vulnerability specifically targets the Camera CPP module driver, which is responsible for handling camera operations and managing memory buffers between user space applications and kernel space drivers. The flaw represents a violation of the principle of least privilege and proper memory management practices, as kernel space operations should never trust user-supplied parameters without rigorous validation.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially enabling attackers to escalate privileges and execute arbitrary code with kernel-level permissions. An attacker could exploit this issue by crafting malicious camera application parameters that cause the kernel driver to write beyond allocated buffer boundaries, possibly leading to denial of service conditions, data corruption, or complete system compromise. The vulnerability affects devices running Android versions from CAF, making it particularly concerning for mobile platforms where users frequently interact with camera applications and where root access or privilege escalation could provide access to sensitive device functions and personal data. The exposure is significant given that this affects multiple device types and platforms, including those from major manufacturers that rely on CAF's kernel implementations.
Mitigation strategies for CVE-2017-11029 should focus on implementing proper input validation and bounds checking within the kernel driver code, specifically addressing the unchecked ioctl_ptr->len parameter. System administrators and device manufacturers should prioritize applying security patches from CAF or device vendors that implement proper memory validation before the kernel driver accesses user-provided buffers. The fix should involve adding explicit checks to verify that user-supplied buffer lengths do not exceed maximum allowed values and that memory operations are properly bounded. Additionally, implementing kernel memory protection mechanisms such as stack canaries, kernel address space layout randomization, and memory protection keys can help mitigate exploitation attempts. This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and relates to ATT&CK technique T1068, which covers local privilege escalation through kernel exploits. Organizations should also consider implementing runtime monitoring and intrusion detection systems to identify potential exploitation attempts targeting similar memory corruption vulnerabilities.