CVE-2017-7364 in Android
Summary
by MITRE
In all Qualcomm products with Android releases from CAF using the Linux kernel, in function __mdss_fb_copy_destscaler_data(), variable ds_data[i].scale may still point to a user-provided address (which could point to arbitrary kernel address), so on an error condition, this user-provided address will be freed (arbitrary free), and continued operation could result in use after free condition.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 01/09/2021
The vulnerability identified as CVE-2017-7364 represents a critical memory corruption issue within Qualcomm's Android implementations that leverages improper handling of user-supplied data in kernel space operations. This flaw exists in the Linux kernel components of Qualcomm's Android framework, specifically within the display subsystem's framebuffer management functions. The vulnerability stems from the function __mdss_fb_copy_destscaler_data() where the variable ds_data[i].scale can retain references to user-provided memory addresses rather than being properly validated or sanitized before use. This design oversight creates a dangerous scenario where malicious actors can manipulate kernel memory operations through carefully crafted input data.
The technical nature of this vulnerability aligns with CWE-476 which describes NULL pointer dereference conditions, though in this case the issue manifests as an arbitrary memory free operation rather than simple pointer dereference. The flaw operates at the kernel level where user-space applications can influence kernel memory management through improper input validation. When error conditions occur during the execution of the display scaling operations, the kernel attempts to free memory addresses that were originally provided by user-space processes, creating an arbitrary free condition that can be exploited to manipulate kernel memory structures. This arbitrary free operation opens pathways for attackers to potentially execute code or cause system instability through carefully crafted memory manipulation techniques.
The operational impact of this vulnerability extends beyond simple denial of service scenarios as it provides potential for privilege escalation and system compromise within the Android framework. Attackers can leverage this vulnerability to perform use-after-free operations where freed kernel memory is accessed after being reallocated, potentially allowing for code execution with kernel privileges. The vulnerability affects all Qualcomm products utilizing Android releases from the Android Common Audio Framework (CAF) that employ the Linux kernel, making it widespread across numerous mobile devices and embedded systems. This condition can be particularly dangerous in mobile environments where kernel-level exploits can lead to complete device compromise, data theft, or persistent backdoor access.
Mitigation strategies for CVE-2017-7364 should focus on implementing proper input validation and memory address sanitization within the affected kernel functions. The primary fix involves ensuring that user-provided addresses are properly validated before being stored in kernel memory structures, preventing the scenario where arbitrary memory addresses can be freed during error conditions. System administrators and device manufacturers should prioritize applying security patches that address the specific memory management flaw in the display subsystem's framebuffer handling code. Additionally, implementing kernel memory protection mechanisms such as stack canaries, memory layout randomization, and strict address space validation can provide defense-in-depth measures against exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation in kernel space operations and the potential for seemingly minor memory management issues to create significant security risks in mobile platforms. This issue underscores the necessity for comprehensive security testing of kernel components and adherence to secure coding practices that prevent user-supplied data from directly influencing kernel memory management operations.