CVE-2021-28663 PoC — ARM Mali GPU 资源管理错误漏洞

Description

A basic PoC leak for CVE-2021-28663 (Internal of the Android kernel backdoor vulnerability)

介绍

# CVE-2021-28663
A basic PoC leak for CVE-2021-28663 (Internal of the Android kernel backdoor vulnerability)

This is a basic PoC for CVE-2021-28663. A design flaw in Mali GPU Android Kernel Driver.

1. Create a `GPU_VA` and also `mmap` to it so we can get virtual addr for phys pages.
2. Create an alias for phy pages, but don't do `mmap` so `gpu_mapping` remains as 1
3. Change flags of `GPU_VA` to `BASE_MEM_DONT_NEED`. Mali will make them evictable
4. Since we have `reg` for aliased page, now we can `mmap` to it. This will give us RDONLY access from CPU

## Example run:

![Example run CVE-2021-28663](ss/1.png)

![Example run CVE-2021-28663](ss/2.png)

![Example run CVE-2021-28663](ss/3.png)

文件快照

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